Other Caliber Great Plains Rifles

[nkbj]

Anybody indulged in changing the caliber on their GPR's?
I've got one made into a .40. And a .54 GPH barrel I'm threatening to do something different with, maybe a smooth bore. Any way, thought I'd open a thread and see what people are doing.

 

[leadhoarder]

Are you asking about Great Plains style rifles or the actual Lyman investarms models? A .40 Lyman rifle would be quite heavy. Now if they made a 58 I would be interested.

 

[nkbj]

The .40 is heavy, right at the limits of what I'll deal with. The rifles you see in museums with thicker than one inch barrels and even smaller bores, well, I have to tip my hat to those fellas for their upper body strength as well as their marksmanship.

As to the rifles I brought up, yeah, GPR's. As well as changing the bore on a GPH.

 

[Sun City]

I have a smooth bore; it's called a shotgun!

 

[Stykbow]

I’ve kicked around the idea of having my 50 cal bored out to 54 or 58, but I can’t justify it. It’s plenty big enough for what I hunt around here.

 

[ThreeCedars]

I didn’t change the caliber on mine (54 cal), but I did modify another Investarms barrel to fit. I wanted to try a 1:48 twist 28” barrel, and found one from a kit gun that was never put together. If you want to fit another barrel to your GPR, this will give you a taste of what’s involved…. I have to imagine there are Investarms barrels out there in other calibers that have the same hooked breech and snail.

Some pictures of the project:

New barrel for Lyman GPR

Also just a thought, if you have a GPH barrel they’re worth quite a little bit and are hard to come by. You could sell it and get a very nice smoothbore octagon barrel from a barrel maker. I have considered this exact thing for putting together a grouse gun.

Anyway, good luck! I would love to see it when you’re done.