This thread is for information only.
Please place all discussion on this topic here:
http://www.theopenrange.net/forum/index.php?topic=9094.0
Thank you!
Cap sizing and the fit to the cones remains the most misunderstood part of percussion firearms usage. Most shooters of single shot muzzleloading rifles and pistols do not agonize over the cap to cone fit the way that percussion revolver shooters do. Even those revolver shooters that do not “agonize,” wrestle with understanding why they have problems with ignition, etc.
The locks on single shot rifles and pistols have three traits that make cap fit (except for them falling off) almost irrelevant: they have much more powerful springs, the hammers usually have significant “over-travel” and there is not a concern about cap fragmenting since they are single shots. What I mean by over-travel is that if the cone face did not stop the hammer, the hammer would continue to be driven for some distance by the spring.
One might ask why potential over-travel is important if it never happens. I primarily has to do with the spring loading at the fully cocked point and at the fully down position. While it is true the hammer spring force can be exactly the same on a hammer with a hard stop and one that would continue to travel if not stopped by the face, the tendency for designers and in manufacturing is to start from the down position and then load the spring as it is cocked. Because of this tendency, 90% of the time a hammer with over-travel will have a higher spring loading at the fully down position.
The high force springs and over-travel make high caps (caps not fully seated) in most cases a non-issue, there is sufficient force to drive the caps home and fire the priming compound. Any cap fragmentation, splitting or caps hanging onto the hammer or cone doesn't pose a problem on a single shot. There is no threat from pieces falling into a hammer channel or clogging the action.
The same is not true for percussion revolvers. On the models germane to these conversations the hammer springs are often intentionally manufactured lighter than the original springs the pistols had in the 19th century. The manufacturers have created a problem trying to cater to the average customer's expectations on the amount of force required for cocking. The method of manipulating a percussion revolver and the shooting sports these revolvers are used in have driven the manufacturers to use spring forces on par with the springs they install in their cartridge revolvers. This along with the fact the hammers are stopped by the hammer channel and may not have sufficient velocity or residual hammer force make caps that have not been fully seated a major problem with reliable ignition on revolvers. Cap fragmentation is the bane of revolver shooters, cap fragmentation can be exacerbated by the cone fit or the back blast and it plays havoc with subsequent shots.
I have never seen a complete compilation of data concerning cap sizes as to what the measured sizes mean in terms of cap to cone fit. I have seen a few charts where individuals have measured a few of the commonly available caps, but instead of helping us understand the caps fits, the authors of those charts often draw the wrong conclusions as to what the sizes actually mean. Those charts have been, and are continuing to be used as “evidence” into the lack of “Cap Standardization” instead of helping the reader know which caps to try, or which will work the best for them.
I'm not trying to be overly critical of people who maintain there is no “standard” because there is confusion over the correct cap size to use on pistols and rifles because there isn't a published “Industry Standard” size for caps such as we have for rifle and pistol primers. In trying to understand technology of the 19th and earlier centuries we often make the mistake of trying to apply 20th and 21st century standards and practices. Modern manufacturing processes were in their infancy, interchangeability and standard sizing was still being developed. In most cases there was no standard other than meeting the needs of the customers, whether that was the military or the commercial markets. The military requirements are what drove most of the standardization we have come to expect today. If you review the caps that were available in the mid-19th century you will find they were almost always not labeled not by a universal size (that came later), but by which firearms they were intended to be used on. For example look at these two tins:
Cap Gun Primer: Percussion CapsCap Gun Primer: Percussion Caps
The cap manufacturers obviously fabricated their caps to fit the tubes of the particular firearms they were intended to be used on. Colt's set the standard for revolver tubes by being the first and also by being the 800 pound gorilla. I have limited data on original Remington cones, but the two I have, though different in length from the original Colt's tubes I have will accept our current #11 caps just as the original Colt's tubes will.
What the posters I mentioned earlier who were trying to prove there is no standardization in modern caps miss is that the manufacture and sizing of caps has changed very little in the last 180 years except for the change in the priming compounds. Based on measurements of commonly available tubes on factory weapons and aftermarket tubes there are common tube geometries that will accept either #10 or #11 Caps (including RWS 1075 caps) today, just as there was in the 1860’s. The modern manufacturers today do what Eley and the others did in the 19th century, they make caps to fit the tubes that are available. How they go about it is the subject of this thread.
~Mako
« Last Edit: January 10, 2012, 06:56:52 PM by John Boy » Logged
Author Topic: Cap Gun Primer: Percussion Caps(Read 7224 times)
Mako
Free Grazer
Offline
Pardner #1287
Re: Cap Gun Primer: Percussion Caps
« Reply #1 on: January 10, 2012, 03:45:04 PM »
--------------------------------------------------------------------------------
There are 5 caps in the #10 and #11 range commonly available today. The RWS 1075 seems to be impossible to find these days and appears to have been "replaced" by the RWS 1075 Plus in availability. The "Plus" cap is actually a "magnum" cap but will work for our purposes. In addition to the five is an entry supplied by Hellgate for an RWS #55 cap, these are also called RWS 1055 caps and I will add to the data sets when I locate a package of them I squirreled away somewhere.
Cap Gun Primer: Percussion Caps
I have now measured:
120 Remington #10 Caps from four distinct manufacturing lots, 20 caps from each package (two lots provided 2 packages)
120 Remington #11 Caps from five distinct manufacturing lots, 20 caps from each package (two lots provided 2 packages)
120 CCI #10 Caps from Three distinct manufacturing lots, 20 caps from each package (3 packages from one lot, 2 from another and 1 from a final lot)
120 CCI #11 Caps from five distinct manufacturing lots, 20 caps from each package (2 packages from 2 lots, and 1 from two other lots)
87 RWS 1075 Caps from one lot
79 RWS 1075Plus Caps from one lot
This is an image from models of the five caps in question, note how all of the caps are arranged to set the height as it would be relative to sitting on the cone face, this will give you some idea of the differences in priming compound thickness between the caps.
Cap Gun Primer: Percussion Caps
These side by side comparisons of the cross sectioned models will help you understand why some caps appear to be "larger" than others on the exterior, but are in fact nearly the same size internally or actually a bit smaller than another cap that might have an overall shorter outer height.
Construction differences are readily apparent between the three manufacturers. The corrugated features show up as a ribs on the inside of the CCI caps, a ghost image of the corrugation shows through on the Remington caps, but are not measurable. The Remington caps have the four "petals" left on them which is part of the forming process. Actually all three styles of caps have these petals at a point in their forming process. CCI and RWS trim the bottom of the skirt and finish them differently. RWS applies an internal chamfer to the skirt to facilitate loading and CCI breaks the outer edge slightly. Only Remington leaves the skirt as formed, this "as formed" condition often manifests itself with petals of slightly different length on the same cap (look at the photo of the Remington #10 cap as an example of this).
Photos in subsequent posts will show the internal features and differences described above.
The external heights are as follows:
The #10 Caps
Cap Gun Primer: Percussion Caps
The #11 Caps (note the RWS 1075s are categorized as #11 caps because they fit the same cones as caps marked as #11)
Cap Gun Primer: Percussion Caps
