Green Mountain Replacement Barrels for Thompson Center Hawkens

[bubba.50]

I can’t figger out this new quote system but, I agree with necchi. GM has sold tons of 15/16ths 54cal IBS barrels. Also, Lyman Great Plains rifles have 15/16ths barrels with dovetailed sights and ya don’t hear anything about their barrels bein’ unsafe in 54cal.

 

[Idaholewis]

I had a Cabelas Hawken that was 15/16” and it was a .58 Caliber, Rifle was Made by Investarms.

 

[bubba.50]

I had a Cabelas Hawken that was 15/16” and it was a .58 Caliber, Rifle was Made by Investarms.

I had one of those 58cal Investarms barrels. Didn’t have a Hawken stock to put it on & didn’t feel like doin’ all the fiddlin’ with to put it in a Renegade stock so I sold it. Wish I’d kept it now.

And I’ve also seen the Investarms gusn for sale with factory 20ga barrels on them.

 

[hinamanra]

Clear back in the days of the Civil War, the military ran tests to determine the thickness of the barrel wall at the breech that would be safe for the expected loads the barrels would see.

They came to the conclusion that a barrel wall of .200 inches was needed.

Things haven't changed and generally speaking, .200 is considered to be the minimum barrel wall thickness that should be used on a muzzleloading barrel made out of mild steel.

A 15/16" octagon barrel with a .54 inch bore has a wall thickness of (.9375 minus .54)/2 = .3975/2 = .1988".
While this is just slightly less than .200" and might be considered "close enough", when you subtract the typical .0625 (1/16") depth of the sight dovetail it becomes more like .136".

In the real world one must also subtract the depth of the rifling grooves. If the rifling is .007 deep, that .136 becomes .129".

Perhaps now you can understand why no good barrel maker will bore a 15/16" barrel out to a .54 caliber?

(No. I don't want to hear about some company that has ignored these sound bits of wisdom.)

Things Haven't changed? I think that a lot of things have changed in metallurgy, engineering, machining and especially in litigation in the last 160 years when it come to barrel steel. The commercial muzzleloading guns are a modern high carbon chromoly barrel steel probably 4140, that's why they can safely build a 15/16" .54 barrel. GM barrels are 1137 steel (Chromoly), That's why they can safely build 15/16" .54 barrel. In my last post, I stated that when I spoke to Rice about making a drop-in for my T/C hawken with his 15/16" .54 barrel, He didn't recommend it due to the dovetails and screw holes. That makes me wonder what barrel steel he is using. I believe it is probably 12L14. It's a carbon chromoly steel but it is alloyed with lead for easy machining. I believe that most if not all of the known barrel makers like Getz, Rice and Colerain to name a few make their barrels for kits and the traditional builders who use traditional tools i.e. files for their metal work so they're probably using 12L14. Sleepy Hill made their barrels from 4140 but they don't make them anymore. We in the U.S do not have a safety standard when it comes to muzzleloader barrels, european manufactures are legally required to proof their barrels and by coincidence most if not all of the commercial muzzleloader barrels seem to come from Spain or Italy. Would 12L14 barrels survive their proof standards? I sure don't know. Douglas no longer makes muzzleloader barrels do to litigation. I don't know what black powder pressures reach with 1,2 and 3F pushing a PRB, conical or shot load but I do know what the different barrel steels can handle (see below). Maybe wee need to stick to the .200 minimum wall thickness. I load my 12L14 barrels as thought they were made in the 1700's. I'd love to hear any BP load pressure data.

12L14
Tensile strength 78,300 PSI, Yield strength 60,200 PSI
1137
Tensile strength 108,000 PSI, Yield strength 76,100 PSI
1144
Tensile strength 108,000 PSI, Yield strength 89,900 PSI
4140
Tensile strength 148,000 PSI, Yield strength 95,000 PSI

 

[Dr5x]

When I disassembled my original 1863 Trenton made Springfirld rifle I was amazed to see the barrel had been made from a flat piece of steel shaped into a tube over a mandrill and the welded along the length to create the barrel. I assume it was rifled later.
It looked about as sturdy as the drain pipe under m y
bathroom sink The thickness of the steel was about a sixteenth of an inch if I remember correctly.

What were the Enfield rifle barrels like from that same period.

Dutch

Things Haven't changed? I think that a lot of things have changed in metallurgy, engineering, machining and especially in litigation in the last 160 years when it come to barrel steel. The commercial muzzleloading guns are a modern high carbon chromoly barrel steel probably 4140, that's why they can safely build a 15/16" .54 barrel. GM barrels are 1137 steel (Chromoly), That's why they can safely build 15/16" .54 barrel. In my last post, I stated that when I spoke to Rice about making a drop-in for my T/C hawken with his 15/16" .54 barrel, He didn't recommend it due to the dovetails and screw holes. That makes me wonder what barrel steel he is using. I believe it is probably 12L14. It's a carbon chromoly steel but it is alloyed with lead for easy machining. I believe that most if not all of the known barrel makers like Getz, Rice and Colerain to name a few make their barrels for kits and the traditional builders who use traditional tools i.e. files for their metal work so they're probably using 12L14. Sleepy Hill made their barrels from 4140 but they don't make them anymore. We in the U.S do not have a safety standard when it comes to muzzleloader barrels, european manufactures are legally required to proof their barrels and by coincidence most if not all of the commercial muzzleloader barrels seem to come from Spain or Italy. Would 12L14 barrels survive their proof standards? I sure don't know. Douglas no longer makes muzzleloader barrels do to litigation. I don't know what black powder pressures reach with 1,2 and 3F pushing a PRB, conical or shot load but I do know what the different barrel steels can handle (see below). Maybe wee need to stick to the .200 minimum wall thickness. I load my 12L14 barrels as thought they were made in the 1700's. I'd love to hear any BP load pressure data.

12L14
Tensile strength 78,300 PSI, Yield strength 60,200 PSI
1137
Tensile strength 108,000 PSI, Yield strength 76,100 PSI
1144
Tensile strength 108,000 PSI, Yield strength 89,900 PSI
4140
Tensile strength 148,000 PSI, Yield strength 95,000 PSI

 

[Eric Krewson]

I considered an IBS barrel for a Renegade I was reworking but went the Bobby Hoyt route instead on the old sewer pipe barrel I had, the same or better rifling as an IBS for $120 less in cost.

 

[Grimord]

I considered an IBS barrel for a Renegade I was reworking but went the Bobby Hoyt route instead on the old sewer pipe barrel I had, the same or better rifling as an IBS for $120 less in cost.

I have done the same Eric, although I have bought a few of the IDS barrels for Renegades when I found them cheap. I can always re-sell them if I get bored with them.

 

[bigted]

It seems like we have opened a can of worms here.

So just for clarification, why is it that green mountain barrels and the Italian makers AND their proofing houses and Colerain as well as the Rice barrels build barrels in 15/16ths inch and 54 cal? I for one do not hear of failures with these barrels. No splits nor explosions with resultant shrapnel injuries. No bad press that I have read.

I have read of good smiths boring the 15/16 ths barrels out to 54 as well and no bad press.

So I for one am a little in need of clarification on the concern over my fav cal 54 and my also my fav barrel diameter, 15/16 inch.

Clarification please. I am eager to learn.

 

[hinamanra]

It seems like we have opened a can of worms here.

So just for clarification, why is it that green mountain barrels and the Italian makers AND their proofing houses and Colerain as well as the Rice barrels build barrels in 15/16ths inch and 54 cal? I for one do not hear of failures with these barrels. No splits nor explosions with resultant shrapnel injuries. No bad press that I have read.

I have read of good smiths boring the 15/16 ths barrels out to 54 as well and no bad press.

So I for one am a little in need of clarification on the concern over my fav cal 54 and my also my fav barrel diameter, 15/16 inch.

Clarification please. I am eager to learn.

This is just my opinion here. I think that the legal requirement for proofing barrels gives the European makers some legal leg to stand on in court if they are sued, the barrels were proofed to a standard so the shooter must have exceeded that standard. Most of those barrels (T/C, Investarm, CVA, Pedersoli and the like) are shallow grove rifling for RB or conical compared to the traditional RB barrels being made for the kits and custom builders they are deep round and square bottom grooved around .003-007 deeper so there's a bit more meat to the fore mentioned barrels.
I think that GM Barrels, and this is just a guess use the steel that they use because they don't just make barrels for muzzleloaders and they probably use this steel in a lot of their other products.
As far as the barrel makers who are using the 12L14 steel every one of them caution you on the depth and placement of dovetails and screw holes. They also publish load data with max loads.
You're right about not hearing too much about barrels exploding, All the ones I've heard of turn out to be shooter error, mostly a unseated ball or barrel obstruction but almost always starts out to be bad barrel or bad manufacturing.
I've read quite a few post here about one of the top barrel refreshers turning down people who want their 15/16" barrel bored to .54 due to minimal wall thickness. Like I said just my thoughts.

 

[bigted]

Rite on. I have fired hundreds of 53 patched balls thru 15/16 barrel with never a bobble nor hickup.

Now having said this, I am a conservative loader and I NEVER overload my guns. I see no reason to do so AND like the recoil of moderate loads in my 54's AND I like the lower cost of moderate loads.

I generally shoot 70 or 80 grains 2Fg powder in my 54's and find my best accuracy therein. Power wise, I see little to non reason to load over 100 grains in the 54. My 62's get up to 100 grains 1.5Fg but they have a 1 1/8th octagon at the breech and I feel comfy shooting this greater charge.

 

[Leatherbark]

For what it is worth. The Pedersoli Blue Ridge in .54 caliber has a 7/8ths inch diameter barrel. It must be special steel?

 

[bigted]

Woww, that leaves only .1675 inch walls at 7/8 diameter unless my math is wrong. This is very little over 1/8th inch walls.

15/16 leaves .1987 inch walls (again if my math comes out correct). This is almost the .200 that is mentioned as being min side wall thickness.

My thoughts about a 58 cal with a 1 inch across the flats barrel being , figuring a .584 diameter groove Leaves .208 for wall thickness. I had thought this is an ideal barrel for a light weight yet sturdy rifle barrel.

 

[Dick Sargent]

I'd like to point out that the alloy 1137 doesn't contain any chromium or molybdenum. In fact it is what most metallurgists would call in the modern world of steels a simple medium carbon steel. Here taken from the AZO online metals site is a breakdown of the alloy.


Chemical Composition
The following table shows the chemical composition of AISI 1137 carbon steel.

Element Content (%)
Iron, Fe
~98
Manganese, Mn 1.35-1.65
Carbon, C 0.32-0.39
Sulfur, S 0.08-0.13
Phosphorous, P 0.04 (max)

 

[Dick Sargent]

Please Hinamanra, Learn your ASIA/SAE steel designation # before you start to attribute elements to different alloy # like 1137 and 12L14 neither of which have chrome or molybdenum in them. Here from wikipedia is the beginning of your research.


Major classifications of steel[2]
SAE designation Type
1xxx Carbon steels
2xxx Nickel steels
3xxx Nickel-chromium steels
4xxx Molybdenum steels
5xxx Chromium steels
6xxx Chromium-vanadium steels
7xxx Tungsten steels
8xxx Nickel-chromium-molybdenum steels
9xxx Silicon-manganese steels

 

[bigted]

Mr. Sargent, you just went way above my pay grade!

 

[hinamanra]

Please Hinamanra, Learn your ASIA/SAE steel designation # before you start to attribute elements to different alloy # like 1137 and 12L14 neither of which have chrome or molybdenum in them. Here from wikipedia is the beginning of your research.


Major classifications of steel[2]
SAE designation Type
1xxx Carbon steels
2xxx Nickel steels
3xxx Nickel-chromium steels
4xxx Molybdenum steels
5xxx Chromium steels
6xxx Chromium-vanadium steels
7xxx Tungsten steels
8xxx Nickel-chromium-molybdenum steels
9xxx Silicon-manganese steels

Please Hinamanra, Learn your ASIA/SAE steel designation # before you start to attribute elements to different alloy # like 1137 and 12L14 neither of which have chrome or molybdenum in them. Here from wikipedia is the beginning of your research.


Major classifications of steel[2]
SAE designation Type
1xxx Carbon steels
2xxx Nickel steels
3xxx Nickel-chromium steels
4xxx Molybdenum steels
5xxx Chromium steels
6xxx Chromium-vanadium steels
7xxx Tungsten steels
8xxx Nickel-chromium-molybdenum steels
9xxx Silicon-manganese steels

I meant to say carbon not chromoly, That was a typo on my part. Long day.

 

[nkbj]

About ten years ago or so I happened into a slew of GM drop-ins and kept two of them for myself. One is a 20" fast twist fifty cal that was just too cute to part with and the other a 32" .58 round ball barrel. Since then I've moved a thousand miles away, put an addition and garage on the new place, planning a work shop and greenhouse, working nonstop and to this day I still haven't gotten around to sighting in that .58. Oh well, reckon I'll keep her oiled and some day...

 

[Dr5x]

WHAT IS AN IBS BARREL?
REMEMBER A LOT OF THE FORUM MEMBERSDON'T SPEAK IN CODE. ME FOR ONE.

DUTCH SCHOULTZ

I considered an IBS barrel for a Renegade I was reworking but went the Bobby Hoyt route instead on the old sewer pipe barrel I had, the same or better rifling as an IBS for $120 less in cost.

 

[Idaholewis]

WHAT IS AN IBS BARREL?
REMEMBER A LOT OF THE FORUM MEMBERSDON'T SPEAK IN CODE. ME FOR ONE.

DUTCH SCHOULTZ

Interchangeable barrel system. Green Mountain made these Barrels to be a Direct Fit “Drop in” Ready for the TC Hawken, Renegade. And a Few of the Investarms guns, But i am not sure of Models etc.? I can only speak for the TC’s, I own 4 of these IBS Barrels for them. These Barrels came completely finished, Under Rib, Thimbles, Ramrod, Nipple, Sights. Fully ready to go. I have seen a few that were not assembled, The parts were in a Plastic bag

 

[nkbj]

And a couple of decades back some were provided in the white.