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Cap & Ballers: Wanna see how cap jams can happen?


Hellgate #3302 L

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I saw this on another board this morning. It is a Remington firing in slow-mo but you can see how the hammer actually "bounces" backward immediately after striking the cap as the early pressure builds to push back the hammer before the ball even clears the cylinder gap. You can see how a cap can get dislodged from the nipple during the rearward movement and drop right into the works (especially on a Colt). I've see lots of pics of perCUSSIN' revolvers fired in the dark but this is the first time I've seen the rearward thrust of the hammer clearly shown. This is why a heavier hammer spring keeps the cap down on the nipple as well as using nipples with smaller flash holes and/or side vents (Slix nipples) to reduce back thrust through the nipple.

 

This isn't the only way to get a cap jam (another is getting the cap caught in the Colt's safety notch on the hammer face and pulled off the nipple to be knocked off into the hammer cutout). You can sure see how using real heavy loads can blow the hammer back too.

 

I just thought it was educational to show the action of the gun each time it is fired to give you a visual feel of what's going on and maybe reduce cap frustrations.

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Prof.,.

 

It sure looked like that to me also. But it is probably just the time it takes for the cap spark to ignite the BP>

 

That was an impressive video and it surely demonstrates the need for either heavy main springs, better venting or a better designed nipple.

I'd sure like to see the same test with the new Slixshot niplle.

 

Ol'#4

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I've had percussion rifles where back-pressure from the main charge blew the hammer back to half-cock.

--Dawg

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Without the rest of the video the real question remains is whether the gun the fired caps jammed it as you claim.

He did not say the gun was jamming in this particular instance. He was illustrating how it can happen.

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The aftermarket nipples have a tapered flash hole. It dramatically reduces the back pressure on the hammer. 58's are the best at not jamming from dislodged caps. But it's cap and ball so no guarantee's.

 

The Colt notched hammer can be solved by filling in the notch with JB weld, per Larson Pettifogger's fix it series.

Ike

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I've had my Remington's jam (usually temporarily) by a spent cap getting blown off the nipple and preventing the cylinder from turning. Usually a quick partial turn of the cylinder on half cock by the off hand would rotate out the dragging cap and allow immediate resumption of shooting.


Seldom,

I have no clue as to whether the gun in the video ever jammed, I was just struck buy seeing the rebound of the hammer on a revolver for the first time on film. I've seen film and had percussion rifles have their hammers blown back to 1/4 cock but I just wanted to show others what most of us already knew about their pistols.

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Took me a while to figure this out some years ago...I was having horrendous cap-jam problems with some new Uberti 1851 Navy .36 revolvers.

I fuanally tumbled to the fact that the excessively large flash holes down at the bottom of the nipples were letting the hammer come back off the nipple cone enough to dislodge the fired cap carcass..This nearly always resulted in the blown cap being mashed under the hammer in the hammer slot, and causing at least a misfire on the next shot.

Installing better aftermarket nipples with flash holes about half the size of the factory stock ones cured the problem completely.

This was happening even with mild charges and plenty stout stock mainsprings.

If you look at the factors involved mathematically, Force (on the hammer face) equals Pressure (from the back blast thru the nipple flash hole which is a function of pressure within the chamber when the charge fires) times the Area of the flash hole itself.

F(lbs)=P(psi)xA(inches squared).

So if you have a stock nipple with a flash hole with a diameter of 0.042 inches (I measued a buch of mine at this dimension, ,plus or minus a few thousandths) versus a nipple with a (proper) flash hole diameter of 0.028 inches (new TRESO and Stainless aftermarket nipples), you can see that the Force on the hammer face to lift it is over twice as much with the larger flash holes.

Area = Pi x R squared or (D/2) squared, where D is the diameter in inches of the flash hole.

Area of a flash hole with a radius of 0.021 inches is 3.1416 x 0.021 x 0.021 = .0013854 square inches.

Area of a flash hole with a radius of 0.014 inches is 3.1416 x .014 x .014 = .0006157 square inches.

Irregardless of whatever the Pressure is within the chamber and thus presented to the hammer face, from this you can see that the Force will be a bit over TWICE as high with nipples with the larger flash holes as with the better nipple with the smaller flash hole at the bottom.

That is why th FIRST thing you do with an imported percussion revolver is to replace the nipples with better ones that not only have smaller flash holes, but cone taper that FITS modern production percussion caps properly so they seat tightly and won't fall off.

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At Hell On Wheels a couple of years ago I had a full auto double tap on one of my Pieta Remies. I had been using the conversion cylinders with the strain screw backed off and did not tighten it when I put the percussion cylinders back in. Fortunately, it was a double tap scenario.

 

It can happen.

 

CR

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  • 2 weeks later...

This is a tale of two 1851 Navys.

 

The first one is a Pietta new from EMF that was timed out of the box, correct arbor length (miracles can happen). The bolt narrowed a little to fit the smallest notch and added SlixSHot nipples. Never did fill in the safety notch on the hammer.

 

The second one is a Uberti bought from a pard on the Wire that has that notch filled in. Timing and everything on the Pettifogger checklist was great, it had the original main spring and Treso Nipples that I changed to SlixShot nipples.

 

I use Remington #10 caps with FFFg powder of modest charge size and a lubed fiber wad. There is a small gap from the ball to the chamber mouth.

 

 

 

Guess which one has constant cap jams?

 

 

 

Cap guns are not for the short tempered.

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At Hell On Wheels a couple of years ago I had a full auto double tap on one of my Pieta Remies. I had been using the conversion cylinders with the strain screw backed off and did not tighten it when I put the percussion cylinders back in. Fortunately, it was a double tap scenario.

 

It can happen.

 

CR

 

 

Yep, theoretically if the flash hole is large enough and the hammer spring light enough but still lights a cap it can go full auto on all 5/6 rounds. ones of these days I'm gonna give it a try.

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Yep, theoretically if the flash hole is large enough and the hammer spring light enough but still lights a cap it can go full auto on all 5/6 rounds. ones of these days I'm gonna give it a try.

 

These cylinders had the original Pietta nipples, which are reliable with #10 CCI caps. I have a light spring (for conversions), and usually tighten the strain screw when I go back to C&B. You can bet I did that as soon as I got to my cart! It was only a double, and it took a second to realize what had happened.

 

CR

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These cylinders had the original Pietta nipples, which are reliable with #10 CCI caps. I have a light spring (for conversions), and usually tighten the strain screw when I go back to C&B. You can bet I did that as soon as I got to my cart! It was only a double, and it took a second to realize what had happened.

 

CR

 

The problem is the original flash holes tend to wash out getting larger and larger. Change em.

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The problem is the original flash holes tend to wash out getting larger and larger. Change em.

 

That was a couple of years ago, now have Tresso nipples in all of 'em. Kinda wish I had tried the new kid on the block - might yet give those Slix Shot a whirl.

 

CR

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