I don't know either, but that is the gun clubs answer to why we cant shoot any thing smaller than a 69 gr on the high power range. I think they had an incident where someone got hurt, and they blamed it on the jacket from a 55 gr bullet
We shot many military matches using 55 gr bullets out of 1:7 twist M-16s. They shot well the majority of the time. We used them at 500 and 600 yard line. The wind was obviously a challenge.
My understanding for not allowing the 55 gr in the OKCGC high power range from the 600 yard line is that the bullets come in at such a steep angle that they strike very low on the berm. You can imagine how scary that would be if you are pulling in the pits.
My understanding for not allowing the 55 gr in the OKCGC high power range from the 600 yard line is that the bullets come in at such a steep angle that they strike very low on the berm. You can imagine how scary that would be if you are pulling in the pits.
I know its not a 10.5 or even an SBR (mine's got a pinned phantom), but on my 14.5", I run a 1/7 with no issues out of the 55gr or even when shooting my .22lr with the CMMG kit. Funny thing is that my 55gr and my 69 gr hunting rounds seem to all be at the exact same place at <100yds.
From what I've heard and been told, if you have a shorter barrel, its more forgiving to the sharper twist rates with smaller bullets and a longer barrel is more forgiving with a 1/9 and larger bullets.
From what I've heard and been told, if you have a shorter barrel, its more forgiving to the sharper twist rates with smaller bullets and a longer barrel is more forgiving with a 1/9 and larger bullets.
no .343 is correct. I just asked a member and he said the same about the bullets coming in at a steep angle and to protect the shooters in the pit. I don't know where I heard that the 55's fly apart. I have been known to black out and find my self walking in the nude in down town okc, so this may have been one of those incidents.
You can't shoot less than 69 because the BC on the 55s is so bad they come into the pits too steep and can be dangerous for the people pulling targets. At lest that is what Dan Arnold told me 2 weeks ago.
Guess it's a little late now, lol, but still...
The twist stabilizes the bullet, a 20 inch 1 in 9 twist may stabilize the 75 gr just fine on account of it having more time to stabilize it compared to a 10 inch barrel where it has much less time to set it flying straight. A 1 in 7 will not pull the 55 gr apart and if you are shooting only .223 and not worried about a 22lr conversion than with the short barrel the 1 in 7 seems the only way to go.
Not sure I follow you. What is the "time" it needs to set it flying strait? A 1:9 barrel will spin the bullet 1:9 pretty much any length. The issue is velocity. The shorter the barrel the lower the velocity giving fewer RPMs on the bullet. The longer barrel in 1:9 will spin the bullet faster because it is going faster, but it is still 1 rotation in 9 inches. Maybe that is what you were trying to say, IDK.
Exactly. The spinning slows down as time/distance elapses. *IF* it's gonna fly apart, it's gonna do so right out of the muzzle.
I've got to call B.S. on the 55s drop steeper into the pits, therefor being dangerous!! The drop on a S.M.K. 69 gr. bullet going 2900 fps. (a fairly warm load) drops 99.2" at 600 yds. from a 100yd zero. A 55gr. fmj round going 3100 fps. ( a fairly mild load drops 99.7" at 600 yds. from a 100 yd zero. So can anyone tell me how .5" makes for a "much steeper" ballistic path? Just to be clear about this a 62 gr. M855 ball round drops 91.2" at 600 yds and a good old M80 ball round from a 7.62X51mm rifle drops 91.2" also we are talking at the most 8" of difference in drop. How these little tid bits get started is just beyond me, but IF enough guys say it often enough ...it must be true......B.S.!!!! KurtM
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