How far can a rifle barrel be safely bored out?

[TNVolunteerEngineer]

I just bought a Thompson Center Renegade percussion rifle in 50 caliber.  The octagon barrel measures 1.0115” at the breech across the flats.   I would like to have the barrel bored out and rifled in as large a caliber as I can, up to about 16 gauge if possible.  I would probably be perfectly satisfied at 20 gauge though.   Would anyone suggest a maximum bore size with plenty of safety margin. It will be used with round balls.

Allan

[omark]

my 62 hawken has a 1" barrel, but i wouldnt push it to a 16 gauge. consider 62 max for 1"   mark

[omark]

forgot to mention, may not be able to go that far and use the same breech plug, i dont know the diameter TC uses.   mark

[Dave Faletti]

Might be easier to get a new barrel and aftermarket breach plug to put together a new barrel assembly.  If you like how it turns out and have no use for the original barrel sell it.

[roundball]

I just bought a Thompson Center Renegade percussion rifle in 50 caliber.  The octagon barrel measures 1.0115” at the breech across the flats.   I would like to have the barrel bored out and rifled in as large a caliber as I can, up to about 16 gauge if possible.  I would probably be perfectly satisfied at 20 gauge though.   Would anyone suggest a maximum bore size with plenty of safety margin. It will be used with round balls. 

T/C's 1" barrel has been bored to .58 & .62cal no problem...and GM makes a 1" drop-in barrel for T/C Hawkens & Renegades and goes up to .62cal in theirs as well.
Ed Rayl will bore it out for about $65 as I recall...he knows barrels of course...simplest thing to do is give him a call and discuss...he'll confirm it one way or another right on the phone.

Ed Rayl Barrel Company
18 Otter Lane
Gassaway, WV  26624-1012
304-364-8269

[54Bucks]

 I don't want to burst anyones bubble but I wouldn't expect the TC to be a comfortable shooter in .62 cal.

[roundball]

No problem at all...had 3 GM .62cal smoothbore barrels in T/C Hawkens that I hunted heavily for a few years.
One Jug Choked Light Modified for small game, doves, crows, etc;
One Jug Choked Full for turkeys;
One with rifling added by Ed Rayl.

[Dphariss]

I just bought a Thompson Center Renegade percussion rifle in 50 caliber.  The octagon barrel measures 1.0115” at the breech across the flats.   I would like to have the barrel bored out and rifled in as large a caliber as I can, up to about 16 gauge if possible.  I would probably be perfectly satisfied at 20 gauge though.   Would anyone suggest a maximum bore size with plenty of safety margin. It will be used with round balls.

Allan

Leave it 50 cal. I would not exceed 54 in a 1" barrel.
The DOVETAILS and screw holes are also a limiting factor. You don't want the metal too thin at the dovetails.
You will not get 16 bore. Trust me you don't want the shoot a 1" barreled 16 bore anyway. .67 +.020 for rifling makes .690. 1" - .690 =.310 /2 + .155 If we tap the breech to 3/4 we have a wall thickness at the threads os .125. If we have .100 deep dovetails then the wall at the dovetails is .055. .580+.020 = .600 this give a .200 wall this then leaves .10 at the .100 deep dovetail.
Mine is 1 1/4 tapered and its plenty light at 30 inches. Round ball guns over .54-58 can make a lot of recoil.

If you want a large bore ML have someone make one thats shootable and has decent wall thickness at the breech and a 5x2" buttplate.

Dan

[Daryl]

I'm glad you brought that up, Dan - the dovetail depth is probably a HUGE restriction in allowable size. Too, the screw depth for the sightsand under ribs can also be a biggie.  On my wife's .36 Seneca, the rear sight screw had been drilled and tapped to only .040" thickness of steel to the bore. It reverse dimpled, then rung with normal shooting.  It had never been short started.  All the cuts and screw holes must be carefully measured to ensure your safety and that of others.

There could be a big difference between a GM barrel and a factory TC barrel as to material and workmanship ie: depth of dovetails and screw holes.

[roundball]

More than one owner of 1" T/C barrels have had them bored out to .62cal, no problem...

[Daryl]

Really? I wouldn't even consider doing that for fear of losing a hand. 

[buffalo]

Sorry slightly different topic,i have a 54, flinter in a greatplains lyman,shoots great ,is there anywhere up here(winnipeg, manitoba canada) i could send it to have a 62 drop in so that i could switch from one to other, if so would i have to ship the hole gun or just the stock an lock, thanks in advance

[roundball]

Really? I wouldn't even consider doing that for fear of losing a hand.  

Sounds like you may need additional information about how T/C and GM make their 1" barrels.
What do you base such a statement on?

It is not uncommon at all for people who pick up one of the odd-ball 1" T/C .56cal smoothbore barrels at a good price and have it bored out to a more conventional .62cal...another had a rusted/pitted 1" .54cal T/C barrel bored out to .62", the examples go on.

I myself even sent a 1" GM smoothbore barrel to Ed Rayl to ADD .012" x 1:72" rifling...and Ed won't rebore something that is improper or unsafe...turned down a request to make a GM 7/8"x.45 into a .54cal smoothbore as he said the thread area would be too weak.

[Daryl]

So - with all that, you're saying they don't drill sight screw holes or mill out sight and barrel wedge dovetails like they used to?  Is this true? If so, that's good.  I still wouldn't make a 1" 62 cal rifle barrel. Not enough steel for me.

[roundball]

What I know is I can post links to threads where individuals have posted they've sent 1" T/C Hawken / Renegade barrels off and had them bored out to .62cal smoothies by reputable barrel people like Rayl, and have been using them right on ever since.

GM 1" drop-in barrels use the same sight mounting that T/C 1" barrels do, and GM made production runs of 1" .62cal smoothbore barrels...excellent barrels.
As I've said, the best thing is to just call and discuss it directly with the barrel folks who do the boring work.

[Martin_G]

Thompson/Center uses 15/16" barrels for 50 cal and a 54 cal is a 1" barrel. The "BIG BOAR" barrel was a 1" 58 cal.

Also, the Lyman GPR barrels are 15/16" barrels in 50 & 54 cal.


HTH,

Martin