Thats right GG the 155gr 6.5mm SMK was a dog and had a very low BC compaired to the lighter bullets
Both the 6.5-06 and 6.5-284 can have accurate barrel lfe past 1000 rounds if the barrel is cared for properly. the 06 does have wee bit more case capacity than the 284 which would offer a wee bit more velocity. My vote goes to the 6.5-06 Ackley improved , you'll get better velocity with the heavier pill you mentioned which I assume will be from Wildcat bullets or some other custom maker , and it will probably feed better even with the steep shoulder. Unless you want to step up to the mag cases this is about the best your gonna get unless you want a Gibbs case which will put you into magnum velocity range with less powder.
I ve got a 27" 1-8 twist Lilja 3 groove thats chambered in 260 , I plan to shoot the 140 A-max , 140 Berger and 141gr Cauterucio bullets to see what will give the best accuracy. Any of these pills out of this little case will get you into the competive ranks without excessive recoil , barrel wear and a great supply of good reloading componets , its easy to make fit in a short action and is inherantly accurate like its big brother the 308. If things don't work out like I want I'll ream it to 6.5-284 and if that don't work I'll ream it to 6.5 WSM !!! From all the reports I've seen and heard the 140 class match bullets don't like being pushed to much past 3000fps then accuracy suffers.
Another great round would be the 6 XC or the 243 Ai chambered in a barrel with a 1-7 twist to shoot the 115gr bullets.
