2217 vs 2213SC which is a more consistent powder

[GSells]

Actually it’s that good !! for sale BART SAUM BARREL WITH BUNYAN/ LARSON TUNER . Sticking with 280 ai !!
Ha ha . Had ya there

[bruce moulds]

weighed primers.
that must be what really makes the difference.
bruce.

[GSells]

weighed primers.
that must be what really makes the difference.
bruce.

Target tells the storey and so does the extreme spreads. Seriously I have better things to do than sharing info !!

[GSells]

Just want to say for the newbies and not keyboard snipers . Very important to clean out the abrasive paste with wd 40 and patches afterward. Cheers .

[bad_primer]

GSells, that’s great advice, thank you. I assure you I will start putting it to use and to see what comes up.

Specifically the numbers I got where from the shoot on the weekend were:
ES- 69
Min- 2801 (1st shot)
Max- 2870
Mean- 2838
SD- 19.3

Of the 11 shots measured, there were 3 outliers. 2869, 2870 and 2801.
The remaining shots were with 4-9fps of the mean.
Are these outliers typical of 2213SC or more likely down to Case prep (definitely what I’m laziest about and weakest in)?

I’m not writing this powder off entirely with the 168gn bullets will look at what is available to get consistent neck tension on the brass.

[williada]

Bruce, I feel you have been a little hasty with the ignorance you argue in the unfounded correction of my comments. Having done considerable testing with “Pressure Trace”, I can assure you peak pressure does increase as the barrel is shortened, not by much but it is significant. Barrel shortening also alters the shape of the pressure curve.

In the peak area, it is broadened so the total chamber pressure is increased. That has two effects: Firstly, in terms of hoop stress, it can in worst case scenarios lead to catastrophic failure; and secondly, a change in the frequency of vibrations which vary group size and suitable tune area.

Hence a longer barrel is safer, and presents a greater range of tuning opportunities if you are a nodal, and or a compensation tuner or utilizing OBT timing to minimise muzzle distortion and timing the barrel lift for group compared to the stiff short range barrel where reduced muzzle amplitude is relied upon to reduce elevation shots.

In regard to the tail, and muzzle pressures, increase dramatically as the barrel is shortened. Hence the transferable thinking of the article that, “the pressure rises exponentially with decreasing barrel length” and the reverse thinking that a longer barrel decreases pressure. Its conceptual and more relevant to ideas people than judgemental types.

Did you read the experimental setup in the article? You would have noticed the barrel used lacked a gas port for operating the mechanism, resulting in a single-shot weapon. So the experiment is very relevant to what we do.

If you want to simulate this on the program, “Quick Load” (QL) you can. However, for convenience, I supply the following SAUM identical loads with 2217 to demonstrate the extremes.

Barrel Length 31.75”, peak pressure 51972 psi, muzzle bore pressure 9473 psi
Barrel length 18”, peak pressure 52113 psi, muzzle bore pressure 17815 psi

Peak pressure differences are small in the upper range but we all know what .3 grain powder charge can do or .005” change in seating depth or a hot primer. If you are on the edge a temperature change can lead to trouble. Yep, I weigh primers too.

While we do not have to worry about blowing up a suppressor Bruce, perhaps you missed the abstract thinking here, how greater or lower pressure pressure points can influence the plasma effect of unburnt powder on steel which has flow on implications for fouling and tune in our gear. If you inspect barrels, wear occurs at the throat and the muzzle. The right barrel length has propensity to sustain temperature and tune. How often do barrels point of impact move in long string and go lower? Why did Obermyer prefer a back bore on a bloop tube? Light bulb moments for some.

Yes, slower burning powders do reduce pressure but they are dirtier because they deposit more powder residue which in itself can be a fouler. It was this aspect which was the main thrust of my previous comment. While the subtleties of tune with 2213, 2217 and Reloader 23 are apparent in 7mm’s, operating temperature and barrel length should not be overlooked for optimisation. 2209 is clean just as 8208 is in .308W. But 8208 must be used in a long barrel because pressure can become an issue in shorter ones. Inspect cases.

It is not so much an issue of a bigger case allowing more slow burning powder in the 7mm’s but how it is compressed to burn efficiently. I take it that is what you were meaning to say, Bruce. Stick to black powder mate its got low ES.

[GSells]

GSells, that’s great advice, thank you. I assure you I will start putting it to use and to see what comes up.

Specifically the numbers I got where from the shoot on the weekend were:
ES- 69
Min- 2801 (1st shot)
Max- 2870
Mean- 2838
SD- 19.3

Of the 11 shots measured, there were 3 outliers. 2869, 2870 and 2801.
The remaining shots were with 4-9fps of the mean.
Are these outliers typical of 2213SC or more likely down to Case prep (definitely what I’m laziest about and weakest in)?

I’m not writing this powder off entirely with the 168gn bullets will look at what is available to get consistent neck tension on the brass.

Hi mate , the odd ones I haven’t seen with 2213 sc with tight reloading practices. To get a fair representation, 2-3 shots is a good idea first before analysing anything. I know many people will disagree but a good load shows up straight away . So I’ll fire 7 shots and get a snapshot of the potential of a load at 100 m’s and adjust group shape with seat depth for OBT ( optimum barrel timing) . But with fast sevens barrels are dead in the 1200 round region . My opinion one can only afford a sample SD ( which technically is no where near enough statistically speaking) . Once happy at 100 m and maybe another follow up snapshot with speed . Then let it show up on paper , at least 900 yds in decent conditions even 600 yds can give an small idea . But the load will need testing at the longs
But I have dribbled on lol! The odd ones maybe neck tension? Try annealing your necks to get a consistent snap back grip on your bullets .

[GSells]

Sorry just thinking about it . The outiliers could very well be not enough pressure eg running too slow . To be getting a efficient burn . Also try like I said chamfering your flash holes. Cheers

[GSells]

Bruce, I feel you have been a little hasty with the ignorance you argue in the unfounded correction of my comments. Having done considerable testing with “Pressure Trace”, I can assure you peak pressure does increase as the barrel is shortened, not by much but it is significant. Barrel shortening also alters the shape of the pressure curve.

In the peak area, it is broadened so the total chamber pressure is increased. That has two effects: Firstly, in terms of hoop stress, it can in worst case scenarios lead to catastrophic failure; and secondly, a change in the frequency of vibrations which vary group size and suitable tune area.

Hence a longer barrel is safer, and presents a greater range of tuning opportunities if you are a nodal, and or a compensation tuner or utilizing OBT timing to minimise muzzle distortion and timing the barrel lift for group compared to the stiff short range barrel where reduced muzzle amplitude is relied upon to reduce elevation shots.

In regard to the tail, and muzzle pressures, increase dramatically as the barrel is shortened. Hence the transferable thinking of the article that, “the pressure rises exponentially with decreasing barrel length” and the reverse thinking that a longer barrel decreases pressure. Its conceptual and more relevant to ideas people than judgemental types.

Did you read the experimental setup in the article? You would have noticed the barrel used lacked a gas port for operating the mechanism, resulting in a single-shot weapon. So the experiment is very relevant to what we do.

If you want to simulate this on the program, “Quick Load” (QL) you can. However, for convenience, I supply the following SAUM identical loads with 2217 to demonstrate the extremes.

Barrel Length 31.75”, peak pressure 51972 psi, muzzle bore pressure 9473 psi
Barrel length 18”, peak pressure 52113 psi, muzzle bore pressure 17815 psi

Peak pressure differences are small in the upper range but we all know what .3 grain powder charge can do or .005” change in seating depth or a hot primer. If you are on the edge a temperature change can lead to trouble. Yep, I weigh primers too.

While we do not have to worry about blowing up a suppressor Bruce, perhaps you missed the abstract thinking here, how greater or lower pressure pressure points can influence the plasma effect of unburnt powder on steel which has flow on implications for fouling and tune in our gear. If you inspect barrels, wear occurs at the throat and the muzzle. The right barrel length has propensity to sustain temperature and tune. How often do barrels point of impact move in long string and go lower? Why did Obermyer prefer a back bore on a bloop tube? Light bulb moments for some.

Yes, slower burning powders do reduce pressure but they are dirtier because they deposit more powder residue which in itself can be a fouler. It was this aspect which was the main thrust of my previous comment. While the subtleties of tune with 2213, 2217 and Reloader 23 are apparent in 7mm’s, operating temperature and barrel length should not be overlooked for optimisation. 2209 is clean just as 8208 is in .308W. But 8208 must be used in a long barrel because pressure can become an issue in shorter ones. Inspect cases.

It is not so much an issue of a bigger case allowing more slow burning powder in the 7mm’s but how it is compressed to burn efficiently. I take it that is what you were meaning to say, Bruce. Stick to black powder mate its got low ES.

Sorry David , dumb plumber . No light bulb moment!! Please explain back boring and harmonics?

[williada]

GMan a long long time ago, I remember some of my advocacy for using tuners was seen with raised eyebrows, yet today they are the norm as people get up to speed with generational change because they understand the reasons why. Its a bit like trying to explain gene therapy to some because small things and their interaction do matter and like gene therapy things can be redesigned to function properly. Some of the commercial tuners used today were based on consultation with me.

In your case, you might remember the thermal mass, I said Cam's muzzle weight added to the last section of the barrel which was the most important section back in the day (as Percy Pavy used to tell me when I drove him back home from the range at Williamstown). Then discussion moved to tuners forward of the muzzle and how the length of of the barrel was related to an harmonic length so the muzzle was not distorted and the barrel thought it was longer so as to take chatter away from the crown. You get what I mean?

Backboring is a method to keep barrel length in tact by utilizing the concept of a deep hole crown. In the past we used to cut the crown at the minimum diameter and the offcut was disposed of. Most barrels have a taper which bells out the muzzle caused by the lapping process. This taper has to be removed. By back-boring you can make fine adjustments on the lathe to nail that minimum bore diameter which reduces in bore yaw. Yet you can trim the end of the backbore to match an harmonic length which retains minimum bore dimensions which small adjustments to load and seating depth can optimise. The harmonic length is a resonant frequency and found by nodal tuners. It is the basis of Quick Load tunes and optimal barrel time. Although that too is a simplistic approach.

I thread the backbore on the outside to add tuning thimbles or weight to adjust macro barrel lift and mico tune. The thermal mass is retained a little. This is really no different to adding a forward of the muzzle tuner and the direction the thimble has to be wound to adjust tune. That direction differs with the thimble placed behind the muzzle like Gene Beggs and therefore tuning has to be seen as whether movement of the vibrations (frequency) is speeding up or slowing down and how that relates to speeding up or slowing down the bullet.

If we had no tuner and we got vertical we normally speed up velocity? A tuner IMO when the added to the barrel after preliminary load testing can perform the same function. But note that variable tuners are far less likely to modify bum loads. Sometimes it only takes a tad of powder to see the effect or change in seating depth and so it is with small movement with the tuner around a node.

When the tuner is right, I like to think it is like adjusting seating depth. Remember those vibrations that open the muzzle also open the throat. It is important because the vibrations move up and down your barrel about 4 times before bullet exit as an example. This was my thinking which I have documented before as have others os, the faster burning 2209 was better for the SAUMS, because full ignition was likely to occur before the bullet met more interference from returning waves. I remember Ecomeat being the doubting Thomas before Canada before he tried it. Seems to me that things have changed since those early experiments. The timing, depending on barrel length might not be right with 2213, yet fall in sequence with 2217. Slower powders tend to have choppy vibrations, so other optimising factors have to come into play. In reality the simple sine wave is not really the full picture in vibration analysis, but it is a simple picture you can use and goes a long way in the tuning process.

Obermyer's bloop tube concept has been refined in tuners forward of the muzzle. Its length can effect harmonics, but its internal diameter affects pressure as noted by the article linked before with regard to suppressors. Importantly, Obermyer saw separation of flack particles having an impact on group. He used the term, "Conditioning the atmosphere". I have refined the harmonics in the system. TR saw other benefits in sight radius extension with the use of a bloop tube, but the tune implications were not considered by most back in the day.

GMan I will PM you.

[GSells]

[quote="williada"]
Slower powders tend to have choppy vibrations, so other optimising factors have to come into play. In reality the simple sine wave is not really the full picture in vibration analysis, but it is a simple picture you can use and goes a long way in the tuning process.

David , I am so thankful for your contributions as I think we all appreciate and I know I have grown because of your willingness to share ! Part reason why Au is still undefeated for some time , that I know of in FO .

Now , so maybe a naked barrel using a slower powder is at a disadvantage. But this is where O rings may have helped in my case . In that they have tamed the reflected harmonics and allowed the likes of 2213 sc to be able to be tuned and be more reliable than if the barrel was just naked ?

Like I’m half Finnish, so I’m all for being naked etc shooting is getting so suggestive with “ big Nobs, rubber modifiers and naked bullets and barrels
Looking forward to your Pm

[Rich4]

Williada, have you seen a smoothing of vibrations with magnum primers? I’m visualising an intermittent flame front, surging and waning of individual kernels creating the vibrations you reference? Perhaps more ignition is better?

[williada]

Yes, Rich4 in terms of rhythmic sine waves. In fact many small primer cases utilize magnum primers in F class to counter the
very thing you describe with unburnt powder being pushed down the barrel too far that is common with bottlenecked cases. The magnum primers penetrate and light the powder column more effectively even in small cases where quality control can be managed by weight batching in smaller cases. I can think of 223, 6br, 6,6x47 and of course 308 Palma cases as just a few examples. Magnum primers have been used with the big magnum chamberings particularly where the powder column is too long to fully burn the powder relatively in situ. There is merit in chamfering the primer hole internally to direct flash to the edges of the shoulder at a coned angle. It is most important to have a consistent production of gas for consistent thrust once bullet momentum takes over. The weighting factor in Quickload is a measure of how much powder burns inside the case. You can tweak this to get a handle on powder performance. Some say if the fill is 100% and the burn ratio is <80% the powder is too slow. I do my primer testing when running in a barrel to establish relative performance with the powder being used.

[bad_primer]

Thanks everyone

I was kind of blown away by the level of expertise on this thread. Thanks everyone who contributed. I have the 2217 on hand and have loaded up some Copperhead 180gn VLDs for a 900M shoot this weekend. Load is as follows:

CCI LR Magnum primers
Hornady cases
59.5gn 2217
Seating - 0.000 jump/jam (or as close as I can get it to that)

I don’t have a tuner on my rifle and I shoot of a Harris bipod so not shooting free recoil. I know I’m not going to win F-open matches but the challenge of shooting a set up like, with a bigger calibre, that is what I enjoy. Will have photos of results as well.

Cheers and thanks for your information and input

[bad_primer]

Okay, so...
2217 behind the 180gn VLDs was trialed at 900m at Canberra in some genuinely hard conditions. The I had two loads; 59.5 and 59.7gn of 2217, pils were seated as close as I could them to -.001” off or just in the lands. Vertical spreads, ES cand SD were average for 59.7gn (ES-63fps, SD-19.3) load and really bad for the 59.5 (ES-153fps and SD - 50.6). Photo included is for the 59.7gn group.

If I try this powder and 180gn again i’ll Be aiming to load up around the 60gn mark maintain the seating depth.