ES / SD reduction strategies

[Pommy Chris]

It is technology that drives improvement and enhancement. If gaps in knowledge get filled its not a criticism of others or their personality - it’s a progression its not an each way bet because it has a factual basis. Observations sometimes discover or re-invent something that has been overlooked or could not be tested in the past that are game changers. Doppler radar has changed a lot of thinking about ballistics that has enabled us to test actual rifle system inputs more precisely. The target has certainly shrunk in the years I have been shooting.

It is the range of ideas that need to be encouraged to build knowledge. How that is expressed can be problematic for some and that goes both ways. That is why shooter experiences are so valuable on this forum rather than gaining persuasive power of the audience referring to other people’s work. If you validate other people’s work with your experience, and it is repeatable fair enough. Some don’t want to know how a microwave works, others do. Its horses for courses. Jargon becomes second nature if you have read widely and understand what is happening by experiencing it. Litz is better at it than others or me for sure, but an open and inquiring mind goes a long way too.

With regards to Moly and ES, dare I say it, it does not lubricate but actually increases friction in the bore. This IMO sits well with the fact we have to add more powder to the charge when using Moly to maintain velocity. On the other hand Hbn does reduce friction and can increase velocity marginally. Could it be then, that the Moly assists ignition and that's where a major benefit of its use could lie in the reduction of ES? Its application could assist when you are near the range energy limit when you want to fill the case more to improve powder density and yet not go over over the top with velocity. It certainly assist seating feel before firing.

With regards to case weight, it is a great discriminator when reasonably new. With progressive firings the distribution of weight and hardness may alter the volume of individual cases in a batch. Annealing of course only tackles the neck. In a pressure vessel it is really the volume and its density that is critical. The best way to ensure this is relatively constant is to sort cases by volume. A 50/50 mix of water and isopropanol reduces the meniscus on the water to enable better measurement.

The volume argument can be examined in Quick Load to explore the changes in pressure. It only takes a small amount of powder added to a case with reduced volume to see pressure change significantly. Annealing the case at the shoulder reduces headspace variability and therefore volume variability. Its affect can be explored in Quick Load. I use a full length die. Annealing certainly stabilizes neck tension but it also shrinks the brass so an expander iron must be used to relieve the neck junction with the shoulder and slightly work harden the brass.

Moly does not increase friction it reduces it, what this does is allows the bullet to get moving much quicker so the bullet travel further down the barrel while the explosion is happening hence reducing chamber pressure which reduces slightly velocity. To get the velocity back up we need to add more powder. The more friction in the barrel the less powder is needed.
Chris

[Pommy Chris]

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.

Hi Peter,
I would agree with almost all you said. Re Moly though increasing barrel life, from my own barrels I would say it does. Betta has a barrel she used with 185's with no moly and I had the same brand of barrel with same chamber I used 215's with moly. Her load was not hot, mine was very hot. 2,000 rounds later, borecoped mine and hers, her barrel was bad with firecracking not good at all, mine was still fine, actually I still have that barrel and it still shows little firecracking and still shoots very well indeed. The reduction in chamber pressure and surface temperature of the metal in the lead is probably what is helping. Moly application used to be put on dry and wiped off easily, a real mess. Now we apply it on wet and the result is a coating that will not wipe off and a barrel that cleans very easily (yes I check with a bore scope).
Chris

[pjifl]

I believe Molybdenum DiSulphide is a lubricant which reduces friction. What I think happens, however, is that the reduced friction allows the bullet to move a bit further ahead each micro second. Thus the volume behind it is a bit larger thus reducing the pressure behind it. This means the explosion is a little less constrained and slowed down somewhat. Graphite greases have also been used but Moly is more stable at high temperatures. Perhaps HBN is even more stable.

I remember when the modern form of using 'Molly' was originally being pushed, some made huge claims about extended barrel life. An article in the paper version of Precision Shooter by someone who worked with test barrels disputed that. He claimed a small increase in life but it always struck me that it was nothing like what many were expected and he was in a better position to know.
His criterion for when a barrel was worn out was based on its delivered accuracy. This is obviously influenced by the type of shooting you do. From memory, for the typical 308 barrels he was using to test bullets for one of the largest bullet makers was usually a bit over 3000 shots. The Moly extended that out typically another 400 shots.

The power of advertising !!!

Peter Smith.

[Pommy Chris]

Aside from what Peter said above, one thing to consider annealing, apart done wrong you are making the round dangerous is how consistent is the annealing? As Peter said with the collet die you should not need to do it anyway, but if you do anneal and due to slight brass differences some cases are more annealed than others then you are introducing another variable anyway.
Peter too mentioned bullet being concentric too, which can be hard full length resizing. I years ago on advice from Peter looked at this aspect of my loading, I changed my seating die and bought a Redding neck sizer, but rounds were still not concentric. Peter told me to try a Lee Collet die which I did (post for advice on setting up if you get one) and the result was amazing runout disappeared.
Chris

[Gyro]

I have been trickling to weight on a gempro 250 which I have running on a large lead acid 6v to limit drift, not bad but still wanders a little, .02 -.04 occasionally, I just rezero as needed, like you gyro it was the old thread on stock design that brought me here and now I just need a few spare years to do all the testing and technique honing , just trying to prioritise my time expenditure for maximum return, I’m a crossbred mechanic- machinist- cocky and I’ve found diagnostics skills to be the largest payoff in time returned over the years so I’m trying to apply that here and concentrate on whatever will give the largest payoff first, whether it’s gun handling, rest refining, ammunition or a large press to squeeze the demons out of my headspace problem that led me to thinking, I can do this
And don’t even get me started on scopes not even sure about my dog

I do believe Rich I have heard very uncomplimentary things being said on the range about the Gempro scales ? I have never used one. I know it is said if ya gonna go electronic then spend a lot of money.

[williada]

Perhaps a read of this paper might be of interest. https://ntrl.ntis.gov/NTRL/dashboard/se ... 8594.xhtml

[Gyro]

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My pics are likely upside down but hopefully they will allow me to shall explain some stuff.

Re pic that shows the scales beam pivot point where the knife-edge sits on the little blocks, what I have done is notched out the little steel plates that capture the knife-edged cross piece. What this does is allow me to routinely pinch both the ends of the knives to ensure that piece sits right in the middle of the blocks. Without this mod what happens is that knife piece works its way across to one side and fouls on the metal capturing plates. This then adds additional friction. Not good.

Another pic shows the screw in the bottom of the pan holder. That screws head has been filled with epoxy so stray kernels dont jam in there. And they will !! Might be none one session then the next session some kernels may drop off the trickler and settle in the screw head. Not good. Not realising and managing that cost me the 2016 Nationals with a gun that would have otherwise carved them up. Easily !!!

Another pic shows the blade that runs in that slot. The magnet there can attract small gremlins that can hinder the free movement of the beam.

[Rich4]

Perhaps a read of this paper might be of interest. https://ntrl.ntis.gov/NTRL/dashboard/se ... 8594.xhtml

Thank you, I couldn’t actually get it to open though, anything adobe has died on me here I’d say is why, would you condense it for me? I’m assuming they found an increase in drag?

[williada]

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.

[williada]

Rich, I will PM with a copy of my original article because searching for it on the web like some of Boatright's info has been hard. Unless it happened yesterday its old news and disappears from the search engines and private banks charge for it.

[Pommy Chris]

I have been trickling to weight on a gempro 250 which I have running on a large lead acid 6v to limit drift, not bad but still wanders a little, .02 -.04 occasionally, I just rezero as needed, like you gyro it was the old thread on stock design that brought me here and now I just need a few spare years to do all the testing and technique honing , just trying to prioritise my time expenditure for maximum return, I’m a crossbred mechanic- machinist- cocky and I’ve found diagnostics skills to be the largest payoff in time returned over the years so I’m trying to apply that here and concentrate on whatever will give the largest payoff first, whether it’s gun handling, rest refining, ammunition or a large press to squeeze the demons out of my headspace problem that led me to thinking, I can do this
And don’t even get me started on scopes not even sure about my dog

I do believe Rich I have heard very uncomplimentary things being said on the range about the Gempro scales ? I have never used one. I know it is said if ya gonna go electronic then spend a lot of money.

I use an A and D 300i which are around 1k and probably the place one should look for electronic scales.
Gempro are actually good scales and far more accurate than a balance beam, but Gempro is much slower than an A and D. A and D are set and forget, you may calibrate but they dont drift at all, even if left all day they stay bang on. Gempro however are a pizo crystal design and drift even between loading pans, so you need to tare, weight powder, re tare weigh next loads, re tare weigh next loads etc. If this is done the Gempro will be just as accurate as the A and D, just a bit of a pain in the butt to keep having to press tare, but still quicker and more accurate than a beam scale.
Even with Gempro you can weigh a single small kernel of powder, not really possible with a beam scale.
Chris

[Gyro]

I have been trickling to weight on a gempro 250 which I have running on a large lead acid 6v to limit drift, not bad but still wanders a little, .02 -.04 occasionally, I just rezero as needed, like you gyro it was the old thread on stock design that brought me here and now I just need a few spare years to do all the testing and technique honing , just trying to prioritise my time expenditure for maximum return, I’m a crossbred mechanic- machinist- cocky and I’ve found diagnostics skills to be the largest payoff in time returned over the years so I’m trying to apply that here and concentrate on whatever will give the largest payoff first, whether it’s gun handling, rest refining, ammunition or a large press to squeeze the demons out of my headspace problem that led me to thinking, I can do this
And don’t even get me started on scopes not even sure about my dog

I do believe Rich I have heard very uncomplimentary things being said on the range about the Gempro scales ? I have never used one. I know it is said if ya gonna go electronic then spend a lot of money.

I use an A and D 300i which are around 1k and probably the place one should look for electronic scales.
Gempro are actually good scales and far more accurate than a balance beam, but Gempro is much slower than an A and D. A and D are set and forget, you may calibrate but they dont drift at all, even if left all day they stay bang on. Gempro however are a pizo crystal design and drift even between loading pans, so you need to tare, weight powder, re tare weigh next loads, re tare weigh next loads etc. If this is done the Gempro will be just as accurate as the A and D, just a bit of a pain in the butt to keep having to press tare, but still quicker and more accurate than a beam scale.
Even with Gempro you can weigh a single small kernel of powder, not really possible with a beam scale.
Chris

Chris, there are a great many people who have posted online thier Gempro 250 was shite !

And BTW even my tired old eyes can see the needle move with one kernel on my Ohaus 505 beam balance scale !

[Pommy Chris]

I do believe Rich I have heard very uncomplimentary things being said on the range about the Gempro scales ? I have never used one. I know it is said if ya gonna go electronic then spend a lot of money.

I use an A and D 300i which are around 1k and probably the place one should look for electronic scales.
Gempro are actually good scales and far more accurate than a balance beam, but Gempro is much slower than an A and D. A and D are set and forget, you may calibrate but they dont drift at all, even if left all day they stay bang on. Gempro however are a pizo crystal design and drift even between loading pans, so you need to tare, weight powder, re tare weigh next loads, re tare weigh next loads etc. If this is done the Gempro will be just as accurate as the A and D, just a bit of a pain in the butt to keep having to press tare, but still quicker and more accurate than a beam scale.
Even with Gempro you can weigh a single small kernel of powder, not really possible with a beam scale.
Chris

Chris, there are a great many people who have posted online thier Gempro 250 was shite !

And BTW even my tired old eyes can see the needle move with one kernel on my Ohaus 505 beam balance scale !

No need for angry reply.
The Gempro is fine it depends what the user wants. If the user sees it drift and for the user posts that this makes it junk, well no this just means the scale needs to be tared (zeroed) regularly also believing too much what people say online is not a good plan, like the guy in the ranting youtube link about full length resizing. I actually know a lot of people who shoot the worlds as I am on the team and most neck size contrary to what your link says.
Re online links people watch and take too much notice of them. Re annealing watching a few how too's maybe 85% are telling you how to do it wrongly and considering this makes the round dangerous these well meaning people are potentially risking peoples lives.
Now re a beam scale ages ago a friend who had polished the knife edge on his beam scale and done all sorts to make it more accurate, wanted to test his skills so he made up 5 test tubes of his load and brought them to my house to test on the A and D. He did OK, but all the loads were different, some a few kernels more some less. Also using digital is a time thing as I have rather a busy life and dont have hours and hours to watch a beam scale drifting back and forth. Even a Gempro with allow VERY accurate loads in seconds only caveat is the need to zero it every time which is just pressing a button..
Chris

[Wal86]

Any electronic scales that has to be zeroed often.. (eg every 2-3 charges, generally deteriorates to everytime) its because too much weight has been on that scale at one point or another.. The weight effects the load cell, which then doesnt allow the scale to return to zero... Can be fixed but i wouldnt be fixing a gempro..

If your going electronic scales pay the extra $$$$.. Or keep the beam scales

Cheers Alan

[Gyro]

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