Barrels for re-bore & rifling

[ZUG]

Never had this done so I am asking for some advice - here goes:
I have two Green Mountain barrels 15/16 across the flats that are .40 cal X 34" (they were 42" but I cut them back for different projects). I plan to make them into Plains rifles. I contacted Bobby Hoyt to have them re-bored to .54 cal. My question is this; what twist and style of rifling (square, round, radius groove) have any of you had good success with shooting a round ball from 50 to 125 yards?

 

[George]

I have a .54 with Green Mountain barrel, have worked up good groups out to 150 yards. Here's what I wrote about the barrel when I bought the gun in 1980.

The barrel is by Green Mountain, 1" x 34", 1 turn in 70", land diameter is .540, groove diameter is .560, and has eight lands and grooves. The rifling is "radius cut" (the bottom of the grooves and the tops of the lands are concentric with the bore), and the width of the lands is 1/2 that of the grooves. The cut from top of land to bottom of groove is on a slight angle, not at 90 degrees, making for easy loading and cleaning.

Spence

 

[galamb]

You will get a lot of opinions - some that agree and some that don't to your questions.

I will say that I shoot both square and round (or radius) rifling and am not more or less accurate with one vice the other - so just one personal experience.

General consensus says (and I'm not cheering for or against any of these statements):

Square rifling will result in better accuracy

Round rifling is easier to clean and fouls less, allowing for "extra shots" before having to clean

The best "roundball" twist and rifling for a 54 caliber is:

1:70 square rifling according to Green Mountain

1:66 round rifling (square if you ask for it) according to Rice Barrels

1:56 round rifling according to Colerain Barrels

all cut fairly "deep" rifling in the 12-16 thou range whether square or round

I didn't include barrels such as Rayl, Getz, Oregon, FCI etc because the (buyer) specifies the twist/depth/style etc - The Rice/GM/Colerain come like they do "off the shelf" so should represent what each maker "thinks is best".

Then of course you had the Hawken Brothers who rifled just about all of their 54's with 1:48, 7 groove round rifling, right hand twist, to a depth of about "14 papers" (12-14 thou) - and they thought "that was best"....

 

[nhmoose]

UH Green mountain barrels hold many records the way they were rifled. Not speculating standing on RECORD

When the original owner of the company owned it the barrels were spectacular Note Branch himself is a world class shooter holding many records.

New ones uh no comment

 

[hawkeye2]

The person to ask is the man who in going to do the work. Get back to Bobby, ask him what options are available and then which one he recommends. Follow his suggestions and when you get the barrels back I guarantee they will do what you want.

 

[ZUG]

Thanks all for your reply's -- good info here.
Bobby gave me a list of his services but did not recommend any particular rifling twist or style -- he said "my choice" :hmm: . I'm leaning towards 1-66" twist & round rifling. Here's a thought -- one barrel in 1-66" twist & round rifling and one in 1-70" twist & square rifling. Then I can see for myself after I get the rifles built (not for about a year or two). Thanks again for your input :bow: .

 

[BrownBear]

Sounds like your zeroing in on a decision. And that's the hardest part for me.

I've been staring at a sewer pipe TC 50 cal barrel for over a year now, trying to decide between 52, 54 and 56 smooth. Leaning toward 52 since I'm already overloaded with 54's and have a 62 GM smooth. But then I have to nose up to the twist and groove shape. Twist? I've become overly fond of 48 for my mix of light and heavy loads, and always wondered what a deep round bottom groove would do with it. Seems the Hawken brothers and lots of others in the day were fond of 48 too, but I don't recall hearing any were round bottom.

Being experimental by nature doesn't help decisions at all!

 

[Rifleman1776]

Thanks all for your reply's -- good info here.
Bobby gave me a list of his services but did not recommend any particular rifling twist or style -- he said "my choice" :hmm: . I'm leaning towards 1-66" twist & round rifling. Here's a thought -- one barrel in 1-66" twist & round rifling and one in 1-70" twist & square rifling. Then I can see for myself after I get the rifles built (not for about a year or two). Thanks again for your input :bow: .

All of the twists given will give good accuracy. But, and I mean BUT the slower the twist the more powder you must use to get that 'sweet spot' accuracy. I am an advocate of the faster twists like 1:48. You will get the best accuracy with less powder. And when you increase the charge for hunting the little loss in accuracy will never be noticed by the deer.
I am suggesting a 1:48" twist with square rifling.

 

[ZUG]

OH - BOY -- now more decisions to consider :hmm: . I have an old Douglas .54 with 1-48" twist that I could never get that rifle to shoot good groups - and I've been trying since 1969. I'm still leaning toward 1-66" twist - I think I'll press Bobby a little harder for his opinion :grin: . Thanks for your input.