will #10 caps work in my t/c 50 cal?
It isn't really the type of gun that determines the cap size, but the size of the cone of the nipple that has been installed in the gun. I'm assuming your T/C .50 caliber is a rifle. Most of the nipples you see nowadays are sized for #11 caps. It is likely #10 caps won't seat completely, resulting in a failure to fire when your hammer strikes the cap. It
may be possible to file or turn the nipple down to a small enough diameter to accept a #10 cap, but I can't say for sure. There also
may be a 1/4-28 nipple out there with a cone already sized for #10 caps, but I can't say for sure on that, either.
I think it is generally accepted that larger caps contain more priming compound than smaller ones, so they have a hotter and more intense flame. I suppose #10 caps work reliably in revolvers because the revolver chambers are essentially "in-lines," with the powder charge right up against the base of the nipple and the cap flash going directly into the main charge. In a rifle with a patent breech, powder has to trickle down around a corner or two to reach the base of the nipple, or the cap flash has to jet far enough into the chamber to reach it. Therefore, a hotter cap might be better for rifles, or even single-shot pistols. I had not thought of this until now, and I don't know if my reasoning is accurate or not, but it seems plausible.
So, will #10 caps work with your T/C .50 caliber? Probably not, unless you modify the nipple, and even if the smaller caps can be made to fit, larger caps might perform better.
Best regards,
Notchy Bob