Because boolits matter more than headstamps,I'd be 6mm,for reasons already cited. Yep,the 6.5 can be slickeryer...but I don't know anyone who shoots their 6.5(s) as much as their 6mm(s). For me,it is all about ACTUALLY shooting.
The last coupla 20" 6XC's I seen(fast twist Montuckys/6x MQ's),did 2950fps+ with 105HPBT Hornies and that ain't a bad place to be. Mild manners,modest report and miserly powder volumes ain't concessions. There are more than a few ways to yield brass. It's a platform,that would be easy to use a LOT and with increased trigger time,"luck" happens by literal default.
I think that if there was a Pop Quiz for 500yd shit,that everyone would drive a fast twist 270 with 105's,if only because there's a shitload of them,6BR's,XC's,243Win SAAMI's,243AI's,6-284's,Twat-Sixes and the like to extrapolate. A .473" Donor mitigates the 270 by default,which is a shame. I'd have zero qualm with a BR,XC,243 or 243AI in OEM ADL Donor guise. A Faux Ti 6XC at no more than 20",would be a BAD Bitch,that was friendly in regards to feed/function and offer alotta throating options in a OEM ADL's issued box.
I LOVE my Montucky Baby BR,but shoot my Itty-Bitty 270 more. That's prolly a function of brass being free(though I've Lapooey BR brass coming out my ass),gaining an extry poke in the belly and it being no more difficult to press the button on the Sig LRF for one,than it is the other. The MQ reticle,really don't give a fuck either and those two things in conjunction,literally rewrote The Book.
Been a while since there's been a mainstay 243AI in the crummy,but it weren't too long ago,when there was a herd of 'em in same. My LFB 6-284 is an incredible fucking hammer,but it don't get schlepped for shit,as I'd rather tote the 18" Montucky 270 or 20" Montucky BR. My Montucky Twat-Six is a WICKED Bitch,but my Baby 270 burns less than half the fucking powder and an 18" spout is handier than 22" and small change. Been alotta folks got their minds fucked,by shooting that Itty-Bitty 270 to multiple distant zipcodes away. I've said it 1000's of times already..."don't MAKE me get the 270 out!".(grin)
I'm hot on the SAAMI 243Win in a Krunchenticker with 105 Hornie HPBT Smooches,as it's a rather nice blend of no bullshit. For day in/day out grinding,I'd rather 18" 243LBC,due the much improved portability/balance of a '15 over a '10.
So were it me,I'd be gearing up for volume,mainly because I'd rather be pulling a trigger than talking about it.
Regarding 6XC,my sole lament is that Lapooey don't offer formed SAAMI cases...but I'm gonna rebarrel Sister's 21" MR contoured 25-284 to 6BR and work the Lapooey brass angle. She's killed a fair amount of shit with the Montucky BR and has all sortsa faith in it.
Me too...............(grin)
