Re: ar lower compatability for 308 vs 223
The magazine well is not long enough for the 308 cartridges. You can do the 50 cal because the conversion is to a single shot bolt action one and the AR lower is used for a handle and as a hammer/trigger system. The magazine well is not even used (the 50 cal conversion is a single shot).
The AR10 (308cal) is a pysically bigger receiver but I think the internal trigger system is interchangable between the AR15 and AR10 (???). The upper receiver, of course, has to be longer as well so that the bolt area will accept the longer fatter 308 cartridge. What is possible is the several roughly 25 caliber wildcat cartridges like the grendel (at least one other) but these are not yet readily available either for ammo or for conversions. There are 22LR conversions avaiable where it is an insert in the original barrel or a complete new upper receiver.
Last edited by LDBennett; 05-11-2006 at 08:00 AM..