i need some help with a pressure problem...

AtownBcat

Sergeant
Full Member
Minuteman
Feb 19, 2009
127
1
49
Aledo, Texas
Hello all...



I am shooting a 6.5x47 and am having some pressure problems.



I am using Lapua brass

H4350(and a test string of 2000 MR)

Federal match small rifle primers

140g A-Max's



I have loaded all the way down to 36 grains of bot 4350 and 2000 MR shot it over the CE M2 and registered velosity all the way down to 2477(most people are between 2840-2940 with this bullet) and even with the lightest charge i am still getting extractor swipe and slighty heavy bolt lift. Every round that has been fired(yes im hard headed and keep trying) has the swipe....I just dont understand..



The gun was built by a great builder with a great reputation and taking it back to him will be the next step.



I have measured the new brass(i did not trim it) but it measured 1.8435 so unless my chamber it short they should be great.



any ideas? someone suggested using varget but with velosity down around 2400 there should be no pressure.



PS the gun is a shooter...I have shot three three shot groups that were all under .2.
 

dieselten

Sergeant
Full Member
Minuteman
Jan 25, 2009
389
0
60
Dallas, TX
Re: i need some help with a pressure problem...

Check your chamber neck clearance. Measure a fired case neck (below the burr on the case mouth if present) and add about .0005 to .001 for spring back. Then measure a couple loaded rounds. If clearance is less than .003 then you should start turning necks as Lapua brass neck walls can vary .001+ which could add up to almost .003 on a loaded round.