1:7 Twist, preferable grain weight [Archive] - Glock Talk

PDA

View Full Version : 1:7 Twist, preferable grain weight


HomeLandPatriot
01-12-2010, 17:40
For a 1:7 Twist bbl, what weight grain bullet should be used for optimal performance.

1:7 twist typically requires a heavier bullet correct? 62gr or more?

crazymoose
01-12-2010, 18:03
55 grain and over will work fine, although many say accuracy at range isn't as good with the 55 grain/ 1:7 combination. Unless you're shooting for tiny groups at 200+ yards, the difference is probably not noticeable. If you are shooting for tight groups at 200+, 55 gr. ammo is a poor choice anyway.

HogGlocker
01-12-2010, 18:09
+1 this

Jim Watson
01-12-2010, 18:09
Performance at what?

A 7 twist doesn't REQUIRE a heavy (long) bullet but will stabilize them. It will shoot the 55 gr FMJ pretty well for casual use or urban shtf.

A 7 twist will stabilize a 90 grain SMK but those have to be loaded over magazine length and fired single shot for long range target shooting.
The heaviest bullet I know of to be loaded to magazine length is the 77 grain, which finds some military use in the Mk 262 round.

RMTactical
01-12-2010, 18:10
It doesn't "require" a heavier bullet but it is made as a compromise between the M855 and the M856. I would say that 68-77gr is the "optimal" grain for the 1/7 (in general).

That said, 55gr works great too.

HomeLandPatriot
01-12-2010, 19:26
It doesn't "require" a heavier bullet but it is made as a compromise between the M855 and the M856. I would say that 68-77gr is the "optimal" grain for the 1/7 (in general).

That said, 55gr works great too.

Thanks RM,

thats exact kind of response I was looking for.

KalashniKEV
01-13-2010, 11:13
It doesn't "require" a heavier bullet but it is made as a compromise between the M855 and the M856. I would say that 68-77gr is the "optimal" grain for the 1/7 (in general).

That said, 55gr works great too.

Exactly what I was going to post... "Optimal" is the word to use when discussing weight/twist.

Kentak
01-13-2010, 22:55
My understanding is: 55gr = okay; heavier than that = better/best

Alaskapopo
01-14-2010, 03:27
For a 1:7 Twist bbl, what weight grain bullet should be used for optimal performance.

1:7 twist typically requires a heavier bullet correct? 62gr or more?

It does not require a heavy bullet but heavy bullets require a 1/7 or a 1/8 twist. I shoot 77 grain bullets in my 1/7 and 1/8 guns for matches and accuracy work. I use 55 grain ball for plinking.
Pat

Molon
01-14-2010, 10:09
My understanding is: 55gr = okay; heavier than that = better/best


Quality 55 grain bullets will do much better than “OK” in fast twist barrels. People try to compare garbage FMJ 55 grain loads to heavy OTM loads and then make the ridiculous claim that 55 grain loads are not as accurate as 75-77 grain loads. Quality 55 grain loads can shoot superbly from fast twist barrels. The 10-shot group pictured below was fired from 100 yards from a Noveske barreled AR-15 with a 1:7” twist using 55 grain Sierra BlitzKings.

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>
http://www.box.net/shared/static/9p6kf1904l.jpg



<o:p></o:p>
<o:p></o:p>
<o:p></o:p>
The next 10-shot group was fired from a Krieger barreled AR-15 with a 1:7.7” twist also using 55 grain BlitzKings.

<o:p></o:p>
<o:p></o:p>
http://www.box.net/shared/static/0fuxcv68qk.jpg<o:p></o:p>
<o:p></o:p>
<o:p></o:p>

gdvan01
01-14-2010, 10:53
http://ammo.ar15.com/ammo/