Question regarding barrel wall thickiness and installing lugs.

[Rolf]

I'm working on a long barreled target pistol with a custom made Rayl barrel . The barrel is 15" long, caliber 0.40, 1:18 twist. I want to use barrel keys and place one key 5" from the breech and one key 2.5" from the muzzel.

• The wall thickness at the breech key is 0.135"
• The wall thickness at the muzzel key is 0.127"

Is it safe to cut dove tails 0.04" deep or should I just solder on the lugs?

Best regards
Rolf

[Jim Kibler]

I would believe .040 to be safe, but that is a little deeper than they need to be.  With just a standard milled or filed dovetail, you could get away with .030".  An even better option is to raise the dovetails with a cold chisel.  With this you can get away with .020" or perhaps just a shade more. 

[Don Getz]

I don't think .040 deep dovetails would be a problem in a pistol barrel, after all, you won't be shooting giant magnum
loads out of it anyway.    I somwhat disagree with Jim about "Upsetting" those dovetails to get a bett.er purchase on an
underlug.   I have seen barrels dimpled on the inside when using a chisel to upset the dovetail edges, especially on a thin
walled barrel.   I'm sure Jim could do it with no harm being done to the barrel, but, I have a lot of faith in Jim...he is a good
gunbuilder.    On the other hand, I replaced a rather thick walled barrel one time, had a dimple right at one of the dovetails, builder claimed it was a faulty barrel...........this was done by a well known,  "expert" gun builder.   ........Don

[Jim Kibler]

Heck I never gave upsetting dovetails much thought, Just cut them in with a cold chisel.  If you insist, Don, I'll say it's a skill I developed over years of hard work from now on   Seriously, if you practice on a piece of scrap material, I think you'll see it's really pretty simple and the chances of messing something up isn't too great.  Next time I do some, I'll take some photos of the process and post them.

[tpr-tru]

Mr. Getz,  would you give an opinion on the minimum wall thickness for a 62 cal smoothbore about 3 inches from the breechplug face.    Thanks

[Don Getz]

tpr.........wish I could give you an answer to that question, but, honestly, I don't really know.   We have done some 1"
barrels in 62 cal. smooth, which equates to .190 thick walls......never had problems with them, even had dovetails cut
into them.   You have basically asked me at what point will this barrel blow..........having never really pushed one to that
point, I don't know................Don

[wetzel]

Don,
How deep were the dovetails on that 62 caliber?  I would like to build a rifle using a 1" 62 caliber barrel but am wondering about how to attach the underlug or a staple. to the thin walls.

[Don Getz]

Wetzel..........I used to use a lot of staples, actually easier than cutting a dovetail.    I normally drilled the holes about
1/16" (.063) deep.   It is best to do the holes with two drills, one a normal drill, and the other with a flat tip to square up
the bottom of the hole.    I used Pete Allan's cast staples which come with a little foot on the bottom of each leg.   In
upsetting the metal around that foot, if you are doing it on a fairly heavy barrel I feel it is OK to use one of Pete's upsetting tool........shaped like a little horseshoe which you strike with a hammer and it pushes the metal in around the
foot on three sides.    When working on a thinner barrel, I used a smaller punch, about 1/16" square, and would punch
about 4 or 5 spots around the foot.   With this smaller punch it doesn't require a mighty swat with a hammer to upset the
metal.     As for dovetails, I only cut them about .050 deep since I make my own underlugs from steel about that thick.
If I use a commercially made underlug, I usually mill the base off to about .050, plenty thick for an underlug..............Don

[Dphariss]

I'm working on a long barreled target pistol with a custom made Rayl barrel . The barrel is 15" long, caliber 0.40, 1:18 twist. I want to use barrel keys and place one key 5" from the breech and one key 2.5" from the muzzel.

• The wall thickness at the breech key is 0.135"
• The wall thickness at the muzzel key is 0.127"

Is it safe to cut dove tails 0.04" deep or should I just solder on the lugs?

Best regards
Rolf

I would soft solder.
Either dovetails or expecially staples can result changes in bore dimension that can be felt with a lap or a tight patch of surprisingly heavy barrels.
I have stopped using staples for this reason.
Will this effect the shooting quality of the barrel? This I cannot say but it can't help.

Dan

[Jim Kibler]

There are obviously several methods that can be used to attach lugs.  Soldering seems to be popular today.  Done well, it will work fine, but I don't believe lugs were ever soft soldered to barrels during the original period in question.  A shallow dovetail with edges upset seems to be the standard and to me this is significant in the choice.  There's no need to be afraid of this method.  It really is quite simple and carries little risk for damage to a barrel.  Even thin walled fowling piece barrels often had shallow dovetails cut with the edges upset.  Just some things for consideration.

[bgf]

Jim,
If you get a chance, please take a picture and post a tutorial on how you upset a dovetail.  I'm afraid to try it, for reasons that Don mentioned, but I'm sure it would be the best way to get a secure dovetail without removing too much metal if done correctly.  I don't know who I would trust more than you as far as seeing how it is done correctly. 

[D. Taylor Sapergia]

Raising the barrel metal increases the holding power of the dovetail by a great deal.  Here's a picture of a rear sight by Jacob Kuntz - photo credit to Thomas Curran and Eric VonAuschwege - set in a raised dovetail.  The other picture is my copy of it.  You can see that the raised metal about doubles the dovetail's depth.

[wetzel]

Thanks Don