What upper to get?

[Asha'man]

Options:

RRA CAR-A4 complete upper from Eagle, $449, chrome-lined, 1/9 twist. Consistently out of stock. Can also get from AR15sales.com for $434, dunno if they're in stock or not.

Eagle Firearms complete upper, $469, chrome-lined, 1/7 twist, Shaw M4-profile barrel, RRA upper receiver.

Has anyone used one of Eagle's uppers on anything? Would it be a good mate to my RRA lower? I kinda like the idea of the light-under-the-handguards M4 barrel even though I prefer the look of the CAR barrel. And what's the diff in the 1/9 and 1/7 twist? What's better for what application?

Brian

[BadShot]

Twist is related to a few thngs, but it's a stabilization issue related to the bullet grain. My next upper will be 1:9 because I generally use 62+ gr. rounds. 1:7 is cool for the 55gr. Google twist rates for AR15 barrels

http://www.ammo-oracle.com/body.htm#whattwist

ect ect

Check out the legal firearms transfers guy (Pete I think) on EE at ARFCOM. I just spoke with him yesterday and he's got so really solid deals on RRA. Just don't know if the shipping offsets the price savings.

Have you tried calling or emailing Eagle? They might not have the website updated.

[The1andOnlyKC]

Whats your plans for the rifle?

Plinker, Defense, hunting?

[Asha'man]

Whats your plans for the rifle?

Plinker, Defense, hunting?

Yes. :)

It's gonna be a pretty much all-around rifle, mostly for plinking with some defensive capability and the odd casual hunting application.

BadShot - AR15sales.com is that Pete/Legal Transfers guy. I got my LPK and buttstock from him back in the spring and it was a pretty smooth deal, so his prices are looking pretty good to me. Plus I'd like to keep the rifle all RRA if possible.

Brian

[HunterCO]

1:9 twist is what you want or even 1:12... as far as brand I will keep my mouth shut just understand you get what you pay for. [wink]

ummmmm......Badshot you kind of got it backwards the faster twist is for the heavier ammo that is why the military uses 1:7 twist because they use 62grn ball.

The ideal twist for 55 grn would be 1:12-1:14 but since you want an all around gun I would go with 1:9. That twist will serve you well no matter what you put through it. That is the best all around twist now get that gun built and come to a shoot. [postal]

[BadShot]

Thanks Hunter, I'm still trying to figure this evil twist rate voodoo out.

[The1andOnlyKC]

Get the 1/9, that should serve you well.

[MPfiveengineer]

since you want an all around gun I would go with 1:9. That twist will serve you well no matter what you put through it.

+1

[2ndChildhood]

Our very own Jensen arms has better prices than AR15sales on complete RRA rifles.
Buy there and you save shipping, transfer fee but you do pay sales tax.
They may have competitive prices on uppers as well.

I'd say stick with an RRA factory upper, better chance you won't have malf's.

And, Hunter - I'd like to hear your brand preference just for grins.

[XJ]

If you are willing to consider breaking up the RRA theme, there are plenty more options.



http://cmmginc.secure-mall.com/shop/?shop=1&cart=396555&cat=27&

[BadShot]

stumbled across this in the reviews section of ARFCOM

By Corey Sattler (Webmanager@olyarms.com)

Here is the info I have collected for .223 twist ratios from various sources (including in-house testing & ammo manf. contacts).

1x7 - technically too tight of a twist for any .224 bullet widely available, including the 80 gr. Manufactured originally to stabilize SS109 and/or tracer ammo, but further military testing has shown other twists to be superior. Some of the very heavy custom stuff (87 gr?) may work well, but why????

1x8 - great twist for 69-80 gr bullets. Sierra once informed me that the perfect twist for their 80gr was 1x8.2xxxxx (blah blah blah big long engineers explanation followed).

1x9 - good all around twist ratio. Best suited for 52-69 gr, but either end of the envelope will be questionable.

1x10 - practically the same as 1x9, but favors the lighter side a little more.

1x12 - great for the 40-52 gr bullets. Most often found on bolt action rifles as their primary use is varminting. All right for the 55 gr, but not the best.

1x14 - if you want to understabilize the .224 bullet, use this twist. Useless except for tumbling effect it causes upon bullet impact. IMHO, better to shoot straight with a good HP bullet as your chances to hit are better and damage will most likely be greater also.

About the author: Mr. Sattler is the Law Enforcement Sales Manager and Archival Records Manager at Olympic Arms, Inc. in Olympia, WA and has been with the company since 1993. He is also a Reserve Deputy in a small Southwest Washington county Sheriff's Office.

[Hoser]

Twist rate doesent care how heavy the bullet is, just how long it is.

The longest bullet you will find is a 90gn. Not seen much at all outside of high power shooters. Made by Sierra, Berger and JLK. Needs a 6.5-7 twist. Needs to be loaded long eliminating mag use. The jury is still out on if a 223 can push them fast enough to be better downrange than the old standby, the 80 Matchking.

The next heaviest/longest is the 80. Same thing. Not seen outside the high power shooters and needs to be loaded long eliminating mag use. Again made by Sierra, Berger, JLK and sometimes Nosler. Needs a 7.7-8 twist.

After those, the 69-77 are common. They need an 8 twist.

A steel core 62 is as long or a touch longer than a lead core 69. So the military just overstabilizes them. The 77gn match ammo does just fine out of the 7 twist M-4s.

If you are trying to shoot benchrest with an AR, get a 12-14 twist and dont ever plan on shooting anything longer/heavier than a 52 gn bullet.

Me, get a 7 or 8 twist and dont worry about it. It leaves you with options. Anything else ties your hands somewhere.

Corey (above) isn’t with Oly anymore, and I am one of the blah blah blah engineers of which he speaks.

[BadShot]

SO, again, still trying to understand this... is that information not any good?

[Hoser]

Coreys info is fine. I just wanted to make sure you understand required twist is a function of length, not weight.

My money would buy a Rock River, Armalite/Eagle or JP upper.