Range report III on Lyman Great Plains rifle

[Maven]

All, Had a chance to test the GPR again today, but this time I brought plenty of .495" RB's (cast from a Lee mold) and 20 .490" RB's (cast from a Lyman mold). When I used the .495" RB and a patch of the "correct" thickness (still trying to determine that), accuracy was VG, but not outstanding with 70gr. Pyro. RS. With the same charge and a .490" RB (actually .4905") + a .018" patch, I was able to put 5+ balls touching @ 50yds. from a rest of course. A little while ago I got the bright idea to measure the diameter of the .490" RB's with the .018" patch and came up with .519" - .520". I then searched around in my patching material for something that would give me the same figure with the .495" RB* and found a 4" strip of cloth that I used to use for my .45cal. Hawken, since sold. It looks like I'll be combing the fabric stores with my micrometer and .495" RB in hand in the next few days. Btw, I have 3 .490" RB molds and none casts to the same diameter. The Lee mold is nominally .495", but in reality drops .499" RB's.


*The most accurate patched ball (.490" + .018" cotton calico cloth) combination measures .519" - .520". I'm hoping to reproduce that with the .495" ball since many have urged me to try it in the GPR.

[44man]

Up the charge of Pyrocrap to 90 gr's. Much more accurate.
Use the .018" patch with the .495 ball. I use up to .021" with that ball. The lube is VERY important and I won't use anything but Young Country. Ballistol is extremely accurate but the bore needs wiped between shots.

[ktw]

The ".535" balls that have worked well in my 54 GPR measure .5350-.5355 (Lee mold, pure lead). They load easily using .013" ticking, Ballistol and a short starter, no mallet required. Hunting load is 90gr of GEOX FFFg.

-ktw