Uh, this doesn't sound right. When you say DPMS carbine buffer, do you mean the short LR-308 carbine buffer or DPMS AR-15 carbine buffer? Either way that is not the correct buffer to use. In your original post you mentioned a DPMS rifle buffer and spring. Did you get the LR-308 specific rifle buffer and spring, or DPMS AR-15 rifle buffer and spring? Nomenclature is VERY important in determining what parts somebody is using, which is why I stress using the terms LR-308 and AR-10 (also DPMS has multiple patterns now).