Breechplug length problem

[Jerry V Lape]

Recently bought a barrel from a friend that has been sitting around for awhile along with a stock blank with barrel channel and ramrod groove professionally cut.  The breechplug threaded portion is 17/32" long (which moves the touch hole that much further forward but it is still not in contact with the shoulder within the bore.  Shoulder is approx. another 1/32" forward of the breech face.  My current plan is to set the barrel back by 1/16" and shorten the breech plug by 1/32" too.  That way will have a 1/2" breechplug in contact with the shoulder.  Have I got this figured out right.  The 1/16" off the barrel won't change the barrel  inletting noticeably. 

[Eric Krewson]

Nope.

[Ky-Flinter]

Eric,

Can you elaborate on why you believe Jerry's figuring isn't correct?  It looks right to me.

The breech plug threads are currently 17/32" long.  Removing 1/32", will make it 1/2" long.

The barrel breech threads are currently 18/32" or 9/16" deep.  Removing 1/16" from the barrel makes the breech depth 1/2".

The barrel will have to be set back 1/16" to contact the stock.

-Ron

[rich pierce]

I think you need to set a barrel back some multiple of 1/(threads per inch of the breechplug) if you want to keep the current top barrel flat on top.  So if 16 tpi, yes.  If 14 or 18 tpi, not exactly 1/16". 1/14" or 1/18". That's what I'm thinking.  If you don't care what flat is on top move it back the amount you want and line the plug up with whatever flat is handy.

[T*O*F]

You don't say if the barrel is straight or swamped.  If it's straight, you don't have to worry about all that math.  The inletting won't be affected.

[Jerry V Lape]

TOF the barrel is swamped and it a bit of a force fit into the inletting.  I am not to concerned about the minimal shift in width as it would be less than .004" difference - probably within the relief it needs anyway. 

Apologize for measuring error.  I measured everything again this morning and the numbers are a little worse than stated originally.  I will need to shorten the barrel by 3/32".  The plug is 9/16". 

Rich Pierce wouldn't I be able to mate up with the same barrel flat if the plug were left a little long and file fitted once the barrel was shortened and squared off? 

[rich pierce]

Jerry, where there's a will there's a way!  I suspect that would work.  I never had any luck filing the tang part of a breechplug where it meets the barrel, evenly.

[Ky-Flinter]

I never had any luck filing the tang part of a breechplug where it meets the barrel, evenly.

He shouldn't need to file that part of the plug, unless he takes too much off the face.

-Ron

[Herb]

See Tutorials, Metal Shaping, "Fitting a Hawken Breech plug by Hand" by Herb July 07, 2010.

[Dan Fruth]

If your plug is threaded 3/4-16 then removing 1/16 (.0625) will keep the breech plug in the same place...3/4-16 pitch is 1 turn in 1/16 inch..So removing 1/32 will put the tang 180 degrees from where it is now..I would sneek up on it and not take the total amount off, but move up on it slowly so you don't overshoot your tang rotation....Dan