Possibilities include part failure, dirt, improper reassembly. Have it checked by a gunsmith.
Browning Pump Shotgun "BPS"
32 year old BPS in 12 gauge.
NO!!! A 12 gauge shotgun takes only 12 gauge shells. A 20 gauge shell would fall into the barrel and get stuck about half way to the muzzle. You would be in for a nasty surprise when you put a 12 gauge shell behind it and pulled the trigger!!!
50-500 uSD
Best left to a gunsmith.
http://www.browning.com/customerservice/dategun/index.asp can help you date various Browning models. Your BPS 12 gauge Hunter was made in 1981.
@500 each
You must call Browning for the answer.
50-500 uSD
Browning.com has a sn function under customer service.
They started to make these in the 80's and are still producing them
double trigger and hammers