Hawken Breech Plug

[Beau]

I am building a half stock Hawken using a Dehaas 1 1/8x1 inch barrel, with most of the rest of the components from TOW.  I finally got the breech
plug mated to the barrel with no light showing between plug and barrel. Feeler gauge indicates proper fit.  Plug was blackened with a candle and the plug
shows a continuous  mark where it contacts the barrel.  I put about 2 ounces of oil into the barrel at the muzzle, left it overnight with a doubled paper towel
under the barrel muzzle (barrel in vise).  I checked it this morning and found a small amount  of oil on the paper towel which had not penetrated thru to the
folded portion of the towel.

What do you think?  Should I try to get a more perfect seal.

[Buffaload]

Contact is required at the face of the plug and the rifling as well as at the shoulder and back barrel face. If your seeing oil my guess is it’s not right.  If it leaks oil it will leak gas.
Ed

[D. Taylor Sapergia]

When you fit a breech plug, the face of the breech plug must contact the breech end of the barrel while the end of the threaded journal firmly contacts the bottom of the barrel's threads, at the same time.  There is no room for a feeler gauge.  I use felt marker to paint all surfaces, and check to see that they are sufficiently 'scuffed' when the plug is tight.  Do not over-tighten.

[P.W.Berkuta]

Remember this - the threads are not an interference fit they are at best 75% of full threads so there will be some gaps in the threads. The plug should mate up with both the interior and exterior of the barrel's surfaces. One or both of your barrel faces are not in contact -- should you try to refine your contact surfaces -- I'd remove the plug and try again it might just need a slight touch with a file. Good luck .

[Beau]

I appreciate the advice from each of you.  I am going to recheck everything and hopefully I can correct my problem.

[D. Taylor Sapergia]

Don't be tempted just to crank the plug in tighter.  When everything contacts correctly, and your flats line up, you are done.

[Gunnermike]

Beau, there is a tutorial done by Herb (resident Hawken master) on fitting a Hawken breech plug located at - http://americanlongrifles.org/forum/index.php?topic=10970.0

The tutorial is in the Tutorial Section on the main menu under Gunmaking tools and techniques - metal shaping.  Read it over a couple of times.    Mike

[Beau]

I removed the breech plug and did some more filing, installed plug, added oil, using another paper towel and left it overnight, muzzle up.

This morning, clean paper towel.  No leaks.



Thanks again for every ones help.   Jack