AR questions for my next build.

[1911 guy]

So I already know that the next AR I build is going to (hopefully) look like a fairly "stock" A3. A2 stock, A3 upper, and now come my questions.

I've decided on a 20" barrel, but do I gain any practical advantage with a 1:7 twist over a 1:9? My 1:9 does 60-65 gr bullets no problem. Am I missing something? Also, do Shaw barrels still have the good quality they were once known for? I can get one for under $300 if so.

Does anyone have an opinion on Rock River Arms' free float tube that installs under the A2 handguards? I'm considering one. It this is a bust, I'll find some other float option.

Optics questions for those more savy than I to follow later. I've got to build the thing before I can shoot it.

 

[mustbe]

Sounds like you want a National Match upper.

The Rock River upper is excellent and can be had complete for less than the cost of the individual parts. An A2 upper from Pete at Legal Transfers is $620 shipped, so the A4 should be cheaper if you don't want the carry handle.

The 1 in 8 Wilson air gauged barrel is good for a wider variety of bullets. The float tube is a very nice piece but does add some weight. If you want stock looking, the DCM float tube from RRA, CLE, WOA, etc. is the only option.

 

[gotigers]

mustbe is spot on. Your description sounds like a national match. Do you want a FSB, fixed front sight? If so, that is a national match upper. As mustbe said, look at RRA.

If you want to shoot national match, you will need a carry handle. Otherwise, i would skip the carry handle. You can always pick up someone elses take off later if you want a carry handle.

I agree that 1:8 is a great option. My National Match is a 1:8. If you can only choose between 1:9 or 1:7, i would go with 1:7. 1:7 wont hurt you with 55gr, but 1:9 wont shoot the 70 grain stuff as good.

I went with a Fulton Armory stainless 1:8, wylde chamber, barrel. FA uses Criterion blanks. I am very happy with it. If White Oak Armory would have had barrels in stock at the time, i would have got the WOA barrel.

You should shoot this while wearing the 5.11 tactical kilt.

 

[1911 guy]

Unfortunately, the 5.11 kilt was a limited time item. Introduced as an April Fools joke, it got so much attention and interest in the first couple days that 5.11 decided to make a limited run to satisfy those who got their hopes up.

I'm not as interested in shooting at Camp Perry as I am in a traditional looking AR with the advantage of a free float. It will likely see the most use as a varmint and target rifle.

I'll have to look into White Oak Armory. Heard of them, know nothing about them.

 

[cfullgraf]

I'll have to look into White Oak Armory. Heard of them, know nothing about them.

Good stuff and good folks to work with. i have a 20" NM barrel in a varmint AR that shoots sub MOA.

If you know you are might shoot heavier bullets, get the faster twist barrel. If not, the 1-9 twist is a good compromise. Some of them will shoot the 68/69 bullets fine. Some won't.

My WOA barrel with a 1-7 twist shoots 55 grain bullets just fine. I would probably never shoot anything lighter than 50 grains anyway in it so the fast twist would not be an issue.

 

[Ramone]

just buttin in-

it sounds like you want an M16A4 look alike- the A3 was the Full Auto version of the A2 (fixed carry handle, 3 RD burst), the A4 was the flat top...

The National Match style free float is a pretty clever rig- works well, and looks like the Service Rifle.

 

[madcratebuilder]

You want this

 

[Welding Rod]

Hard to go wrong with a RRA NM upper. But they are heavy. That float tube adds weight you can feel.

I had one, but now compete with a standard RRA A2. It has the 1:9 HBAR (chrome lined), but is not floated. It is a 1 MOA upper when I can shoot the irons that well, which is plenty accurate for CMP style matches at my local level.

Our matches are shot entirely at 200 yards. At this distance I shoot 69 grain SMKs in my handloads and sometimes 75 grain Hornady match ammo. Both shoot quite accurately at that distance. I frequently win one or two of the five stages with it.

The non-floated HBAR does flex some and change POI when slung up tight, but nothing like Gov-profile barrel does. But if the shooter knows what to expect and is consistant in his different position holds, it can still be done without a problem.

I can not bring myself to wear a shooting coat when I shoot. I think they are just too artificial of an aid. Without the aid of a coat, I find I shoot offhand better with the lighter non-floated HBAR than I can shoot with the heavier floated HBAR.

In any position the non-floated barrel is still very capable of easily holding the 10 ring so I don't see any real advantage in the floated barrel... unless a shooter does not shoot enough to know what to expect in POI change due to changes in sling tension / use, or is quite inconsistant in their sling tension between shots in a string.

Honestly since I drop most of my points while shooting offhand, I think I could shoot match scores almost as good with my non-floated Gov profiles. But I am not trying this soon as the points scores for our season are very close and we are nearing the end of the year.

I guess my point is you have to be pretty good shot and shooting at pretty small targets for the float tube to matter much, and in the mean time you have the extra weight 100% of the time.

 

[skywalkrNCSU]

Why do you want a 20" barrel? There is really not much benefit when compared to an 18" barrel or even a 16" barrel for that matter. The quality of the barrel is what makes it accurate, not the length.

 

[1911 guy]

I'm hoping to use this rifle for both local competition and varminting. My thinking is that the longer barrel, with longer gas system, would give me more velocity due to not bleeding gas off as soon as a 16" barrel would. Am I all wet? I admit to being more competent in using most firearms (including the 1911 and AR) than I am at understanding their inner workings.

Weight isn't a huge concern for me, as I dont intend to be running through the underbrush with this one, but I also don't want to get ridiculous and have a rifle that's a pain to use and carry. Years ago I ditched a good shooting Remington for that reason. Heavy as all get out. Laminate stock and bull barrel varmint gun.

 

[back40]

find a rock river NM and get a feel the wieght for yourself. i think you'll be fine with it for what you're doing, but that's me. if it feels ok, check out WOA. i'd personally lean towards the 1:7. as said, some 1:9s will shoot the heavy stuff just fine....some won't. with 1:7 your odds are better. also consider an aftermarket trigger. rock river's nm trigger is ok, but leaves a lot to be desired imho.

will you be using irons or are you adding an optic?

 

[skywalkrNCSU]

I'm hoping to use this rifle for both local competition and varminting. My thinking is that the longer barrel, with longer gas system, would give me more velocity due to not bleeding gas off as soon as a 16" barrel would. Am I all wet? I admit to being more competent in using most firearms (including the 1911 and AR) than I am at understanding their inner workings.

Weight isn't a huge concern for me, as I dont intend to be running through the underbrush with this one, but I also don't want to get ridiculous and have a rifle that's a pain to use and carry. Years ago I ditched a good shooting Remington for that reason. Heavy as all get out. Laminate stock and bull barrel varmint gun.

Yeah I mean that should work for you then. Personally, I would get an 18" upper with a rifle length gas system but a 20" will work fine as well.

 

[Taurus 617 CCW]

The 1:7 twist rate barrels tend to wear out faster than the 1:8 and 1:9 counterparts. This is mainly due to increased friction as the twist rate becomes more aggressive.

 

[gotigers]

Many matches require a 20" barrel. So, if the OP wants to shoot those matches he will need a 20".

 

[helotaxi]

The 1:7 twist rate barrels tend to wear out faster than the 1:8 and 1:9 counterparts. This is mainly due to increased friction as the twist rate becomes more aggressive.

When the typical barrel life of a 1:7 twist, chrome-lined barrel is measured well north of 10k rounds, this is such a non-issue that it doesn't even bear mentioning. Even non-lined stainless barrels have their lives measured somewhere beyond 10k rounds provided you don't do repeated mag dumps and get and keep the barrel super hot. When a match barrel costs less than 1k rounds of ammo, why worry about whether the barrel lasts 11k or 11.5k?