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7.62x54 light vs heavy

1608 Views 5 Replies 3 Participants Last post by  ammolab
Does anyone have an idea of the cup pressure of light ball ammo vs heavy ball? I am asking for a general measure not specific to any particular mfgr.year or country. The hungarian light ball load shoots wonderfully in all my Mosin rifles (no extraction or sticky bolt)... but any heavy ball in the same rifles will cause me to reach for a 2x4 to beat the bolt open and quite often tear the rim from the case. Is there a significant difference in velocity or chamber pressure between these different bullet weights? I am curious about surplus ammo (have not fired any commercial loads yet).
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I never noticed a problem between heavy and light in my Mosins as far as the bolt, and I have over twenty of them. I DID notice a hard bolt opening on some steel case but the was either dirty chambers, very hot receiver from rapid fire. You may have a bolt or head space problem. The only difference between light and heavy is, the heavy takes a little longer to get down to barrel, so just a little more TIME of pressure is behind it, but any MORE pressure. Were you shooting steel cased or brass cased? I shoot brass cased HB and the bolt is smooth as butter, no matter which rifle I shoot it in. Steel case, that my be a little stiff sometimes even with a clean chamber but never hard enough I need to beat it open.
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