breech plug face question

[juano2001]

Just recently put together an underhammer I picked up from blue grouse. I had to shorten the breech plug for my GM barrel that I was using in order for it to fit properly with the under hammer action. I did this using a grinder being as carefull as possible to keep the face square.

My question is should I find someone with a lathe to properly square the face up or will I be ok with the eyeballing/grinder job I did?

Cheers

 

[44-henry]

No need for a lathe, but eyeballing it probably won't do either. You need to have the face but up against the shoulder squarely and in full contact. One good way is to paint the face of your breechplug with prussian blue, magic marker will work also screw it in and see where it contacts, you should see shiny marks where it's rubbing. Carefully file these high spots away, repaint, and keep going until you see uniform bearing all around. Yes you will have a high spot in the center that will go into the bore a small distance, but this is what I strive for.

 

[CoyoteJoe]

Alexander is right, however I don't understand why you had to shorten it from the threaded end. Isn't the plug secured to the action with set screws? If so, the length of the protruding plug is pretty non-critical, it's really just a large bolt with the head removed. ::

 

[Darkhorse]

Obviously I don't understand the way underhammers are breeched.
"The breech plug is secured by set screws" ? Hmmmmmm?
"The plug is just a bolt with the head removed and the length is not critical"? Hmmmmmm?

Understand I have never examined an underhammer so someone please explain the difference between them and sidelock longrifles. Because fitting a breechplug to one of those is very critical and thread length is very important.

 

[Metalshaper]

Darkhorse,

I think the confusion, is in the wording..

The breech plug itself, is fit just like any plug. You have to make sure the seal is correct and all is tight. What I think you might have missed(?)was the statement the breech is fitted to the 'action' with screws.

On the underhammer I built for my son, the plug is fitted and a stub 5/8" diameter and about 3/4" long sticks out from the breech. this stub goes into the frame and is held by 3 set screws. as in this picture,,( you can see one of the screws, set back from the frame's front )

Unless I'm totaly jacked up :hmm:, I believe this is what he meant!

Respect Always
Metalshaper

 

[BS]

Metalshaper, you do nice work!

 

[Metalshaper]

Metalshaper, you do nice work!

BS,

Thanks! ::

its a clone ( of sorts ) to the H&A design, that MRW and I make these up in our shops. I never cared for the pins that go through the H&A frame, so I came up with the idea for the lockworks to ride on an insert. When I finally figure out how to engrave properly, we'll be able to dress them up a bit.

fairly easy to make. quick change feature for different calibers and the lock time is very fast. the picture shows the gun fully cocked..

Respect Always
Metalshaper

 

[CrackStock]

MetalShaper,

Do you make pistols also?

CS

 

[jimbo15563]

Metalshaper,

I'm looking a my H&A action from Blue Grouse (see my thread in the Builder's bench section - Jimbo's Underhammer). I have 2 breech plugs for it. One came with the action and the other I ordered from Bruce to accomodate the threading of a GM dropin barrel (which I subsequently decided not to use). I have ordered a custom barrel from Ed Rayl, and Dave, my gunsmith, will breech it for one or the other of these plugs.

The action is now by itself and the hammer is up (down?). With no barrel on and thus no nipple for the hammer to contact, the breech plug when inserted stops when it contacts the hammer. The plug barely reaches the Allen screws, leaving aboout 1/4 inch of unthreaded plug protruding out of the action.

I am assuming that the hammer should be at half cock when the plug is inserted and that the nipple will prevent the hammer from interfering with the plug. Thus, the plug will be able to go the whole way in to the threads. Is this correct?

My second question concerns removing the barrel for cleaning and then returning it to its orignal position before tightening the Allen screws. This is important because I plan to have an action-mounted peep sight. Rather than putting register marks on the barrel and action as Bruce suggests, do you think that small indentations could be machined into the plug where the Allen screws hit it that would guarantee a perfect barrel position?

Thanks,
Jimbo

 

[jimbo15563]

Metalshaper,

I think I answered the first question myself. Upon further inspection, the hammer is not what is keeping the breech plug from seating itself up to the threads. I believe that it's a slight imperfection in the hole in the action. Both plugs I have stop at the same place. I think it just needs a little polishing.

I'm still interested on the best way to insure that the barrel returns to its original position after it's removed for cleaning.

Jimbo