Starting AR-15 Build.. Got questions.. .

[crackhead]

So I think I want to build an AR.. Looking to go .223 for long range paper, PD's, Coyotes, Antelope, and GA whitetails.. Mostly for the first 4 though.. Im pretty sure Im looking at a 20" barrel.. 1:8 twist right?? Im going to build it myself, all but maybe the upper.. I may buy the upper already assembled.. If I decide to buy it in pieces, any decent smith should be able to throw it together and headspace it right?? Im going to be buying a lower here real soon.. Is there anything I need to stay away form when dealing w/ lowers? Hows Anvil Arms? Should I get the lower already assembled?? If so whats the advantage?? Am I going in the wrong direction building a long range toy w/ an M4 style stock?? Ive shot the M-16 and dont really like the A2 style stock.. Sorry for all the quesitons.. Thanks..

Brian

[Sucka]

For precision work, a 20" barrel would be ideal. As far as twist rate, i think that depends on the ammo you'll be using. Someone who actually shoots precision rifles could probably better advise you than i could.

No doubt a competent smith could assemble an upper for you. I wouldn't be surprised if a board member here could help you do the work yourself. I've never done an upper, so no clue there.

Anvil Arms makes fine lowers, and they are among the cheapest i know of. I don't have the list, but there are only a few machine shops that crank out the lowers for pretty much all the companies. Outside of finish and the roll mark, they're all pretty similar. You might want to figure out what upper you want, and try and match the finish of the lower, as well as check user reports on how they mate (no wobble and such). Just remember if you buy a stripped lower, to buy the appropriate buffer tube (commercial vs. mil-spec). No advantage one way or the other except you get to pick your lower parts kit, and it's typically cheaper to assemble yourself.

Most precision rigs i've seen use stocks like the Magpul UBR or some other stock that gives much more adjustability over a standard M4 stock. You'll probably want something with a better cheek weld.

[crackhead]

Looks like Anvil Arms is sold out.. Thats probably going to be SOP for everyone for a while at least huh?? Cool.. Thanks for the info..

[Sucka]

Looks like Anvil Arms is sold out.. Thats probably going to be SOP for everyone for a while at least huh?? Cool.. Thanks for the info..

Oh yeah, for a long while probably. If they're still taking back orders, i would get on that list. Same goes for any other place accepting back orders on lowers.

[HunterCO]

You want a faster twist rate for heavier bullets so you need to decide what weight of bullet you wish to shoot. I also would not recommend hunting antelope with a .223 in CO as it is illegal.

Give Alan Samuel a call he stocks a lot of stuff and could set you up with what ever it is you need. He is also very reasonable on his prices. He has his own forum on this site in the dealer section. You can also go to machineguntours.com.

[crackhead]

Hunter CO, Thanks for the info... I wasnt aware that a .223 was illegal to hunt w/ in CO.. Just looked up the regs.. Interesting... My Coworker is a neighbor of Alans, so I may have him introduce me and see what he thinks.. As far a bullet weights go.. Why is an AR barrel so finnicky with them.. We never cared what weight bullets we shot through our rifles growing up, lighter bullets for lighter game, etc.. What am I looking at shooting through a 1:8 twist??

[HunterCO]

1/8 is a middle of the road twist it will probably shoot 55 grn up 69 grn ball well. I am not trying to say that an ar is finicky with twist rates, it's just that certain twist rates will be more accurate with a given bullet weight.

There are many rifles that are more accurate with certain weight bullets. I have a 30-06 that loves 150-165 grn bullets. It is one of the most accurate high powers I own however if I jump up to 180 grn bullets it hates them. At 100 yrds with 150-165 quarter size groups 180's softball size groups.

Get in touch with Alan he can tell you everything you need to know as well as get you what you want.

[sniper_tim]

There is a good article (http://ammo.ar15.com/project/AR15_Ammo_FAQnRules/index.htm#What%20bullet%20is%20the%20most%20accura te) about this on twist rates on ar15.com. Here is a rough guidline:

1-in-14" 55gr or less
1-in-12" 35gr up to 55-60gr
1-in-9" 45gr-75gr, possibly up to 77 if you're lucky
1-in-8", 1-in-7" 45gr - 80+gr

I think 1/9 used to be a good general twist rate to shoot everything, but guys who shoot matches started to use 1/8 cause it stablizes the heavier bullet better.

[mightymouse]

To quote Dan Flowers, et al from www.theballisticedge.com


Twist relates to bullet weight in a "round about way".

Actually the bullet length is more related to twist. Bullets that are long in terms of their caliber need to be spun faster than those that are relatively short in terms of caliber. Bullets of conventional construction usually get heavier as they grow longer so weight comes along with BC. However as with the monolithic turned projos the weight doesn't increase as much when the length grows.

It is length, not weight that requires the faster twist to get the bullet to stabilize properly. The longer they are, the more they want to yaw if not perfectly aligned on axis, and more gyroscopic stability is required to keep them straight. Choosing barrel twist for a combat weapon system and ammo combination however, is more complicated than choosing one to put holes in paper.

As I see it, twist rate should be chosen by the ammo you intend to use for your application and that you can afford to practice with. MY rifles intended use is self-defense. At the ranges a civilian can justifiably shoot (generally >100yds), 55gr is plenty lethal if do your part. Therefore, I reload, practice with, and load my defensive rifle with 55gr FMJ in a 1:9 barrel. YMMV