barrel thickness under dovetails

[Reddog]

Hi guys, I was given this project that has had the dovetails already cut for the tenons, the barrel is a 45 cal Douglas, 13/16ths with the dovetails cut .125 deep,this only leaves .062 barrel thickness under the tenons at the thinest point, safe or scrap? I know that wall thickness on shotgun barrels is thought to be safe at.030 16 inches from the chamber, but have no idea on a long rifle barrel, any help would be greatly appreciated   Thanks, Bill

[Acer Saccharum]

The highest pressure on a blackpowder barrel is right at the breech, when the burning powder builds enough pressure to overcome the static bullet.

In my opinion, your barrel is fine. I'd never cut dovetails that deep, but it's not unsafe unless you do something stupid with your loading, but then, any barrel is subject to that caveat.

[jerrywh]

 I agree with Acer.  The pressure on that small area is so little I doubt if you could blow the barrel even if you tried. The surrounding area provides a lot of support and the Douglas barrel steel is very strong.

[Ky-Flinter]

Reddog,

That is some seriously deep dovetails!  Your barrel wall thickness calculation does not seem to include the depth of the rifling.  (And I came up with .056 not .062, then I still need to subtract the rifling depth.)

13/16 = .8125 - .45 = .3625/2 = .18125 - .125 = .05625 - depth of rifling = ?
 
Are all three tenon dovetails .125 deep?  Have the sight dovetails been cut yet?  I would be concerned with any/all the dovetails that are that deep, but especially the one(s) nearest the muzzle.  If the user of this barrel happens to short start a ball and forget to push the ball all the way down, the barrel has a good chance of failing at that dovetail.  See this previous report…. http://americanlongrifles.org/forum/index.php?topic=6386.0

If it were my barrel, I would “proof” fire it and check it over carefully before I built a rifle around it.

-Ron

[Ky-Flinter]

A further thought....  you mentioned you were "given" this project.  You could buy a new barrel for $150 - $200 and cut the dovetails properly, and you have all the stuff to build a nice rifle for only the price of the replacement barrel.

-Ron

[P.W.Berkuta]

A further thought....  you mentioned you were "given" this project.  You could buy a new barrel for $150 - $200 and cut the dovetails properly, and you have all the stuff to build a nice rifle for only the price of the replacement barrel.

-Ron

This is what I would do also -- why take a chance? If you sell/give that rifle to someone and it blows up and hurts them you WILL be sued and could lose everything you own -- my two cents .

[jerrywh]

 I will take the old one for $25.00

[bob in the woods]

Is this build for you, or someone else?   Personally, I don't see a problem with using it.
If for someone else, tell them what 's been said here, and see what they want to do.
Make sure that any short starter used is long enough not to leave a ball just short of the 1st lug. { just in case , but a good practice regardless ]

[RichG]

put 150gr 3f and a round ball in the barrel and light it of with some cannon fuse.(from a safe distance) if it bulges or blows up get a new barrel. If it doesn't then use and don't worry.

[smylee grouch]

I myself would not do what I'm about to ask but what would happen if you welded the dovetails full and recut them?

[jerrywh]

 Welding on it would make it more dangerous and probably warp it

[Boompa]

   I asked the same question last year. I have seen some factory dovetails cut scary deep and I had a gun with dovetails cut deep enough that the barrel wall was .072".  It was shot a bunch with no bulges, etc.

[Reddog]

Thanks for all the info guys I really appreciate all the feed back.