I am thinking about my next build: a long range precision target rifle. I do not have the tools or expertise (yet) to build my upper from scratch. So I am currently limited to buying a complete upper. I am considering a RRA EOP Varminter, or possibly a Bushmaster Varminter or V Match. Does anyone have experience with with this RRA upper configuration in terms of fitting optics to it? It seems like a better solution than Bushmaster's. Also, am I correct in understanding that the 1/8 twist on the .223 Wylde RRA will outperform the 1/9 twist 5.56 BM with the heavier bullets? The weight of the weapon is not an issue; I could care less about the fluting. Is there an overwhelming advantage to 24" vs. 20"?

Finally, there is the possibility of adding a suppressor in the future. Should I have the muzzle threaded? I seem to recall a different type of flash suppressor on a few SPR builds I have seen, any info would be appreciated.