204AR has the info and has shot this stuff extensively. He is spot on. I have not shot the G2, but understand it was a game changer in the large frame AR world. He is also correct on the after market parts for the G2, they are G2 ONLY. What you find with the LR308 or R25, is that alot of the after market parts, in fact most, are using the LR308 as a base line. In other words, most parts you can find are all referenced to LR308 compatible, or DPMS pattern. Float tubes, barrels, BCG, bolts, etc...
Now, you are still stuck with the LR308 receivers, but like AR204 stated, you can really change the feel and in some cases, lose a few ounces.
Having said all that, I did have an LR308 laying around for years that never got shot due to weight and bulk. Having a thermal, and wanting to play around in the AR platform, I got to thinking .243 for that rifle. I spun a Wilson Combat 16" barrel on it, real skinny float tube, and a light adjustable stock on it. That changed that rifle night and day! We are probably talking ounces in the weight change, but the feel was phenomonal. Again, this was all possible because the after market part world is primarily all referened to the DPMS pattern.
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