I used T-7 in cartridge guns and it works well as long as you use smokeless powder bullet lubes. With BP lubes I got the crud ring and it is is a chore to clean out.

Just like BP you must clean the bore after shooting and if you don't it will corrode.

I found that it didn't shoot any better than BP and was not any easier than BP to clean up.

It is pretty rough on brass cases and will eat them very fast if not taken care of promptly.

I don't think it's any better or worse than any of the other BP subsitutes.

There is nothing wrong with T-7. It'd just another tool in the tool box.

But I prefer Swiss BP.