Touch hole placement

[Martin S.]

I am installing a white lightening 5/16 liner in a new build.

Rice barrel, breech plug seems to be right on .500.  Gotta love those guys at Rice.  It is right on the money.

Top part of liner (part that is sawn off) is .375.

Half of that is .1875

So, I do I want to put the pin punch mark at .688 from the end of the barrel?

Or do I add a few hundredths, for "mom and the kids" as they say in my business?

Would .700 from the breech be too far or within limits?

[Kevin Houlihan]

Martin,
 Measure the threaded part of the liner, and not the part that gets cut off.  The counter sink portion is bigger than the threaded section using that measurement puts the liner further forward than you need to.  5/16 should measure around .3125 - check yours to make sure.  Divide by 2 = 0.156.  Add that to the .500" for the breech plug plus a few thousandths and I would punch it at .660.  That should miss the face of the plug.  I like the lock to be as far back as I can get it.
Good luck,
Kevin

[TDM]

I’m sure you’ve already done this but what I do is scribe where the breech ends on the barrel face. Install the lock with the frizzen removed and scribe the top of the pan and the center of the pan. I drill the pilot hole right below the line at center. Then drill your tap size, I use an “L” for a 5/16” tap. Than tap and chamfer the the top as the liner flare required. I use a bore scope to make sure nothing is protruding into the bore. If it is, remove and trim/file as necessary. When it’s flush, inn no put a bit of RIG on the threads and tighten down. Then cut and file smooth.

https://ibb.co/zXkqbnq

[Martin S.]

OK, that makes sense.

[Martin S.]

Martin,
 Measure the threaded part of the liner, and not the part that gets cut off.  The counter sink portion is bigger than the threaded section using that measurement puts the liner further forward than you need to.  5/16 should measure around .3125 - check yours to make sure.  Divide by 2 = 0.156.  Add that to the .500" for the breech plug plus a few thousandths and I would punch it at .660.  That should miss the face of the plug.  I like the lock to be as far back as I can get it.
Good luck,
Kevin

OK, so measure the threads, not the cut off.  Thanks.