308 208gr AMAX .... AR10

[blklabs]

I am a self professed newb to not only reloading, but my attempt, or lack thereof of long range shooting. 400 yards to me sounds like a long long shot. Anyways, I love the forum and have been able to absorb a ton of information from the site.

My first question for the brain trust is will a 208gr AMAX feed into the AR10 or will I need to bump down to the 178gr? I have some LC brass, RL15, and some GM210M primers (1st primers I have seen in 6 months!).

Before you ask, I don't know the twist of the barrel as I bought the gun used. (Was told it was a match barrel?) I have taken the handgaurd off and nothing is written as far as a model or manufacturer anywhere on the barrel that I can find.

Thanks for the help gentlemen.

 

[cwshooter]

Re: 308 208gr AMAX .... AR10

That's heavier than I'd want to put in mine. I've shot 175 SMKs, 178 Amaxs, 155 lapuas, and 155 amaxs with good results in three dpms rifles.
CW

 

[kombayotch]

Re: 308 208gr AMAX .... AR10

Do not even attempt to use a 208 in a 308 Win. if you are a newb, especially not in a gas gun. There is no data (or very limited data) for that bullet in 308 Win. Follow loads listed in the manuals and use the 178.

 

[BOLTRIPPER]

Re: 308 208gr AMAX .... AR10

i would save the 208's for the .300winny.......gassers chew up brass anyway, no sense in pushing a weighty pill.....to what end ?

 

[Falar]

Re: 308 208gr AMAX .... AR10

Do you have an actual AR10, (as in Armalite) or is it another .308 variant, DPMS LR308, Bushmaster BAR-10, RRA LAR-8, etc? The reason I ask is because as far as I know AR10s have always had 1:11.25" twist rates. RL15 is probably not the most ideal powder for a bullet that heavy in .308 anyway, I think RL17 and N550 would work better. I think some of the above posts have some merit, I don't know how that bullet would work loaded to mag length. However, if you are dead set on a heavier bullet I know of several people that have used 190gr SMKs in AR10s with some success.

 

[blklabs]

Re: 308 208gr AMAX .... AR10

Thanks gents. I have seen several posts about using the 208gr in a 308 and they had claimed success.

I do have an Armalite AR10A4. I am just looking for an accurate bullet out of the gun. Thought about the bergers, but I really like the thread in the hunting section where the guy laid out 4 pigs with his 168gr AMAX.

Would there be any benefits of using the 178 over the 168? I have 5 boxes of TAP FPD, 168gr, I guess I could just use the 168 and try to mirror ballistics, and leave the TAP as a backup to the reloads?

 

[wildcats]

Re: 308 208gr AMAX .... AR10

blklabs,
First off,i've never personally tried them,they might be a little to long and also the 208 grain bullet is a little to heavy for the 308 case size.you would have to load them pretty hot to get any velocity out of them. that gun is more than likely 1-10 or 1-12 twist.
you are better off with bullets in the 155 to 175 range.(155smk,168smk,175smk,168Amax 178Amax- 155-170 Lapuas.
as far as powder,i've had very good results with IMR3031.
this is the powder to me of choice for the 308 gas guns.
my load is 168smk Moly with 39.5 to 40.5

 

[cwshooter]

Re: 308 208gr AMAX .... AR10

308, sure. Gas-gun... not so much.

I don't think you'd notice the difference in a 168 and a 178 on a hog or deer inside of your stated 400 yards, terminally speaking.
I haven't shot the 168s, but I've been very pleased with the effect of the Amax on game (texas deer and hogs).
CW

 

[MontanaMarine]

Re: 308 208gr AMAX .... AR10

You'd likely end up loading long, and have a single-shot proposition, kinda like loading 90gr SMKs for the AR15.

The 208 is fairly long at 1.53", and uses up a good amount of case volume if pushed down to a OAL of 2.80". 2400 fps would probably be a realistic safe velocity if loaded at 2.80", probably a charge of about 40-42gr RL15, W748, or similar, depending on brass used.

I'm not well versed on port pressure issues (or non-issues) with the AR10, so that would probably be something to find out about.

 

[Falar]

Re: 308 208gr AMAX .... AR10

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: blklabs</div><div class="ubbcode-body">Thanks gents. I have seen several posts about using the 208gr in a 308 and they had claimed success.

I do have an Armalite AR10A4. I am just looking for an accurate bullet out of the gun. Thought about the bergers, but I really like the thread in the hunting section where the guy laid out 4 pigs with his 168gr AMAX.

Would there be any benefits of using the 178 over the 168? I have 5 boxes of TAP FPD, 168gr, I guess I could just use the 168 and try to mirror ballistics, and leave the TAP as a backup to the reloads?

</div></div>

It is very possible some have had success with the 208gr Amax out of an AR10, I have never tried it but like the other posters above I would advise caution. If you do try it I still would recommend using a slower burning powder to get the best results. Keep in mind that is a LONG bullet and you will have significantly reduced case capacity. A lot of people will say that you will be limited to 2.800" COAL because of the AR10 magazine, but I've loaded up to 2.845" with 155gr Scenars (distance to the lands with this bullet is 2.856") and not had any feeding issues from the magazine. The only bullets I've loaded for my AR10 are 155gr Scenar, 155gr Amax, 175gr SMK, 150gr Ballistic Tip, and Win 147gr FMJ. Hopefully someone else can chime in who has used the 168s/178s.

ETA:

Here is an interesting look at the terminal ballistics of a few bullets in .308 Winchester. It is one of the articles that made me pick up the 155gr Amax for SD/hunting loads. It has a few Hornady bullets, including all 3 that they use for TAP ammunition, 110gr Vmax, 155gr Amax, 168gr Amax.

http://www.m4carbine.net/showthread.php?t=19878

 

[wildcats]

Re: 308 208gr AMAX .... AR10

Exactly my point!
even in my 308 bolt guns i don't shoot anything heavier than 180s.<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BOLTRIPPER</div><div class="ubbcode-body">i would save the 208's for the .300winny.......gassers chew up brass anyway, no sense in pushing a weighty pill.....to what end ?</div></div>

 

[blklabs]

Re: 308 208gr AMAX .... AR10

I will look into the 168 and 178 and see what I can find locally. I had not seen any information on the 208 in a gas gun, which is why I referred it to the brain trust.

I appreciate your help and I will post the results when I get them dialed in.

 

[wildcats]

Re: 308 208gr AMAX .... AR10

blklabs,
i will also add that you don't use Reloader 15 powder as well.gas guns tend to like faster burning powders in order to cycle well.i've used IMR 3031 on both my M1a supermatch gun and my AR-10 with very good results. <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: blklabs</div><div class="ubbcode-body">I will look into the 168 and 178 and see what I can find locally. I had not seen any information on the 208 in a gas gun, which is why I referred it to the brain trust.

I appreciate your help and I will post the results when I get them dialed in.</div></div>

 

[blklabs]

Re: 308 208gr AMAX .... AR10

I have been using Varget with good results. I purchased the RL15, as a replacement since I have not seen Varget in months. They appear to have very similar burn rate and velocity characteristics.

Am I missing something or is Varget not a good option for a gas gun?

 

[Falar]

Re: 308 208gr AMAX .... AR10

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: blklabs</div><div class="ubbcode-body">I have been using Varget with good results. I purchased the RL15, as a replacement since I have not seen Varget in months. They appear to have very similar burn rate and velocity characteristics.

Am I missing something or is Varget not a good option for a gas gun? </div></div>

I've seen one or two guys post some nonsense about it being dangerous, but it is all I use (I've used BLC-2 and RL15 in the past) and I've never had issues. When I first started loading for an AR10 everyone I consulted with experience reloading for them was using it as their go to powder for everything in the 147-175gr range.

 

[R-TAC]

Re: 308 208gr AMAX .... AR10

I tried the 208 AMAX in a .308 Bolt Gun, no luck. To heavy of a bullet to get up to speed out of a .308 case. I am not saying it can't be done, I have seen claims where people are shooting it well out of a .308, I suspect they are using long barrels that allow a full powder burn to get the bullet up to speed. With my rifle having a 20" barrel, I could not get a fast enough load that I felt comfortable with in terms of pressure.

My .308 gas gun is a DPMS SASS with a 18" Barrel. My "standard" loads are:
168 Sierra HPBT or 168 Hornady AMAX
44 grains of Varget or 45 Grains of Reloader 15
These chrono out at around 2,600 fps, give or take 50-75 fps depending on variables.
I use these loads because they are very similar in performance to the Federal Gold Medal Match and Hornady TAP, that way I can switch back and forth from Handloads to Factory Ammo and not have to worry about the ballistics be drastically different.

For my SASS these loads are easily sub MOA. They will also go the distance to 1,000 yards, where they are coming in at around 1,150 to 1,175 fps.

Obviously you have to taylor the load to your rifle. Things like barrel length, twist rate, freebore/jump all impact the performance of any load.

Best of Luck,
Capt Richardson

 

[blklabs]

Re: 308 208gr AMAX .... AR10

Capt Richardson that was exactly the information that I was looking for. I am going to pick up a box of 168 gr AMAX and give them a try. I would love to have a load that duplicated the ballistics (or close) of the 168 TAP.

Thanks for the help.