AR in 308? Details on how to?

[gnihcraes]

So I'm fairly new to the AR world... Do you have to get a new receiver to build an AR in 308 or can you just use a new uppper? what are the specific differences?

thanks Kc.

[Hoser]

New upper, lower, mags, ect.

[ryanek9freak]

The difference? about $1000. The lower is MUCH bigger in dimensions, as the magazine is pretty wide. if you've ever held up a .308 next to a 5.56, you'll see what I mean.

[Graves]

Note the lowers. Obviously the uppers are different, as well are the mags.

http://media.photobucket.com/image/compare%20223%20308%20lower/proxy2/AR10AR15-1000.jpg?o=1

[gnihcraes]

that's what I thought... but I heard someone say the other day "just buy an upper" they are all the same lowers... but I didn't believe it... I thought the lowers in 308 where a little heavier too...

thanks for the info.

[Circuits]

The "lowers are the same" comment is correct only for those calibers which will physically fit inside the AR magwell. 95% of the AR caliber conversions can use a standard lower, with special mags or a magwell block to adapt it for the desired (smaller) magazine dimensions.

.308 happens to be one which won't fit in a standard lower, though - and also was a dedicated platform (the AR-10) from which the smaller AR-15 was ultimately derived.

[ryanek9freak]

that's what I thought... but I heard someone say the other day "just buy an upper" they are all the same lowers... but I didn't believe it... I thought the lowers in 308 where a little heavier too...

thanks for the info.

i wish that were the case. I wouldn't have to build a .308 lower.