.32 cal vent considerations

[JB2]

All this talk of vents got me to thinking of my current .32 'bunny gun' project.  It will be iron mounted, southern mountain style.  Are there any quirks to avoid with vent location in smaller caliber rifles?  I've run a couple of searches, but I haven't found anything yet specific to smaller bores. 

 This is an 'A' weight barrel, and maybe not HC, but it's what I've got.  The breech end is .950", so plenty of wall thickness (too much?).  It also looks like I'll have 7/16" of breech thread as it stands now.  Should the vent hole be far enuff forward to clear a liner, if it needs one in the future.  Also, would a coned vent be helpful with so much barrel thickness at the breech?  The 'coned' vent hole would definitely need to clear the breech plug as well!   I would think smaller bores would be less likely to erode out the vent than larger bores.  Also don't want the hole to be so far forward to risk ever being blocked by the patch with a lighter load, but I'm thinking a load that small would be almost useless.  Also, would a 'Nock' style breech have any advantages, or not needed or more problematic on such a small bore?  I'm a little less worried about this thing being HC internally, and more concerned with it working like it should.

I know, so many questions from a newb, but us newbs really do appreciate the help.

Thanks
Jim B

[HardBall]

I would think a patent breech would be a bit of trouble to keep clean on a small .32 as the antichamber would be pretty small, wouldn't it?

[Daryl]

The nock breech would be misplaced, I think.  A normal liner, 1/4X32 WhiteLightening would be perfect. Just make sure the outside counterbore on the side of the barrel allows the liner to seat properly.  If the chamfer on the outside is not deep enough, after cutting snd filing the 'waste' material off, there will be insufficient veb between the inner cavity and the pan. Other than that, which pertains to all rifles, no problems.  With a patent breech, the liner will be installed 1/2" or so ahead of the tang in the solid portion of the breech itself, not the barrel - placing the vent at the rear of the powder chamber, probably, no problems. I have just such a breech on my 1/2 stocked English style Fowler.

[dannybb55]

How about drill a touch hole and avoid all of the problems with drilling a 40 calibre hole into a 32 calibre bore.

[JB2]

And that was my first option in my original post.  But, a 1/4X32 liner is not .40", it uses a 7/32" drill.  My bigger concern is that I do have .32" barrel wall thickness at the breech.  That makes for a pretty long and narrow touch hole.  A touch hole that is internally coned or a  WL liner, will put the charge much closer to the heat of the pan flash.

[Daryl]

Jim, my .32 was built with a high lock with a drum. The resulting 1/4" X 24 hole in the side flat was too high to install a larger Whitelightening liner. Too, the resulting vent of a commercial 1/4x32 was way too high above the pan and caused ignition problems.

We solved the problem by making a new liner in 1/4x24 that was hollowed normally on the inside, then drilling the connecting vent hole upward on a slight angle to reach the inner chamber. The length of this hole is no more than .030", but it works - perfectly.

The same idea or method could be used if the vent runs too low- or maybe I'm not understanding the problem.

[D. Taylor Sapergia]

Your barrel wall, at the internal face of the breech plug, may be thick enough to allow you to install the liner without interfering with the plug's threads.  thus, the actual touch hole can be right adjacent to the face, rather than for'd of it.  I installed a Chamber's WL liner in my .50 Virginia rifle just that way, and it fires flawlessly, and flushes perfectly clean.

[Vomitus]

  Taylor,with that being said,"the touch hole can be adjacent to the face", a thinner walled barrel's liner will be forward of the breech face by the width of the liner? Do the threads of either the plug or the liner ever intersect? Newby question,sorry.
 Now if the vent is forward of the plug say an eighth inch,several more newby questions become apparent(to me). Lock/barrel/tang placement and ignition.
  Will ignition be any different with the vent adjacent to the plug then having it 1/8" for'd?
  Will the lock/barrel/tang placement change having the vent at the front of the plug? Hey Jim,sorry to jack your thread.

[JB2]

For Daryl, I don't have any problems, yet.  No touch hole-no problem?  I'm just trying to avoid anyting that I haven't yet thought about.  You guys are definitely helping me think this through.  Your words of high lock will have my hands shaking when I do drill for the vent/liner.  uh, thanks?  Mebbe that high drum/lock was to keep the powder dry, above the water-line?  Huh?!  Just kidding guys, all thoughts are appreciated.

Taylor, I guess I'm not getting a picture of that in my head (memory almost full).  Are you saying the touch hole went all the way to bore, but the liner diameter hole was basically a threaded counter-bore, with the liner seated on the bottom of counter-bore?

LB, your questions were some of the things I had bouncing around, too, but couldn't put into words yet.  I don't have tang or lock inletted yet, so those will work around barrel and vent placement (if I do my part).  I do have lots of thread for the plug (1/2" +), so that can be shortened up a fair amount to get the touch/hole lock further back if it looks too goofy.
 
Like Danny said, a straight touch hole would be reeeeaaaalllllyy simple.  Lots to be said for that!

So, waddya think, have we beat this to death?

[D. Taylor Sapergia]

This is the breech from my Chambers' Virginia rifle.  It has a 5/16" Chambers' White Lightning liner installed, and as you can see, there are about 2 1/2 threads (32 tpi) left that do not engage the threaded hole.  In other words, the barrel wall is thick enough to carry the liner without intruding into the bore, and the vent itself is 5/32 for'd of the breech face, which bottoms against the shoulder in this Rice manufactured and breeched barrel.  The plug is 3/4" x 16 tpi.  There is nowhere for fouling to build up, it is easy to clean by flushing thoroughly with cold water, drying and oiling.  Years later, the bore is as new after 1000's of rounds.  Ignition is as good as a flintlock gets.  There are no problems.
If your barrel wall is thick enough to carry the length of the thread journal of the vent liner, and be installed this way, it's the way to go, in my opinion.

[JB2]

heyhey Taylor!  That pic helps a bunch!  Now if I can just get such a precise placement!  Thanks again!

[Vomitus]

 Thanks Taylor. A picture tells a thousand words.