Thread: Lapua 6.5 PRC Brass - Split Necks

I have done the usual google searching and understand all the usual suspects for the cause of split necks however my issue doesnt seem to be consistent so with so many experienced reloaders on this forum i thought id ask the question and see if anyones experienced a similar situation.

Tikka 6.5 PRC, brand new rifle about 4 months ago. Lapua Brass. Hornady Dies.

Gun shoots great, load isnt hot (143eldx with 2217 @ 2950fps, 24" barrel.

My issue is, im up to the 3rd loading on this batch of brass now and 1 in every 5-6 pieces of brass now has a split neck. But the strange thing is, Its one extreme or the other. The ones that arent split are like brand new still, neck looks great/normal. The ones that are split are really bad & have multiple vertical splits that you can see daylight through.

My process is always the same with every loading. Brass gets ultrasonic cleaned, dried then tumbled in a walnut media tumbler. Deprimed using a depriming die in my press, then annealed in AMP annealing machine. I anneal every loading just because i can. Lubed & full length sized with a 2 thou shoulder bump, primer pocket cleaned OAL measured trimmed if need be, chamfered, final clean, lube neck load powder charge & seat projectile.

My last PRC i loaded for i also used lapua brass, no problems. Load for a bunch of other rifles using lapua brass also, and not had any issues with some of the brass being on its 8th-9th loading with pretty warm loads.

Has anyone experienced this before? Has there possibly been an issue with the brass from lapua recently?

have you spoken to the retailer you bought the brass from ? they may be able to talk to the importer and raise your concerns ? there may be others affected by a bad lot of brass etc etc
No hate, not having a dig at all, hope you find a solution

That is an unusual split, not going through to the case mouth.

Because you are so through with the brass prep and the Lapua brass should be just fine.
I think there is something wrong between the chamber neck diameter, case neck diameter and case neck thickness.

Originally Posted by dannyb

have you spoken to the retailer you bought the brass from ? they may be able to talk to the importer and raise your concerns ? there may be others affected by a bad lot of brass etc etc
No hate, not having a dig at all, hope you find a solution

I think bad lot of brass from Lapua least likely cause
Look at the numbers carefully for the things you have and can create hard data from. Rifle, sized brass and fired brass

Im getting that on soke .308 brass now but its being loaded countless times but same split

Originally Posted by dannyb

have you spoken to the retailer you bought the brass from ? they may be able to talk to the importer and raise your concerns ? there may be others affected by a bad lot of brass etc etc
No hate, not having a dig at all, hope you find a solution

Not yet, just figured theres so many blokes far more experienced than i on here, be a good place to ask and see if anyones running into the same issues.

Would be interested in cartridge lengths. You indicate "trimming where nescessary". It is possible you are not trimming back far enough.

Seems odd, what is the OD of a fired case neck, and a sized case neck ?
I prep my brass similar to yours in my 6.5-284, and haven’t split a case neck


Sent from my iPhone using Tapatalk Pro

I'm just having the same issue with Norma brass in my 260rem. All cases which have been amp annealed. Splits on 1 in 4 cases on first, 2nd and 3rd firings. I've checked neck diameters on new, loaded and fired and they are within spec or better than my 6.5prc which has no issues. Splits on some completely different loads to 120gr and 130gr. I'm about to try some peterson brass to see if it's just that brass batch.

Fired brass with the splits in it measures .297 which is SAAMI reamer spec for 6.5 PRC. Freshly sized brass measures .291 and loaded with a projectile .293. So 6 thou of expansion total after springback (not incl however much the chamber grows when firing) 4 thou of that when the cartridge is fired. So theoretically this should be fine? I dont have the gear to measure chamber neck but one would assume it has to be .297 or close to if the brass is coming out at .297? Or should i expect to see less than .297 with the brass if the chamber was .297?

Disclaimer - im far from a gunsmith or engineer just a guy fumbling around with some verniers

You have likely had a reaction whilst ultrasonic cleaning. All brass is not perfect. Recall on another overseas forum someone was experiencing same issues. Will try track it down.

Are all the splits the same shape/type?

The photograph you posted looks like the split is inwards not outwards as if the expanding case has been forced onto something.

I'd be surprised if it was the brass or ultrasonic cleaning.

I shoot Lapua Palma Brass in 308, ultrasonic clean before reloading, anneal after every 5th firing.
Lapua don't recommend annealing their brass BTW.

My oldest brass is up to its 19th reload with a few (3 or 4) split necks in about 2000 cases.
The splits didn't appear until after the 15th firing. The splits on the neck along the case, almost straight.

I reckon talk to Alex at amp annealing.
He is very approachable and I would imagine there's not much he doesn't know about that sort of thing.
Ultra sonic cleaning is an interesting thought

Sent from my SM-A226B using Tapatalk

Originally Posted by 6.5 CRD

Fired brass with the splits in it measures .297 which is SAAMI reamer spec for 6.5 PRC. Freshly sized brass measures .291 and loaded with a projectile .293. So 6 thou of expansion total after springback (not incl however much the chamber grows when firing) 4 thou of that when the cartridge is fired. So theoretically this should be fine? I dont have the gear to measure chamber neck but one would assume it has to be .297 or close to if the brass is coming out at .297? Or should i expect to see less than .297 with the brass if the chamber was .297?

Disclaimer - im far from a gunsmith or engineer just a guy fumbling around with some verniers

You generally get 0.5 thousandths of spring back when firing. So your chamber will be 0.2975 - 0.298 at the most.

is that a weird reflection or is there another mirror crack semi formed further down/around the neck..same shape but in mirror