[mykeal]

These are the measure dimensions for those caps:

CAP I.D. Height
Rem 10 0.166” 0.175”
Rem 11 0.166” 0.154”
CCI 10 0.161” 0.163”
CCI 11 0.166” 0.165”
RWS 1075 0.165” 0.160”

What's your source for those dimensions?

[makos_goods]

mykeal,
Direct measurement of caps using pin gauges, an optical comparator or a toolmaker's scope (depends on the feature) and a caliper. Every picture and every model I show is mine, if they aren't mine you will know because I will always give the originator the credit for the work. The microscopy was using an Olympus scope with an SLR mount. I did the inspections and the photos right before Christmas. The model of the 1860 was started last summer. I also have an 1851 and a 2nd Model Richards model. I have been working on the project with Flint for a little while.

Those measurements are the average of ten caps of each flavor. The Remington caps are less than 3 years old (probably newer), The CCI caps were purchased no earlier than 5 years ago, the RWS caps are over five years old. The ages are important because Remington has changed their cap design in the last ten years.

I have a lot more photos and models of the caps as well.

http://i627.photobucket.com/albums/tt358/Mako_CAS/Files%20for%20Cap%20Gun%20Primer/CapAssy2b.jpg http://i627.photobucket.com/albums/tt358/Mako_CAS/Files%20for%20Cap%20Gun%20Primer/CapAssy1.jpg

http://i627.photobucket.com/albums/tt358/Mako_CAS/Files%20for%20Cap%20Gun%20Primer/CCI11v12c.jpg http://i627.photobucket.com/albums/tt358/Mako_CAS/Files%20for%20Cap%20Gun%20Primer/RWS1075Capc.jpg

Why do you ask?

~Mako

[mykeal]

I made these measurements using a caliper about 3 years ago.
http://i122.photobucket.com/albums/o254/mykealsm/Guns/CapSizes.jpg
Each number is the arithmetic average of at least 20 samples of each brand and size of cap; most of the individual measurements were repeated 3 or 4 times before recording the result. The opening diameter measurement was quite difficult as you can imagine, so I believe the error in those numbers is on the order of 0.002" and could be as much as 0.004".

I ask because a number of people have provided similar measurements on smaller sample sizes with differing results. I believe cap dimensions vary considerably from batch to batch.

[TheRodDoc]

Now I can see why the Remington 10 caps jam in my 1860 vs. the CCI 10's I use for my 1851. The Rem's blow apart. Even with no main charge in the chamber.
I haven't looked that them that close before.

The Rem caps have stress cracks from work hardening of the copper. CCI 10's don't. That would mean the rem caps are most likely more brittle and break apart more then the CCI's.
Those ripples are the remains of the tuck for shrinking the metal. Each ripple is an area that is thicker then the original disk they started with. Not for expansion.

What would be nice to know is the depth of powder in each brand added to the other measurements. That is what has changed since even the 60's.

[makos_goods]

Statistically speaking similar results even though there is a nominal shift in lengths. Actually I am impressed. Have you measured any other caps or just the same same five as I?

I will tell you that the Remington results I got this Christmas were different than what I had measured before. My old dimensions for both the 10s and 11s were probably same as yours. I'll dig up the data. The reason I remeasured was a couple of people on a different forum were getting different results so I took the new measurements.

Then I noticed this on the newer Remington packaging:
http://i627.photobucket.com/albums/tt358/Mako_CAS/Cap%20N%20Ball%20Questions/2a.jpg

They say right on the package they changed the geometry. Look at this photo of a Remington #10 cap that shows one of the reasons we get such a variation in the length of Remington caps:

http://i627.photobucket.com/albums/tt358/Mako_CAS/Files%20for%20Cap%20Gun%20Primer/Rem10d.jpg

The "petal" length of the skirts are left as formed and they are quite irregular. This is not an optical illusion or a result of the photography, notice how the one petal is noticeably longer than the other three. CCI and RWS trim and bevel the edges of the skirt. The populations I measured where more consistent in length.

~Mako

[makos_goods]

Now I can see why the Remington 10 caps jam in my 1860 vs. the CCI 10's I use for my 1851. The Rem's blow apart. Even with no main charge in the chamber.
I haven't looked that them that close before.

The Rem caps have stress cracks from work hardening of the copper. CCI 10's don't. That would mean the rem caps are most likely more brittle and break apart more then the CCI's.
Those ripples are the remains of the tuck for shrinking the metal. Each ripple is an area that is thicker then the original disk they started with. Not for expansion.

What would be nice to know is the depth of powder in each brand added to the other measurements. That is what has changed since even the 60's.

Doc,
The CCI and RWS caps have forming cracks as well. They all start out looking like the drawn Remington caps. CCI and RWS trim theirs which gets rid of the crotch area. The Remington caps are not harder, I had my metallurgist check them they are all almost pure copper and in the same hardness range. They start out fully annealed and If memory serves they end up about 1/4 hard. I can look at the report.

I don't understand your statement, "Each ripple is an area that is thicker then the original disk they started with. Not for expansion." Are you talking about the corrugations?

Remington used to trim their caps, after talking with one of their manufacturing engineers he admitted they originally stopped trimming as a cost saving step and then they realized it actually made the caps more versatile because they will fit on more cones. If you have been around the Treso cone discussions you will hear people swearing allegiance to both Rem #10 and #11 Caps. The guys at The House of Muskets make them and advertise them as being for #11 caps. The long skirts of the Remington Caps along with the I.D. being the same on both the 10s and 11s along with the he shallow taper of the Treso cones "allows" both to work.

Rem 11s actually fit better, but you can seat a #10 with a push stick. Quite often the caps will split slightly at one or more crotch point allowing the tighter cap to fit. That is actually the "secret" improved geometry of the current Remington caps.

I notice you said the #10 Remington caps you use on your '60 will split with merely a hammer strike. You didn't say which cones you have on that revolver but I will guess factory original which have a greater taper. I would council you try #11s, I believe you will have better results. Do yu ever get misfires with the #10 caps?

All caps may split and flatten with the back pressure coming back through the flash hole. This of course assumes you are using a charge above 25 grains of BP in a '60. The Remingtons as you might imagine split right at the crotch and open up like flowers. The CCI and RWS caps ususlly have a more jagged flattened appearance.

Oh, and I actually know the thickness of the priming compound in each brand along with the composition of the bursting disk on the Remington and CCI caps. I can speculate what the RWS sealant is based on what I learned from the guys at CCI.

Regards,
Mako

[TheRodDoc]

I have a Uberti 1860 made in 2007. The rem 10s fit by a easy push on fit with my thumb. The 11's are loose and will fall off. Nipples are factory.

The CCI 10's are a perfect on my 1851 colt. The caps split on one side only and always the same. Never a fragmented one. Of 300 shots, they all looked like these I picked up. 20 grain load of GEOX. (photo below) They all fall of the nipple right at the loading gate. Couldn't ask for a better performing gun.

http://www.theroddoctor1.com/1851colt/Dsc00004.jpg

[makos_goods]

Doc,
Looks like you have a good combo there. 20 grains is a great load in a Navy model. Nice and accurate, low pressure, a martial load in a .36 caliber. Fall off right where the design intended.

In a '60 with a heavier ball and more powder you will probably have them open up a bit more. It's hard to tell from your photo, but it looks like you may have less than 100% retention on a few of those caps.

If you take a CCI cap and inspect it under a scope you will find forming cracks on them especially on the outside, they tend to be hidden by the corrugations and the smearing you get from the rolling operation. If you mark then with a Sharpie you will find the split you get on the caps correspond to one or more of your previously identified cracks.

Please be careful seating those caps with your thumb. I can show you a picture of a friend of mine who has a "percussion cap thumb." Noz, Hellgate and others on the forum would recognize the photo. We always use cappers and a push stick instead of one of our digit.

Regards,
Mako

[TheRodDoc]

I do use a inline capper. The thumb thing was just to explain how easily they fit on the nipples.

Here is 4 caps from the Uberti 1860. 2 on the right were fired with no BP in the chamber. Just to clear nipples.
2 on the left were fired with fully loaded chambers.

Rem no. 10 caps. Both blew open about the same.
Rem is over loading the caps I would say. These are new caps. That say NEW - HOTTER CAPS - 40% more flame volume. I say they should have went the other way with less.

137544

[SleazyRider]

Thanks, gentlemen, for that data! Being new to black powder revolvers, I haven't given much thought to caps and cappers, always assuming that the thumb is normally used. May I ask a novice question or two?

Is it logical that one should first determine which brand and size cap to use by seeing how they fit the nipples without charging the cylinders, and then purchase an inline capper based on the brand and size? Also, are these caps really that sensitive that thumb pressure alone can set them off? Yipes! I've been capping my Thomson Center Hawken for years using my thumb, having no idea that this practice was hazardous.

Again, my thanks for the information!

[mykeal]

Have you measured any other caps or just the same same five as I?

That's all the data I have.

[Geneseo1911]

This thread is a prime candidate for stickyfication. This is one of the most confusing parts of trying to get set up with a new BP revolver.

FWIW, I recently got a Pietta Remington, and the RWS 1075s fit like they were made for it, while new Remington #10s fall right off. I can't help any more than that, as that is all I have ATM.

The good news is that if I can't find RWS, I have some data to make an educated guess as to what else is likely to work. Thanks!

[Vermonter]

This is the first I've heard of caps going off with thumb pressure. Scary.

I've been having good luck with both Rem #10 and #11 on my ROA, although I don't have a lot of rounds through it yet. 777 3F 35g under conicals or 40g under roundballs. Will try a bit more when I get my two deepened cylinders :)

[AbitNutz]

Yee....so I've been thinking of some kind of widget to fully seat the caps on my ROA. Seeing how I need my thumbs for other things...(don't ask). I guess I'll think a little harder and a little faster.

Thanks for the info...

[mykeal]

I can show you a picture of a friend of mine who has a "percussion cap thumb." Noz, Hellgate and others on the forum would recognize the photo.
Indeed, I probably would. I'm really glad to finally find someone who can put a face on that photo. It's the only incident I'm aware of where someone was injured in such a manner.

In a former life I had occasion to provide safe/arm designs to the various service weapon safety boards for approval. As you might imagine the chemistry of the elements in the explosive train was of great interest, and while I'm not a chemical engineer I did learn a few things about the various materials used. IIRC the lead styphanate used in modern percussion caps is quite sensitive to heat and static electricity, but only mildly so to impact. The primary feature making it the compound of choice in modern caps is that unlike the fulminates and azides it does not react with the copper in the caps.

Anyway, I recall that impact sensitivity of lead styphanate was defined by a fairly large 'delta dirac', or impact, function - that is, a sharp blow of some significant magnitude, as opposed to a longer time history like someone pushing on it. That made it very, very unlikely (the safety engineers never say never) that someone pushing a cap on a nipple could set it off. Your friend's experience is the refutation of that and lots of people would like to know about it. Would your friend be willing to provide details of the incident, like where and when, what caps, firearms, etc. were involved?

[Hellgate]

http://www.cascity.com/forumhall/index.php?action=dlattach;topic=1620.0;attach=855

The above photo is from Cuts Crooked hisself.

[arcticap]

Research was posted that specifies the impact sensitivity of lead styphnate.

http://www.thehighroad.org/showpost.php?p=5668534&postcount=28

Based on a test using a 2 kilogram weight (4.40924524 lbs.), the impact sensitivity of lead styphnate is 3 inches.

The Ruger ROA manual warns about the use of excess force when seating caps, and some BP clubs only allow percussion caps to be seated using a push stick.

http://www.thehighroad.org/showpost.php?p=5668360&postcount=23

[SleazyRider]

Gentlemen, I can't thank you enough for your contributions regarding percussion cap safety. I hope to be shooting my revolver for the first time when the weather warms up, and it looks like I've got quite a bit to learn. You may have saved me a thumb or finger!

[mykeal]

Based on a test using a 2 kilogram weight (4.40924524 lbs.), the impact sensitivity of lead styphnate is 3 inches.
Interesting. But I already knew that. What I don't know is whether the human thumb is capable of generating the shock load described by dropping a 2 kilo weight from 3 inches. The key to the answer is the time history of the shock function, not the amount of force - generating the equivalent of 2 kilos of weight with your thumb is easy, but doing so with the same time history so that the impact requirement is met is another thing altogether, and that's important to lead styphanate. I am doing some research on that but so far haven't had much luck. I'll keep trying and report back if I find anything.

By the way, my goal is not to prove that using your thumb is safe, although at this point I generally think the anecdotal evidence is on that side. I'm trying to gather enough information on the physics to at least build a good case one way or the other.

[AbitNutz]

Capt Baylor's page shows him using a piece of stag antler to fully seat the cap on his ROA after he caps it using a Ted Cache snail capper.

After seeing the above picture of what can happen to a thumb when a cap goes off under it....I'm definitely finding some unique, clever, good looking tool to do this.

[mykeal]

http://www.cascity.com/forumhall/ind...0.0;attach=855

The above photo is from Cuts Crooked hisself.

I find that I can't contact Cuts Crooked to interview him without first joining the cascity forum membership; since I'm not a cowboy action shooter that seems at least disingenuous, if not downright unethical. Would someone who is a member be willing to pass my questions along?

Where and when did the incident occur?
What brand and size of cap was being used?
Approximately when were the caps purchased - an estimate of the year is good enough.
How well did the caps fit the nipples - were they loose or tight?
Were there any misfires with that batch of caps on that gun?
What gun?
Was the nipple OEM or aftermarket, and if so, what brand?
For the next question - I'd like to make a distinction between just installing a cap and seating one: installing means just placing the cap on the nipple with little or no force, and seating means deliberately forcing the cap down on the nipple cone until it's clearly resting on the top.
Was it your standard practice to simply install caps or to seat them?
Was the technique you used in this incident the same as your normal routine or was it unusual in some manner?
If it was unusual, what was unusual about it?
If it was unusual, why was the departure from routine necessary?
Describe the technique that lead to the cap going off - was it a 'jab', a gentle push, a heavy push, etc.?

[makos_goods]

since I'm not a cowboy action shooter that seems at least disingenuous, if not downright unethical.

I've read some interesting posts in my time, I believe this might be the new all time champion.

I tell you what mykeal. Send me a PM with a good email address and I'll sent it to Cuts. Cut's isn't just a member over on CAS City he is the respected and long time respected moderator of the Darksider's Den on that site which is the equivalent to this BlackPowder forum on this site.

This should be interesting...

Regards,
Mako

[arcticap]

As others mentioned in the previous thread, lead styphnate is sensitive to static discharge. It's listed as having a static discharge of .0009 joules.
1 millijoule = 0.001 joules

http://www.teledynerisi.com/products/0products_8td_page02.asp

A comparative list of the static discharges required for ignition of:

Typical ignition energies are:
0.017 mJ for hydrogen
0.2-2 mJ for hydrocarbon vapors
1-50 mJ for fine flammable dust
40-1000 mJ for coarse flammable dust

.02 mj is often below the threshold of human visual and auditory perception.

http://en.wikipedia.org/wiki/Static_electricity


Sparks can cause serious explosions because of the high temperatures reached in a spark. Methane and coal dust explosions have been caused by electrostatic discharges. The Hindenburg disaster has been attributed to spark discharge ...supposedly occurred when mooring ropes were dropped as it came in to land in New Jersey in 1937.

http://en.wikipedia.org/wiki/Electrostatic_discharge

The premature ignition of a percussion cap when hand seating is so rare that the odds would seem to be less than a person being struck by lightening. The gun club mentioned in the previous thread found 3 possible instances of it having occurred.

http://www.thehighroad.org/showthread.php?t=452938

[CharlesK80]

On the issue of a "clever" cap seating tool, I have found a number 2, chinese yellow, Ticonderoga lead pencil to be just the ticket. Eraser end doing the soft work. Unsharpened, naturally. Or you may opt to glue an appropriate sized spent brass cart case to the non working end. Polishing the brass may enhance the item.

As an option, I have flipped the in-line capping tool end for end and used the ball end to seat the cap. When I could not find the pencil.

[45-70 Ranger]

Well done gentlemen. This is a fine example of how many of us will go the extra mile so to speak in our sport. This is informative, of great interest, and most of all, points out not only dimensions, but safety as well. Well done indeed!

Wade

And yes, this would be helpful as a Sticky...

[grxy]

Primers are much more sensitive to friction than direct
pressure. Thus if there is any twisting motion when trying to seat
a cap it is more likely to go off. Or, it the primer some how got
on the sides of the cap instead of just in the bottom there could
be friction when pressing it on. Its safest to use a dowel.

[mykeal]

Primers are much more sensitive to friction than direct
pressure.

That's very interesting. I've never heard that before. What's your source for that information?

[arcticap]

With all of the discussion about toy caps lately, there may be some confusion about the different properties between types of caps because they are made with different ingredients.
The toy caps made with Armstrong's mixture are extremely friction sensitive, but those aren't the same as modern percussion caps made with lead styphnate.

Armstrong's Mix

WARNING: THIS COMPOSITION, WHEN MIXED, IS EXCEEDINGLY DANGEROUS. IT IS VERY SENSITIVE TO SHOCK, FRICTION, AND ALL OTHER PHYSICAL OR ELECTRICAL DISTURBANCES

Armstrongs mixture is an extremely friction and shock sensitive mixture, that consists of a powerful oxidizer, such as potassium chlorate or potassium perchlorate along with red phosphorus. In consumer fireworks, potassium chlorate is used, since it is much more friction sensitive than potassium perchlorate.....

http://www.pyroguide.com/index.php?title=Armstrong's_Mix

[ZVP]

I've tried lots of brands of 10's and had little luck. Iust use #11's and pinch them into an oval and push them home with a wooden dowel. I have had best luck with Remingtons installed in this fashon.
I get constant ignition and very few ever fall off.
I wonder if a smooth or ribbed nipple is best tofor caps?
with a smooth the cap would fall off easily, with ribbs it would stay put and follow around the trough to be shaken free by the next shot.
Wish I knew the secret because it gets difficult when the caps go bad or if you cant get your normal brand.
ZVP

[makos_goods]

You have some strange ideas... What is a ribbed cone?

Caps should fit and not be pinched. Pinching causes a host of problems.

[CharlesK80]

Perhaps not so "clever" is the use of a bullet starter which is nothing more than a wooden ball affixed to the end of a 5 inch brass rod. Normally used to start a ball down the muzzle of a rifle. Really seats the caps nice n tight.

[351 WINCHESTER]

My ROA likes Rem. # 10's. CCI'S go to pieces.