Range report-cast lead 45/70

[snuffy]

Not to spout off on any supposed skill, just a thread about how different alloys do different things. The first two pics are using a 20 parts pure lead to 1 part tin. Oh the load is as follows. 340 gr. Lee 2 cavity mold RNFP, 27.5 grains of surplus 4759, new starline nickel plated brass, winchester large rifle primer. Rifle is a H&R buffalo classic SS sporting a 3X9 B&L scope. Range was 100 yds, temp was low 70's slight breeze. (beautiful early summer Wisconsin weather!) (finally!).

This next picture is the same load as above, the difference is the lead alloy. These were a mix of some dead soft, nearly pure lead I got from a scrapped machine counter weight. Mixed with linotype metal, 17 lbs. weight metal to 3 pounds of lino. BHN is around 15.

The group is over 6 inches, the best of the first two is 2.138 Not bad for an old f**t and an inexpensive single shot rifle!

Oh, the chrono readings are as follows:

Best of 2 5 shot strings with the harder alloy.
AV 1610
hi 1652
lo 1568
ES 83.3
SD 30.6
AD 20.5

Then a 10 shot string for the 20-1 alloy
AV 1573
HI 1605
LO 1561
ES 44.5
SD 13.1
AD 8.5

Why the higher vel. with the harder lead? I dunno. The worse readings,(the first string), were 83.3 ES, and that is the last group pictured.

 

[dmftoy1]

That's pretty interesting . . .I wonder if the dead soft stuff is stripping out at those velocities? I tend to shoot pure WW's out of my 45-70 at those velocities. (PB and HB molds).

 

[redneck2]

Have you tried any with gas checks? I'm wondering if dead soft would bite into the rifling but the checks would stop the lead stripping.

Same lube on both?

 

[kragluver]

His alloy was not "dead soft" after mixing with Linotype (he stated BHN 15). I typically shoot the same 340 gr Lee bullet cast from pure WW over 23 gr of 4759 in my Marlin 1895. I've had 2" accuracy with iron sights at 100 yds. MV = 1265; SD = 8 fps. I suspect you could get just as good of accuracy from your BHN 15 alloy if you tried a clean sheet load workup. Also, the Lee bullet is PB -- no GC.

 

[snuffy]

Darn it, I forgot to mention the boolit prep. They were all sorted, weighed, then lubed/sized in a Lyman 450 lubrisizer with NRA formula 50/50 alox. Sized to .458, the bore slugs to .457.

The alloy mix of soft lead/linotype is very near wheel weights in hardness and casting quality. The 20-1 is from Midway, but is mixed by me using their pure lead and pure tin I bought several years ago. It casts a nice shiny boolit, but since tin doesn't harden pure lead much it is quite soft. So, the 20-1 alloy is the softer of the two. The tin is only in there to lower the melting temp and vastly improve the castability. It makes the pure lead flow better for fill-out.

My theory is that the softer 20-1 boolit obturated better to more precisely grip the rifling. It also must have generated more friction, as the velocity dropped a little. There was no leading with either alloy.

The lee 340 is a plain base boolit, not possible to put a gas check on it. At the velocities I'm running, a GC is not needed. IF I were to up the speed, then maybe a GC would help, BUT the pian from recoil would be severe! ;eek;

 

[MMCSRET]

I use that same Lee mold over SR-4759 loaded to about 1500 fps in my Ruger #1, shoots much the same as yours. AND YES pain is a very definite consideration in these short, light single shots.