Is Lapua brass thicker?

[Bill Steele]

I usually take pride in my math skills, but for the life of me I can't explain where I came up with that number.

What I do know is the point I was trying to make is that the new unfired Lapua's had a head space measured on my Lock-N-Load head space guage of 1.615". My fire Remington cased measured 1.623-1.624". The fired cases won't allow the bolt to close. The min size to chamber a case is 1.620, so I resize the Remington's to 1.618. The fired Lapua's measured 1.622, and using the same die set to resize the Remington brass to 1.618, resizes the Lapua's to 1.616.

So the point that I think I was trying to make is that the datum on the shoulder of new Lapua is around .005" tighter than the fired Reminton which isn't showing any ejector signs.

So, I'm wondering if after the Lapua has been fired as many times as the Remington, will the case expand to the same head space measurement at the Remington? I did measure the capacity of the unfired and fired Lapua brass using fine walnut shells, and it does seem to hold between 3/4 and 1 grains less than the Remington brass.

I'll be going out to the range Wed. I'll be trying some more new cases and the 1st fired cases loaded about 1 grain below my previous load. Hopefully I won't see any more pressure signs or lose that much velocity in my long range loads.

I am still confused on the headspacing but I suspect it is me. I just got back from a long trip and am a little tired I suspect. As long as you know what is going on, that is all that matters.

It has been a long time since I loaded Remington rifle brass. In my experience, R-P tends to be on the thinner side, so if in fact it still is, then for sure you will be able to pack more powder into it than a case with thicker walls. A thicker walled case will generate more pressure with an equal load. It sounds like a load that will generate no pressure signs in your Remington brass is tight enough in the Lapua to start to show signs. If you happen to try LC, it will likely be even tighter (more pressure).

Your strategy of trying a little less powder is a sound one. As I said in my inital post, I always do a new ladder when I introduce a new component into a tried and true load. Sometimes I get identical results, sometimes my optimal load is quite different with the new component.

Good luck, have fun.

[Wrangler John]

Wrangler John,

Were you using "brown" box or "blue" box Lapua? The newer "blue" box Lapua that I have bought since they switched has not had any of the defects that you are speaking of.

Blue box, purchased last year.

[Wrangler John]

What's nice about Lapua is you don't have to ream primer pockets and flash holes or weigh your cases. When you cull out the bad cases, Winchester costs the same. But you do have more internal volume.

Nonsense, the primer pockets proved to be shallow and inconsistent requiring uniforming. The slight ridge at the entrance to the primer pocket and tight dimension can make seating primers difficult. Primer seating depth inconsistency can have a significant effect on accuracy, as can deforming the cup when seating in undersized primer pockets. Flash holes still needed cleanup. Small diameter small rifle flash holes need to be gauged and reamed for consistency and to prevent interference with depriming pins.

When I measured neck thicknesses of various brands including Winchester, the variance was between .000"-.0015" with most running .0005"-.0007", not worth neck turning. In my 6mm PPC with a .261" neck all brass has to be turned to fit, negating any difference between brands.

Weighing cases is a waste of time, the differences between case weights is insignificant when compared to the variation in the chemical reaction caused by powder charge and primer interactions. Neck pull and concentricity is a larger factor in accuracy. Only the most precise benchrest rifle would be able to make use of eliminating any minor variation in case weight. Environmental variations would make determining which shot displacement was due to case weight variations or wind, humidity (including moisture changes within the powder charge) or other factors impossible.

Winchester brass has a maximum of 2% +/- per 100 culls. That amount 2 per 100, will not offset the difference between (.223 Remington) Winchester @ $31.00 per 100; Lapua @ $62.00; Remington @ $32.00; Federal @ $28.50. The premium brass offered by Hornady, Nosler and Norma are comparable in price to Lapua. For the volume shooter that requires sub-MOA accuracy any domestic brand offers significant cost savings.

In another test done by a gun magazine, five groups of five shots using a mixed batch of five brands of brass produced the smallest groups fired. This is similar to my experience with mixing brands and lots of brass in precision barreled varmint rifles. Even under extreme field conditions switching between Winchester, Privi Patrisan and Hornady brass had no effect on accuracy out to 300 yards.

[J-cat]

Nonsense, the primer pockets proved to be shallow and inconsistent requiring uniforming. The slight ridge at the entrance to the primer pocket and tight dimension can make seating primers difficult. Primer seating depth inconsistency can have a significant effect on accuracy, as can deforming the cup when seating in undersized primer pockets. Flash holes still needed cleanup. Small diameter small rifle flash holes need to be gauged and reamed for consistency and to prevent interference with depriming pins.

I dunno what dies you are using or what primers you are seating, but this is simply not true. I have abasolutely zero issues seating/depriming FC/CCI/WIN primers in Lapua brass. I do not have any issues with a step at the entrance to the primer pocket. That's a priming tool issue, not a brass issue. I found the pockets consistent. Just because the tool removes metal does not mean the pocket is bad. The tool is designed to cut the pocket to the maximum allowable depth. Don't mean they have to be that deep.