PDA

View Full Version : AR15 help


garciach1
07-02-2012, 12:11 AM
AR 15 help. . . I want to build a sniper rifle (223/556) hitting targets at mid range around 250-300ish yards away. Also light weight if possible so no heavy bull barrels... First thing first, uppers... barrel

What will be the best barrel length 18" or 20" and twist? (I'm thinking 18" with 1:7 twist, but is that over kill for my target goals?)

Barrel weight:
Heavyweight= less muzzle rise=heavyasfook -VS- lightweight= muzzle rise= mobility

Also Gas tube piston Vs Direct gas for a midrange sniper rifle. Which one? why?

What you think?

If you have a good ARwebsite. . . share.. thanks:chris:

SocomM4
07-02-2012, 6:51 AM
24 inch stainless/heavy
DI rifle
1/9

ocabj
07-02-2012, 7:00 AM
If you want a "sniper rifle", you want maximum accuracy. To obtain maximum accuracy, you need consistency. To obtain consistency, you need to minimize effects on the rifle platform. To minimize effects on the rifle platform, you need to be able to handle heat. To handle heat, you need a heavy barrel.

Arnelcheeze
07-02-2012, 7:31 AM
250-300 yards, you don't need a sniper rifle and you don't need heavy barrel.
you could hit that range with a regular chrome lined carbine barrel, if you got good eyes you could hit that with iron sights.
- From what you are asking looks like you want to build something like a DMR(Designated Marksman Rifle) maybe. go with an 18-20 inch barrel med to heavy, but when you say "sniper rifle" and DMR it makes most of us think 308 caliber.

Yemff
07-02-2012, 7:35 AM
you can hit a target 250-300 yards with a 16" carbine with iron sights

killathrilla
07-02-2012, 7:46 AM
...

SocomM4
07-02-2012, 7:54 AM
Op said he wants a sniper rifle. Whats all this carbine talk and how he doesn't need this or that.

I think a Bushmaster Varmiter upper would fit the bill.

Go to YouTube and search "ZombieMax!!!"
by tnoutdoors9 . 700yards.

the86d
07-02-2012, 8:00 AM
20" 1:8 for 62 grain Green Tips... 20" 1:9+ for 55 grain (+ for 40 grain) (I know, I know...)

What are you going to shoot out of it mainly, cheap stuff?

newglockster
07-02-2012, 8:00 AM
http://www.calguns.net/calgunforum/showthread.php?t=555451

FMJBT
07-02-2012, 8:40 AM
Op said he wants a sniper rifle. Whats all this carbine talk and how he doesn't need this or that.


OP also said he wanted lightweight, no bull barrels. Shooting to 300 yards could be done out of a 7" pistol upper, but for the sake of keeping it legal in a rifle configuration, a 16" barrel will be more than enough for the OP's needs.

Something like this would be about perfect IMHO:

http://www.riflegear.com/p-1323-adams-arms-16-midlength-fluted-barrel.aspx

On the subject of stuff the OP doesn't need, I'd like to add the 1:9 twist to that list as well :chris:

1:7 or 1:8 are going to be the best choices for all around performance. The 1:9 is great at stabilizing 55-62 grain bullets and under, so it would be well suited for a varmint rifle. If you ever want to shoot anything heavier though, you can see some pretty interesting things happen that can be detrimental to accuracy. As a general rule, I like to over stabilize a bullet rather than under stabilize. Overspinning a light weight bullet generally doesn't detract from accuracy unless it's a poor quality bullet. Under spinning even a high quality heavy bullet like a Sierra Match King can result in it tumbling end over end and keyholing into the target (if it hits at all).

noob_tube
07-02-2012, 11:29 AM
For a true "sniper rifle" you need to go with a bolt action rifle. Preferably in .308. If you are determined to go with an AR platform, read all the posts above mine.

garciach1
07-02-2012, 1:51 PM
Getting good info, thanks. I want to hit, up to 250-300 yards with ease, leaning more towards precesion (1-2in" grouping) then CQB... I know for sure I won't be using this rifle to it's full potential, hitting targets @ 800+ yards so no need to go all out with sniper grade parts. So what i'm asking is between CQB and a long rang setup...

FMJBT
07-02-2012, 3:07 PM
Getting good info, thanks. I want to hit, up to 250-300 yards with ease, leaning more towards precesion (1-2in" grouping) then CQB... I know for sure I won't be using this rifle to it's full potential, hitting targets @ 800+ yards so no need to go all out with sniper grade parts. So what i'm asking is between CQB and a long rang setup...

Sounds like you are looking for somethng like a RECCE or SPR styled rifle. Essentially, the RECCE and SPR are nearly the same rifle other than barrel length and gas system. SPR uses an 18" barrel with rifle length gas system, the RECCE uses a 16" mid length.

The SPR has been documented to successfully engage and eliminate hostile targets at 700+ yards using 77 grain MK262 NATO ammunition. With good optics and ammunition, I would expect an SPR to do well against steel plate out to 800 yards, maybe a bit further. The RECCE will have slightly less velocity due to the shorter barrel, but should carry decent accuracy out to 700 yards. I have a few AR's built up on 16" mid length barrels, and they will get consistent hits out to 650 yards without much effort, so I don't think adding another 50 yards to their theoretical max range is much of a stretch. The barrel I linked earlier would be a great starting point for a RECCE build.

stix213
07-02-2012, 3:20 PM
Op said he wants a sniper rifle. Whats all this carbine talk and how he doesn't need this or that.


OP said "sniper rifle" but then he wants 250-300 yard range while light weight. His range can be handled just fine with a carbine, and his light weight goal is best attained by a carbine. 250-300 yards is nowhere near "sniper" range. I think the OP is just confused with regard to what is needed for that range, and will do best with a 16" to 20" barrel and a good scope.

TwinStick
07-02-2012, 3:24 PM
For a true "Sniper Rifle", don't you need to go to Sniper School? Maybe "Precision Rifle" is what he/she meant.

garciach1
07-02-2012, 6:23 PM
A good website to buy from. . .

Wicked K5
07-02-2012, 7:43 PM
No offense, but it sounds like you need to do a lot more reading before buying
I'd start by studying the flowchart (http://www.calguns.net/caawid/flowchart.pdf)
Then read up on websites like Calguns, Weapon Evolution, and M4carbine.

tpat663
07-02-2012, 8:07 PM
Here is my sniper rifle I built in 5.56/.223. I went with a Black Hole Weaponry 24" barrel and a LAR Grizzly Side Charging Upper. LAR is a good upper for a heavy or long barrels. My buddy Colby has a website he is located in Texas and I buy most my AR needs from him. Great prices and superior customer service. westernsportonline.com Also I would go with a traditional gas tube set up. Piston is ok keeps your BCG cleaner, but more working parts means more crap can go wrong. Also go with a free float rail for better accuracy.

http://i1185.photobucket.com/albums/z353/trpatrick36/photobucket-2008-1333125975386.jpg

http://i1185.photobucket.com/albums/z353/trpatrick36/photobucket-4335-1333125959195.jpg

tpat663
07-02-2012, 8:10 PM
Also this might help with your twist rate.

http://i1185.photobucket.com/albums/z353/trpatrick36/6704c969.jpg

russ69
07-02-2012, 8:19 PM
...I want to hit, up to 250-300 yards with ease, ...

Mid range is 600 yards. Long range is 800, 900, 1000 yards. Anything around 300 meters is combat range.

SocomM4
07-03-2012, 8:12 AM
Getting good info, thanks. I want to hit, up to 250-300 yards with ease, leaning more towards precesion (1-2in" grouping) then CQB... I know for sure I won't be using this rifle to it's full potential, hitting targets @ 800+ yards so no need to go all out with sniper grade parts. So what i'm asking is between CQB and a long rang setup...


Well as said by others a carbine with iron sights can hit a 300m target all day, so you could grab an M&P sport and get the accuracy you want. IMO
you could have a very nice rifle , hitting the well beyond the accuracy you describe with a 20in barrel and a few upgrades like a nicer stock , 2 stage trigger and a decent optic to give it the precision look and feel.


My rifle is a 16in, I use a standard trigger and an eotech , hitting clay pigeons at that range.

And Fmjbt, 1/9 is perfect for the most commonly used ammo,55gr to 62gr Bulk .

jsipe007
07-03-2012, 1:34 PM
I think your best bet will be a 16in or 18in barrel with 1 in 8 or 1 in 9 twist. My rifle actually has a 1 in 7 twist and it is very accurate at 100-200 yards with 55gr ammo.

Just a few last questions... do you want your rifle to have the capability of shooting 800+ yards? If you do, you might consider a 20in barrel with 1 in 8 twist.

a 16in barrel is easily capable of targets 400-500yards away. So if you prefer to sacrifice a little range for mobility and less weight, a 16 or 18 in barrel will do just fine

FMJBT
07-03-2012, 3:10 PM
And Fmjbt, 1/9 is perfect for the most commonly used ammo,55gr to 62gr Bulk .

I won't argue that point. 1:9 works really well for anything up to 62 grain. You can even run heavier (longer) bullets in a 1:9 if you have a long enough barrel to generate the velocity needed to compensate for the slower twist rate. It's not uncommon to see guys shooting 75 and 77 grain bullets out of a 24" or 26" bull barrel with good stability. My issue with the 1:9, with shorter barrels in particular, is that it severely limits the choice of bullets you can accurately shoot out of it. It's the only twist rate available in mass produced barrels that limits bullet selection to that degree. Going with a tighter 1:8 or 1:7 twist allows the use of anything from 40 grain varmint bullets up to 80+ grain match bullets for long range competition. Granted, if you run with a sub-par unbalanced bullet in those lower weights, that extra spin is going to make it do some lazy spirals on it's way out to the target, but it will most likely still hit. An understabilized 75 grain bullet will simply tumble end over end, it's trajectory going who knows where. So in summary, if you want to be limited to shooting up to 62 grain ammo, the 1:9 twist barel will likely be just fine. If you think you might want to experiment with different bullet weights to try stretching the rifles legs out a bit, the 1:8 or 1:7 are going to be a better choice.