7-08 out 0f LC problems

[McSweep]

Got 1000 Lake City 7.62 brass to neck to 7-08 and made sure they were clean. Annealed the necks and put them through my rcbs FL die. These are for a Savage bolt and when I tried them the bolt closed rather hard so I adjusted the die to where the bolt closed easily.
Started load development(162 Amax-Varget). Immediately had sooty necks and the primers had gas escape around them. Pockets are swagged,not cut. This was at 39 grains of Varget.

Figured I was over-charging and dropped to 35 grains and started to work back up. Still have sooty necks on every shot, but only get primer blow-by about once in 8-10 shots.

Anybody have this happen to them or happen to know what is going on?

 

[ksthomas]

McSweep,

Could be a number of things here, and without actually seeing what's going on here, it's a bit of a crap shoot. I'm sure you're probably aware of this already, but I'll say it anyway; when reforming cases, and especially when necking them down, you need to KNOW all the pertinent dimensions involved. Specifically, the neck diameter of your chamber, the case wall thickness at the neck, and the finished O.D. of the loaded rounds. You need to have at least .002" or so clearance between the neck of loaded round and the chamber walls to make sure the case can cleanly release the bullet upon firing. Failing this, you get into all kinds of problems, many of them relating to pressure spikes. That, would explain the blown primers. Another thing to be aware of is that like any military 7.62mm brass, the LC cases are considerably heavier than most commercial cases, and have a corresponding reduction in capacity. Not talking anything "slight" here, and military cases need an entirely different set of loading tables. If you're using what are recommended "safe" loads that were developed in commercial 7-08 cases, the loads in the reformed LC cases are going to need to be reduced dramatically. Likely, at least 10% or so.

It'd be easier to diagnose this with some pics, but these are some areas you should take a look at first. The problem is likely in one or more of these things, and should be easy enough to remedy. Check 'em out, and get back to us.

 

[McSweep]

Thanks for the tips. It does appear the neck walls are too thick. I see some turning in my future.