Average bore diameter for Buffalo Classic

[Tennessee.Traveler]

45-70 should be .450 for bore diameter.  My groove diameter is .458 but the bore appears to be about .452  Do they usually run a little large?  What do they average?  Advise appreciated!


Tennessee.Traveler

[quickdtoo]

45-70 groove diameter should be around .456"-.457", H&Rs are usually about .0005" more open at the muzzle than at the throat. For cast bullet fitting, the groove diameter is the important dimension, although nice lands are important too, the shallow rifling makes it more critical to fit the groove diameter plus .001" to .002" for good accuracy with cast bullets. I shoot .458" and .459" in mine, others even shoot .460" very well.

Tim

[Tennessee.Traveler]

I am trying to find out what diameter bullet I need to use to create a paper patched bullet that is .002 under bore diameter after 2 wraps of .002 paper. Thanks!

[quickdtoo]

Good luck, I don't recollect anyone shooting PP in their H&R, but my recollector doesn't always work!! But if anyone knows, I'm sure they'll offer help.

Tim

[linwin3000]

   After slugging the bore on my BC I found .4565 just ahead of the throat and .457 near the muzzle. This is consistent with Tim`s info above. Equally important is the throat diameter, BC`s seem to be a little large here, I`m now shooting .460 lead slugs and this larger diameter seems to shoot better than any of the .458 stuff I`ve used.
  See ya,
                                 Richard

[dodd3]

45-70 groove diameter should be around .456"-.457", H&Rs are usually about .0005" more open at the muzzle than at the throat. For cast bullet fitting, the groove diameter is the important dimension, although nice lands are important too, the shallow rifling makes it more critical to fit the groove diameter plus .001" to .002" for good accuracy with cast bullets. I shoot .458" and .459" in mine, others even shoot .460" very well.

Tim

tim mine is the outher way round tighter at the muzzel than the throat.
bernie

[quickdtoo]

That's unusual Bernie, due to the way the barrels are made, they're bored first, then turned from what we've learned, resulting in a slightly larger muzzle dimension than throat area where the barrel is bigger. All 3 of my 45-70 and the 45-120 bores are that way, the newer 444 and 45 Colt too, just by .0005", not a lot and certainly not enough to affect accuracy obviously, my 444 is one of the most accurate barrels I own, with cast or jacketed!! Yours may also be an older barrel, so maybe that's the difference.

Tim