for that particular rifle. This was at 200 yards using a .40-65
Not a fluke, that's the third group with this load that was this tight or very close to it. Which for me and iron sights...
This is the Lyman Snover 400-grain bullet, cast of 20-1, over a .060" fiber wad(Walter's Wads, I recommend them), 58.0 grains of Olde Eynesford 1.5f black powder, ignited by a Federal Large Rifle Magnum Match primer, all held together by a Starline case(formed from .45-70) of 2.10" length. Overall length 2.97". I found that the max length with this bullet is 2.975 by my caliper, at which point the bullet is engaging the rifling, a PITA to chamber, and does not shoot nearly as well as this.
I also may have the long-range load for the .45-70. Also 200
Second, I've had this two-group crap happen before, and every time it's been my fault. In this case it was six rounds total, both the sub-groups are just a bit over 2", if you measure them together the horizontal spread is a bit over 4".
Specifics are the Lyman 535-grain Postell bullet, 20-1*, the same .060" thick wad, 65.0 grains of Goex 2f, Federal Large Rifle Magnum primer, Winchester cases of 2.1". OAL on this load 2.987" (near as I could keep it).
Couple of things I've found out:
The Olde Eynesford black powder seems to prefer match primers.
With all cases I only resize about the first 3/4" of the case to give enough tension to hold the bullet. With Starline cases I expand deep enough for the length of bullet that fits inside the case; Winchester cases have thinner walls, and I don't expand them, only bell the case mouth. Seems to work best that way.
Now I need to try the .45-70 load with the OE 1.5f and see how that works. And try the .45-70 with a standard match primer; doesn't shoot as well in the .40-65, but with black powder that means nothing as to what another rifle will like.
It just hit me that Dad will never get to try these rifles out. I'm done.
*I've been using 20-1 for all the bullets used with black powder