Sizes of Caps and Nipples

I am looking for relative cap and nipple dimensions for #10 and #11 sizes.

This issue came up when I shot my new Traditions KY pistol. The CCI #11 caps would fall off the nipple. It occurred to me that since this was a pistol, maybe I should be using #10 caps.

I went to the Traditions website and downloaded a manual. It did not list the required sizs but did tell me it had a M6 x 1.0 thread. I was also cautioned to use the proper size cap, but never thought to mention which one.

Do the #10 and #11 sizes represent a difference in physical dimensions in either the caps or nipples? Are they interchangeable?

That is a metric thread. You should be able to go to your local sporting goods store or gun store and purchase either #10 caps or a nipple that is sized for #11 caps. Also, A good machinist could drill the threaded hole out to a 1/4-28 thread. I know you can get a #11 sized nipple for that thread.

If that Traditions has a shiny stainless steel nipple on it, replace it as soon as you can. They have a tendancy to crack or splinter. Both of mine did. The replacement nipple you get will use #11 caps with no problem. I got mine from Dixie, but there are many options out there.

hawken hunter 60 said:

That is a metric thread. You should be able to go to your local sporting goods store or gun store and purchase either #10 caps or a nipple that is sized for #11 caps. Also, A good machinist could drill the threaded hole out to a 1/4-28 thread. I know you can get a #11 sized nipple for that thread.

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Since most m6 l nipples have a thread O.D. of .235 it would apear that you could tap it out to a 1/4 -28. But the actual thread pitch is such you would not get a full thread. Due to the metric spacing being different than the english. The crests and valleys would cross. It will work to some extent but I personally would not recomend it for safety reasons. I would recommend you get a good m 6 1 nipple from Track of the Wolf ,Dixie, or Log Cabin as the all stock them.

Yes, the #10 and #11 caps are physically a different size, and are NOT interchangeable. Generally, you will find the #10 caps made for use on the small nipples found on Replica Revolvers. The caps aren't as tall, or as wide in diameter. If you try to put a #10 cap on a #11 nipple, you will have to hammer the cap down on the nipple with a couple of blows of the hammer before the cap will fire.

The #11 caps are a bit wider in diameter, and taller( Longer) than are the #10. The standard #11, and #10 caps seem to have about the same power. But you will also find "magnum " #11 caps, designed to burn at a hotter temperature to ignite the Black Powder substitute powder, made from Axcorbic Acid compounds, with an ignition temperature almost twice as hot as Black Powder has.

You need to know these little facts when buying nipples and when buying percussion caps. With black powder there is absolutely NO reason to spend more money and buy the "magnum " caps. I test fire my standard caps on my ML shotgun. At night, when I fire the shotgun out of doors, you can clearly see a streak of fire leaving the muzzle of my 28 inch barreled gun, and the streak is another 6-10 inches longer. The Standard caps have all the fire you need to ignite black powder. Even with my 39 inch barreled rifle, fire would exit the muzzle of the gun when I fired a cap off in the dark, using standard #11 caps.

Because much of the replica gear is being made in Europe, most of the measurements will be metric. If you need help, call the suppliers on their phones, and talk to their in house experts about the nipple size you need, and the caps that work for that gun. They sell oversized nipples( the threaded portion is made oversized to be used in guns that for any reason had to be drilled out and a new nipple thread size tapped into the gun.

If you are trying to learn what the actual thread size is on your existing nipple, take it to any hardware store, or machine shop, where you will find tread gauges, in either American, or metric scales to use to tell you the exact tread size. A caliper will give you the exact diameter of the threaded portion of the nipple. ALWAYS USE THE CORRECT SIZE NIPPLE for the threaded portion in your drum or patent breech. The last thing you want to experience is that nipple shooting back at you when you fire the gun. Been there; seen that. Ducked. Don't want to duck ever again that fast. :shocked2:

Nipple thread sizes - here are the most common nipple thread sizes:


Cap sizes - There is no standard or specification for caps sizes. "No. 10" means only what the manufacturer says; another manufacturer's No. 10 will be completely different. Also, caps cost about 4 cents apiece, so there's no three digit dimensional precision involved here; that means that even within a given brand the dimensions of a No. 10 cap can and will vary considerably from batch to batch.

Here are the results of some measurements I made. Each number is the average of at least 20 different caps of each brand and size. The measurement of the opening diameter is very difficult to make so the error in that number is probably .002 to .004 inches. I should also mention that others who have made similar measurements have gotten significantly different answers; whether that's because of batch differences or better/worse measurements I have no idea.


Ed: Winchester brand caps are repackaged CCI's.

Very interesting. The first caps I bought were Italian made, through Navy Arms, and they fit a replica revolver nipple okay. Those same caps would not fit on a standard rifle nipple, without pounding the copper down to fit.

I know there are differences in the sizing of the Standard #11 caps, because I have shot, at various times, Remingtons, CCIs, and RWS. The RWS were the tightest- so much I questioned whether I had been given $10 caps instead-- and caused me the most troubles getting them OFF the nipple when fired.

The European caps seem to be the shortest, but once in awhile, I see short Remingtons, too.

I believe your comment about there being variations even within the same company depending on what batch is made is probably the best explanation anyone can have about all this.

I try to buy caps by the thousand. I take a spare nipple with me when I shop, to make sure the cap fits on my nipple, before I buy. The last 1,000 I bought were from CCI, and they have been more " Loose " on my nipples than any other cap I have fired- to the point that I pinch them a bit to stay on the nipple in the field. ( If I shot more percussion than just my shotgun, I would buy caps by the 10,000 unit. The price never goes DOWN!)

Thanks for the information. I imagine mic'ing the caps was a challange that required a delicate touch.

I agree my problem is probably caused by the normal manufacturing variation in both the nipples and caps. My plan is to get several nipples from various mfgrs and switch nipples for the best fit with each batch of caps.

KV Rummer said:

Thanks for the information. I imagine mic'ing the caps was a challange that required a delicate touch.

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It was far more entertaining than watching HGTV, which was SWMBO's choice for the evening. :snore:

mykeal said:

Nipple thread sizes - here are the most common nipple thread sizes:

Ed: Winchester brand caps are repackaged CCI's.

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Mykeal, you are a never-ending source of charts and info. Thank you!

I replaced the original Traditions nipple with a CVA nipple which seems to be slightly larger and the caps are snug and don't fall off.

I will now maintain a variety of nipples so I can swap them around till I get a good fit with whatever batch of caps I have.

mazo kid said:

Mykeal, you are a never-ending source of charts and info. Thank you!

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Well, thank you, sir.

However, I need to emphasize that this chart:



is a bit misleading. The three decimal place format implies that the data is reliable and consistent, when exactly the opposite is true. I perhaps should have included error bands, or standard deviations, to show the true meaning. However, the sample size is too small to have good statistics, and the measurements are too difficult with hand tools to get a large, meaningful sample size.

I think it is useful to show relative sizes, and to demonstrate that No. 10 or No. 11 are not really sizes, but rather model numbers, meaningful only within a brand name.

I guess what I'm trying to say is, use the cap size data with a good dose of skepticism, and take away from this the message that this is not cast in bronze. Or copper, either. When someone says a No. 10 cap will fit well on a Magnus Superwhiz .46 cal, the answer is, "Well, maybe."

I am so glad this info is available. I know this is an old thread, but it helped me determine what I needed. Context - I picked up an FIE 1862 Navy 36 cal.
For a couple years now, #10 caps have not been available. I walked in sportsmans and got 2 tins of #11. Tried one or three and they came apart and wanted to fall into the action.
I came here. Then I went to Track and they had 2 sizes for FIE. I used a thread gauge to determine they were 6x .75 and their dimensions and even instruction on how to arrive at them were spot on.
Got 6 for #11 caps on the way.
Thanks for keeping the info alive.

Yep, Searching is how I found it.

What I’ve found while trying to measure with pin gauges over the years- tolerances from today’s manufacturers aren’t great. Tolerances cost $.
Here is a Vintage Eley display board.

52Bore said:

What I’ve found while trying to measure with pin gauges over the years- tolerances from today’s manufacturers aren’t great. Tolerances cost $.
Here is a Vintage Eley display board.
View attachment 343047

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So your saying I need some #54 caps??? Gonna be hell trying to find those.

RobertsGunsmithing said:

I am so glad this info is available. I know this is an old thread, but it helped me determine what I needed. Context - I picked up an FIE 1862 Navy 36 cal.
For a couple years now, #10 caps have not been available. I walked in sportsmans and got 2 tins of #11. Tried one or three and they came apart and wanted to fall into the action.
I came here. Then I went to Track and they had 2 sizes for FIE. I used a thread gauge to determine they were 6x .75 and their dimensions and even instruction on how to arrive at them were spot on.
Got 6 for #11 caps on the way.
Thanks for keeping the info alive.

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Give the RWS 1075 caps a try. They are slightly smaller in diameter than the #11 and may fit the cones on your FIE Navy Colt.

Blackpowderart said:

So your saying I need some #54 caps??? Gonna be hell trying to find those.

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If you want #54 made by Kynoch - go for it.
#11 is indicated as its the Eley numbering system we still utilize today.

Grenadier1758 said:

Give the RWS 1075 caps a try. They are slightly smaller in diameter than the #11 and may fit the cones on your FIE Navy Colt.

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I will keep the original nipples with the gun and mark them. It will greatly depend on what caps are available. CCI #11 and 11M are all that have been available here for the last 3-4 years. And only recently at that.