Is this a known problem with 308 barrels then too? other 30 cals in general? How exactly does threading them cause them to bell open like that? is it the profiling/threading process itself? or something you feel the manufacturers are doing incorrectly? Would you care to share which make/model of barrels you gauged? was it a sample of multiple manufacturers? or multiple samples from a limited group of manufacturers? What gets me is how accurate it is considering how many of those things noted above are present in most set ups.
In realty, the 300 BLK is and can be a very accurate little cartridge if things are handled right with it and you work within its limits and confines.
There are other things I could go into but that's my "rant" for today on some "biggies" I see as messing with the 300 BLK and it's accuracy. I can take the same load and bullet using the different types of brass mentioned in this piece and see very different results in terms of accuracy (mostly the elimination of those "what the heck" flyers). For accuracy work, brass that's made as 300 BLK virgin brass and has an annealed neck generally gives better bullet release consistency and lower E.S. into 300 BLK) once fired military 5.56 brass where the non-annealed and work hardened body becomes the neck of the 300 BLK cartridge. Brass can be and is an accuracy issue, especially chopped off and re-made (i.e. I can take some of the "hot" factory supersonic ammo that shoots crappy, pull it down and re-load it with the same bullet and powder, but drop the charge a couple grains, and voila, typically a much more accurate and consistent loading.Ĥ. The plain fact of it is that a lot of the "hot loads" typically don't shoot well or consistently. sizzling velocity sells and ammo makers know many purchasers are suckers for velocity and "knockdown power" so they load the stuff up to get the numbers that sizzle). Much of the supersonic factory ammo (at least just about all of the factory ammo we tested) is loaded quite "hot" (i.e. Big no no, you don't need or want to mount a muzzle device with 100 ft lbs of torque - bad bad for accuracy!ģ. Some of the muzzle devices we have seen put on were literally put on with "crush washers" or threaded on so tight to make them time properly that the bores and rifling of the barrels were stretched and/or deformed in an accuracy robbing manner. Needless to say this is not good for accuracy, it's like shooting a blunderbuss.Ģ. 3015" in the area where the muzzle threading was done). if the bore pinned out at 300", the muzzle was. Within the past weeks we pin gauged a number of 300 BLK barrels threaded with 5/8" x 24 threading and with just about all of them, right where the bore reached the shoulder of the threaded section, the bore opened up, in some cases up to.
If yours is so threaded, congratulations, you are likely shooting a barrel that is like a trumpet at the end. Most of the 300 BLK barrels are threaded on the end with 5/8" x 24 threading for a muzzle device or suppressor of some sort. The operative words in the preceding sentence are "consistent accuracy" because a 3 shot group does not qualify for consistent accuracy, nor does one 5 shot group, but when you put together two 10 shot groups back to back or four 5 shot groups back to back, you then see accuracy patterns emerge.įor whatever reason the 300 BLK cartridge is "taking the hit" as the source of accuracy issues, but IMO that's "the big lie" and it's really not the cartridge at all but other things that sabotage its accuracy abilities. In accuracy circles the 300 BLK is know more as a "blaster" cartridge than anything else because most of the rifles chambered in it typically seem to only be able to manage to get about 1.5"+ worth of consistent accuracy out of them at 100 yards.