IF you can find them:
Dynamit Nobel # 1075.
No question. They will not be the cheapest, and they will be more difficult to find, but over the years they have been a GO-to choice for serious caplock shooters.
I got some RWS 1075s here because at the time that's all I seen. They worked fine as have all the caps I buy and yes they are a little more. Others available now so I get them because they are almost half the price. Fit is probably the main thing as long as they fire and I have had no problems getting any cap to fire that fits right.
For target shooting I use any and all available caps with no problems. But for hunting which is often in the rain I use only the RWS which I have found to be more consistent in wet weather. Last Saturday was the muzzle loader season in Ohio and as usual it rained all day. My nephew and his son were on stand and I drove the multiflora gullies for two hours and all three guns fired resulting in three deer! :idunno:
I use a lot of Remington caps, have used the RWS caps but are harder to find, CCI Magnums, have some Winchester Magnums but haven't tried them yet. DANNY
In this area, the best caps to use on a caplock is whatever you can get your hands on. The only kind of caps I can find, when I can find them, are most often CCI or Winchester. I am fortunate in having bought a bunch of caps the last time I was in Friendship.
The best cap...?
Well that changes with the times. The best today may cut corners tomorrow.
Was a time I would have said CCI magnums. Now I would tell you Remington #10, followed by the RWS1075 and then CCI.
To be truthful, its not so much the best brand of cap for a particular make of rifle, its the best brand of cap for the nipple and the specific powder being used.
The cap needs to fit the nipple. The hammer needs to make good contact on the nipple/cap as the hammer falls. Then the powder needs to get enough heat to set the charge off. The substitute powders require a lot more heat from the firing of the cap to ignite the main charge. Therefore a number of nipples have been developed to get more heat to the charge. Hot shot nipples and Spitfire nipples are brands that come to mind.
That said, some cap brands are hotter than others. Use the CCI magnum caps or RWS caps. These seem to be a bit hotter and can send more heat down the flash channel.