lefty patent breach with a drum?

[gmerrell]

I'm building a hawken percussion lefty for my son . Since I can't find left patent breach, I'm going with a patent breach and drum.  My ? Is this, the powder chamber in the breech plug is only 1/4" the barrel is 40 cal. So should I drill out the powder chamber to say 3/8" so it's larger?

Thanks so much
Greg

[smylee grouch]

What size is the barrel across the flats? I think track of the Wolf used to sell left hand Hawken breech plugs. Muzzle loader Builders Supply also might have them.

[Bob Roller]

I'm building a hawken percussion lefty for my son . Since I can't find left patent breach, I'm going with a patent breach and drum.  My ? Is this, the powder chamber in the breech plug is only 1/4" the barrel is 40 cal. So should I drill out the powder chamber to say 3/8" so it's larger?

Thanks so much
Greg

Take it to 13/32 so it will be bore size and easier to clean.

Bob Roller

[gmerrell]

barrel is 13/16" with 5/8x18 threads.

thanks
greg

[P.W.Berkuta]

Take it to 13/32 so it will be bore size and easier to clean.

Bob Roller

barrel is 13/16" with 5/8x18 threads.

thanks
greg

I would not drill it to 13/32" --- Minor thread diameter of a 5/8" bolt is 0.555" -- 13/32=0.406 -- wall thickness at the bolts minor diameter is 0.555" - 0.406"  = 0.149" / 2 = a wall thickness of only 0.0745".

[P.W.Berkuta]

If you have a lathe or know someone who does & a 4 jaw chuck - make one --

[JB2]

whatever size you bore the powder chamber to, make sure you measure the powder chamber "volume" before the plug goes in the last time.  This will dictate the MINIMUM amount of powder to use.  Since the ball cannot go into a smaller-than-bore size chamber, using less powder will leave an air space, resulting in higher pressure.  Probably not too much of an issue with a .40, but safer is always better.

[gmerrell]

I love this site so much good info. Thanks so much.

[D. Taylor Sapergia]

Nice bit of machining, Mr. Berkuta.