I had bought 400 lapua brass in .243 and developed loads all year with virgin brass. I was at the range recently with the same lot of brass only neck sized for second time around. My point of impacts changed and the pressure on some loads seemed higher. When I got home I filled with ball powder a single new case I still had, then I poured the same powder from that to the "neck sized only" case. I could see that it would only fill it to the junction of neck and shoulder. What could or should be done in this situation?

Yes, fired brass will have more internal capacity than unfired brass. This will have NO effect on your chamber pressure.

If you are experiencing pressure problems in fired brass with the same load that showed no pressure in unfired brass, then your cases have likely stretched to the point of pinching on the chamber leade. This would cause both point of impact change and higher pressures. Measure and trim your cases accordingly.

Good luck!

HEIDER,
My testing has convinced me that that a load fired in a full length sized, or virgin, brass will give a lower velocity than a case that has been fire formed and neck sized only. The larger the case, the lower the velocity. .222 Rem. seem to loose about 15 fps. The .300 Win Mag loses about 45 fps. I think this is due to the pressure used to expand the case to fit the chamber. Neck sized cases will supply slightly higher pressures, but I'd find it impossible the slight increase is the cause of your problem. As STONECREEK has already pointed out, cases in need of trimming may well be the cause of the problem. An expanded cases will have a larger case capacity than a full length sized case. This greater capacity. The same charge of powder, of the same lot, should not cause a problem. I'd look to see what else may have ghange to create the problem. Good luck.

[ 09-17-2002, 05:20: Message edited by: BigBob ]

heider,For best accuracy, everything should be the SAME each firing.I full length resize every time in my 243 win. If you must neck size only, use a bushing die like Redding makes.The type s redding fl bushing die works best for me.243winxb.

What makes you fell that "pressures seem higher"? If there is definite indications, such as primer pocket stretching, hard extraction, ejector marking of case heads, etc., do as Stonecreek says, measure your cases, and trim them to at least "trim-to" length. Check the mouth of a fired case to make sure a bullet will FALL FREELY through the fired case mouth before you size it!!