Fore and Aft Location of Vent Liner

[JCurtiss]

What is the preferred fore and aft location for the vent liner?

I have a ¼”-28TPI vent liner installed such that the root of the female thread is about 0.050” away from the face of the breech plug. This positions the center for the vent hole 0.175” from the face of the breach.

However, I’ve read where the vent hole is located tangent or even drilled into the breech plug.

So, I'm wondering just what is the optimum position of the vent hole?

Thanks!

Jason

[Mike Brooks]

I like the vent hole threads to brush the face of the breech plug.

[JCurtiss]

Thank you for responding Mike.

My vent hole threads are obviously not "brushing" the breach plug face, but hopefully I'll still get good service from the liner positioned the way it is.

I thought it was odd that many sources discuss the recommended vertical height of the vent liner, but not much is said about the fore and aft location.

Best,

Jason   

[flehto]

My first build which was my squirrel LR for 35 yrs and has the TH 1/8" in front of the plug face and through the yrs have had no problems w/ the amount of prime and its location.  After  swabbing the bore when hunting have  never had a failure to fire. It has a 1/4-20 SS set screw for a liner and the hex is towards the bore

Tried moving the TH closer to the plug face which req'd a funnel shaped relief in the face of the plug, but it wasn't  worth the trouble and didn't clean as well.

I now use a 1/4 dia  White Lightning liner and locate its center 5/32" from the plug face and again ignition is w/o failure.....Fred

[t.caster]

What Mike said, works good for me too. You will be fine with what you have, or you could drill & tap that hole for a larger 5/16" liner. And it has a slightly larger dia. inside cone.

[Hungry Horse]

I use the diameter of the ball as a guideline. The touch hole should be somewhere between the breech face, and where the ball would be it’s widest. This allows you to trickle powder in behind a dry ball load. I like the 5/16” white lightening liners the best.

  Hungry Horse

[rich pierce]

Good practical advice. On smaller calibers it could be challenging to get powder in behind the ball.

[JCurtiss]

Hey guys, thank you all for the advice.

Best,

Jason

[Jerry]

I use the diameter of the ball as a guideline. The touch hole should be somewhere between the breech face, and where the ball would be it’s widest. This allows you to trickle powder in behind a dry ball load. I like the 5/16” white lightening liners the best.

  Hungry Horse
Hungry Horse, If barrel dimensions (width permit) I like to go with the 3/8" White Lightening touch hole liner. When drilling for tapping, I leave the breech plug in. When tapped, I can just barely see traces of threads left from the tap.