A 50 yard target at a club usually means wheel bows? At the public range I use they have the compressed carpet bales. Very heavy, very thick, and stops arrows. The center will get shot out after a lot of use from the wheel bows. Funny thing is our arrows bounce back. I have read about a few guys making their own from carpet renaments and glue compressed together.
Excelsior bales are another option but they are getting hard to find. They will last a long time with some care and rebanding.
They get better when wet, actually they swell making them tighter.