OzFclass

Bindi, the fact you neck sized is now focussing my attention towards a tight neck as you indicated a considerable speed variation in the cases. I assume the Lapua was faster as you did not state which was. As the Lapua brass has a thicker wall than Winchester the pressures will be higher in a tight configuration, but sometimes what will pop a primer, is the length of the neck, if the projectile is pinched because the trim length maybe less than .005” from the end of the neck. It does not take much carbon build-up here to be a problem if the setup is on the limits. Because another fault sometimes is the length of the chamber, and if your trim length is not enough you will pop primers.

If reloading overworks the case, and it is not in your case Bindi by your description of your process, a crack or mark often appears if the chamfer cut on the back of the barrel on the barrel tenon is too deep as I mentioned earlier, so the case head is not supported. This is despite what reamer is used. It can mean that tougher brass can survive this, but this has to be traded off with the even wall thickness and less weight variance of good brass which generally produce tighter groups. So there can still maybe an underlying fault in the armouring.

If anyone has copped a fast lot of powder a quick way of telling is to use a lighter pill to see if symptoms disappear.

Yes, I have copped a bad batch of soft brass (not Lapua) before, just once, and it still has to be considered. It would be interesting to see if others are experiencing similar problems, because I think posters have covered all the options. David.

Williada My cases variation was in single digits all three lots. The 3 case lots rem. win. and lap were under 50fps fastest to slowest. I used 155.5, 168 and 175gn projectiles in two totally different rifles. The common denominator the brass.

Ok ... I have to weigh into the Holden Ford debate! Also being of Finnish descent, I have to stick up for this Scandanavian marvel. What I've read is very biszare for Lap brass! I've been using 308 lap brass in large rifle and in past few years in Palma version at 46.2-46.5 2208 155gr. I get 10 firings out if them and retire them as just good practice . I've never had a neck split or head separation ever or until now have heard of Lap Brass doing it .Alan summed it up in his previous post of "he'll take all of the Lap brass that no one wants lol!"

I think in this case , feed the rifle what it likes . And put it down to another mystery of the universe .

Regards Graham.

plumbs7 wrote:Ok ... "he'll take all of the Lap brass that no one wants lol!"

It is all his. I will take the once fired Winchester.

I think in this case , feed the rifle what it likes . And put it down to another mystery of the universe .

Regards Graham.

Agree and I do.

Hello Phillh,

I've just joined the Ozfclass forum and the first article I read of interest was yours regarding the expansion of Lapua .308 brass extractor grove diameter.

I shoot F-Class Standard on the Belmont range in Brisbane and have just converted a Omark to use as my second F-Class rifle. After about 4 reloads of the otherwise new Lapua brass I found I could no longer fit the case into the shell holder on my Lee hand primer! Exactly the same problem as you - and can assure you and the other contributors that my shells were properly dry when fired!

I spoke to my armourer who had only recently fitted the barrel and he advised that he was aware of other Lapua users who had been having primer pocket expansion problems but that my issue was the first of its kind he had encountered. He also noted that changing the batch of brass had cured the issue for the others. He has cut open a Lapua case and noted that they have reduced the amount of brass around the base, probably to save money. This could be the cause of our problem.

I'm going to purchase another box of Lapua brass to see if the problem arises again after a few reloads.

I have not experienced anything like this in several years of reloading Lapua brass for my two Barnards and my Neilsen action.

Cheers,
Greyrider

Have you re checked your headspace? I recently had a problem with an incorrectly head spaced barrel (it was 12 thou too long) and it caused very significant pressure on the cases causing ejector marks, popped and pierced primers and case head separation.