Most of my revolvers have the nipples they came with.
I use either No. 10 or 11, depending on which fits snuggest on the nipple. Then I pinch each cap into an elliptical shape before placing on the nipple.
To ensure the cap is fully seated on the nipple, I sometimes use a short length of 1/4" dowel to gently push the cap onto the nipple. The operative word being gently.
Obviously, don't have your fingers or hand in front of the cylinder when you do this, and keep the pistol pointed downrange.
One of my revolvers has the Treso nipples and they are very fine. However, I'm waiting for when the current nipples wear beyond use, then I'll replace them with Treso. Currently, I have no problems with the original nipples as long as I use the right caps and pinch them into an elliptical shape, so I'm not in a rush to replace them.
Pyrodex P is designed to be used volume-for-volume with FFFG black powder. That is, unless they have recently changed it. I've used Pyrodex P off and on since 1979. From the beginning, it was intended to replace FFFG in revolvers and pistols, volume-for-volume. It is also used in small-caliber rifles, such as the .32-caliber squirrel rifles.
However, Hodgdon 777 is NOT designed to be used volume-for-volume. It should be reduced by 15 percent before use. When 777 was new, I got hold of one of the first cans, though it was difficult to find. I foolishly did not pay attention to the label and used it volume-for-volume in my Uberti-made copy of the 1858 Remington in .44 caliber.
Good thing I selected that stout revolver! From the first shot, it was evident this was a powerful load. I fired all six loads, without damaging the gun, but now admit I should have stopped firing and reconsidered.
Imagine my shock when, right there on the label, it said it was not to be used volume-for-volume!
You're never too old, or have so much experience, that you can't be a dumbkopf once in a while.
I took it as a life-lesson.
I used the 40gr. measure that day but now, when I shoot the Remington with Hodgdon 777, I use the 24 or 30 grain measure.
I don't use 777 much, though. It's not nearly as accurate as Goex FFFG black powder.
Nor have I found Pyrodex P to be as accurate as Goex FFFG black powder. In truth, I haven't found anything as accurate as FFFG black powder.
Through the years I've also found that ball size should be slightly larger than commonly suggested, in cap and ball revolvers. For the .36 caliber this means .380 inch instead of .375. For most .44s, this means .454 or .457 instead of the .451 usually suggested.
The Ruger Old Army is an exception. Ruger suggests .457 inch balls. I don't own one, but if I did I'd probably try it with .460 balls and see if there is an accuracy improvement.
The larger ball, upon ramming, creates a wider bearing band for the rifling to grip. I have long believed that this improves accuracy and my experience with .451, 454, 457, .375. 378 and .380 balls seems to prove this out.
I also strongly believe in a greased felt wad between ball and powder. The best lubricant I've found is what I posted years ago others have since dubbed Gatofeo No. 1 lubricant, to recognize my contribution.
For more information, read my Sticky above entitled, "Proper Use of the Cap and Ball Revolver."
You'll find a wealth of information in it.
Others may disagree with minor points in it, but on the whole it will help a beginner on the right track. I've been shooting cap and ball revolvers since 1970 and I'm still learning. They are not as cut-and-dried as people think!
