accuracy with 55gr using 1in7 twist?

**SteveO666** · April 26th, 2014, 05:07 PM

Ok I was having a conversation with someone today and he stated that a 1in7 twist barrel works best for accuracy with 75gr bullets and that using 55gr I would have trouble getting small groups.
Now I am new to rifle shooting so pretty sure I won't have small groups anyway but I would like to know if it is because of technique or equipment.

Anyone have a 1n7 barrel shooting the 55gr ammo experiencing accuracy issues?
Thanks,
Steve

**USMC3531** · April 26th, 2014, 05:27 PM

itll stabilize them fine. ask yourself how far do you regulary shoot? are you buying cheap ammo? carbine or rifle? if your answers are <100yd, yes, and carbine. it realy doesnt matter what twist you get.

**AJ C-burg** · April 26th, 2014, 06:01 PM

1/7 does better than 1/9 with heaver projectiles but will stabilize 55's fine. I prefer 1/7 or 1/8 for my purposes but if a varmit 223 light grain(50<) I'd want a 1/9. Just my 2¢.

**Pilot321** · April 26th, 2014, 06:48 PM

The U.S. armed forces standard 5.56 round is 62 grains, and they use 1/7. 1/7 will stabilize 55 grains just fine. My Colt M4/le6920 is 1/7, and I can tell no difference in accuracy between 55 grain, and 62 grain.

**Lycanthrope** · April 26th, 2014, 07:10 PM

My 1:9 guns consistently outshoot my 1:7 barrels with 55gr rounds.

YMMV

Lycandidtheworkthrope

**dkf** · April 26th, 2014, 07:17 PM

This guy makes some good vids.

**aubie515** · April 27th, 2014, 01:50 PM

The twist rate isn't going to make the rifle more accurate. The twist rate is going to mean the difference between being able to stabilize X weighted projectile.

If your friend's flawed logic was true...that would mean that an ER Shaw barrel would outshoot a Krieger barrel if the twist was "better" since it has a 1:7 twist using 75gr projectiles.

The fact is for most people using AR15s a 1:9 twist will work for most people.

I personally choose to go 1:7 since I use 55gr, 62/64gr and 75gr bullets.

Once you go 75gr and above for bullet choices, you might end up loading it one at a time since the longer/heavier bullets won't allow you to seat them in an AR15 mag.

There are way too many variables to say that X twist rate with Y bullet weight is going to be more accurate. Every firearm is different and you must account for shooter skill, optics, mounts, reloading components or ammo selection, temperature/humidity...etc etc.

**Lycanthrope** · April 27th, 2014, 03:14 PM

Originally Posted by aubie515

The twist rate isn't going to make the rifle more accurate. The twist rate is going to mean the difference between being able to stabilize X weighted projectile.

If your friend's flawed logic was true...that would mean that an ER Shaw barrel would outshoot a Krieger barrel if the twist was "better" since it has a 1:7 twist using 75gr projectiles.

The fact is for most people using AR15s a 1:9 twist will work for most people.

I personally choose to go 1:7 since I use 55gr, 62/64gr and 75gr bullets.

Once you go 75gr and above for bullet choices, you might end up loading it one at a time since the longer/heavier bullets won't allow you to seat them in an AR15 mag.

There are way too many variables to say that X twist rate with Y bullet weight is going to be more accurate. Every firearm is different and you must account for shooter skill, optics, mounts, reloading components or ammo selection, temperature/humidity...etc etc.

Sort of.

My DPMS barreled Gator in 1:9 outshoots my 1:7 White Oak barrels with the lighter bullets (both shoot .5 moa or better with the preferred loads). Yes, the 1:7 WOA barrels "stabilize" the bullet, but certain bullet lengths will prefer a sweet spot in terms of twist rate that will produce best accuracy. It's also one reason why 50gr match bullets and 80gr match bullets do not produce the same size groups out of the tight twist guns.

I never had trouble seating 80gr bullets inside mag length. The real reason to go single shot with the heavy bullets is to get them close to the lands for accuracy and mag length rounds are nowhere near close to the lands in most chambers.

LycanYMMVthrope

**Palerider** · April 27th, 2014, 03:37 PM

OP: You just posted asking for advice between PMC 223 and AE 5.56 ammo. So I'm thinking you're looking for something to get a zero with and shoot at the range. Please correct me if I'm wrong.

If it's for fun and plinking, then I'd say 55 or 62 grain will serve you just fine.