Rws 1075 caps

[smoothshooter]

So got several hundred of these caps.

Shot a few with my home brew BP in a cva 50 cal cap gun. 490 ball, .012 patch etc. So after a few shots the nipple literally clogged up with cap gunk residue. Gun went off but after 3 or 4 shots, fail to ignite. Why? Nipple plugged with gunk from caps. It was stuffed with stuff. I mewn packed.

Is this an experience with other shooters? I mean the caps ignited the main charge but like not all the materials ignited. Caps are 15 years or more old I am guessing. But stored in a locker in climate controlled basement.

Cap issue? Age? Good hits from hammer and lite off all other caps. Maker of the cap? Thoughts?

The “ home brew “ part of your question makes me suspicious of that.
Sounds like a partially-blocked flash channel to me, caused by the powder not burning correctly.
The powder going off should blow any cap debris back out of the top of the nipple.
Clean the entire flash channel thoroughly with some water based cleaner, or even straight water. After everything is totally dry inside try some factory black and see if your problem goes away.