Rock River Varmint A4 1/8 vs. 1/12 Twist ?

[amauro1]

Hello all,

Well I finally ordered another AR-15. I narrowed my choices down to the RRA Varmint A4 in the 24" SS Barrel or the 20". Both these rifles are offered in a 1/8 or 1/12 twist rate. I will mostly be shooting prone and or on a bench, paper punching and matches with this set up. Which do you guys prefer? 24" or 20"? and 1/8 or 1/12?

All help is appreciated!
Thanks

 

[RADcustom]

Re: Rock River Varmint A4 1/8 vs. 1/12 Twist ?

It would help to know what bullet you intend to shoot.

I would choose the 1-8 20" if those were my only choices.

 

[SMH]

Re: Rock River Varmint A4 1/8 vs. 1/12 Twist ?

1:8 twist has served me well shooting 52-77 grain bullets.
I'm surprised RRA offers a 1:12

I have/had 16, 18, 20 and 24 inch SS 1:8 twist barrels.
Accuracy was very comparable with all of them. I parted with the 24 inch as it was a bit cumbersome for hunting and seemed to be a fraction of an inch less accurate then the others.

However, the extra length (velocity) might be beneficial for longer range shooting.

 

[amauro1]

Re: Rock River Varmint A4 1/8 vs. 1/12 Twist ?

Thanks alot for your quick response, Yea I was pretty surprised myself when they offered a 1:12 twist. It definately threw me off. But I am going to take your advice on the 1:8 since most other AR's are 1:9. I am just torn between the barrel length now. 24 or 20.

 

[amauro1]

Re: Rock River Varmint A4 1/8 vs. 1/12 Twist ?

I reload so I will have to develop a load for the set up I get. I mainly use Sierra MK. But I am going to try all SMK's from 52-69 grains.

 

[SScott]

Re: Rock River Varmint A4 1/8 vs. 1/12 Twist ?

I have one with a 20" 1-8 and it loves 52grn BTHP. I also load 68 grn HP's over Varget and it does very well, although I haven't tried any heavier.
I would only select a 1-12 if you were going to try to push really light bullets really really fast, otherwise a 1-8 will serve you well.
SScott

 

[daveog]

Re: Rock River Varmint A4 1/8 vs. 1/12 Twist ?

In 223, I don't think you gain much from barrel length past 20" so I think 24" is overkill. Definitely go for the 1:8 twist though or you will be limited to shooting little bullets that aren't good for long range.

 

[DavidAR10]

Re: Rock River Varmint A4 1/8 vs. 1/12 Twist ?

I helped an acquaintance by directing him to info to make his own decision on a RRA V rifle a few years ago. He's an aerospace engineer at Lockheed/Martin and didn't need preachin' at. He chose the 24" 1/8.

While he was waiting for his scope to come in, the burn to try it out was too great so I took him up to the farm and let him borrow an AETEC made in Japan. The AETEC has majics because I have used it for load development for 6.8 and 458SOCOM. It let me bracket and then nail loads that went sub-0.5" most riki-tik during the pain of funding my first high end glass.

Well, with knees in the dirt, tailgate for a bench and an MTM gun cradle for rests:

John up at the farm sighting in and then shooting for groups/having fun @ 100yds.

A fair example of the many groups that he shot that day.

He told me at the end of the day that he had three rounds left and that I should shoot them. He knew what I used to do for a living {I think my Dad might have told him, Dad was the Senior Flight Engineer Instructor on the aircraft that John was modernizing}. He kept pushing even after I told him that it was his day to have fun, relax and fall in love with his new rifle.

I had brought up my ARMALITE AR-10T 24" and AR-10AR 20" Chrome-Lined but didn't fire either one so that he could have more trigger time.

Well, came down to him not selling me his rifle at twice his cost... da-da-damn.

 

[Highpoint]

Re: Rock River Varmint A4 1/8 vs. 1/12 Twist ?

No complaints with the RRA varmint 1-8 20" barrel I have , usually 1/2-3/4 moa with 69 gr nosler bthp at 2825 fps.

 

[ORD]

Re: Rock River Varmint A4 1/8 vs. 1/12 Twist ?

1:8 twist 20" barrel is what I'd opt for which will run anything from 52gr through 77gr loads without excellent accuracy. As others have said, I'd only opt for the 1:12 twist for a dedicated varmint rig where all I want to do is run lightweight (45gr or lighter) bullets at crazy-fast MVs.

No real advantage to the addt'l 4" of barrel unless you just need the extra velocity and slightly extended range it offers you. However, with that particular contour barrel, you end up adding roughly 1/2lb of muzzle weight when going from the 20" to the 24" tube which combined with the addt'l length is more of a PITA than its worth.

 

[holy cow]

Re: Rock River Varmint A4 1/8 vs. 1/12 Twist ?

As pretty much what everyone else said i would opt for the 1/8 twist and 20 inch barrel. I have owned several different models in 223 and have been more than happy with all of them. They where all good shooters, had nice out of the box triggers and well put together and reliable. I think for the money they are 1 of the best all around out of the box AR's.

 

[bugshooter]

Re: Rock River Varmint A4 1/8 vs. 1/12 Twist ?

I have the 20" 1:8 bbl and it really likes the Hornady 75 gr BTHP match bullets. It's a spectacular shooter.