RLTW
“What’s New” button, but without GD: https://www.m4carbine.net/search.php...new&exclude=60 , courtesy of ST911.
Disclosure: I am affiliated PRN with a tactical training center, but I speak only for myself. I have no idea what we sell, other than CLP and training. I receive no income from sale of hard goods.
Don't know but here is a picture of one with some other 62 grain bullets. The reason it is so long is the requirement to trace out to 800 meters.
Found a pic next to a 70 TSX.
Attachment 64898
Last edited by mack7.62; 01-16-21 at 12:12.
“The Trump Doctrine is ‘We’re America, Bitch.’ That’s the Trump Doctrine.”
"He is free to evade reality, he is free to unfocus his mind and stumble blindly down any road he pleases, but not free to avoid the abyss he refuses to see."
Should not be as accurate, I believe most match shooters use 1/8 but that is not a apple to apple comparison, I don't know if anybody makes a combat grade chrome lined 1/8 that could be used to confirm the difference. Don't get me wrong, some 1/7 barrels shoot quite well, just curious if 1/8 would be noticeably better.
“The Trump Doctrine is ‘We’re America, Bitch.’ That’s the Trump Doctrine.”
"He is free to evade reality, he is free to unfocus his mind and stumble blindly down any road he pleases, but not free to avoid the abyss he refuses to see."
“Should not” and “curious”. The truth is that 1:7” barrels are every bit as accurate as any other twist, all things being equal. 1:7.7” is quite popular in high-power crowds. Shooters typically want to have “enough” twist to get by and not so much as to cause increased barrel wear with heavier bullets.
If you’re going to shoot a “combat” barrel, what competition shooters do shouldn’t be a major concern when a barrel is “shot-out” after around 2,000 rounds of 80 or 90 gr bullets—meaning it will no longer hold a 6” ten-ring at 600 yards for a ten round string.
This is all mental masturbation and there is no significant difference in the real world of combat rifles.
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Last edited by PracticalRifleman; 01-16-21 at 12:32.
Because its not. There is no downside in shooting light bullets out of a 1/7 and is just as accurate as slower twists given equal barrel quality.
An issue only arises when you shoot really light thin jacketed bullets like 36gr varmint grenade out of 1/7 20" barrel. The same barrel will shoot 40gr vmax just fine.
This. Its been proven. Molon shot 52gr SMKs out of 1/9 and 1/7 barrels with the same results.
Last edited by vicious_cb; 01-16-21 at 13:18.
RLTW
“What’s New” button, but without GD: https://www.m4carbine.net/search.php...new&exclude=60 , courtesy of ST911.
Disclosure: I am affiliated PRN with a tactical training center, but I speak only for myself. I have no idea what we sell, other than CLP and training. I receive no income from sale of hard goods.
If I recall, the DSM, at least Compass Lake SAM-Rs were 1/7.7” & Douglas DMR 1/8” instead of 1/7, supposedly for accuracy, but I don’t know how practical the differences are vs 1/7. As noted, Molon showed no difference using a typical (for him) methodical approach & he’s a wealth of unbiased info.
Won’t a faster twist theoretically heat up quicker than slower? Again, I doubt it’s significant, but it seems there are members here way more mathematically savvy than I am.
To answer OP with my own experience: I had a .223 Hbar AR custom made in the late 1990s with a 1/9 twist, because that’s what the internet & ‘smith stated was “best...” a few years later, when the 77grain OTM became common, I was maxed at 69gr, because it was all the 1/9 would stabilize. Within 300 yards I was shooting, it didn’t matter, but I did eventually sell that gun & had a Krieger 1/8 built for 77grain OTM use.
If it were me, I would go with a 1/7 or 1/8, because with the way the ammo situation is currently, who knows what 5 years will bring. Or, if restrictions on replacement parts is in the future with Biden & Democrats in power. But if I had 10K rounds of M193 in my hands, I wouldn’t think twice about using a 1/12....but I would still buy a 1/7 barrel....but I like spares & options, and have had spare screws evolve into retro carbines & rifles....
Best of luck with your build & choices, OP. Options: keep them as open as possible.
Last edited by MSW; 01-16-21 at 19:56. Reason: Clarification
My thoughts: Original design (after the 1:14) was for 20" barrel, 1:12. This gives 1 full rotation plus some... They originally used 1:14 just because that's what the .222 parent cartridge used. They went to 1:12 to optimize for 55gr M193 (so says Wikipedia). For a 16" barrel, 1:9 will do about the same as far as number of rotations before the bullet exits the barrel. Lots of people on here smarter than me though....
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