Author Topic: 1" octagonal 20 gauge? (Read 1626 times)

Kurt · « **on:** August 30, 2025, 10:30:23 PM »

Could a safe 62 caliber/20 gauge flintlock Fowler be made from a modern steel barrel measuring 1 inch across flats at the breech? .190 +or-

Thank you.

smylee grouch · « **Reply #1 on:** August 30, 2025, 10:44:08 PM »

I'm sure they have been made. Are they safe??? $:-\$

reddogge · « **Reply #2 on:** August 30, 2025, 11:08:37 PM »

I just measured my Curly Gomstocki trade gun barrel from 1980 and it measures 1.025 at the breech, .615 bore at the muzzle, .080 wall thickness at the muzzle. It's very safe.

Daryl · « **Reply #3 on:** August 31, 2025, 02:47:00 AM »

Some of those Indian made muskets are 1" OD at the breech, and are .69 caliber. I've not heard of one blowing up, YET.

2 shots · « **Reply #4 on:** August 31, 2025, 03:56:47 AM »

I have a 20 gauge barrel made by armsport for their "hawken" its 15/16 ths. maybe call mr. Hoyt.

Kurt · « **Reply #5 on:** August 31, 2025, 06:33:07 AM »

15/16 across flats, 20-gauge would have a wall thickness about the same as three dimes stacked. If I did the math right.

One company that imports Indian made guns has a disclaimer saying that their products are for display only. People shoot them.

I read somewhere that the wall thickness at the breech of a muzzleloader is to be at least 200/1000s and would be with the common 1&1/8 inch fowlers. 1 inch across flats 20ga would be 190/1000, so close. Modern guns, a quarter-inch at the forcing cone.

I haven't found a 20 gauge barrel with a breech end smaller than 1&1/8" for sale.

2 shots · « **Reply #6 on:** August 31, 2025, 06:03:10 PM »

oh and i also had a toledo arms 20 ga. barrel made to fit a 15/16 t/c hawken.

Levy · « **Reply #7 on:** August 31, 2025, 06:19:16 PM »

Like 2 Shots, I have a 20 ga. barrel that was made by Sharon Rifle Barrel Co. to drop in a TC Hawken. It is 15/16" across the flats. I've used it some, but not a lot. I've also owned 1" .62 cal. rifle barrels by Montana/Orion barrel companies. James Levy

sz · « **Reply #8 on:** August 31, 2025, 11:40:54 PM »

"Safe" can be defined in many ways.
Keep in mind that modern 3" mag 20 gauge barrel are seldom over 1" at the breach and they use smokeless powder. But they also use ammo made by factories that control the pressures.
In the world of the muzzleloader it's very easy for someone to load a 10 ga load into a 20 Ga barrel, and there-in lays the potential for problems.

Safe can be more about shooters then barrels depending on who that shooter is

Bob Roller · « **Reply #9 on:** September 01, 2025, 12:19:47 AM »

If the steel is CERTIFIED as a material suitable for gun barrels.Jim McLemore who bought all of Bill Large's shop got his barrel material from another barrel maker who had ongoing contracts to furnish barrels for rapid fire cannons and 50 caliber machine guns.Other than McLemore I know of no maker of muzzle loader barrels who uses certified for gun barrels steels. Jim said he sleeps well and no worry about a call from a lawyer bout a bad injury from a blown up muzzle loader.
Bob Roller

Daryl · « **Reply #10 on:** September 01, 2025, 07:20:08 PM »

Seems to me I read that Jim Mc. uses 4150 barrel steel.

Bob Roller · « **Reply #11 on:** September 01, 2025, 08:20:25 PM »

Quote from: Daryl on September 01, 2025, 07:20:08 PM

Seems to me I read that Jim Mc. uses 4150 barrel steel.

That could be the number.I think the man making fast fire cannon barrels may have been named Obermeyer and Jim bought that same material from him.Most of Bill Large;s barrels were 1144 "Stressproof" and I never heard of one blowing up.I made lock tumblers from it and it machines easily and no problem contouring it and it hardens in oil like drill rod.I don't know if Jim McLemore is still active in barrel making and he is close to my age and I'm 89 and due to Lower back spasms little or no shop work will happen for me and it's bothering me now as I type this.
Bob Roller

HSmithTX · « **Reply #12 on:** September 02, 2025, 07:36:53 PM »

Boots Obermeyer made outstanding barrels, 22 cal up to artillery sizes. He made a lot of R&D barrels for agencies that can afford 'what if', dream it up and he could make it happen. Some of his personal interests were highpower and black powder cartridge rifles, and they shot extremely well. I lost track of him and some of his guys 15 years ago or so, not sure if the company is still in business or not.

Kurt · « **Reply #13 on:** September 02, 2025, 09:46:31 PM »

On your suggestion, I searched for Jim McLemore, and he is no longer making barrels and has a webpage to that effect. Colrain makes a barrel that is 1& 1/16th at the breech. I have a rifle I thought about converting to a 20 gauge, but I would have to file .032 from each flat, and I don't know if that is wise.

L T Grey · « **Reply #14 on:** September 16, 2025, 06:28:17 PM »

I purchased a 1 inch .62 caliber rifle barrel from Colerain to make a switch barrel for a TOW Kit Carson Hawken. It has a percussion patent breech. I've seen no issues with it. Bobby Hoyt opened up a 1 inch .50 Orion barrel to .62 for me and rifled it. Bobby said he's never seen a problem with a one inch .62cal, but won't go any bigger. That barrel was built into a flint hawken with a flint style breech plug. Again, no issues. Both barrels are 12L14. I would imagine that a smooth bore would create less pressure than a rifle bore in your case.

Daryl · « **Reply #15 on:** September 16, 2025, 10:59:32 PM »

If you have the old Lyman Black Powder Handbook, or can reference an online version, you will see that velocity and pressure are very close to equal, depending on which powder is used in each calibre.
That means that 2 guns, let's say a .54 and a
62, if both guns are using the same grade of powder & producing the same velocity, the pressure will be very close.
Thus, as an example, take 1,200fps. At that velocity, both guns will be produced ing the same pressure, even though the charges are very different to get that speed.
You can heck this with both 3F and 2F. The powder used was G.O. Gearheart Owens. The predecessor to GOEX AFAIK.
Thus, the larger the bore(lower the vel.), the lower the pressure with top loads.
You can even(with that books help), compare Brown Bess velocities & pressures with rifles of very much smaller bore. A correlation can be seen between vel. and pressures as long as the same granulation of powder is used.
Another example would be a .54 shooting it's ball at 1,550fps, using perhaps 110gr. 2F. My .69, to get that speed required 165gr. 2F GOEX. Both guns will be produceding VERY close pressures.

kutter · « **Reply #16 on:** September 17, 2025, 12:02:43 AM »

Just for comparison sake

I have a Parker VH in 20 ga. An early 19-teens mfg.

Standard Parker Armory Steel bbl (Trade name for the bbl steel was 'Vulcan Steel').
Not Damascus or a Twist Steel bbl. Nor anything like the 12L14 softy stuff being commonly used for many
M/Ldr bbls.
Gun Bbl Steel material.

The bbls measure 1.030 dia right at the breech. Remember that they are cut for a 20ga chamber for 2 1/2" out from there plus a forcing cone.
That chamber and forcing cone end at the very end of the bbl flats,,,3" from the breech. From that point is the standard 20ga bore diameter.

At that 3" point the bbl OD is .865.

The gun and many many like it shoot 2 1/2" 20ga standard pressure loads (smokeless). 8000/9000psi range
MAny people will handload them to lesser pressures to be kind to the gun, stock, and the shooter.

Just note for a comparison.

I have a Remington Model 17 20ga Pump shotgun as well that I can take the specs off of as it is apart right now.
It was made in the 20's. Steel bbl as well and a light weight shotgun. It has seen a lot of use.

Bob Roller · « **Reply #17 on:** September 17, 2025, 04:56:08 PM »

I started a comment about the use of uncertified barrel steels and it vanished.A WVa barrel maker who fortunately had liability insurance had to use it to save the business.He was quitting the black powder part when this happened because in that time period,anything made for a muzzle loader had to be cheeeep.My lock and trigger offerings were mostly rejected and I got a call from a German who asked for an example of my work and I sent him a lock made on the Chet Shoults external castings with an upgraded mechanism and that was almost as good as hitting a lottery for us.This man was Guenter Stifter in Trimbs,Germany and he connected me with Helmut Mohr in Mayen/Hausen and those two enabled me to keep the shop open.Certainly a more affluent market with a higher level of interest in both flint and caplock rifles and pistols.I give credit to L&R Lock Co.for being willing to sell ANY parts I needed for this German venture and I used a lot of their external flintlock parts and the caplock Schuetzen rifle plates and hammers.By 2019 I was tired of shop work and made only a few triggers and no plans to restart.Now closing in on 90 and my wife has health issues and is 82,the idea of not working has worked well.
Bob Roller

Kurt · « **Reply #18 on:** September 17, 2025, 08:46:09 PM »

Colerain has barrels advertised with 1" octagonal breeches turning to round in 20ga.

chuck-ia · « **Reply #19 on:** September 18, 2025, 05:33:29 PM »

I just bought a 1" oct. to round barrel from pecatonica 20 gage, said it is a rice barrel, no stamp though. chuck

Bob Roller · « **Reply #20 on:** September 18, 2025, 05:52:38 PM »

With the arrival of nitro based propellants the gun barrels HAD to be made from whatever material that could be relied on to stand the abrupt pressure rise of more potent powders.With the development of fully automatic fire called "machine guns"using high pressure ammunition the advance in gun barrel steels was accelerated.During WW2 Germany had their MG42 that had a rate of fire of 1200 shots per minute and 6000 of these were in place at Normandy.I know this is not the venue for WW2 history but advances in metallurgy made these terrible guns possible.A far cry from the soft iron barrels of the flintlock era.
Bob Roller

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Author Topic: 1" octagonal 20 gauge? (Read 1626 times)