I just bought a Lyman GPR in a 54 cal.

Would some of you guys that shoot a Lyman GPR (54) help me out with some basic info?

Like, what size ball you shoot? powder (FF or FFF)? Cap size...10 or 11? grains of powder (70, 80, 90)? patch thickness and lube recommendation?

Right now I'm casting my own balls, using a Lee mold, for a 44 Remington. They seem to be a tad bit larger than the 451s that are store bought. I'm wondering if this will hold true for round balls I cast for a 54 cal. rifle?

Thx!

I don't own one now, but i've had three of them, so I can help some.

I used a .530 ball with a .015 or .018 patch. I used mink oil for patch lube bought at TOW.

I used 3F powder. It ignites a bit easier, has a bit more power, and less fouling. 70-90 gr will work. See which one is the most accurate.

Use #11 caps. The #11 CCI magnum caps worked the best for me.

As you can see the .44 C&B revolvers are really .45 cal. It doesn't apply to the GPR. It's a .54 cal.

I have two of the Great Plains Rifles and two of the Lyman Trade Rifles. They can take the larger size ball and still fit with a .015-.018 patch. I use moose milk as a patch lube, but there are countless lubes out there. In my 50 caliber I shoot both the .490 and .495 ball. In the .54 caliber I shoot both the .530 and .535 ball.

They take a #11 cap. And if you find ignition problems, order a RMC stainless steel nipple for the Lyman Rifle. For some reason the nipple that comes with the Lyman sometimes don't seem to have a large enough flash hole.

The .535 were tight but you can load them. 90 grains of 2f powder and then a patched roundball. What I would suggest is get some store bought first and see which size works best for you.

Thanks for the replies.

Right now I have about 5 pounds of Pyrodex P that I use in my 44. I've heard of guys shooting it in a big bore. It will burn faster...I suppose the load would need to be a bit lighter? Other than that any problems using it in a 54 cal?

Pyro P is just Hodgdon's way of saying 3F. It will work fine in the 70-90 gr range.

Thanks Muley!

I had one it worked best with a 535 ball and 90 gr of P or 110 gr of RS.

I have several . Been hunting with a 54 GPR since 1980. The hunting load that works best for me is #11 cap, .018 patch and 90 gr triple 7 . I soak my patches in a mix of 7 parts water 1 part ballistol and let dry .
Very accurate hunting load for me but each gun is different . You got a great .54 there . You will love it

my lyman 54 flinter likes a .530" RB with .020 patch and 90 gr of FFg Goex