Best DMR for $600?

G&G M14 Veteran, a bag of SGMs and 2 standard mags, take the full auto cam off to lock it to semi only, job done, that is all you need

I'd run another cheaper .28 until the rubber has bedded in then switch to the SGMs after about 500 rounds.

If you still want to upgrade from that a Madbull V2 black Python 509mm and a Guarder black rubber with a H/SCS nub.

+1 for the G&G M14 Veteran. I'd recommend checking out a G&G M14 in person before purchasing one.
Beefy rifle, but manageable. Not for everyone though.

KWA SR12 is very nice when running on a M130-140. Best Armalite style airsoft DMR in my opinion.
smaller, lighter than a G&G M14.

TM M14's work well, but need after market internals to run stronger springs.

G&G is coming out with a light weight EBR M14 here shortly and that is going to be a hot purchase for many.

Please don't put a M170 in a MP5, or make a MP5 into a DMR.

YOU WANT TO CONVERT YOUR MP5 INTO A DMR!!!! No offense, but this is not the best idea. If you want too, go for it, but i would really suggest getting a G&G M14.

Yah I know, It was just a little thought in the back of my mind "Gee wouldn't it be cool if" and as it turns out I was looking at the G&G and the KWA so +1 for both of them. The thing is though is I need something that will shoot as far as possible with as small a spread as possible and I am not one for picking up 100 guns and leaving not ever thinking about them again I plan on squeezing as much performance out of it as godly possible so not which gun is better out of the box but which gun has the most potential. Again the G&G and KWA are both great and since in my mind it's performance then looks. I really don't care what it looks like as long as it can consistently get hits from at least 250 feet.

Go with the G&G then.

MP5 comment removed.