Range Report AR's: 5.56 vs 7.62

Re: AR's: 5.56 vs 7.62

Depends on the barrel.

You can get an 80 5.56 SMK to 1,000 easy using a long-barreled bolt gun. An M16 will get a 77 to 1,000 out of a 20-inch barrel and it'll go through paper targets and break the skin. We'd watch Marine bullets go through targets at Quantico Range 4, hit the berm, and bounce back towards the pits. We watched one guy bend down to pick one up and it burned his fingers.

An 80 will get to 1,000 easy out of an M16, but you'll load them singly through the loading port as they're too long to magazine feed.

A 175 may get to 1,000 sideways out of a 12 twist M14 but go way past 1,000 from a longer barreled bolt gun.
 
Re: AR's: 5.56 vs 7.62

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: okiefired</div><div class="ubbcode-body">So, I'm hearing on other forums that 5.56 chambered AR's shooting the heavies are getting to 1K better than 7.62's using 175's. What do those of you with experience in such matters say? Thanks.

okie </div></div>


What do you mean by "better" in that comparison? Are you refering to the drop or the wind drift?
 
Re: AR's: 5.56 vs 7.62

If one is going to compare the heavy .223/5.56 bullets to a .308, you ought to be comparing it to a higher BC .308 bullet than the 175.

However, as DesertHK hints, drop is irrelevant in known-distance shooting, and the .308s are going to do better in the wind for match shooting - and much better if you're talking about terminal ballistics in human targets.
 
Re: AR's: 5.56 vs 7.62

I've been a M14/M1A shooter for over 30 years, but I'm starting to drift to the AR. I tried my White Oak upper service rifle at 1000 yards and was impressed. That was with 80 grn SMKs.

And yes, in service rifle, the ARs are beating the M14s in HP and 1000 yard matches.

But this year, I think I'm going to the 90 Gn Bergers. I load my 175s in 308 to 2550 out of my Super Match M1A. I load my 90 Bergers to 2600 fps out of my White Oak.

At 100O yards the 175s have a trajectory of 36.88 moa, and a wind drift of .90 moa per mph of wind.

The 90 Bergers has a trajectory of 33.60 moa and .80 moa per moa of wind.

The Remaining energy of the 90s is 356, and remaining velocity of 1330 fps, the 175s has the remaining energy of 596 and remaining velocity of 1239.

Both will still punch a hole in the paper target at 1000 yards.

Also, (mainly because of the powder charge) the 223s cost 6 cents a round less to reload.

Now understand, I'm taking about target shooting, I dont hunt at 1000 yards, nor am I going to be sniping anyone. I just want to punch holes in a paper target at 1000 yards.

I'm thinking the 223 is the way to go for me.
 
Re: AR's: 5.56 vs 7.62

Kraig, at the AMU we used 1-6.5 twist Pac-Nor three-groove barrels for the long range uppers shooting 90s. I understand there were quite a few civilian fellas who shot 90 SMKs at 600, and the 6.5 twist shot 75s and 77s really well.

The ammo guys looked at a number of 90s (I believe Sierras, Bergers, and JLKs) and came back to the Sierras.

I don't have the eyes to shoot the M16 with irons at 1,000.
 
Re: AR's: 5.56 vs 7.62

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">The ammo guys looked at a number of 90s (I believe Sierras, Bergers, and JLKs) and came back to the Sierras.</div></div>

Thanks for that info, I'll give the Sierras a shot.
 
Re: AR's: 5.56 vs 7.62

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DesertHK</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: okiefired</div><div class="ubbcode-body">So, I'm hearing on other forums that 5.56 chambered AR's shooting the heavies are getting to 1K better than 7.62's using 175's. What do those of you with experience in such matters say? Thanks.

okie </div></div>


What do you mean by "better" in that comparison? Are you refering to the drop or the wind drift? </div></div>


I mean which one is going to buck the wind better and stay supersonic? And BTW, I didn't mean to limit either rifle to specific bullet weights or types. Limit barrels only by keeping them under 26" just because IMHO, anything longer gets in the way afield. If anyone has experience to 1K with both and was able to use whatever combination they wanted as far as rifle and load, which did or do you prefer? Sorry, maybe thats a little clearer. TIA for your imput.

okie
 
Re: AR's: 5.56 vs 7.62

Supersonic to 1000 is not an issue - both will work.

The VLD bullets in .308 will give you a wind advantage over the .224s.

Service rifle, which places limits on the rifles which can be used, is another story, as Sinister and Kraig have noted, because there's a limit to how hard you can push an M14/M1A.

And as Kraig noted, it's cheaper to shoot the .224s.

If you really want a wind advantage, though, neither is the cartridge you really want to shoot.

So, it really depends on what your game is.
 
Re: AR's: 5.56 vs 7.62

The average human does not have access to the technology to effectively shoot the 90s out of 20" barreled 223 AR. Throw in a special run of brass with crimped in primers and special powder and the 90 can work well out of the 223 AR. I think you get my drift on that one in regards to Sinister's comments.

Every time I shoot factory 175 SMK 308 ammo (HSM, BH, FGMM)I think man this stuff drops like a stone. Personally I'd rather have my good long range 223 loads in the same barrel length as a factory 308 175 load when shooting at the 1k hard line.

A long barreled 308 with a load optimized around the bullet will flip things back in favor of the 308 175 for me, though I love the high BC 155s in the 308.
 
Re: AR's: 5.56 vs 7.62

That's why I said it depends on what your game is.

If you look at what's working in open F-class and tactical matches, you'll find that neither .308 Win nor 5.56 is what you want to be shooting if you have a choice - and the choice depends on what the game is.
 
Re: AR's: 5.56 vs 7.62

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">The average human does not have access to the technology to effectively shoot the 90s out of 20" barreled 223 AR. Throw in a special run of brass with crimped in primers and special powder and the 90 can work well out of the 223 AR. I think you get my drift on that one in regards to Sinister's comments.</div></div>

What special technology is there in a Pac-Nor 1-6.5 3-groove chambered by John Holliger using 90 SMKs, commercial brass, N550, and Remington 7 1/2 primers?

For 80s set your rear sight drum to 600 yards and bring your front sight down three complete revolutions. Winchester commercial brass, 80 SMKs, 25.0 grains of Varget, your choice of primer.

I shot on my own dime before I got to the AMU and have been shooting on my own since I left.

They're rifles and pistols, not lasers beams out of a national lab or some other planet.
 
Re: AR's: 5.56 vs 7.62

Lindy, I was wondering how much difference the VLD's made at the extreem.

I seem to be having a little trouble getting some to get off the M1A/175 thought patern
smile.gif
. How about the AR10/155 combo, or a GAP built bolt gun in .308 shooting 155's against the same in .223 shooting 80's? I'm not talking any particular game or set of rules just a "no holds bared" between the two cartraiges. I know there's better for going to 1K but we're talking between these two calibers. BTW, I wont just keep modifying my question, this is it.....I think. Great info so far guys, thanks.

okie