From one dilema to another

[draken]

You'll recognize this picture from my previous thread where I related how I somehow managed to drill my liner in the wrong place. (Still can't figure out how I could screw up that bad)......

I've decided to re-breach the barrel to move the vent closer to center.   I'd like to move everything back 0.125", but  my breach plug is  0.500"   If I remove as much as I want to from that, I'll be left with only 3/8" and I'm not sure if that's safe for a 50 cal. barrel.

[dannybb55]

Could you take out the vent and screw in a plug and file it flush, then drill a 3/16 vent in the right spot and call it done?

[Dennis Glazener]

I've decided to re-breach the barrel to move the vent closer to center.   I'd like to move everything back 0.125", but  my breach plug is  0.500"   If I remove as much as I want to from that, I'll be left with only 3/8" and I'm not sure if that's safe for a 50 cal. barrel.

I don't think I would want to shorten it that much. I have pulled originals that are that short but I don't shoot them! You might be ok but I personally wouldn't want to do it. One option is to tap one more thread in the breech. to do this you would need at least a bottoming tap and I suspect a tapered tap as well.

I believe if I were you I would open up the pan cavity and see how it shoots before I did anything else. I doubt there will be a problem with pan ignition.
Dennis

[smshea]

 If you are not happy with the way it is, I would just plug it and redrill as per Chuck Dixon's book....You ain't the first guy this happened to .
 If you take care you can peen the plug into any countersink you have, file clean and just redrill.  I would likely just drill a straight vent and cone from inside myself. If your browning/bluing the barrel you wont see it. It wont be a problem.

[bob in the woods]

Open up the pan. there is room to do that, and I think it is a good thing to do anyway. More surface to catch a spark. I wouldn't touch the plug, and I reallydon't think that the vent is a problem either. The more you fool with this the more likely you'll be fitting a new barrel, tang etc etc !!!  It'll work fine.
I'd just finish up and go shoot it   

[billd]

Don't take 1/8 of the breeech plug   Tap the barrel 1/8 deeper.

[JDK]

What Bill D said.  If you what to move the barrel back, you file the barrel not the plug.  Of course, you will then have to tap the barrel deeper to maintain the 1/2 plug length that is desirable.

If you know your thread pitch somebody here can do the math to tell you how much set back you will get with a full turn of the pug....so you end up on the right flat.

The tricky part then is going to be tapping it to the correct depth to have the barrel index on the correct flat....the one with the vent.....and having a good gap free breech.   I wish you luck.  J.D.K.

[Dennis Glazener]

Could you take out the vent and screw in a plug and file it flush, then drill a 3/16 vent in the right spot and call it done?

I suspect you mean 3/32nd but even that is a little on the large size. I use 1/16" to start with, then increase from there if needed.
Dennis

[Acer Saccharum]

I think it will shoot fine as is. You have excellent latitude, but just a bit East of the ideal.

Seen much worse. The worst is a hole low in the pan.

Tom

[dannybb55]

Could you take out the vent and screw in a plug and file it flush, then drill a 3/16 vent in the right spot and call it done?

I suspect you mean 3/32nd but even that is a little on the large size. I use 1/16" to start with, then increase from there if needed.
Dennis

Noted

[ottawa]

from the pic and other comments and from my own mistakes I would start with widening the pan and try it. that has to be easyer the rebreeching .
just a thought

[JDK]

Maybe he will be convinced yet but "just shoot first" was the overwhelming recommendation on his last string.  It seems he has made up his mind to move the barrel back.  To each is own.  J.D.K.

[Dphariss]

You'll recognize this picture from my previous thread where I related how I somehow managed to drill my liner in the wrong place. (Still can't figure out how I could screw up that bad)......

I've decided to re-breach the barrel to move the vent closer to center.   I'd like to move everything back 0.125", but  my breach plug is  0.500"   If I remove as much as I want to from that, I'll be left with only 3/8" and I'm not sure if that's safe for a 50 cal. barrel.

This is why people building guns should have at least a small lathe.
With a even a small lathe its possible to turn a shaft to just .001 under bore size for about 1/2" for a pilot then turn the second diameter to just under the tap drill size. File cutter teeth on the part that fits into the threaded hole so it will cut the breech plug hole deeper. Harden then use it to cut the hole deep enough to accept a 1/2" plug. This assumes the plug is on the same center and the bore... If the bore is off center compared to the plug it will not work with a pilot.
If you only shorten the barrel 1 turn of the threads, probably 1/18" inch if its a 5/8 plug you will still have 7/16 plug lenth and it should move the vent back .055. A smaller pan mod could then be done to center the vent in the pan. This also depends on if the breech plug has a 2 thread rebate at one end or the other this reduces the number of threads engaged. But reduces having to counter sink the breech of the barrel.
Proof the barrel with a standard load then a proof load of double service charge of powder, double ball and if nothing moves it should be OK.
Be careful seating the second ball check it 2-3 times 10 seconds apart to assure that the second ball has vented all the air and will not be pushed up by air pressure. Using a thinner patch on the second ball is a good idea too, lets air escape.

Dan

[Dphariss]

Maybe he will be convinced yet but "just shoot first" was the overwhelming recommendation on his last string.  It seems he has made up his mind to move the barrel back.  To each is own.  J.D.K.

He is the one that has to look at it. There is more to gun making than its going "bang" most of the time.
Its supposed to look like quality work as well.


Dan

[JDK]

Yes, I agree completely.  Just pointing out to others hoping we wouldn't have to read the same advice over and over again from the first string.  I take it his he has decided what to do after that post and now wants advise on setting the barrel back.  I would probably do the same as he as I would want it to look as perfect as possible, esp. since it is a gift for someone else.  J.D.K.

[frenchman]

is there not a thread about 2 hole vents maybe now is time to try it . The second hole would be just about perfect

[rsells]

You might  be able to get one of Jim Chambers locks that has the rectangular unshaped lock plates and shape it into a plate that is a bit longer in the back to move the pan forward.  Jim could possibly supply the uncut plate only and use your internals.  Not sure how the finished lock would look, just depends on how much its length has to be increased.  You would have to glue a piece of wood behind the pan fence to make up for the pan fence moving forward.  You would also have to make sure that the mortis area on the lock side has enough wood in front of the lock plate to take the longer part.  There could be issues with the trigger plate and triggerguard if the stock has been cut for the inlets.  Just some thoughts.
                                                         Roger Sells

[B Shipman]

@!*%, Frenchman stole my idea. Keith Casteel uses a double hole liner routinely. It'll work. No the placement  doen't look good. But hte fix is a safety compromise for the sake of appeareance.  In building, MARK the position of the center of the liner, then install the lock with that in mind, and THEN punch the spot in the perfect position and drill and install. Ideally the liner , INMHO, should just scratch the face of the plug.  But it'll work fine if you scoop out the plug as well.

[draken]

I'm sure glad I sought advice from the experts here before I went ahead and had at it.   This is a 50 cal. B weight barrel with a breech plug diameter of .750"  and if I make a (temporary) threaded insert to act as a tool guide and using a mill cutter tool held in a tap wrench to extend the depth of the cavity and then tap it.  

I know this gun will shoot in its present condition and if it were mine I'd widen the pan cavity and let it go at that.   But about twenty years ago I told my grandson that when he was as tall as a longrifle I'd make him one.   Well, he never showed any interest in shooting and I never made the gun.  Then he joined the military and discovered he had a talent for shooting, qualifying expert on every weapon he got to fire.   Last year he reminded me of the promise I made when he was six.    

It has been close to fifteen years, since my last build and I wish I'd gone ahead and built this rifle when one then, because in addition to now being arthritic, hard of hearing and failing eyesight, the skills I developed back in the twentieth century have become shaky at best.  
It sucks to get old.