I must apologize here, as I did not make that fact clear.
The 45/70BC and the 38/55 while both being fine weapons have some ideosyncracies that are not apparent to the casual shooter; I dont mean to be facetious here. The chambers of both weapons have been cut with a very subtle taper in their total length; this is to accomodate commercially manufactured ammunition, SAAMI specs. The barrels of both weapons do not conform to SAAMI though. The barrel, in the case of the 45/70BC is .4575 groove to groove. Now, if you fire commercial ammunition therer is no problem with its intended function;however, if you fire cast bullets in the five hundred grain category, 500 gr.R/N[round nose], the original GI infantry round, the 500 gr. Lee variant [not a Schmittzer or a Postell but an amazingly accurate round at 100 yards], or the 535 grain Postell the bullets must be sized to the grooves. Anything under "1 mil" in size and the rifle will not hold a group consistently and the rounds will "keyhole" on the target. The 535Postell is a very stable round and is the least effected by wind; it has five driver bands and four grease grooves. It casts up at .460; if you size it down to .459, distortion and "out of round" compression created by the sizing die [naturally] are minimized and you get a round that is true. The problem comes that once the round comes off of the press if you attempt to load it the receiver will not accept the round and it will not chamber, because of the taper in the chamber, this is assuming that you develop the round as it was originally configured as a Black Powder Rifle Cartridge with an overall lengfth that excedes "safe" loading specs as detailed in the Lyman, which are 2.55 for commercia grade ammunition which is typically a 405 grain jacketed flat head bullet jacked up to about 1700fps. From experience that is a very unpleasant experience, but you've got to get it up that high if tyou want "knockdown"; two things dominate in the world of "knockdown" first is velocity and the second is mass. You can get as much knocdown, and more in some instances from a bigger bullet driven at a moderate velocity because it maintains its velocity more efficiently by virtue of its inertial mass than a smaller bullet given the constant of velocity as an equal in both cases. In the case of the 535 grain Postell, if you try to handle it the same as a 405 grain round it is physically impossible to load it in the case and hold 2.55" and you will come away with a compressed or "reduced" powder charge anyway, neither a safe situation. So you load the round to 2.935" which exposes the bullet at the ogive which terminates at the first driver band, and configures the round to its original Black Powder Cartridge functional characteristics. The chamber was moved forward .030" to accomodate the new round comfortably so as not to bite into lands.
What I describe here is not in anyways, shapes or forms to be interpreted in this forum as a recommendation or as a paradigm. My rifle range reports are simply historic recitals of data derived empirically from range testing and consultation with established gunsmiths. For the record, the "smithing" was done by Richard Clark in California; he is a very reputable gunsmith and has a very high regard for Harrington and Richardson rifles and I regard his recommendations to me as those coming from a subject matter expert. He is direct and to the point and will not hesitate in the least in telling a person that "maybe" their expectations are not grounded in reality, as situation dictates.
Anchor's Away/Semper Fi
CPO Bull
PS2 "Quick"
Yes I have, look very soon for a repoprt on the .308 Ultra; it's even better.
