I've obtained a few more data from this project - one of many that are on the go.
My materials:
1867/89 Swedish rolling block, unmodified
50x PRCVI 8x56RS brass, fire formed and now re-fired several times. Annealed after every third firing
Lee-mold cast 205gr bullets with gas-checks (lead is soft pistol bullets recovered from a club)
CH4D 8x58RD dies, .327" expander ball
Lee expander die
Three powders: Unique, H4198, SR4759. I experimented with weighed loads
Winchester Large Rifle primers.
COAL is 2.900". This comes nowhere near the lands - that would require a bullet around 2" long!
The best results are with SR4759 - 24gr: m.v. 1693fps s.d. 20 e.s. 50
Second best is H4198 - 24gr: m.v.1511fps s.d. 44 e.s. 123. The problem with this powder is that it doesn't seem to be developing enough pressure to seal the neck, and there is black sludge blowing back around the neck and shoulder. The loads are accurate, but I don't like the idea of any blow-back with this old gun. The reason for blow-back, I believe, is the lack of crimp (see below).
Unique is OK, but I find it relatively weak and inconsistent, bullets all over the paper, and I dropped it.
If I full-size the brass, it becomes apparent that the shells rattle around in the chamber, and when fired, they expand asymmetrically. In order to re-insert them, they have to be turned just right. If, before firing, I wrap a single turn of 1/4" masking tape around the case head, the fully-sized cases are less loose and expand symmetrically.
--> my rifle has an "oversize" chamber. In retrospect, I could have taken a chamber cast and ordered a custom die set from CH4D.
However, I've found that partial-resizing - just enough to size most of the neck - keeps the cases closer to the chamber dimensions, with no need for taping.
The bigger issue with the standard 8x58RD seating die is that it is too long to crimp my brass, which is shorter than 58mm.
Since there is no crimp, this is affecting the burn efficiency, especially for H4198.
I could cut off a few mm on the bottom of the seating die, but that would require machining equipment and skills that I don't have. I'd rather not mutilate it with a hacksaw, if that were even possible. The steel seems pretty hard. It's easier to just stick with the SR4759 loads.
My materials:
1867/89 Swedish rolling block, unmodified
50x PRCVI 8x56RS brass, fire formed and now re-fired several times. Annealed after every third firing
Lee-mold cast 205gr bullets with gas-checks (lead is soft pistol bullets recovered from a club)
CH4D 8x58RD dies, .327" expander ball
Lee expander die
Three powders: Unique, H4198, SR4759. I experimented with weighed loads
Winchester Large Rifle primers.
COAL is 2.900". This comes nowhere near the lands - that would require a bullet around 2" long!
The best results are with SR4759 - 24gr: m.v. 1693fps s.d. 20 e.s. 50
Second best is H4198 - 24gr: m.v.1511fps s.d. 44 e.s. 123. The problem with this powder is that it doesn't seem to be developing enough pressure to seal the neck, and there is black sludge blowing back around the neck and shoulder. The loads are accurate, but I don't like the idea of any blow-back with this old gun. The reason for blow-back, I believe, is the lack of crimp (see below).
Unique is OK, but I find it relatively weak and inconsistent, bullets all over the paper, and I dropped it.
If I full-size the brass, it becomes apparent that the shells rattle around in the chamber, and when fired, they expand asymmetrically. In order to re-insert them, they have to be turned just right. If, before firing, I wrap a single turn of 1/4" masking tape around the case head, the fully-sized cases are less loose and expand symmetrically.
--> my rifle has an "oversize" chamber. In retrospect, I could have taken a chamber cast and ordered a custom die set from CH4D.
However, I've found that partial-resizing - just enough to size most of the neck - keeps the cases closer to the chamber dimensions, with no need for taping.
The bigger issue with the standard 8x58RD seating die is that it is too long to crimp my brass, which is shorter than 58mm.
Since there is no crimp, this is affecting the burn efficiency, especially for H4198.
I could cut off a few mm on the bottom of the seating die, but that would require machining equipment and skills that I don't have. I'd rather not mutilate it with a hacksaw, if that were even possible. The steel seems pretty hard. It's easier to just stick with the SR4759 loads.
