Quoted:
The spring can be replaced from most well stocked hardware stores, and you save shipping and handling. The spring dimentions are 1.15" long, 0.294 OD, 8 coils of wire that is  0.029+/0.001 in dia. I recieved a LPK  once without magcatch spring and didn't want to wait for replacement. I went to Ace hardware and found a spring that gave me 4 magcatch springs for less than one from mail order and they work good, without disaasembly you can't tell difference between ar spring and hardware spring.

Quoted:
Boy did I blow it, I read the wrong spring dimensitions for mag catch. the actual spring size for bolt catch is 0.517 long, 0.154 OD and 11 coils. sorry massive brain fart