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Here We Go Again

26 Jun 2020
@ 06:38 am (GMT)

Charles Wyatt

On a recent trip to the range, I took the old P14 303 British rifle to the range for exercise. After a couple of rounds downrange, I noticed some cracks in the neck of the cartridge. This anomaly occurred frequently, but not all the time.

On another trip to the same range, a potential cracking anomaly merited more investigation while ladder shooting a 6.5 Creedmoor from a Bergara B14 HMR.

Researching this for the 303 British, I found that using a surplus rifle with new brass, this is a common occurrence. So why wouldn't it occur all of the time? Then one post on the net stated that annealed brass is the answer. Then another one said there was a burr causing the cracking in the chamber, and so on. Since I am reloading this brass with Sierra 150 grain with 38.7 gr of IMR 3031 powder, the load workup is no way close to max load. Then I sized the COAL for a fit using an article from the US Army Marksmanship Team posted on the NRA Website, the COAL seemed to be right on the money at 3.069". So the only thing that I can conclude from the research and what other say is, "after a few reloads on the same brass, it will fatigue enough to cause cracks in the necks of the cartridge. Therefore the solution is to throw away the cracked brass and use new brass in its place. BTW, the 6.5 potential anomaly does not show itself as a reloading problem, yet. But definitely worth monitoring.

Has anyone ever encountered this before? Any comments or advice is welcome.

Replies

26 Jun 2020
@ 10:18 am (GMT)

Nathan Foster

Re: Here We Go Again
Hi Charles, loading for the .303 is often misunderstood. Besides the head spacing (length), the chambers can also be relatively wide (same goes for 7x57, 8x57 and other mil cartridges). Without wide neck dimensions, pressures would rise as the chambers became fouled with carbon and crud from the battlefield.

It was also common in days gone by, to start with a chamber reamer of generous proportions in order to maximize its usable life.

Generally speaking, the .303 rifles behave well with factory / arsenal ammo, but many may cause problems with reloads.

The second issue / myth is that full length sizing dies can be backed off and used as neck dies. This is only true if the die has wide body dimensions. If the die has tight body dimensions (99.9%) versus wide rifle chamber dimensions, then it is more likely that the die will draw (or extrude if that makes more sense to you) the case, making it longer when the die is backed off. The hand loader is fooled into thinking that the die has simply not started working yet so he turns it in a bit, then more, continuing on until he has fooled himself into thinking that the die is finally neck sizing without the die touching the shell holder. In reality, the die first made the case longer, then as the man turned the die in, it finally reached a point where it pushed the shoulder back in again. The case is by this time, heavily distorted and possibly weakened at the case head (circ splits at case head on next firing).

A longitudinal split at the neck is a sign of:

1.Case is too hard (possibly your 6.5) or has been work hardened with repeated hand loads (annealing can only partially resolve work hardening in a wide chamber).

2. Case design is too thin compared to the old mil brass (Also occasional flawed batch of brass - may apply to your 6.5).

3. Chamber simply too wide, regardless of how well the brass has been annealed.

4. All of the above occurring simultaneously.

In order to minimize issues

1. You may wish to start with a heavy case for the .303. Brass marked NNY or PPU tends to be heavy (though relatively soft).

2. You may find it optimal to employ a Redding neck bushing die. The correct bushing diameter for PPU / NNY brass is .335".

3. Regrding the 6.5, you may simply have to bin the dud brass. The cases may either be too hard to begin with or showing some flaw. It is nevertheless an indicator that if you wish to continue using any of this batch of brass for reloading, it may be best to anneal it.

Two rifles, but two different sets of problems due to the major differences in reamer specs.

Or perhaps I am just another voice on the internet.


29 Jun 2020
@ 02:31 am (GMT)

Charles Wyatt

Re: Here We Go Again
Hello again and thanks for the reply Nathan. I agree with your assessment to both rifles. The 6.5 uses Lapua brass and I believe the problem is not related to the 303. In fact, I'd be surprised if there were neck cracks in the future (might be just burnt powder on the neck). After cleaning the cartridges, I will give them the usual QA with emphasis on the necks.

As for the 303, spot on. I will be replacing the cracked brass with new unfired brass and probably experience no issues. Since this anomaly only happens intermittently, do you think measuring the neck thickness before and after firing is a worthwhile endeavor?

Take care....
29 Jun 2020
@ 08:36 am (GMT)

Nathan Foster

Re: Here We Go Again
It may not help you a great deal (measuring neck thickness) but you may want to observe the neck diameter before and after. Although there will be some spring back, it might help you to understand the chamber a bit more in comparison to other rifles you are using.

It will take time for all of this to come together, depending on how far you take it. You might start with PPU brass for a bit, see how it goes. If case splits continue to occur, you will need to decide whether you wan to perhaps just keep shooting factory PPU or perhaps reload only once or twice. Or you may want to go the full hog and purchase the Redding dies if you enjoy shooting this rifle regularly.
30 Jun 2020
@ 12:18 am (GMT)

Charles Wyatt

Re: Here We Go Again
A while back I bought 200 brass cartridges and at the moment, do not remember who manufactured them. I believe it was PPU but will check and see. Thanks so much for the advice.

I shoot the 303 infrequently as I want to preserve the bore and receiver as long as I can to keep it in good order. It is a P14 Sniper with matching serial numbers and it is so accurate. It is fun to take to the range just to see the attention the old girl still gets.

Thanks again for you help and we'll keep in touch, especially when I encounter something where more expert advice is needed.
 

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