20 Ga Pistol

[WALKERs210]

I picked up what appears to be a Tower Pistol that might have been a CVA kit from way back there. The barrel that is on the gun is nothing but a pipe that is plugged about 1 1/2 inch from the muzzle and the breech is open. The pipe/barrel is roughly 3/4 in O.D. and in no way will I even attempt to use it for anything other than to get measurements. Started looking for a replacement barrel but so far no real luck, so the wheels started turning. I have a brand new barrel from a 45cal Winchester in-line has the breech plug and has never been mounted much less fired. So it got me thinking of just cutting out about 10" of the barrel, boring it out for a 20ga or maybe 28 ga smooth bore. The breech plug can be sealed and fit in a safe manner but I can not find the dimensions for the INSIDE either 20 or 28ga. The barrel is Stainless so I trust that it will be more than enough to do what I want, but for the touch hole should I use an insert or just line up with pan and drill straight in? Thanks and I will appreciate any and all recommendations as long as they are serious and don't put my favorite person (me) in harms way.

 

[paulvallandigham]

28 gauge is nominally .550" Bore Diameter.

20 Gauge is nominally .615" Bore Diameter.

You want at least .020" of steel between the inside bore diameter, and the nearest point on the outside of the barrel, which includes both "flats", and dove-tails for hangers, or sight. Most .45 caliber barrels are too small to be bored out to .62 caliber( 20 gauge). Stainless steel does Not make a Barrel Stronger- in fact it can be softer, or weaker steel, than that used for most barrels. It might be wiser to simply turn over the existing barrel and ask a barrel maker to make you a new one of correct steel and caliber, with the outside dimensions intended to allow the barrel to be seated in the existing stock.

FWIW, it sound like you bought a "Wall-hanger"- a gun made of cheap materials, that is intended to be a wall decoration, and never was designed to be fired. If this is true, you will find more problems with the parts used in the lock, trigger, and other parts of the gun. This project could end up becoming a "money pit". Caveat Emptor. Have a gunsmith check this gun before you spend another nickle on it. :shocked2: :surrender: :thumbsup: :thumbsup:

 

[mazo kid]

I concur with Paul; you would be better off hanging that "gun" on the wall and getting a pistol kit from NSW.

 

[WALKERs210]

Called Deer Creek today and have all the correct parts on the way now. The only reason I thought about using the barrel I have is - well because its just sitting here collecting dust and I will never put together an in-line. Thanks guys for your input and info.

 

[matt denison]

[i]You want at least .020" of steel [/i]

:hmm:

excuse me but...

shouldn't the decimal point be further west?

.200"

yeah, that looks better.

 

[Joel/Calgary]

[i]You want at least .020" of steel [/i]

:hmm:

excuse me but...

shouldn't the decimal point be further west?

.200"

yeah, that looks better.

Maybe, and there are probably places where I'd like more for a minimum, but not near the muzzle. IIRC, the Birmingham Proof House allows as thin as .020" in shotgun barrels to still pass proof, but I cannot recall how far from the breech/breech-plug that has to be - 12"? 18"? - and that'd be very easily dented. For comparison, my 7lb 16ga modern flint double is around .035" at the muzzles, and my 4.3/4lb± Belgian 16ga hardware-store-grade caplock single with a "laminated steel" barrel is .080" at the muzzle and feels positively stout in comparison.

Regards,
Joel

 

[paulvallandigham]

Joe: Your answer is probably better than I could have given. The minimum thickness I wrote about comes from discussing the issue with several BP gunmakers, and was the result if reading an article in The Buckskin Report anout a replica Hawken style rifle that had the barrel rupture where a key slot was cut too deep in the bottom of the barrel. Compounding the problem, the grooves in that barrel were cut too deep, leaving less than .020" of metal between the bottom of the groove, and the slot! :shocked2:

I suspect that I have discussed this issue with just about every machinist, gumsmith, and gun maker I have met over the last 40 years, because I am always interested in their take on the subject, and whenever new steels are being used for barrels, its worthwhile considering if you can get away with a thinner barrel.

I have some VERY THIN muzzles on 19th century shotgun barrels , but as suggested, you will usually find more Metal around the barrel back towards the breech. Two Tenths of an inch is a LOT OF METAL, and I don't see that much metal in most breech loading shotgun barrels! :shocked2: My fowler was made leaving extra metal at the muzzle and rounded end of the barrel so that I could have the barrel jug-choked if I choose to do so. But, the rounded portion is slightly tapered from the wedding bands to the muzzle, leaving it much thicker back at the bands, and even thicker in the back, octagon portion of the barrel. Your highest pressures are going to be at the rear of the barrel, with pressures dropping as the powder burns, and the PRB or shot load moves forward towards the muzzle.

The problem with the gun that John Baird covered in The Buckskin Report was that it had two barrel keys, putting one of them only a few inches ahead of where the PRB is seated on a substantial load of black powder. The Weak spot above the key slot simply could not hold the pressure at that point, and the barrel ruptured. The stock was split, the ramrod broken, and the key blown out and bent. There was a long split in the bottom of the barrel, too, IIRC.

We are fortunate that today's barrels are made of modern steels, and that the steels chosen can pretty well anticipate "mistakes" by owner that would have blown up an iron barrel 200 years ago. Those mistakes can be contained by the new barrels. You might bulge these barrels, but its much less likely that the barrels will rupture and send metal and wood to harm or kill anyone.

The nightmare that barrelmakers live with is the guy who builds his own gun, without realizing that all those parts he buys have extra metal on them, so that he can file them to required dimensions, retaining a margin of safety. Unless you ask the question on this forum, as the poster of this thread has, or happen to read a forum like this one, ignorance can destroy weeks of work, and cause permanent injuries.

Its not the barrelmaker's fault that someone cuts their dovetail slots, or the grooves, too deep. :nono: :surrender: :thumbsup: :thumbsup:

 

[matt denison]

This poor fellow is talking about boring a .45 cal. barrel out to .62. Paul told him he needs .020" thickness to be safe. No one has brought up thickness at the muzzle, it's a non issue. Take five sheets of copy paper, it will be approx. .020" thick. Do you want to shoot a gun - any gun - with a barrel that thin? :nono:

How thick should it be at the breech? Two tenths of an inch + or - a few thou. Then taper to the muzzle as you see fit. If you can't keep the breech diameter that thick then it's time to change your perameter to a smaller bore or forget the project.

 

[BEP]

Two playing cards from a standard deck of cards measures just over .020. I'd want a lot more metal than that between me and an explosion.

 

[paulvallandigham]

I have owned shotguns where the muzzles were barrel the thickness of ONE playing card! And they shot just fine. However, the breech of these guns was much thicker than that thin muzzle. With today's steels, and straight walled, smooth bore shotguns, I would think that .100" of metal between the bore and the bottom of a dovetail slot will be sufficiently safe to shoot with BP loads.

The issue of safety is Not with how thick the muzzles are, but what kind of method is used to affix a sight(s) to the barrel, and what kind of hanger is used to hold the stock to the barrel. That is where care is needed to avoid creating thin spots in the barrel that will not withstand the pressures placed on the barrel. :surrender: :thumbsup:

 

[BEP]

"I would think that .100" of metal between the bore and the bottom of a dovetail slot will be sufficiently safe to shoot with BP loads."

Paul,you do realize that ".100" is five times thicker than ".020", right?

 

[Zonie]

Paul
I hate to disagree but one of the issues of safety IS how thick the muzzle is.

We are not talking about modern high strength steels heat treated to their maximum conditions for use in a gun barrel. We are talking about low strength low carbon steel so your easily dented one playing card thick muzzled shotgun has nothing to do with the gun being discussed.

As I've noted before, I personally think .020 is WAY to damn thin for any muzzleloader barrels thickness at a dovetail slot and to even dream of having a muzzle this thick, even on a muzzleloader is asking for trouble.