Miroku 1886 with "original 45/70 spec chamber???

[Dolt]

Hi guys. I have a Japanese made 1886 Winchester in 45/70 that will not chamber factory ammo. Bolt comes within a hair of locking when I lever the round in. Gunsmith says it is because it was cut (chambered) with the original 45/70 dimensions and not the "new" 45/70 dimensions. Has anyone else heard of this bulls....? Personally, I think the chamber may have been cut with a worn reamer or somehow short chamber.

[Tom Trevor]

If anything pre SAMMI specs. 45-70 as well as other chambers were larger. You are being fed FUD.

[PhillipM]

Hornady's leverevolution brass is , I think, .060 shorter.

[JimF]

Might be, you have a piece of an old broken case in the forward portion of the chamber. --Jim

[Stephan]

I own a couple Trapdoor .45-70 chambered originals and a older Miroku/Browning 1886 saddle-ring carbine. I got my TD rifle first. Also started casting 405gr bullets and reloading modest .45-70 ammo for the ancient rifle. A few years later bought the 1886 Browning carbine('cause I always wanted one). The Miroku/Browning .45-70 rifles/carbines have a reputation for a short lead...meaning the barrel's rifling has an abrupt start ahead of the chamber and may not chamber just any shape/style/weight/oal bullet.

Anyhow...I quickly learned that if I wasn't careful with my casting alloy that my self-cast bullets could be too big...loaded rounds wouldn't chamber in the Browning carbine(too fat for the chamber)...and that if the self-made ammo wouldn't chamber in the Browning then it darn sure wouldn't chamber in the vintage Trapdoor rifle!...The old rifle's chamber being as tight or tighter than the much newer modern made 1886 Browning SRC(I think my Browning carbine is approx. 1992 vintage). No problems with any brand factory 'cowboy' 405 gr ammo in either rifle.

I have noticed that my recently acquired 1880 vintageTrapdoor carbine(which is much cleaner mechanically than my Trapdoor rifle) has a somewhat/slightly more generous chamber than either the Trapdoor rifle or Browning carbine. I had a handful of 'reject' .45-70 reloads that were just slightly too fat for either my TD rifle or Browning carbine and these would fit the TD carbine fine.

Chambers vary obviously...the Miroku made Brownings seem to have minimal chamber dimensions and a reputation for an abrupt start to the rifling....