Half my handloads from last year splitting necks

[livetohunt]

So I ran into an issue this last weekend.

I had 40 rounds loaded up from last summer. Always stored inside the house. All was once fired Sig Brass I bought new.

20 of them had been on hunting trips with me on multiple occasions thru last fall and this spring (wet multiple times). These looked weathered. The other 20 sat in my house this whole time and the brass looked new.

The 20 that went hunting with me are splitting necks. I caught it when I shot the first two and both were 10" high at 500 yards. After catching the split necks I went to the ones that hadn't left the house. They were exactly where they should have been.

Was this my powder getting damp after these wet hunting trips? They never got blatantly wet, but were in a lot of damp weather.

 

[MagnumManiac]

Simple answer is no.
Inclement weather is most likely not the reason, BUT travelling with them probably is.
It's more likely the CHANGING conditions, cold welding of the bullets to the brass and temperature changes causing the issue.

Many years ago, my 25-06 Winchester brass started separating at the neck/shoulder junction during firing, or when re-sizing them.
There was a lot of green corrosion inside those necks, never saw the bullets as they had been fired, but suspect they had corrosion on them too.
They had been taken hunting dozens of times and stored in a box on the tray of my truck for several years. Although the box had a seal on the lid, temps inside would have been from 32 F to 120 F, this, I think, is the issue.

Cheers.

P.S.
I bought 100 NEW 22-250 Remington cases 2 years ago, fires them in comp last year and 80% of them had multiple splits on the necks with the FIRST firing. Go figure, I have no idea why they split.

 

[Dmagna]

Could of cold welded on the brass. I had this happen when I had a box of loaded ammo open and they got some snow on them. Also condensation can do it as well, pull one of them and see how hard it is to pull the bullet out of the case.

 

[LVJ76]

Unless submerged in water then provably not. Have you shot the ones you left at home yet and if so any issues with those?

 

[livetohunt]

Ya, I shot them and they shot perfectly fine.

 

[Gar Guru]

I noticed something similar on some .308 win shells I loaded about 30 years ago. They sat in my dads gun cabinet inside his house for about 30 years until he acquired another .308 rifle 3 years ago. I told him to sight the new gun/scope combo in with the old shells and about 2/3 of them had neck splits when fired. I pulled the rest using a kinetic bullet puller and they came out easily when whacked with the bullet puller.

 

[LVJ76]

Ya, I shot them and they shot perfectly fine.

Never had that happen to me before, I've shot reloads after 7 years with no issues, some have gotten wet but not too much though. I always try to keep them dry.

 

[DartonJager]

Never heard of such a phenomenon. Oddly and coincidentally enough, I just shot my 338wm and 7mm stw using handloads I made in the late 90's and early 2002-2003 and they were exposed to temp swings from the teens to high 80*s and no issues at all.
Been quietly and patiently sitting on my shelf in my ammo cabinet for well over 15 years now. All were loaded using brass on it's 3rd reloading. All were absolute max safe reloads in my rifles, all were over published max.

 

[Mikecr]

Lookup 'season cracking' or 'stress corrosion cracking(SCC) of cartridge brass'

 

[Legionnaire]

^^ This. Sounds like exposure to ammonia vapor somewhere along the line.

 

[freddiej]

I am going to have to agree with legionnaire. this is most likely a case of ammonia contact on the brass. urine could have done this as well. another reason is if the brass was over 50 years old. but you said the brass was new and once fired. that rules that out. I had a bad batch of R-P brass more than once and Privi-Partizan brass. They used, evidently by mistake, an ammonia based polishing agent. this made the brass useless after the first firing. for more than a few reasons I do not use Privi or R-P brass anymore. mainly very poor performance and case to case weights varied so badly they could not be trusted not to blow primers on certain loads.
you stated that the brass in question looked weathered as it was in your backpack or in a coat pocket and got wet... and the temps were swung from 32 F to 120 F.. umm, my suggestion is do not do that again. get a water proof ammo carrier ( I think it's called an Ammo Vault) from MTM. the primers will disintegrate and be worthless. I used to be a guide up in Montana in the late 90's and early 2000's. My boss, Ron, would always leave his ammo on the dashboard of the truck and it nearly killed him once. the hot to cold rapidly and back up to hot again rapidly breaks down the powder and the primer. some primers do not do this.. however the powder, all powders degrade with this hot and cold rapid swing cycle. just imagine if H-4320 turned into something akin to H-110 or H-Clays? big over pressure problem. well, it so happened Ron and I were on a scouting trip and we saw an injured Elk, we had to put it down to be humane. he took the shot and his gun came apart in his hand. BTW Y'all this was factory 338 Win Mag ammo. After saying a prayer for his rifle, and thanking God Ron was uninjured; I took the Elk with my 338 W/M with home brew loads. He called the MFR of the rifle and had it replaced. He never allowed his ammo to sit in the sun ever again. they never were on the dashboard.

 

[25WSM]

I had this happen to me. I sized 300wby down down to 7-300wby. It was rp brass. New brass. Loaded them up and the ones I fired were all fine. The next yr half the unfired ones had cracked necks. I just assumed sizing them down work hardened them so much they were brittle. But the ones I fired were all good. That's the only time it's ever happens to me. I don't know why.
Shep

 

[dsteve931]

NECKS GET THINNER AFTER RELAODING AND TRIMMING ETC. MOST LIKELY CAUSE

 

[Legionnaire]

No, not if it was truly "once-fired." Cases do fail due to thinning, but that takes multiple firings.