What are the heaviest bullets that this type of barrel will stabilize? I doubt that I will go much higher than 130 grain, but 140+ are available. Has anyone had any experience running heavier pullets through these 1:9 polygonal rifled barrels?
I see in the faq that Carl recommends 1:8 for heavier bullets in 264. Is there any reason not to just go right for this twist? What if you throw in the possibility of a suppressor?
Apologies if this has been asked before, I tried a search but could not find it.
Post by floatpilot on Dec 26, 2011 16:34:08 GMT -8
It is the bullet length and not the weight that is your real concern regarding the rifling twist rate. I shoot lots of 6.5mm projectiles in my various 6.5x55 Swedes. the original twist rate on those was 1 turn in 200 mm. They shoot the 142 grain Sierra match bullet just fine and the long Berger VLD bullets. I also have a CG-63 target rifle with a 1 in 9 twist Schultz and Larsen barrel. It does not like the longer bullets like the 142 grain Sierras and will just barley shoot the 130 grain VLDS. Notice from the attached photo that the 140 grain SMK is actually shorter than the 160 grain Hornady Round nose. Of course you have o consider if the long boat-tail bullets will seat deep enough to allow them to feed in a short AR magazine length and if they will take up a bunch of powder room, thus giving you reduced velocity.
PS:: A 1 in 9 twist 6.5mm loves the 120 grain SMK and 120 grain Ballistic tip.
Last Edit: Dec 26, 2011 16:35:46 GMT -8 by floatpilot
Retired Mil and LE Weapons instructor. Experimental Hand-Loader Float and Bush flying instruction Dragonfly Aero, Homer-Alaska