ar lower compatability for 308 vs 223
 

Can I put a 308 upper on a 223 lower? I found a RRA 223 lower reasonably priced locally and when I asked if a 308 would fit he didnt know. He said it was a 223 lower and didnt have any 308 lowers. I didnt know there was a difference. Thanks for any answers.

Steve Lubecki

Re: ar lower compatability for 308 vs 223
 

That I don't know. But You can get a .50 kit

Re: ar lower compatability for 308 vs 223
 

The short answer is NO. The magazine well on the 308 is larger than the 223 version.

Re: ar lower compatability for 308 vs 223
 

Islubecki:

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.

LDBennett

Re: ar lower compatability for 308 vs 223
 

Thanks for the reply. I never even thought about cartridge size. DUH! It all makes sence now.

Steve Lubecki

Re: ar lower compatability for 308 vs 223
 

ISLU the .50 cal kit I found is semi-auto with a 7-round mag from http://www.cabelas.com/cabelas/en/te...RFX_xtspring06

Re: ar lower compatability for 308 vs 223
 

OOOO! Bolt on .50! My wallet feels lighter already.

Steve Lubecki

Re: ar lower compatability for 308 vs 223
 

What kind of upper is it? If you can't find lower in your price range I may be interested in buying the upper