I'm starting to build a copy of an SDM-R and need some help.  I know this already:

base rifle is an a4
uses Daniel Defense 12.0 rail
Matech Ind. 600m BUIS
Harris S-L Bipod with ARMS 17 mount
Douglas 1:8 20" fluted ss barrel with a2 flash hider

I'm using a RRA a4 as a base rifle.  What i'm trying to figure out is where to get ahold of the same type barrel, and i've been looking for the Harris S-L bipod but haven't been able to find one listed with that model??  

Any information or insight that you can provide to help me complete this rifle would be much appreciated.

Thanks,
Mark

ADCO can hook you up with the correct barrel:

www.adcofirearms.com/sprbuild.cfm?page=build

I'm about 99.9% sure on those barrel specs.