ES / SD reduction strategies

[pjifl]

A check weight is your friend. Make one from an old coin or copper foil. Do not use anything magnetic.

It does not need to be absolutely accurate but for testing consistency cannot be beaten.

I have a GemPro, Lab scales, and beam scales. No matter which I am using I try the check weight at the end of every row of 10 reloads in a bullet box.

The Gempro is intermediate between cheap Chinese digital weighing scales which give up quickly in a humid climate and the lab scales. Mine have so far lasted over 15 years. I use them as a double check to pick up gross errors even when I am using the Lab scales.

Beam scales can be excellent but just because you can detect the effect of 1 kernel does not mean they are always repeatable to 1 kernel. And they are slow to use. Weighing 200 loads before going to a major shoot tests ones patience.

[Pommy Chris]

Rich here's another link that might be of interest to you and others which explains methods to evaluate powder friction. http://precisionrifleblog.com/wp-conten ... m-nato.pdf. It is not jargon free, but those with a little mathematical understanding should be able to get something from it. The take home message is that added friction heats the barrel and maybe problematic in long strings.

That means a faster powder is more desirable in some circumstances where less friction is desirable. It was me that suggested (to some aspirants for the Worlds Open FC Canada who sought my advice few years before) to use 2209 instead of 2213 or 2217 which were slower powders in the 7mm's, for good reason. Things eventually filter down. That may have been considered an edge by some for that competition. But there is a lot of preparation by many to make it happen. In tired barrels other forces come into play and have to be balanced as Peter has said and slower powders have a place. Energy limits now pose issues for the magnums. Powder selection for a complete burn is critical if full case capacity can not be utilized. I have posted on that before.

The devil is always in the detail. There is always a trade off. I'm used to the scrutiny of others, it goes with the territory of putting it out there. But hey at least I do. I remember the queries and knocking with regard to barrel tuners. I simply viewed it as a storming of ideas period until norms and benchmarks were established. Seems that many use tuners now very effectively.

Many things change form with heat and pressure, like limestone to marble. Moly also attracts water. One of the byproducts of ignition and pressure in the barrel is water. Those who shoot black powder will know what I am talking about because you can see droplets in the barrel after shooting. Patches can come out wet. Then you have to ask questions about why a lubricant would become a retardant. It would seem lubrication properties are less effected while seating etc with moly, so concerns about in bore yaw from this process are reduced and maybe carbon buildup in the throat, but the balance of the decision to use moly lies in the friction component in the whole barrel under heat and pressure. This is relevant to long strings, heat build up can increase ES and barrel droop unless it stabilizes. I would add by way of edit, that heat also reduces vibration, so a point on a basic sine wave concept on which you have tuned may become less meaningful. Copper is a natural lubricant.

My mind is divergent. You ask a question and I see many implications. Sometimes it is hard for others to follow I admit, but I leave that to the convergent thinkers to distill the information to find what is relevant to them to take it or leave it. I take great heart that many young people complete mathematics to year twelve have few hangups with regard to science or their education and are technology savvy. Last night on the news I saw where government funding was cut to researchers who claimed they were weeks away from a vaccine for SARS a relation of Covid 19, which has implications for a vaccine for Covid 19. Seems the attitude towards good science needs a re-jig.

Moly does not attract water no more than carbon which is in your barrel, the supposed issue of moly was the sulphide part, actually the free sulphates that could potentially combine with water and make a sulphuric acid. How much of an issue is this in reality?
Non. Basically with wet moly application at least any free sulphates have been washed down the sink when you rinse your bullets. I have been using moly for years and bore scope checking my barrels and I will bust many of the moly myths right now. First moly collects in your barrel and you cant get it out.. Rubbish, normal cleaning with your fav cleaner and it is gone. This myth probably came from the old days when people said moly meant you did not have to clean your barrel at all. Some shooters ended up with barrels totally clogged with carbon and moly hence the myth. Shoot 5,000 rounds and dont clean without moly and the barrel is going to be a mess
Re moly attracting water, again not true, this supposed issue is probably linked to the first myth. People thought that they did not have to clean barrels so they left moly and carbon in the barrel for long periods. A shooter last year gave me his barrel to bore scope that he had left dirty for a few months. Barrel was almost new, but left in safe uncleaned. No moly used and a stainless barrel too.. Barrel was stuffed big time serious rust and pitting it was scary how rusty this barrel was. Moral of story is if you are not going to shoot for more than 2 weeks clean the barrel if you use moly or even if you dont. I dont clan till the 150 round mark sometimes I go longer, but I never leave my rifle dirty if I know that I wont be shooting for a few weeks as the carbon, powder fouling etc will hold water and barrel will rust.
Often myths have a plausible reason, but we need to look at the facts and work out what is really going on.
Chris

[Old Trev-39]

Many years ago moly was the rage in short range B/R. It no longer is. The reason for this was in a Precision Shooter magazine quite awhile before it went out of publication. As you know most short range B/R shooters clean after each detail, 7 or 8 shots. They found that the moly build up was not consistent, and at times would leave the barrel with un-uniform coating, thus affecting m/v and group size. Many years ago I used moly in a .308 at the beginning of F/Class. The barrel shit itself around 3000 rounds. Even after vigerous cleaning with Sweets ect. Traces remained in the barrel. I sectioned apiece and under a 60x microscope traces could be seen.
I o longer have that piece of barrel and the P/C. magazines have been given away. Maybe someone out there can find it.I know ths is not related to the heading but moly has been mentioned quite a bit.
cheers,
Trevor.

[Rich4]

Well Trevor I feel investigations should go wherever the proof takes them, My interest in moly was initially peaked by Keith who uses it as a carbon buffer to allow easy carbon removal, makes sense mechanically to me, I also like the idea of lowering pressure, however it seems like 55000 and up is where we need to be anyway, I was thinking it may help unify bullet-case grip???? No testing yet as I can’t obtain any, in the interest of testing I got out my old ohaus’s tonight and set up a cheap hornady digital set, my gem pro 250, and a lee set which don’t go over 100 grains, I have the hornady 10g check weight and the ohaus’s 250gr check weight also a 75gr bullet, the Lee was precise but not accurate, the ohaus was accurate but not precise, the hornady and gempro were accurate and precise to their particular levels, absolutely shocked as I only used the hornady for case batching due to mistrust, turns out it was the balance beam after all, now I shall try the few modifications that gyro suggested and see if that tunes them up, however my shaky faith in the gempro has stiffened up a little, they do require a consistent routine for best results however it’s a small price for single granule accuracy and I have found powering them from a lead acid battery has steadied them I believe, also need a closed room for drafts

[GSells]

depth, now I’ve never tried adjusting neck sizing diameter to change tension, except unintentionally by skim turning necks in a factory chamber.
What do you feel is the largest return on investment for reducing ES ?
Neck tension adjustment?
Bullet pull?
Powder Charge?
Primer selection?
Case selection?
Headspace via Fls? Ie
not the one between my ears

I believe one must be more focused in that it depends somewhat on the distance and the number or shots in a string. Like 15 and 20 shot strings, especially beyond 700 y benefit more from finer tolerances. Most important is to never spend too much time on one factor and neglect another. BALANCE is essential. Best SD is always useful beyond a certain point but strive for balance.
Maybe I am going off on a tangent because low SD is only one factor in many.

Some things like powder charge and case consistency always matter but are not too hard to control - They are less important for the short and midrance shooter. Cartridge concentricity is another but a good seater is essential and usually solves that one.
Firstly, get the best cases you can. If reused many times, shoot then the same number of times.

Bullet pull and neck tension are more or less the same thing. I believe the most consistent neck tension goes hand in hand with quite low neck tension. Some lubrication may help with consistency. Annealing, in theory, may improve neck tensio but I doubt it is worth doing every shot and a good collet die - used on cases shot the same number of times - is a good substitute. Collet dies work the neck far less so they work harden less.

I have used both a carefully made custom FL die and cheap Lee Collet dies and I cannot really see much difference on the target. Cheap commercial FL dies are, however not a good idea. Have a policy of avoiding donuts at all costs and Lee is most useful in this regard - thus neck tension becomes more consistent.

I have watched with interest the use of moly but have never used it. I do not believe it improves accuracy and is an added complication. As someone mentioned, in other forms is as old as the hills going back 100 years. One 'molyed' each bullet individually by wiping it against the little finger immediately before chambering the cartridge. It may have other benefits but I consider them quite small. The modern craze for moly was really driven by commercial interests. I does not extend barrel life very much.

Primers - I would not know. But beware of inadequate testing that only reinforces myths.

What it eventually comes down to is learning to manage an accurate rifle in a balanced way and make good decisions when actually shooting.

Some barrels seem to thrive despite the worst attempts by shooters to mismanage their rifle.

And most lost matches are due to the nut behind the butt. A top rifle is useless in the wrong hands. Try to analyse your performance - this is very very hard to do.

Sorry - I have drifted away from SD. It does become more important at the longs where you cannot achieve sufficient compensation with a stiff barrel.

Peter Smith.

Great post Peter. And as you say none of these things exist in isolation. Shooters are apt to get myopic about some stuff and not know what's actually affecting thier performance.

Where you say ... "inadequate testing that only reinforces myths" .... is absolutely true. Lots of myths and wivestales have persisted in this game for a very long time.

Just imagine someone wanted to get really serious about testing primers and thier effect on SD/ES. To do that test even half arsed would take a good deal of time and effort. You would need to first rule out the shooter, so a machine rest would be required. You would need to test each primer/powder combination at the same barrel fouling state. You would need to weigh/volume check the cases to be used ..... the list of controls required actually goes on and on.

Anyway Rich, have u checked your scales ? I checked my bloody old Ohaus 505 scales against a mates very expensive electronic scales. I just weighed out 5 powder charges and took them to his place and all my charges were within one kernel of his. So that's ticked that box. Mind u I have done a 'mod' to my Ohaus scales which has really helped. I shall get a pic up of that.

I suspect nk tension has very little effect on ES/SD only because annealing ( which CAN - and I believe should - do the shoulder too !!!!!!!! ) tests have shown no real gains for this.

I went to a shoot the other day ( the first one in over a year ) and watched an F Open guy set up his gear on the mound. He has been F shooting for about 15 years. He plonks down his very light low-inertia value front rest. Then he puts his matt down and sits his light steel plate on top of the mat. Then he sits his light poxy bouncy-mid-section rear bag on the plate and gets it all lined up. I really really wanted to say something !!! To help the guy. To help others over here shooting with dodgy gear or shooting with good gear and then not setting it up properly. I could go on and on but I'd end up with less mates than I already have hahahah. My dog loves me !

This forum is good because there is very little personal abuse type writing and that's important because we all have different backgrounds and moods and blah blah blah. Cheers Rob.

Sorry Rob , I must interject! When we went to that awful windy place called Trentham, you were one of the first to get in touch with the team wanting to help ! You have won at that place a number of times in f open and ftr and beat all of us Aussies . I have great respect for you as a competitor and person !
Just saying mate ! I think you deserve the respect ! God willing I hope to get hopelessly beaten up again at that God Forsaken Windy place again with you and the other lovely Kiwi shooters ! I had so much fun there ! But yes Rob !

Sorry for getting of topic Alan !

[williada]

Chris, I am certainly not criticizing the performance of your gear. The achieved friction your load may well produce a rhythmic sine wave in your lighter FTR gear. There are a lot of balancing variables to identify but the science says your conclusions about cause and effect have a few gaps. None of us can know what we don’t know.

What I am saying is the moly transforms, and that is responsible for an increase in friction. I thought I provided sufficient mathematical evidence and method to say that is right. So, there is a point where ES will suffer with variable friction and more likely in long strings. But the maths based on observations says its happening but fails to say why?

So, I guess we have to look at the chemistry a little deeper. What is happening in your barrel? Shot after shot layers of residue are being deposited. These layers get scrubbed and break down into fouling. The residue has carbon for sure but the element of copper can be found as well as water and moly, but moly what and what else? Ever noticed why the fouling hardens time? Perhaps the water evaporates. The temperature of the gases that precipitate out are a good average 3000 degrees C for burning propellant under conditions of pressure according to Rinker, (Understanding Firearms Ballistics 2004). Yet bulk chemical changes happen at much lower temperatures.

We know molybdenum disulfide is stable in air and water free but with heating it turns into molybdenum trioxide. Wikipedia will tell you that and that has an affinity with water. Perhaps I should have clarified that. Sorry, but these articles are rushed and its small beer compared to the outcome.

Let’s see what the real experts say.

Norton and Cannon in 1964 looked at the reaction between water and molybdenum sulfide. Some of their findings are as follows:
• Molybdenum disulfide undergoes bulk oxidization at temperatures above 450 C
• It is possible that such layers are involved in the frictional transients observed when molybdenum sulfide is used as a lubricant in wet atmospheric environments.
• We have now extended the work to higher temperatures, with the following interesting results. The water adsorption work was repeated at 180° C, 20µ water vapour pressure, in quartz microbalance equipment like that described before1,3. The surface-area limited reaction with a permanent weight increase proportional to the specific surface area was seen again. 20 g samples of molybdenum disulfide (Σ = 15 m2/g) were then exposed to 20 mm water vapour at progressively higher temperatures between 200° and 500° C.

Haltner quoted in the above paper, found that when an MoS2 film, supported on certain metals, and particularly copper, was exposed to rubbing and shearing forces in a wet atmosphere, hydrogen sulphide could be detected.

Now if you go to NASA archives and you might care to look up:
Lubrication and Failure mechanisms of Molybdenum Disulfide RL Fuzaro, 1978.
Friction, wear and wear life of films rubbed on 440 C
How failure occurs and the roles of oxygen and water in the failure process.

I also read in the past that when the moly is powdered is can absorb moisture. No time to find the source at the moment.

So I think its reasonable to believe that the mix of oxygen copper, moly, water and heat are the source of the friction.

[John T]

Hello all.

Rich4, The title of your topic says a lot. The accuracy of a load is not determined by a printout or display on a chronograph of ES and SD. I could take up the running with Wal86 and Keith but I will cut to the chase.

Look at the Oehler site. In the introductory pages you will read this;
"We can't guarantee that ammo with the most uniform velocities will always shoot the best groups or even shoot good groups."

As Wal86 says "The paper tells the only story."

Neither Wal, Keith nor I is saying a chronograph is a waste of time and money. The chronograph has its uses, but it must never be regarded as delivering the "golden fleece" and must be pursued to the exclusion of all else.

ES and SD are nothing compared to CHAMBER PRESSURE WHICH IS ALL!

Your list of candidates is a good start. The Devine Davies has granted us access to his top 3. Never to be disregarded. Powder type. Powder charge. Primer. I am a little surprised that neck grip and seat-to-lands are not mentioned, but who am I .....

Regards,
JohnT.

[GSells]

Ok gem pros 250 do get a bad rap . They need a bit more TLC but have nearly won me a Queens last year , help win a trans Tasman and many other prize meets and things Qld team's etc. One thing to make sure is no kernels get caught under the load tray and you always return the hopper back to the load tray and make sure it goes back to zero .
Gempro working right loads consistly to the kernel. But many have had trouble .and so have I from time to time but have found out how to fix it ! After that very rarely gives trouble . But you can't go wrong with an A and D too !
I anneal with a drill and map torch and a dark room , just as Cam Mac used to ( miss him ! ) . It's a skill , love the amp but can't part with the money when I can do it the old way . I only anneal when it needs it .

Ok one of my secrets that won't be so secret now and this is purely to help the newbies out there !
Is to internal chamfer the flash hole . Here Litz states in one of his books that this is a waste of time ! I greatly respect Bryan, but in my testing in my guns from 308,284 and especially the 280ai ! Has shown it promotes more consistent ignition and a better OCW ( optimum charge weight ) and make a load more tolerant to slight charge variations . E.g. user friendly! For the newbies it's a Sinclair internal primer chamfer and pilot tool

For me and so many have different ways of tuning and they are all correct ! But if a load doesn't show low ES straight up after 5to 7 shots , it ain't going to get any better ! Don't waste your time and money, stop ! Go to another load ! A ocw load shows up straight away , then you can try different primers, seat depth and group shapes . The group shapes vary from what purpose e.g. long range load or short to mids load ?
But rule of thumb is a round one hole group at 140 yards with a low single figure SD over 10 shots will tell you enough . Then take it to 1000 yds and let the target tell the story. Can't get 1000 yds ? 600 yds can tell you a bit of info . Not perfect but after a while you can read what the target is telling you at 600 yds !

But I'm very lazy in my testing and tuning , I should do a lot more and be more scientific. But I rely on past learnt experiences as I don't have the time ! Life gets in the way of extreme accuracy and good shooting ! They are always at a disagreement with each other, Life , Family and extreme accuracy!

[GSells]

Chris, I am certainly not criticizing the performance of your gear. The achieved friction your load may well produce a rhythmic sine wave in your lighter FTR gear. There are a lot of balancing variables to identify but the science says your conclusions about cause and effect have a few gaps. None of us can know what we don’t know.

What I am saying is the moly transforms, and that is responsible for an increase in friction. I thought I provided sufficient mathematical evidence and method to say that is right. So, there is a point where ES will suffer with variable friction and more likely in long strings. But the maths based on observations says its happening but fails to say why?

So, I guess we have to look at the chemistry a little deeper. What is happening in your barrel? Shot after shot layers of residue are being deposited. These layers get scrubbed and break down into fouling. The residue has carbon for sure but the element of copper can be found as well as water and moly, but moly what and what else? Ever noticed why the fouling hardens time? Perhaps the water evaporates. The temperature of the gases that precipitate out are a good average 3000 degrees C for burning propellant under conditions of pressure according to Rinker, (Understanding Firearms Ballistics 2004). Yet bulk chemical changes happen at much lower temperatures.

We know molybdenum disulfide is stable in air and water free but with heating it turns into molybdenum trioxide. Wikipedia will tell you that and that has an affinity with water. Perhaps I should have clarified that. Sorry, but these articles are rushed and its small beer compared to the outcome.

Let’s see what the real experts say.

Norton and Cannon in 1964 looked at the reaction between water and molybdenum sulfide. Some of their findings are as follows:
• Molybdenum disulfide undergoes bulk oxidization at temperatures above 450 C
• It is possible that such layers are involved in the frictional transients observed when molybdenum sulfide is used as a lubricant in wet atmospheric environments.
• We have now extended the work to higher temperatures, with the following interesting results. The water adsorption work was repeated at 180° C, 20µ water vapour pressure, in quartz microbalance equipment like that described before1,3. The surface-area limited reaction with a permanent weight increase proportional to the specific surface area was seen again. 20 g samples of molybdenum disulfide (Σ = 15 m2/g) were then exposed to 20 mm water vapour at progressively higher temperatures between 200° and 500° C.

Haltner quoted in the above paper, found that when an MoS2 film, supported on certain metals, and particularly copper, was exposed to rubbing and shearing forces in a wet atmosphere, hydrogen sulphide could be detected.

Now if you go to NASA archives and you might care to look up:
Lubrication and Failure mechanisms of Molybdenum Disulfide RL Fuzaro, 1978.
Friction, wear and wear life of films rubbed on 440 C
How failure occurs and the roles of oxygen and water in the failure process.

I also read in the past that when the moly is powdered is can absorb moisture. No time to find the source at the moment.

So I think its reasonable to believe that the mix of oxygen copper, moly, water and heat are the source of the friction.

So David in short going Scandinavian with naked bullets is better? By the way I shoot shoot naked ! Mean naked bullets

[Pommy Chris]

I give up. I'm reading BS here. You're on your own Rich. Just be thorough and ALWAYS look critically at all this advice, if in fact u are serious about upping your game.

As Peter said IT IS NOT ANY ONE THING ......

N.B. I see your post is just in Wal and my being totally over this thread is not due to your post

Peter told you the same as others did re the Lee neck sizer and basically everything. Peter is a big part of Aus winning Gold when he was involved.
Peter also has a Gempro..
You need to take a deep breath and listen. I will give advice to anyone and give my secrets away as in the end to win you need to be able to read the wind too and even if you beat me I will be there clapping as you get your prize as this is all about the sport and are friends we see at each comp.
I dont care though if people take my advice or not, we all do as we please. If someone wants to bless their bullets before shooting good on them do what you think helps. Advice though on this site there are some of the best in the world and Peter has been up there with them. They dont know everything but they have knowledge to share and only a fool would choose not to listen. Not sure how many Queens Peter has won, I just know I cant remember how many I have seen as it is so many..
Chris

[Pommy Chris]

Chris, I am certainly not criticizing the performance of your gear. The achieved friction your load may well produce a rhythmic sine wave in your lighter FTR gear. There are a lot of balancing variables to identify but the science says your conclusions about cause and effect have a few gaps. None of us can know what we don’t know.

What I am saying is the moly transforms, and that is responsible for an increase in friction. I thought I provided sufficient mathematical evidence and method to say that is right. So, there is a point where ES will suffer with variable friction and more likely in long strings. But the maths based on observations says its happening but fails to say why?

So, I guess we have to look at the chemistry a little deeper. What is happening in your barrel? Shot after shot layers of residue are being deposited. These layers get scrubbed and break down into fouling. The residue has carbon for sure but the element of copper can be found as well as water and moly, but moly what and what else? Ever noticed why the fouling hardens time? Perhaps the water evaporates. The temperature of the gases that precipitate out are a good average 3000 degrees C for burning propellant under conditions of pressure according to Rinker, (Understanding Firearms Ballistics 2004). Yet bulk chemical changes happen at much lower temperatures.

We know molybdenum disulfide is stable in air and water free but with heating it turns into molybdenum trioxide. Wikipedia will tell you that and that has an affinity with water. Perhaps I should have clarified that. Sorry, but these articles are rushed and its small beer compared to the outcome.

Let’s see what the real experts say.

Norton and Cannon in 1964 looked at the reaction between water and molybdenum sulfide. Some of their findings are as follows:
• Molybdenum disulfide undergoes bulk oxidization at temperatures above 450 C
• It is possible that such layers are involved in the frictional transients observed when molybdenum sulfide is used as a lubricant in wet atmospheric environments.
• We have now extended the work to higher temperatures, with the following interesting results. The water adsorption work was repeated at 180° C, 20µ water vapour pressure, in quartz microbalance equipment like that described before1,3. The surface-area limited reaction with a permanent weight increase proportional to the specific surface area was seen again. 20 g samples of molybdenum disulfide (Σ = 15 m2/g) were then exposed to 20 mm water vapour at progressively higher temperatures between 200° and 500° C.

Haltner quoted in the above paper, found that when an MoS2 film, supported on certain metals, and particularly copper, was exposed to rubbing and shearing forces in a wet atmosphere, hydrogen sulphide could be detected.

Now if you go to NASA archives and you might care to look up:
Lubrication and Failure mechanisms of Molybdenum Disulfide RL Fuzaro, 1978.
Friction, wear and wear life of films rubbed on 440 C
How failure occurs and the roles of oxygen and water in the failure process.

I also read in the past that when the moly is powdered is can absorb moisture. No time to find the source at the moment.

So I think its reasonable to believe that the mix of oxygen copper, moly, water and heat are the source of the friction.

It the friction was higher then velocity would be higher. Velocity is lower with moly because of lower friction due to reduced chamber pressure this is fact. The longer barrel life comes from this fact too as the surface of the metal is cooler due to lower temp and pressure.
Lots written re moly affinity to water, also so does powder fouling and general crud in our barrels. Leave this in the barrel (normal shooting not moly) and the barrel WILL rust.
Now in a barrel how wet do you think it is after one shot? Answer not wet at all. Also moly with no free sulphates is not the same as moly with it.
Then there is the temperature data, temperature is not the only thing to consider, time too and much as moly can transform molybdenum disulfide can transform under heat to another substance that is also more slippery than just steel, also remember the new projectile has more moly on it.
We can go deep int the science, but down and dirty chamber pressure IS lower with moly.
Friction is not the killer of your barrel it is heat.
Heat is reduced with moly due to lower chamber pressure.
And leave ANY barrel moly or not dirty for weeks and weeks it will rust.
I shoot for as I said 150 -200 rounds with no cleaning as long as I shoot each week as in a week nothing will hurt the barrel even with fouling and moly, even two weeks or three, but if I am not shooting for 3+ weeks barrel gets clean no matter how many rounds shot.
All my barrels are spotless inside and all stored with oil patch passed through and oil patch re done every few months in all barrels moly or not.
Chris

[KHGS]

Many years ago moly was the rage in short range B/R. It no longer is. The reason for this was in a Precision Shooter magazine quite awhile before it went out of publication. As you know most short range B/R shooters clean after each detail, 7 or 8 shots. They found that the moly build up was not consistent, and at times would leave the barrel with un-uniform coating, thus affecting m/v and group size. Many years ago I used moly in a .308 at the beginning of F/Class. The barrel shit itself around 3000 rounds. Even after vigerous cleaning with Sweets ect. Traces remained in the barrel. I sectioned apiece and under a 60x microscope traces could be seen.
I o longer have that piece of barrel and the P/C. magazines have been given away. Maybe someone out there can find it.I know ths is not related to the heading but moly has been mentioned quite a bit.
cheers,
Trevor.

Not sure what you do that is different than what I do Trevor. I have read the same stuff you refer to and it seems compelling I agree. As I am sure most of the readers of this forum would be aware, I am a bit of a nonconformist, tend to think outside the box, don't always follow popular trends kind of guy. I have used moly for 20+ years and the negatives you mention can and do happen through sloppy maintenance and poor cleaning techniques. There is one moly negative I don't like however and that is that I have to apply the stuff and being lazy I am well known for not doing anything I have proven to myself that I don't need to do. Having looked inside countless stainless barrels in my profession I am convinced that the constant use of ammoniated solvents in stainless is not a good idea and now do not use such products myself at all, they are not good carbon & moly removers either. Yes there is such a thing as moly fouling, but it is usually a combination of moly and carbon brought about by incorrect cleaning methods.
We do seem to have wandered a long way off topic, sorry Alan.
For the record I agree with most of Rod's points in the quest for low E.S. once again in the quest for accuracy I urge all to keep an open mind, the box was made to think beyond it's borders, good stuff everybody.
Keith H.

[williada]

Chris, my point is the moisture comes from the ignition of the propellant and perhaps a small degree from the atmosphere. There is a multiplier effect of the water given the heat of the pressure cooker environment and the water in gas form throughout the barrel length, not liquid as perhaps you are implying. It does not have to be much to see the ES wander with the chemical reaction to change the the oxidized layers of moly to destroy the lube effect. Its about scale of the reaction, but getting to 3000 C is pretty hot at the muzzle and a small amount of water vapor super heated can go a long way. Ever got molten lead mixed with water? I believe what other professionals say about the role of copper, oxidisation and water in the reaction with moly are the cause of increased friction observed by them across different fields of expertise. Think about this, why does a longer barrel reduce peak pressure with the same load? Its longer there should be more friction? My tests in Project Penumbra and that of the British Consortium Trials revealed that chamber pressure may rise in tighter barrels but velocities dropped. Bisley introduced the 150 rule as a consequence of their testing to prevent catastrophic failure. The chamber pressure is a different consideration from pressure along the curve for total pressure. Bear in mind that slow powders burn beyond the chamber. So rather than try an convince you about different friction effects, I guess we just have to disagree. Good shooting Chris, keep safe. David.

[williada]

Keith you make a good point about the stainless and ammonia. Yep, we all had to convinced at the time and found old habits hard to change until a light was shined on it by people with more knowledge.

[Wal86]

Keith you make a good point about the stainless and ammonia. Yep, we all had to convinced at the time and found old habits hard to change until a light was shined on it by people with more knowledge.

I still use sweets, and have seen no evidence of harm to stainless barrels, if used correctly..

Ammonia on its own is not corrosive to stainless steel.

I believe barrels that have been damaged are operator error, where there has been a cross contamination causing a chemical reaction, this can happen with any cleaning products given the right environment...

Cheers Alan