Lyman GPR rate of twist

[StanD]

Did the Lyman Great Plains Rifle ever come with a 1 in 48 twist. I have one that was a kit with a 32 inch barrel and I swear it's a 1 in 48??

 

[BrownBear]

Could be, but I don't know for sure. I have a couple of non-Lyman Investarms rifles and they're both 1:48. The GPR has been around a long time, so I wouldn't be surprised that at some point it was 1:48 like the TC Hawken. But I'm ready to be corrected!

 

[StanD]

None of the books I have reference a 1 in 48. They all say the Great Plains Rifle came in 1 in 60. The rifle was sold to my brother in 1986 and my books only go back to 92. He, of course is no longer here so I can't ask him. Maybe some one with an older rifle will know?

 

[RADeO]

As far as I know, and I sure as heck don't know it all by a good looong way :surrender:, the GPR has always had a 1:66 twist barrel. If I recall correctly, that is the way they were marketed. :hmm: Somebody will correct me if I'm wrong about that.

Is the barrel in question original to the rifle? It is possible the barrel has been replaced.

 

[Sperit de bois]

Go to the source www.lymanproducts.com

 

[StanD]

Acorn
He bought this rifle as a kit in 1986. I just found the answer in my 1992 Lyman Black Powder Handbook. The 54 did come with a 1 in 48. The 50 cal. came in 1 in 60. Thinking it was supposed to be a 1 in 60 I was surprised when I ran a rod down and came up with 12 inches in a quarter turn. My 2005 catalog references only a 1 in 60 for the Great Plains Rifle with a 1in 32 available. So I guess I’ll have to see how the Lyman with a 1 in 48 stacks up against my TC Hawkins at 1 in 48. He used this one quite a bit but then went to a Knight MK 85 for his go to rifle. He also left a Green River 50 and a TC Hawkins in a 50 with an additional 36 barrel. Thanks for answering.
Stan

 

[George T.]

I believe that it's the Great Plains Hunter that has the fast twist and the GPR has the slower. They look the same but the Hunter is intended to shoot the bullets. Geo. T.

 

[Matt85]

I believe that it's the Great Plains Hunter that has the fast twist and the GPR has the slower. They look the same but the Hunter is intended to shoot the bullets. Geo. T.

this.

the GPR has (to my knowledge) always had a slow twist. but the GPH had a fast twist for shooting conicals.

-Matt

 

[cowpoke1955]

I bought my .54 GPR about 35 years ago and it has a 1 in 60" twist. As far as I know, all GPRs .50 and .54 had 1 in 60" twist. Before the GPR, Lyman use to offer a Plains Rifle. I believe this rifle had a 1 in 48" twist in a shorter barrel (28" I think). The Lyman Trade Rifle now fills that void.

 

[StanD]

Well, surprise to me. This one is sure enough 1 in 48 and it's 32 inches long and is stamped
"Great Plains Rifle" 54 cal. I would never have guessed that.
Stan

 

[MattC]

Stanley, you mentioned running a rod down the barrel and coming up with a measurement. Could you expand on that? If a barrel isn't marked, how do you manually figure out what the ROT is?

 

[StanD]

Matt
What I do is mount a cleaning jag on one end of the rod and at the other end I screw in a T handle. Then with a tight patch I start the patched end into the bore. The handle will turn as it follows the rifling. Using an 8 inch carpenters level I run the rod in till the T handle is vertical and measure the distance from the T handle to the end of the barrel . Then continue running the rod in till the T handle is horizontal which will equal ¼ turn. Again measure the distance to the end of the barrel and multiply by 4. It’s not exact but it’s close enough to tell if it’s a 1 in 48 or a 1 in 60. In this case I came up with a little over 12 inches in several tries.
Stan

 

[StanD]

Matt
I have the rifle lying flat when I do this.
Stan