Green River Barrels with Choke?

[alaskasmoker]

I found a gun made with a Green river Barrel, that the owner says has about 3"'s of choke on the end. Its a .50 cal. He says its pretty tough loading at first, but after you get past the choke its easy. He says the choke really helps accuracy and he and his gun has won many a match back in the day.

Any one have any more info or opinions on this barrel?

 

[BrownBear]

I've got a Green River barrel that is "choked," too, but mine's a 58. I've been in contact with the GRRW smith that built it, and he sent me a good explanation of GRRW's barrel boring methods, and in fact confirmed they end up slightly choked. He said that the choking was unintentional and resulted from their methods. He said only subsequent miking revealed that's what happened. By the time they discovered it however, it was too late to change. Folks were making great accuracy claims and had high praise for the barrels. I can sure testify that if the others shoot like mine, it's a good thing they didn't do away with the choke. I've heard GRRW guns are more scarce than they should be, because lots have given up their barrels to custom builders using them for their own creations.

I gotta say too, that there's a practical side or a down side to it. While mine is technically a 58 caliber, it's too tight at the muzzle for traditional .575 or .570 patched round balls. Heck, a bare .575 ball sits on top of the muzzle and won't drop. Even a .570 hangs on even the tiniest little surface irregularity, and a .010 patch is virtually too thick. As a result I'm using .562 balls and .018 ticking patches.

 

[longcruise]

I have heard before of the excellent accuracy provided by a chocked ml barrel and it sets me to wondering if it is the chocke that helps or maybe they are just very well made barrels in other respects Pedersoli chokes their Gibbs long range slug gun about .001 and say it helps accuracy and obturation. But, that's apples to oranges when looking at prb results.

Did the fellow you talked to mention why their rifling process produced a choke?

 

[BrownBear]

Here's an except from the letter he sent me, dealing with the barrels:

"I can tell you that the secret to the accurate barrel is the way they were bored and rifled.
They were first drilled as usual. But what is unusual is that they were never reamed as most if not all barrel makers do now - and did then. We first cut the lands and then cut the grooves depending on the bore size. It's been a long time but as I recall the big bores had the grooves cut first. This made for tool marks that ran the whole length of the barrel on both lands and grooves in the direction of the bullet travel. Also, as the cutter head advanced towards the muzzle oil pressure and some cuttings put a minute amount of pressure on the cutter and you ended up with a sort of choke near the muzzle. This was accidental and was discovered while "slugging" a barrel to check for rough spots. Once found on a test barrel we noted it on all of them and theorized the above means by which it occurred. The result was a barrel that needed just about zero break in and was wonderfully accurate as you have discovered. To the best of my knowledge no one is producing barrels in this manner. So you have a real prize there no matter which of the old GRRW crew made it."

Whatever the explanation, the choke is there and the accuracy to go with it.

 

[alaskasmoker]

Thanks for the information BrownBear. This guy actually has two of the barrels, one in .50 the other in .54. From what I can tell he did a pretty good job building them.
I might have to take them off his hands! He is practiclly giving them away I think.
The 50 he says he uses a .495 ball, 80 grains of 2F and pillow ticking :shocked2: for his match load. Its a long barrel too 42-44 inches I think. Gun weighs 10 pounds!
The .54 he says he hasnt shot much. So cant give me a reliable load for it.

 

[LRB]

I am lost here. How does one cut lands first, when the grooves make the lands????

 

[JayDee Flohr]

I am lost here. How does one cut lands first, when the grooves make the lands????

That's how I've rifled the few barrels I've done.
You actually cut "grooves" first, then index over and cut more. This second set being cut deeper. The bottom of the first grooves cut now become the top of the lands.
The theory I was taught was that since cut rifling has chatter marks, even if microscopic, they all run the same direction.
Take it for what it's worth but they shoot great for me.

 

[Zonie]

Just guessing here but if the barrel was initially drilled with a undersize gundrill, both the lands and the grooves would need to be cut.

Passing a bore size cutter thru the undersize hole which only is the land width (or slightly wider) would cut the "lands". This cutter would have to be in a rifling machine so it had the proper twist.

After the lands were cut a new cutter that produced the groove depth and rotated from the position so that its cutting action was done between the lands that had been cut would produce the grooves.

This whole process seems to me to be much more complicated than it needs to be but it could be done.

As the letter indicates the older method, and one used by many barrel makers is to drill the hole slightly undersize and then ream the hole to bore size.
This would be followed by a cutter that cut one or many grooves into the reamed bore.

Using this method would be much more cost effective but as was noted, the bore and grooves would be of uniform size on the finished barrel.

 

[JayDee Flohr]

After the lands were cut a new cutter that produced the groove depth and rotated from the position so that its cutting action was done between the lands that had been cut would produce the grooves.

Only one cutter is needed.

 

[LRB]

Okay, I get it now, but agree with Zonie. As for the direction of chatter cuts, I would think if the bore was reamed, then lap polished, it would not matter. I have never heard before of such a method as you describe.

 

[ohio ramrod]

The principle of "choked" rifles was common on old time bench rifles. Many of the "false muzzles" used on these guns were actually undersized by from .0003 to .001 of an inch.The thought was that a slightly undersized muzzle would "size" the bullet (or prb) and allow for easier loading down the barrel and prevent deforming the bullet , (or prb).Since it was common on the top guns of old, and the replica Gibbs dominate long range shooting today in many areas. I would tend to think they were right.One thing I do know is that the one rifle I intentionally lapped to leave a choke, loaded much easier than any other.It was at least as accurate as any that were not lapped.But that just lapped the lands aand not the grooves.

 

[Trench]

I have a Pedersoli Frontier rifle that appears to be choked for the first quarter of the barrel. Once you get passed it, the ball and patch seem to drop right down. I do believe this does help accuracy if only because the fit is so tight. It's a .36 and the .350 balls get stuck in the barrel without a patch. It's fine on the bench, but horrible to load out squirrel hunting.

I remember reading a snippet from an 1830's shooting journal in Muzzle Blasts that said it was always better to have a barrel that is tighter at the muzzle than at the breech. Interesting.

 

[Dphar]

I found a gun made with a Green river Barrel, that the owner says has about 3"'s of choke on the end. Its a .50 cal. He says its pretty tough loading at first, but after you get past the choke its easy. He says the choke really helps accuracy and he and his gun has won many a match back in the day.

Any one have any more info or opinions on this barrel?

Maybe its just rough reamed at the muzzle.
It could be choked but usually they are not really any harder to load once the ball is started and sized to the bore.
I find it unlikely it was choked by the maker takes a lot of work with a lap. Hours...
It would require casting a lap in the bore or otherwise slugging it to confirm a choke.
Dan

 

[longcruise]

Actually, I mis stated the nature of the Ped Gibbs barrel. It's actually a .001 gradual taper from breech to muzzle according to Pedersoli.

 

[Dphar]

Actually, I mis stated the nature of the Ped Gibbs barrel. It's actually a .001 gradual taper from breech to muzzle according to Pedersoli.

They claim to have a proprietary system that chokes barrels. Never checked one so I could not say.

Many barrels were choked in the old days. Often had a slight funneling at the muzzle then a couple of inches of choke then a looser bore down to the breech.
Getting a tapered bore with a square bit reamer was the norm. But getting tapered bore with rifling is a lot more work.

Dan

 

[zimmerstutzen]

I have an H&H barrel, made when Hoppy was in Elk Ridge Maryland. It has a slight choke at the muzzle, and is accurate as can be. Wide round/oval bottom rifling with narrow lands.

In the 1860's Alexander Henry experimented with various chokes in rifles. He came up with the rifling for the Maqrtini Henry adopted by the Brit War dept. It had two chokes. the first narrowed the bore a couple thousandths just ahead of the chamber and then the second was a few inches at the muzzle. His system of rifling was designed to be made that way. Not by accident. Hisw rifling also doesn't have lands and grooves, so much as a spiraling serious of convex and concave waves. Even the center of the "groove" is a raised hump. Strange yes, but "those boys are shooters."