Be careful what you use"from work"I used a freebee O ring(I've got a source) and although it worked well for quite a while it eventually swelled up a bit and prevented the action from cycling completely(maybe a 32nd of an inch short) and the trigger wouldn't set.I had to get my gunsmith to figure this one out as it left me baffled.He replaced it with a Remington O ring and problem solved.They are expensive if you buy them from a supplier but you can usually get the real Remington item off Ebay(USA) pretty cheap.They usually go for $7 or $8 US for a half dozen of them.Dave