I keep one (a .32 ACP adapter) in an empty oiler in the butt of my LB No4. The rifle is surprisingly accurate with .32 ACP.
I had one for 7.62x25 and nearly ruined my rifle. It swelled up so bad that I almost couldn't get it out. In fact, I had to tap it , turn a bolt into it and then carefully drive it out with a steel rod. A standard stuck case remover was a fail in getting this thing out.
Al