45-70 Trapdoor

[alfajim]

The issue rifles had a 3 groove 1:22 twist. The chambers were cut a touch long so they could be fired dirty in combat. You can do what I did with my rolling block, take a 45-90 case and trim it a little at a time until it chambers my rolling block has a Springfield chamber and will take 2.2" case. The 500gr Gov bullet shoots great in the slow twist I use it out to 500 regularly with good results. Both Lyman and SEACO make a copy of it. Try the stock front sight out for awhile. I have fired a few trap doors with the buffington sight and the original front sight. It is an accurate combination capable of very good accuracy out to 500 and beyond.

I like the idea of maybe using 45-90 cases to work up a round with a little more umpf to shoot longer ranges for doing some shooting at a match or two. So I'll get a few to try that my question is if the rim dia. and thickness is the same as the 45-70 gov. so the TD extractor will throw it out and also headspace? The pictures of the 45-90 cases looks like there is a groove in front of the rim whereas on the 45-70 gov. is straight no groove is that a problem?

Jim
Fly Navy