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Re: marks on bullets
Posted by Larry Gibson on Thursday, 28 July 2011, at 12:04 a.m., in response to Re: marks on bullets, posted by steven gabrielli on Wednesday, 27 July 2011, at 12:55 p.m.
If this were the case of a high pressure cartridge using jacketed bullets you would have a valid point. However this is about shooting cast bullets with BP loads in the 45-70. The bullets engrave very easily and are fully engraved in one bullet length of travel. You can do that by hand. Just how many additional psi's do you think it takes. I've no problem what so ever telling any one here to "load into the rifling" with such cast bullet loads because it is safe, does not raise presures and most often increases accuracy. I've been pressure testing cast bullet loads, smokeless and BP, for some time now in numerous cartridges and firearms. I have yet to find a single instance where the psi is raised.
Years ago in my conversations with Spence he was well aware that the 405 HB bullet Lee made at his request to replicated the original M1873 bullet would not expand ala a minie. It was intended to obturate from inertia during initial accelleration. The lee bullet, just as the original M1873 bullets, did not do this well enough. The rifle loads (70 gr BP) would do better than the carbine (55 gr BP) but neither were capable of complete and sufficient obturation to bump up from .459 to fill the .460+ groove depths of many M1873s. This is why the 500 gr M1882 bullet and why it was much more accurate than the 405 gr M1873 bullet. The heavier mass of the M82 bullet caused sufficient obturation the expand to fit the groove depth of the TD barrels. Those who shoot the TD seriously use correctly sized bullets and do not depend on "bumping up" .458/.459 sized bullets. Thus accuracy is much better.
If one is following Spence's instructions to replicate M1873 and M1882 ammuntion then sizing to .459 is done and "bumping up" is necessary. However, if one is shooting for accuracy then don't depend on "bumping up" but fit the bullet to the throat/bore correctly to begin with. Yes 1 1/2 moa is possible and I've seen many a M1884 on the line at BPCR matches. Some of us even have target rifles made out of the old warhorse. Problem is a TD in excellent condition is worth a lot as a collector piece. It's not adviseable to make necessary alterations to make them competative. Much easier to get a rifle made for the game and with a bore common to most bullets of .458/.459 to begin with.
BTW; I don't believe anyone implied store bought "cowboy action" loads were going to shoot 1 1/2 moa out of TDs.
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