Thanks for the help fellas, but I am still very slightly befuddled. Only slightly.
Bore size on my 1877 - I have not actually slugged it, but it seems to be the .375 of the original bores (a .358 just falls in easily). However, there are two different terms being tossed around, both with the initials "HB". "Heel based" and "hollow base". I believe I understand the difference; the heel based were the original configuration, nearly of the .375 bore size. However, I understand from some writings that a common and easier solution developed later on was a hollow base bullet of the normal .357-.358 diameter, of pure load, which would easily fill the bore upon firing.
Montana Slim, when you refer to 148 gr. HBWC, does the "HB" refer to hollow base .358 or heel base .375?
Also, I may just try your suggestion, backed by experience, that a normal hard cast .358 may work well enough.
If I buy a box or two of factory 38 colt, like some of the cowboy ammo companies sell, am I getting .358 hollow base bullets in those? The descriptions I have seen, like Ultramax, do not say. I "think" it must be hollow base .358 ?
Thanks again,
Daybreak Dave