What ammo should i use for my AR (specs inside)

[SouthBendIN]

Hey everyone. I'm heading down to the Indy 1500 on saturday. One of the things I will be looking for is some good ammo for my AR. This spring I want to start doing some distance shooting (100-500 yards). Reviews I have looked up about my rifle say that it is viable to hit targets at around 600 yards. Here are the specs:

Barrel:
20" Length w/ A2 flash hider (birdcage)
416 Stainless steel heavy barrel (not chrome lined)
Fluted w/12 custom groove flutes
6 grooves, right-hand 1x8 twist, button rifled

Chamber:
5.56 NATO

Method of Operation:
Gas operated rotating bolt

Bolt & Carrier:
8620 steel bolt carrier, heat treated and plated per Mil Spec
Phosphated steel bolt, heat treated and plated per Mil Spec

Sights:
National Match front sight post.
With four set screws for front sight adjustment

Weight:
Empty – 8.85 lbs.

Length:
39 1/2"

Upper Receiver:
A3 Flattop, Forged
7075-T6 aircraft aluminum alloy
Hard coat anodized per Mil Spec and Teflon® coated black
Dust cover
Shell deflector
Round forward assist
Right hand ejection

Lower Receiver:
Forged 7075-T6 aircraft aluminum alloy
Hard coat anodized per Mil Spec and Teflon® coated black
Two-stage semi-auto trigger group
Aluminum trigger guard
Aluminum magazine release button

Stock:
Standard A2 black Zytel Mil Spec w/ trap door assembly

Handguards:

4-Rail aluminum Free Float Tube
Includes 6 rail covers

Here is a pic for reference: DPMS 20" SDMR Barrel Assembly : Parts4ar15

My question is, what would be some good ammo to look for for this setup? What grain can I use? TIA

 

[IndyGunworks]

1x8 twist... you should be good w/ about anything mid weight... it MIGHT like 55 grains and it MIGHT like the heavies, but if you stick with 62 ish grain up to say 70-75 you should get pretty good results.

 

[edsinger]

This is a great question. I wish I knew....But I will ask the same to see if I can get some answers from those that own a S&W OR with a 1:9 twist?

 

[mconley]

my ar really likes the hornady tap fpd 60gr.

 

[mconley]

but I guess it would depend on what you are using it for as this can get expensive, if it is just punching holes in paper, black hills is always a good choice, if its going to be a man stopper go with the hornady

 

[bigdaddy1427]

Anything 55 grain and up should be okay. Try to stay away from steel case ammo.
Some rifles like it, some don't.

 

[IndyGunworks]

This is a great question. I wish I knew....But I will ask the same to see if I can get some answers from those that own a S&W OR with a 1:9 twist?

1x9 for the heavies... wouldnt go higher than 62

Anything 55 grain and up should be okay. Try to stay away from steel case ammo.
Some rifles like it, some don't.

1x8 may not properly stabilize a 55 grain bullet. but it very well could.

 

[edsinger]

1x9 for the heavies... wouldnt go higher than 62

Thanks...

62G for a 1:9 twist........

When I get some range time I will do a comparison.....

 

[sloughfoot]

For up to 600 yards, look for 75 or 77 grain cartridges. 68 or 69's work great up to 300 yards. Soft points from 55 to 60 or so work well also up to 300 yards.

Your 1X8 barrel can stabilize 80's, but I don't know if you can find commercial loaded 80's.

It would be easier on you if you reloaded, but you might find 77 or 75 Black Hills or Hornady ammo. My reloads outshoot the factory stuff, but our Club used Black Hills 75's in the Rattle Battle match a couple of years ago and the ammo did just fine on the silhouette target out to 600 yards.

 

[Litlratt]

A 1 X 8 twist should stabilize anything from 52 - 80 grain bullets.
The longer the distance the heavier the bullet.

 

[slow1911s]

Your 1X8 barrel can stabilize 80's, but I don't know if you can find commercial loaded 80's.

Black Hills loads an 80 gr, but it isn't for ARs, at least not this one. For one, it won't go in a mag (too long, max OAL is 2.275") and two (most important) that barrel isn't throated long enough for the 80 gr head.

The 8 twist bbl will stabilize 55 gr heads all day long. It will do better with heavier heads, especially the 70, 73, 75 and 77's.

 

[sloughfoot]

slow1911s;

2.275 is only .015 beyond max magazine length for the AR 15. Normal is 2.250 to 2.260. (at least that is how I load em) Are you sure about that OAL? I seem to remember a Nosler load with an 80 at mag length, but I ignored it because of slow speed.

Do you know what speed the Black Hills 80's achieve? There can't be much room for powder after pushing that long bullet into that case......

In my experience, the 5.56 chamber is huge and has a very long leade. I haven't loaded for one in a number of years, but OAL length of 2.450 with 80's are what I remember. Natch, too long for the mags, but I have always single loaded my 80's for 500 and 600 yards.

I totally agree that the 1X8 will stabilize 55's just fine, but I think 55's are best used inside 200 yards. I believe that 75 and 77 are the better choice out to 500 yards.

Regards

 

[Litlratt]

It would surprise me if the Black Hills offering wasn't made available with the AR in mind specifically.
80s are the standard for slow fire prone stages in NRA Highpower as well as prone only Palma and Long Range matches out to 1k.

 

[edsinger]

So does a 5.56 barrel with a 1:9 really care what ammo it needs? I am ignorant of this topic. I have some misc ammo but it is too damn cold to shoot it...

Anyone have a link to example of different ammo and results with a S&WMP15? BTW I will be shooting at 100 Yards until the new range in Fort Wayne opens this year, then maybe 200-300.

 

[IndyGunworks]

A 1 X 8 twist should stabilize anything from 52 - 80 grain bullets.
The longer the distance the heavier the bullet.

i just find this hard to believe... if a 1x8 can stabilize ALL the weight bullets why aren't ALL ar barrells in 1x8? clearly there is an OPTIMAL weight in there and will a mid range twist one could determine that optimal weight to be midweight bullets.... or i could just be looking to deeply into the issue.

 

[sloughfoot]

So does a 5.56 barrel with a 1:9 really care what ammo it needs? I am ignorant of this topic. I have some misc ammo but it is too damn cold to shoot it...

Anyone have a link to example of different ammo and results with a S&WMP15? BTW I will be shooting at 100 Yards until the new range in Fort Wayne opens this year, then maybe 200-300.

What new range? Fort Wayne Rifle & Revolver Gun Club... Home just had its 100 yard offhand winter club match this last sunday. Next match is second sunday in Feb. We will have 200 and 300 yard matches starting in April. The schedule is on the website.

Your 1X9 will prob like 75's or lighter. Maybe 77's but you have to try to find out.

 

[sloughfoot]

i just find this hard to believe... if a 1x8 can stabilize ALL the weight bullets why aren't ALL ar barrells in 1x8? clearly there is an OPTIMAL weight in there and will a mid range twist one could determine that optimal weight to be midweight bullets.... or i could just be looking to deeply into the issue.

I think the 1X9 optimizes barrel life compared to the 1X8. I think it is a good compromise for most users, as determined by the manufacturer.

IMO and experience, the 1X8 is the ideal twist for all bullet weights from 55 to 80. Even better, is the 1X7 5.56 that is on my rattle battle rifle used with 75 grain Hornady's at 2750FPS.

 

[edsinger]

Hey I just found this link for those who dont have it..

http://ammo.ar15.com/project/AmmoOracle_061808.pdf

IT CONTAINS A WEALTH OF INFORMATION WHICH WILL HELP YOU AVOID ASKING QUESTIONS WHICH ARE ALREADY COVERED. It contains sections on the history, basic design and performance of .223 ammunition.

 

[edsinger]

What new range?

I heard on wOwO that the Sherrif was going to open theirs this summer. I will have to check on the one you just mentioned. thanks for the link..

 

[jblomenberg16]

This is a great question. I wish I knew....But I will ask the same to see if I can get some answers from those that own a S&W OR with a 1:9 twist?

That's exactly what one of my AR's is.

Mine shoots the 55gr stuff great, and seems to really like the 62gr SS109 rounds.

I've worked on some 75gr Hornady BTHP for my other AR (16" middy with 1:9 twist) that shoots ok, but not stellar. Not sure if it is my load, or if my 1:9 doesn't want to stabilize it. Haven't tried them out of the M*P15 yet.