Flint plug with drum?

[Scota4570]

The next project is a Leman 1/2 Stock.  I'd prefer a hooked breech.  What if I make a flint style chambered plug with hooked breech, and add a drum?  I have a parts set already, it includes a lock with the drum cut out so I am a bit stuck there.  The scheme would allow the drum to be closer to the rear which is good. 

Anyone make an integral drum with the plug?  I've made Hawken style patent breeches.  The fake drum would be easier to shape and stronger Than the screwed in type.  .   

Any wisdom on 5/16" drum threads?  All my factory made drums are 5/16" NF.  Seems sketchy after the hole is drilled down the middle.  I also do not like skinny flash holes from a reliability standpoint.  I do fit my drums to be supported by the lockplate.   I mostly shoot targets in NMLRA club shoots.  IF the drum can come off and hurt someone that is not an acceptable risk.  Is there any reason to use  3/8" NF threads?  I am also considering buying some 4140 1/2" round stock to make drums. 

Am I over thinking this?

[bama]

Tip Curtis used to make a breech plug with a cast on bolster for a cap lock. I have never used one because I make mostly flint guns but it looked like a good set up.

[T*O*F]

What if I make a flint style chambered plug with hooked breech, and add a drum?

I have done several that way and actually prefer it to screwing a drum directly into the barrel.  The flint plug will have a greater sidewall thickness...hence more threads on the drum.

[okieboy]

 Not sure what parts set you have, but Leman locks generally have a cut-out for a 9/16" drum, not 1/2". Have you checked your lock's cut-out size?
 I like the idea of 3/8 NF threads and if you are turning your own, have you considered S7 steel?

[Bob Roller]

What T*O*F said goes for me too.

Bob Roller

[Scota4570]

You all are confirming my opinion, thanks.

I was just sizing up my parts.  I see that the 15/16,  54 cal barrel uses a 5/8 NF plug.  I did some measuring.  The bore is 0.558".  The minor thread diameter is 0.562".  That leaves a "shoulder" of .002.  There is no functional shoulder.  That means the seal is from grease and fouling.  Being an obsessive type should I will bore out the threads and re-thread to 3/4" NF?

On the other hand a 3/4" plug leaves 0.093" wall thickness around the threads.  How much is enough?

Anyone?

[mountainman70]

Yep , ditto T O  F sez. I prefer to do this also. Another plus, is if you get tired of the percussion gun, it aint so difficult to repurpose the barrel into a flinter. 

I would definitely prefer the 3/4 16 plug in a 54 and larger, if you have the safe room for it.
Have a goodun, Dave 

[Bob Roller]

You all are confirming my opinion, thanks.

I was just sizing up my parts.  I see that the 15/16,  54 cal barrel uses a 5/8 NF plug.  I did some measuring.  The bore is 0.558".  The minor thread diameter is 0.562".  That leaves a "shoulder" of .002.  There is no functional shoulder.  That means the seal is from grease and fouling.  Being an obsessive type should I will bore out the threads and re-thread to 3/4" NF?

On the other hand a 3/4" plug leaves 0.093" wall thickness around the threads.  How much is enough?

Anyone?

I would be very skeptical of a 3/32(.093) thickness.Who made the barrel and WHAT is it made from??
What about the breech plug? Does it have full depth and diameter threads or is it one with precast threads
freshened by a rethreading die?

Bob Roller

[Dphariss]

You all are confirming my opinion, thanks.

I was just sizing up my parts.  I see that the 15/16,  54 cal barrel uses a 5/8 NF plug.  I did some measuring.  The bore is 0.558".  The minor thread diameter is 0.562".  That leaves a "shoulder" of .002.  There is no functional shoulder.  That means the seal is from grease and fouling.  Being an obsessive type should I will bore out the threads and re-thread to 3/4" NF?

On the other hand a 3/4" plug leaves 0.093" wall thickness around the threads.  How much is enough?

Anyone?

Sell the 15/16 and buy a 1" breech barrel.
Dan

[Dphariss]

What if I make a flint style chambered plug with hooked breech, and add a drum?

I have done several that way and actually prefer it to screwing a drum directly into the barrel.  The flint plug will have a greater sidewall thickness...hence more threads on the drum.

This is better than in the barrel.
Still stuck with a cold rolled drum though. Unless one is shop made from better material. They must be fully supported or there is a very real risk they will break off at the thread rebate. Shoulders with no radius and the threads are stress risers and this stuff does not like such things.
We need to remember that the originals were made a more shock resistant material than cold rolled screw stock.
I would just use a patent breech. But thats me.....
Dan

[Scota4570]

You all are confirming my opinion, thanks.

I was just sizing up my parts.  I see that the 15/16,  54 cal barrel uses a 5/8 NF plug.  I did some measuring.  The bore is 0.558".  The minor thread diameter is 0.562".  That leaves a "shoulder" of .002.  There is no functional shoulder.  That means the seal is from grease and fouling.  Being an obsessive type should I will bore out the threads and re-thread to 3/4" NF?

On the other hand a 3/4" plug leaves 0.093" wall thickness around the threads.  How much is enough?

Anyone?

I would be very skeptical of a 3/32(.093) thickness.Who made the barrel and WHAT is it made from??
What about the breech plug? Does it have full depth and diameter threads or is it one with precast threads
freshened by a rethreading die?

Bob Roller

I was not clear.  IF I retread the 15/16 54 cal Green Mountain Barrel to 3/4" NF, there will be a remaining wall thickness between the flats an the the major thread diameter of 0.093"

Intuitively that seems thin to me.

If it matters, To do the internal threads I would bore them in the lathe then finalize with a bottoming tap.  I also put a chip breaker relief cut on the shoulder end of the threads that matches the internal thread major diameter.  The breech plug would be a flint style patent hooked type with a drum screwed into the side.  I would machine it from scratch out of scrap bin mild steel. 

I'm starting to gravitate toward retaining the 5/8 NF threads.  The shoulder between the rear face of the barrel and patent breech would be a perfect crush fit, thus making a seal.  The nose of the threads would also fit tight , of course.

Scot

[Dphariss]

If you have a lathe then go with 11/16-18. Get taps and dies from MSC online. This should allow re-tapping the 5/8-18 with little hair pulling and just some incremental tap grinding to get a good bottom threaded hole.
You are on your own with the drum. I won't use them.

Dan