venting a caplock?

[Cory Joe Stewart]

I am still studying up for an upcoming cap lock build and ran across another question.  In Peter Alexander's book he suggests drilling a vent hole either through the clean out screw or at an angle into the flash channel to relieve pressure. Have any of you tried this trick?

Coryjoe

[David R. Pennington]

I remember seeing that in the back of Dixie's catalog long ago, but I haven't tried it.

[Hungry Horse]

 That trick used to be standard information found in the back pages of Dixie Gun Works catalogs. A lot of target shooters did it years ago. Does it help? I think it does, but, I found it tends to not spread the cap much, which make them hard to remove if they fit tight on the nipple. You also have to think long, and hard, as to just where you want that expelled flash to go.

              Hungry Horse

[moleeyes36]

There is a vented nipple called the Hot Shot.  I haven't shot much percussion in years, other than shotgun.  However, I used to use these nipples and I though they might marginally spread the fired cap.  I don't know of what value they would be in relieving pressure.  If your gun is built right, kept in good working order, and loaded safely, excessive pressure shouldn't be a problem.  Of course the only real way to make a percussion gun right is to keep the butt plate and replace everything in front of it with a flintlock gun.   . 

http://www.trackofthewolf.com/Search.aspx?search=HOT-SHOT-RST

Mole Eyes

[Hungry Horse]

 The Hot shot nipple doesn't accomplish what the vented drum does. The Hotshot was designed to keep caps from getting stuck on the nipple after firing, not relieve the compressed air in the flash channel.

             Hungry Horse

[Cory Joe Stewart]

The hole is not in the nipple. It is through the clean out screw or the drum itself.

[shortbarrel]

i don't think this great site cares if it is a flint lock or a cap lock, they are all long rifles.

[JBJ]

I vent the cleanout screw with the idea that as the powder is poured in and the ball rammed home, compressed air is vented out the side and  the lack of back pressure perhaps helps to insure that the powder is free to enter the drum. I think that it facilitates a more sure/faster ignition but I cannot prove it. As Horse pointed out, target shooters used to do it (certainly in my area they did). A word to the wise, be careful what is allowed to come into close proximity to the vented drum - people or objects. That jet of fire exiting the vent hole is nasty.

JB

[JTR]

I vent the cleanout screw with the idea that as the powder is poured in and the ball rammed home, compressed air is vented out the side and  the lack of back pressure perhaps helps to insure that the powder is free to enter the drum.

That jet of fire exiting the vent hole is nasty.

JB

Maybe I'm just getting dense in my old age,,,, scratching head,,,. But back when I was shooting my percussion gun, I'd just shoot the shot, then put the lock on half cock and flick off the used percussion cap if need be. Then I'd go to loading again and when I pushed the load down the barrel, the air would just vent out the hole in the nipple with no problem.
Funny, but I never saw the need for a nasty jet of fire shooting out from some vent hole! In fact, I sort of thought of the muzzle as the primary vent hole!

What am I missing here?

John

[moleeyes36]

i don't think this great site cares if it is a flint lock or a cap lock, they are all long rifles.

Shortbarrel,

Of course they don't care and nobody should.  It's just part of the good natured ribbing that goes on everywhere in the ML world.  Shooters of smoothbores, flintlocks, percussion guns, full stocks, half stocks all kid each other.   As long as they have a lock on the side, a wood stock, and load from the front they're just fine.

Mole Eyes

[WadePatton]

i don't think this great site cares if it is a flint lock or a cap lock, they are all long rifles.

Shortbarrel,

Of course they don't care and nobody should.  It's just part of the good natured ribbing that goes on everywhere in the ML world.  Shooters of smoothbores, flintlocks, percussion guns, full stocks, half stocks all kid each other.   As long as they have a lock on the side, a wood stock, and load from the front they're just fine.

Mole Eyes

Yup, goes like this in cycling:

Beginners think 100-mile riders are crazy,
Roadies think mountain bikers are crazy,
Mtn bikers think Single-Speeders are crazy (one-gear, no clicky-clicky).
SS'ers say that FIXED gears are crazy (direct drive, no coasting/no freehub),
Fixies say the Velocipeders are nutz (the big High-Wheeler/Penny Farthing),
and we all think that (quite correctly)

Unicyclists are dippy!  (they has off-road uni's now too.) 


Flints and Rifles is my gig here. (And I've ridden all but the PF and Uni)
 
And I'm with John, what vent? Cap and snap!  I thought cappers gained velocity by not having an open vent.

 Only vent i want has a pan next to it.   

[retired fella]

Wade, I agree with you.  Why would you want to vent and lose velocity?  I guess it would give your shootin' neighbor sumthin' extra to think about with both of you standing on the line.  Used to shoot with a fella that had an oversized touchhole.  After a while he sort of faded away.  Don't think that it was done with malice but it was a bit aggravating.

[Topknot]

Fellows,the way peter alexander explained it in his book is that the percussion lock when fired is a closed system. It doesnt have a vent hole like a flintlock. To keep the hammer from raising up and venting out the nipple on heavy or misweighed loads and to maybe give the system another way of venting pressure on over loaded powder and also to keep the barrel from potentially blowing up . Just a little extra protection is peters reasoning. On some old english percussion rifles they had platinum plugs that would blow when pressure was too high, thus keeping the barrel from blowing up.
                                                       
                                                                            topknot

[Dphariss]

Venting a percussion is a waste of effort. The only thing it will do is make the percussion less water proof. Unless of course the design is deficient in some way.
Vented nipples.
These were invented (and early ads say so) to prevent hammers from blowing back to 1/2 or full cock on firing.
The reason this occurred was the cheap coil spring locks used on the  various Wal-Mart etc purchased MLs that had locks that did not function as a percussion lock should. Add to this the use of various bullets that greatly increased gas vented onto the hammer nose and the "need" was born.... Another fix for a deficient design.


Dan

[galamb]

Sam Fadala also suggests the same in the Lyman Blackpowder manual - with the addition that if you don't have a clean out screw, as is the case with many snail breeches, that you drill a small hole through the breech itself down into the channel.

Likewise, there are a number of old English rifles and shotguns that had a blow-out plug, some with a small hole in the center of the plug that was meant to pop out in case of over charge.

I only build and shoot "cap guns", all with patent breeches (snail or Allan drum style) and have never felt the need or seen the need to drill a hole anywhere.

A Hotshot nipple does help flare the cap upon firing (resulting in virtually no stuck caps) and use them anytime I can get away with a full length rifle cap, but agree, that has nothing to do with releasing any of the pressure when ramming the load down.

Keeping the cap off in that process, which is the safe thing to do, allows the pressure to escape unless your flash channel is all mucked up (which would tend to prevent ignition anyhow) - so again, don't see the need for the hole.

If you keep your charges "reasonable", you shouldn't need to relieve any pressure upon firing (JMO).

PS - while I have read Peter's book and noted that particular point. I have handled a number of his rifles, and while he rarely builds a caplock, the couple that I have seen I don't remember a hole in the screw - so maybe something he suggests that he picked up from someone, but doesn't practice himself ??

[Dphariss]

If anyone should doubt the deficient lock statement above then read Forythe's "The Sporting Rifle and Its Projectiles". Specifically his comments on "the heavy first lifting" of the hammer.  Or if you can find one cock a late English flintlock of good quality or a percussion of good quality (the lock guts are the same). Like a Manton or Rigby.  Its instantly apparent what Forsythe and myself are trying to explain. The cock/hammer should have the heaviest pressure with it in the down position and the lightest pressure at full cock, this is a great aid in getting a light trigger pull.

Dan

[Dphariss]

Sam Fadala also suggests the same in the Lyman Blackpowder manual - with the addition that if you don't have a clean out screw, as is the case with many snail breeches, that you drill a small hole through the breech itself down into the channel.

Likewise, there are a number of old English rifles and shotguns that had a blow-out plug, some with a small hole in the center of the plug that was meant to pop out in case of over charge.

I only build and shoot "cap guns", all with patent breeches (snail or Allan drum style) and have never felt the need or seen the need to drill a hole anywhere.

A Hotshot nipple does help flare the cap upon firing (resulting in virtually no stuck caps) and use them anytime I can get away with a full length rifle cap, but agree, that has nothing to do with releasing any of the pressure when ramming the load down.

Keeping the cap off in that process, which is the safe thing to do, allows the pressure to escape unless your flash channel is all mucked up (which would tend to prevent ignition anyhow) - so again, don't see the need for the hole.

If you keep your charges "reasonable", you shouldn't need to relieve any pressure upon firing (JMO).

PS - while I have read Peter's book and noted that particular point. I have handled a number of his rifles, and while he rarely builds a caplock, the couple that I have seen I don't remember a hole in the screw - so maybe something he suggests that he picked up from someone, but doesn't practice himself ??

The vented breeches on the English guns were to allow loading with the hammer on the nipple without the pressure pushing the wads back up the bore. Might find it on a rifle or two but in general rifles don't create as much pressure.

Dan

[Bob Roller]

Sam Fadala also suggests the same in the Lyman Blackpowder manual - with the addition that if you don't have a clean out screw, as is the case with many snail breeches, that you drill a small hole through the breech itself down into the channel.

Likewise, there are a number of old English rifles and shotguns that had a blow-out plug, some with a small hole in the center of the plug that was meant to pop out in case of over charge.

I only build and shoot "cap guns", all with patent breeches (snail or Allan drum style) and have never felt the need or seen the need to drill a hole anywhere.

A Hotshot nipple does help flare the cap upon firing (resulting in virtually no stuck caps) and use them anytime I can get away with a full length rifle cap, but agree, that has nothing to do with releasing any of the pressure when ramming the load down.

Keeping the cap off in that process, which is the safe thing to do, allows the pressure to escape unless your flash channel is all mucked up (which would tend to prevent ignition anyhow) - so again, don't see the need for the hole.

If you keep your charges "reasonable", you shouldn't need to relieve any pressure upon firing (JMO).

PS - while I have read Peter's book and noted that particular point. I have handled a number of his rifles, and while he rarely builds a caplock, the couple that I have seen I don't remember a hole in the screw - so maybe something he suggests that he picked up from someone, but doesn't practice himself ??

The vented breeches on the English guns were to allow loading with the hammer on the nipple without the pressure pushing the wads back up the bore. Might find it on a rifle or two but in general rifles don't create as much pressure.

Dan

 The easy way to vent a breech is to place the hammer on half cock.Works fine
and the compressed air will push the powder as close to the nipple as possible.

Bob Roller

[Turtle]

  I understood that venting was to allow the backpressure in the barrel to escape so the fire of the cap could get to the powder? Some shooters I used to shoot with swore it cured unexplained failures to fire.
                                           Turtle

[JBlk]

I have a cap lock that I vented several years ago because it wouldn't fire every time.I  accomplished my vent by drilling a 1/64 hole in front of the drum at a downward angle.The whole idea of the vent was to keep the cap you were firing to keep from compressing the air under the cap and thus letting the spark go to the main charge without interference.My rifle still miss fired so I decided that the hammer was not hitting the cap squarely even though it appeared to be doing so.I tweaked the hammer bend by eye sight and that solved the problem.

[Steve-In]

I have vented two rifles, both with good results.  Neither suffered accuracy loss and I could tell if there was velocity loss.  Both give quick reliable ignition.  I don't know if the hammer lifts on either rifle that would be a project for a high speed camera.
My wife's .40 would crud up in the breech area and require cleaning before going back to shooting.  After venting I do not remember a time when it did this.  She was happy with the results so that made me happy too.  My rifle is vented the same way.

[D. Taylor Sapergia]

AS far as I know, the Hawken bros never vented their breeches.  I have never vented a percussion rifle.  I believe it is a solution to a problem that doesn't, or at least shouldn't, exist.

[T*O*F]

the Hawken bros never vented their breeches.

Boy, that's a straight line if I ever saw one, but I will resist the temptation.   

[Mad Monk]

Going back to the 1980s.

We were faced with some black powder that could badly foul the passages in the percussion breeches.  Drum and nipple or snails.  I had problems with my flinters fouling inside the vent hole.

The idea of a vented nipple or a small hole in the snail's clean out screw or in the bottom of the snail was to allow gases from the firing of the powder to blow and built up crud out of the ignition passages.

I played with the nipples that had one hole covered by the cap and some with two holes.  The single vent nipples had no effect on muzzle velocities.  Those with two holes created velocity drops.

When I was playing with the vented percussion systems I had discussed it with the guy in Australia I was helping with his powder plant plans.  He had a very large collection of old original English sporting rifles he picked up in Australia.  He then took a closer look at them and found that most of them did indeed have tiny vent holes in the percussion ignition system.

During the 1980's and 1990's I was looking at ml barrels coming back into Chuck Dixons for replacement.  These were barrels that had to be replaced due to short-started ball firings.  Some simply bulged.  Others in numerous pieces.  Only one flintlock barrel failure was seen and this was because the rifle had been left loaded from one flintlock season until the following year.  Holes in the breech plug and big time pitting of the bore where he charge had been.  The rest were all percussion barrels.

That little vent hole in a percussion system will help prevent bulging and bursting in the event of a short-start firing.

Mad Monk

[Daryl]

AS far as I know, the Hawken bros never vented their breeches.  I have never vented a percussion rifle.  I believe it is a solution to a problem that doesn't, or at least shouldn't, exist.

Dave - lets print the WHOLE statement.  I wholly agree with Taylor and Dan - venting cap- locks today, is merely "a fix" for a cost cutting or manufacturing screw-up.

Some time ago (maybe 5 years back), I did an accuracy test comparison using new 'hotshot' nipples as opposed to a new standard stainless nipple, both from Track. My testing was with identical loads and performed at the range of a only 50yards.  Non-vented nipples routinely shot smaller groups, roughly 1/2" to 3/4" smaller.  Thus, I threw the Hotshot nipples away.  Had I attempted to find a load for this 'relieved' load, I suspect it would have eventually shot as well as non-vented nipples did.  It simply would have taken more powder, something many people seem loath to try, and ultimately accept mediocre accuracy.

The same steel nipple in my .69 now, perhaps 500 shots down the spout, the caps are very slightly spread after firing (as they were when the nipple was new and are easily removed after bringing the cock to 1/2 bent position - works for me.  After firing, I have to remove the spend cap, in order to reload the barrel, as the trapped pressure will push the ball back up the bore - sometimes 1/2 way. It is easily felt when running the ball down, as the pressure builds in a fluid fashion, becoming stiffer and stiffer.  

I stop, reach down and move the cock back to 1/2 cock, and as I do that - SHPEWW, out comes the trapped air as it blows the spend cap off the nipple. I then go ahead and finish seating the ball - usually silently chastising myself for forgetting to remove the cap before loading.