Breech plug question

[alex e.]

I think I know the answer to this but  I need some validation.
 I have a  6" smoothbore pistol  barrel, .50 caliber, octagon to round.maybe  3/4' at the breech. Is there any good reason why the breechplug needs to be 5/8" of an inch long? I'm using  a  "Becky" lock and there is NO room for my rear lock bolt at all,and touchole placement even with a direct drilled vent is poor. If i shortend the plug and rebreached the barrel to maybe less than a half inch it would work.
Now how short is too short? we are talking about a barrel which when fired will only have a charge of maybe 25 grains or so of powder patched loosely.

Thanks in advance, Alex E.

[Bill of the 45th]

I'm pretty sure you could go to 3/8"  A 5/8" 18 plug gives you 9 threads in 1/2" so 3/8" will give you 6 1/2 to 7 threads, more than enough of a safety factor, for a 50 cal smooth bore pistol.  Just my two cents.  If it were my build, I would do it without hesitation.

Bill

[FALout]

For years I just used what I bought for barrels, now it's automatic to just cut back to 1/2" and then fit the breach plug.  Fitted correctly, doubt you would have any trouble.

[LH]

You can drill a short ante-chamber into the face of the breech plug to meet with the touch hole liner hole too.  That will serve another purpose in eliminating fouling buildup on the face of the breech plug.  I breech all my rifles this way and you can get the lock precisely where you want it.  Cone the chamber hole out to bore diameter and dont leave any square edges or steps. 

[Swampwalker]

Hope your breech is larger than 3/4 inch.  If not, this means the wall thickness around your breech is only 1/16 inch!  Would perhaps consider a 9/16 inch breechplug.

[Dphariss]

Hope your breech is larger than 3/4 inch.  If not, this means the wall thickness around your breech is only 1/16 inch!  Would perhaps consider a 9/16 inch breechplug.

Exactly.

Dan