Subsonic Rounds and Long Barrels
Subsonics Do Not Like Long Barrels!
We just had another customer ask about subsonic use, etc. Thought I'd share some info. This Arkansas cop was having trouble with his gun and our ammo. Turns out it was the same phenomenon we discussed years ago with Al about the first shot being much slower due to the cold steel soaking up energy. His gun/EBR ammo chrono'ed about 650 on the first shot, then in the high 900's to mid 1000's on all succeeding shots.
I noticed his barrel was WAY long, and I think this exacerbates the problem, so we're having it cut by a competent 'smith (Jared Joplin of Patriot Arms http://www.patriotarmsinc.com / 706-367-8881) and rethreaded to 20" at his request.
Pretty sure this will cure the problem from the testing evidence; I'll let you know. If not, I just bought another barrel
Got the customer's gun back, shortened to 20". The very first round from the same box of EBR PBS's chronographed at 1046 ft./sec. with no warming shots fired. Mean Average for the 5-shot group was 1021 ft./sec. - PERFECT!
The moral of this story is that if you intend to shoot subsonic .308 Rifle ammunition in your platform, it is best to not only rebarrel the gun to put a better tube on it, but to also have it cut to no longer than 20". For those who think this ruins the Long Range capability of the weapon, I say "HOGWASH". We regularly shoot to 900 yards with the 16" Wraith with excellent results on calm days. It has been proven beyond the shadow of the slightest doubt that a short, stiff tube is more accurate than a long whippy one, *especially* if you put a weight (suppresser) out on the end of it.
While we're on this subject, I do not consider the .308/7.62mm to be better than a 750-yd. weapon IN REAL LIFE. Yes we shoot them much further, but if there is any wind at all...especially if it is gusty...the results get real "iffy". If you need more than the 750-800 yards, it's Time to consider the .338 Lapua or Mr. Fifty so as to be able to buck the wind.