Tuesday, November 05, 2019

Since, between weather and the eye thing

I don't know when I'll get a chance next, today was a range day.  Mostly trying out some loads.  Only going to note a few of those.  All .45-70, all at 200 yards.

I've mentioned before- I think- that with modern cases you cannot get 70 grains of black into this case and have the bullet seated so the case covers all the lube grooves*, especially with a heavy bullet like this.  I have gone up to 68 grains, and it takes a LOT of compression; 70 would probably cause the case to bulge a bit.  There's a writer named Mike Venturino who's written a lot on .45-70, and has expressed the opinion that with most rifles you can get as good a performance with 65 as you can with more, with a lot less compression.  So this was five rounds over 65.0 of 2f, using a .060" wad under the bullet
 That high/left was called, I thought I might've pulled it a touch, and I was right.  That's a quite nice group, and I'll shoot it again to be sure.

 This one was the same bullet and wad over 24.0 grains of Accurate 5744, which is one Venturino really likes for this cartridge(so do a lot of other people)
Again, I managed to pull one.  That's a very good group(especially for me).  I didn't think to throw in the tripod for the Chrony before I left, so no hard knowledge of velocity, though the Lyman book shows 1101fps.  Also shows this as likely to give the best accuracy with this bullet.

I did try a few with the Lee 405-grain hollowbase over 26.0 A5744, didn't group as tight as last time.  Which is quite possibly me, by that point I was getting to the 'concentration slipping' point.  Ah well, I've got a few more for next time.

By the way: I can't remember if I mentioned this before(and I'm too lazy to check right now), there's a very good piece(in pdf form) on 'Introduction to Black Powder Cartridge Rifle Loading' by a guy named Chuck Raithel available online, and it's got a lot of good information in it.  I'd post a link, but the one I had saved isn't working right, you should be able to search by that title and find it.

*A lot of guys loading specifically for long-range matches will seat the bullet as far out as it will go until it almost touches the rifling, and do not crimp; that lets them get as much powder in as possible for a little more velocity.  It also means some of the lube grooves are exposed, and if you turn the cartridge over the bullet will fall out.  Not shooting a those kind of distances, I want the case to cover the lube grooves, and use enough crimp to keep the bullet in place.  That's with black, with most smokeless propellants you get better performance from a strong crimp as well.


crow said...

Which bullet are you using in the 2 photos?

Firehand said...

This one
Lyman says 535 grains, out of my mold with 20-1 it's 525.