AR Build- Rookie Needs Help Please

[Robusto]

Hi all,
I am building my all-purpose AR. It will be used for target, fun, home defense, SHTF, you name it. Being a student, this will be my only AR as I really cant afford to have two (or more), but I want to build a good, reliable AR. I have been doing a lot of reading, but I really need some help making a few executive decisions.

I have a POF lower on order, but need help choosing some upper components. I think that I would like an 18” barrel because it seems like a good compromise between a carbine and a rifle length, but was thinking that maybe I should just stick with a 16. Also, should I stick with a regular upper and charging handle, or go with a side cocking upper (pic below).

Rate of Twist???
What rate of twist is best for all around use? I see a lot of 1:9 and 1:7, 1:7.5, but what about the 1:8-1:8.5. I would like to be able to shoot the widest variety of bullet weights. I don’t need to go super heavy, but would like to be able to shoot heavier bullets if I find that I would like to try my hand at competition.

Can you “over stabilize” or over spin a light bullet? I know that if spin a heavy bullet too slow, that accuracy will diminish, but will spinning a light (say, 55gr) bullet too fast (if possible) hurt accuracy?

Thank you all,

Tom

 

[Tarvis]

or go with a side cocking upper

I was thinking those were designed to be used for hunting in states where autoloaders are banned for taking game. Get a standard semi auto upper. Come to think of it, you could still tun one of those semi auto.... *ponders*... never thought of that. I would still get the rear charging handle unless you are left handed, but that's just me. The beauty of the AR platform is you can get whatever you want. Keep in mind you need to be semi careful not to get gunk in the action when you aren't shooting/carrying the rifle with the side charging handle as there is no breech cover. Also, there is no forward assist, so you'd better plan on shooting really clean ammo. Never mind, I'm apparently not thinking today. You don't need a forward assist if you can bump the handle on the side. *snore*.

Can you “over stabilize” or over spin a light bullet?

Yes. Light bullets have a thin jacket which can come off if over spun. I recommend a 1-8 as you should still be able to shoot 40gr bullets and will be able to handle up to 70grs or so; correct me if I'm wrong please. Also, for the best answer you should tell us exactly what weight of bullets you plan on shooting/trying so we can tell you exactly what twist. If you speculate on the weight we can only speculate on the twist.

 

[Robusto]

Tarvis

Thanks for the reply.

you need to be semi careful not to get gunk in the action when you aren't shooting/carrying the rifle with the side charging handle as there is no breech cover

Good point. I really havent thought of that.

Also, for the best answer you should tell us exactly what weight of bullets you plan on shooting/trying so we can tell you exactly what twist.

I will most likely will be shooting 55-69gr surplus or lower priced ammo, but would like to be able to shoot the 77gr Match kings if I get into competitive shooting.

 

[cracked butt]

The rate of twist isn't all that important unless you are trying to shoot heavy bullets out of a carbine or trying to shoot very heavy bullets at long range.

A rifle with a 1:9 barrel will often stabilize bullets up to 75 gr. A 1:9 carbine probably will not. A 1:7 rifle will shoot bullets from 52-80 gr with no problems.

Carbine length ARs are very popular right now, but unless its going to be used for clearing rooms or possibly 3-gun competition, they are pretty much just tacticool toys. Rifle length ARs are a lot more useful, but that's just my opinion.

but would like to be able to shoot the 77gr Match kings if I get into competitive shooting.

One more reason to get a rifle length of 1:8 or better. If you plan to shoot in NRA or CMP highpower events, save up the money and get a Compass Lake or White Oak Armaments Upper- they aren't cheap, but will save you a huge amount of money and aggrevation in the long run.

 

[Tarvis]

I don't know much about shooting high power, but I think NM sights would help a lot.

It sounds like you want a 1-8 20" barrel.

 

[MACDD]

IIRC you only lose 150-200fps between 16 & 20" barrels with most ammo, probably more important is what role you're going to use it in most. 18" barrels don't seem to be very common.

1:7-1:9 will work with most weights, though if you'll be shooting light (40-45gr) varmint bullets you'll probably want 1:9 which is more common anyway. I like 1:7 since I don't shoot anything lighter than 55gr. 1:8 is usually only available in stainless steel barrels for some reason.

I don't have any experience with side-charging uppers but don't like the idea of missing material on the side of my receiver, and don't really see the need.

Barrel weight/profile and gas system are other things to consider.

It's hard to buy a rifle for competition if you don't know which one since different guns will be legal/better for different courses.

I'd probably get a 16" carbine/midlength for now, then if you're still interested in competition buy that upper later after a little more research.

There are thousands of different configurations, look at www.cmmg.com to get an idea for what's out there.

 

[SSN Vet]

18" barrel

you just decreased your selection by a factor of 10 and drove your price up.

1:8 twist

just did the same thing again.

get a 16" middy kit from Del-ton, spring for the chrome lined barrel and you're good to go for ~$520

 

[dewage83]

I got the 20" and would have rathered (now that I've shot the heck out of it) the 16". The 20" just moves the balance point more towards the front of the gun.

Del-ton has great service and parts. +1 for Del-ton.

 

[Organdonor]

+1 on the mid length 16" barrel setup. At 16" the barrel will be long enough so you still have a good amount of fps, and the midlenth gas tube will prevent a lot of the issues the carbine length tubes have.

I have a 20" rifle length on my .223 and .308 AR's, and will be going with a 16" when I start my 7.63X39mm AR build shortly.

 

[dewage83]

Organ donor are you putting together an AR in 7.62 because you cant get a hi cap 7.62 rifle? Thats what I was planning. I just cant see paying about .40 cents a rd. to plink with.

 

[drgrenthum]

I 2nd the vote on a 16" delton. You mentioned this will be your only one for a while because of price, the delton you can get for under $550 which will hopefully leave you some room to get an optic of some sort. Get the 16" since you are looking at it for home defense and shtf. Shorter length of course means its a little bit easier to swing around.

I assume that you are going to be plinking away with the most cost effective ammo you can find. In that case a 1:9 barrel will do the trick as you will probably be shooting 55g or 62g ammo.

By the time your out of school and have more money and want to hunt larger game or need a bada$$ rifle, you will have the money to get an upper to shoot the heavier stuff or change out the barrel or other goodies on the delton so that it can be your ideal weapon, also by that time you will have a better idea of your likes and dislikes.

 

[Brian Dale]

MACDD, thanks for mentioning CMMG; that link didn't work for me, though. Try this one: CMMG