I want to put a collapsable stock on my Colt Sporter 'Lightweight' pre-ban carbine. I want to be able to shoot both 7.62X39 and .223. The shorter collapsable stock has a shorter buffer  and Spring. Will this smaller combo stand up to 7.62X39 or should I jam the original A-2 buffer spring in there and will that be too heavy for the .223? I've used both .223 and 7.62X39 uppers with the A-2 stock and .223 buffer and spring without any trouble. Mikke

Same buffer, same apring. Works just fine[:D]