Muzzle loader experts

[lonewolf172]

Are there any ML experts here who knows what the measurements of the lands and grooves are for the .50 cal Investarm Gemmer Hawken are. I know the bore is probably .500-.501 but you need the other 2 figures to know what's the best size round ball and patch to use.

 

[Bad Karma]

Are there any ML experts here who knows what the measurements of the lands and grooves are for the .50 cal Investarm Gemmer Hawken are. I know the bore is probably .500-.501 but you need the other 2 figures to know what's the best size round ball and patch to use.

It could vary depending on the condition of the tooling used at the time the barrel was rifled. Probably .010-.012”... The only way to know is to have the rifle in your hands. That’s a round ball rifle. Get a box each of .490 and .495” balls. An assortment of patches from .010 to .018” and shoot the rifle from a solid rest.

edited:Not claiming expert status mind you... there are others here who can...

 

[1874sharpsshooter]

I am pretty sure the 50 cal was .010 . I have a couple investarms but they are the ones made for lyman, the GPR
The 50 is .010 and the 54 is .011.

 

[Idaholewis]

Personally, If this was a Hunting Rifle, i would get a .490 Ball and Play with a few different Patch thicknesses, and powder Charges til I found what Shot the Best in the Rifle. I would care less what the Groove Diameter was? Let the rifle decide what it likes

 

[Muley Hunter]

The gun is the Lyman GPR. It might be easier to find the specs for the GPR. It used to be on the Lyman website. I seem to remember the GPR had deeper grooves.

All the GPR's I had worked with a .490 ball and PT .018 patch. You have to use too thin of a patch with the .495 ball.

 

[1874sharpsshooter]

The gun is the Lyman GPR. It might be easier to find the specs for the GPR. It used to be on the Lyman website. I seem to remember the GPR had deeper grooves.

All the GPR's I had worked with a .490 ball and PT .018 patch. You have to use too thin of a patch with the .495 ball.

2 post above for those specs

 

[lonewolf172]

The gun is the Lyman GPR. It might be easier to find the specs for the GPR. It used to be on the Lyman website. I seem to remember the GPR had deeper grooves.

All the GPR's I had worked with a .490 ball and PT .018 patch. You have to use too thin of a patch with the .495 ball.

I've checked and the Lyman GPR grooves are .012 deep. Oh another question if you know. The Investarm Hawken has 5 lands and grooves. Good, bad no difference? I'd think with 5 there's more metal on the lands to grip the ball and patch better

 

[Muley Hunter]

2 post above for those specs

I just went and looked. The GPR .50 has .018 deep grooves.

https://www.lymanproducts.com/media/catalog/product/t/r/trade_rifle_p4.pdf

 

[lonewolf172]

I just went and looked. The GPR .50 has .018 deep grooves.

https://www.lymanproducts.com/media/catalog/product/t/r/trade_rifle_p4.pdf

Ah you're right. Some how I missed that. Even better. If that's the case for the GPR I wonder if they're the same for the .50 Investarm Hawken, .018 deep grooves

 

[Muley Hunter]

The Lyman version of the GPR was always the same gun. I don't think they'd change that now that they don't make Lyman's gun. You can ask Investarms what it is. They have a website.

 

[lonewolf172]

The Lyman version of the GPR was always the same gun. I don't think they'd change that now that they don't make Lyman's gun. You can ask Investarms what it is. They have a website.

Already emailed and called yesterday so waiting to hear back from them. I'm still trying to decide if I should spend about $600-625 for a Lyman .50 or .54 cal GPR kit and build it my self or spend $660 for a factory .50 Investarm Gemmer Hawken

 

[Muley Hunter]

That sounds high for a GPR kit. I think MidSouth got around $500 for a kit. The problem is finding one now.

I'd get the Investarms personally. The warranty might be better than Lyman's now.

 

[lonewolf172]

That sounds high for a GPR kit. I think MidSouth got around $500 for a kit. The problem is finding one now.

I'd get the Investarms personally. The warranty might be better than Lyman's now.

Well that $625 figure was for the kit, some wood working tools and metal and wood finishing items. But like you said the warranty is probably with Investarm. When I emailed Muzzle-Loader I also asked them why the .54 cal Investarm Gemmer Hawken wasn't available since it is listed at Investarm website. Muzzle Loading Rifle 160 - Investarm

 

[Muley Hunter]

Another one that you never see is a LH Trade Rifle but Investarms makes it. I bought a few GPR's because it was the only production Hawken style gun I could buy in LH and .54 cal. with a slow twist.

 

[LanceS4803]

For truly accurate bore dimension, you can always "slug" the barrel. This gives you something to hold in your hand to measure. Mil surp Russian rifles are notorious for having widely varied bore diameters, and by slugging them you know what bullets you need when reloading.
Use lead sinkers. Get some slightly oversized, the softer the better. On a really clean barrel, lube well and using a wooden dowel start knocking them down the bore. You'll feel spots where the bore is narrower than other spots. That is fine. What you are looking for is to identify the smallest portion of the bore.
What drops out the other end is an exact representation of your bore, ready to measure. I keep the sinker, identifying which rifle it goes to.