Please showhigh pressure extractor mark pics
- Thread starter coach71
- Start date
Bullet is 40gr Berger Varmint Match, OAL 2.250, powder is IMR 8208. I did load development, so loads varried from 26.4gr of powder up to 26.8. First noticed the notching from some of the 26.8 loads, so checked and found more from previous loads.
OK. I checked the IMR load data site (http://www.imrpowder.com/) for 8208 and a 40 gr bullet (Berger not listed; .224 Nosler used). They list the powder load range as 25.0 - 26.7 gr. In other words, based on their data, you were starting near the top end and went over it.
Given that and given that smaller cases are more sensitive to increases in propellant WRT pressure, I'd say your notches are due to a serious overpressure problem. If the Berger bullets have a harder jacket than the tested Noslers, that might have raised pressure still more.
Could be wrong, but every rifle handles different loads differently; were it not so, most of us could stick with factory ammo, right?
EDIT
We all watch for the classic signs of overpressure - cratered primers, flat primers, expanded primer pockets, base brass having flowed into extractor hole, etc. The problem with those is that they're not scientific measurements. They're wet-thumb-in-the-air indications, like 'Red sky in morning, sailor take warning" weather prediction lines. Just as looking at the clouds is no substitute for scientific meteorology, one cannot work at the top end and rely on visual clues alone to prevent accidents or damage from dangerously high pressure.
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