308 win AR platform reloading question

DUSTY NOGGIN

Well-Known Member
Joined
Mar 18, 2015
Messages
743
Location
salt lake city
ive loaded up a couple different bullets to try to get this thing broken in 150 and 168 with imr4064 to finish off that bottle .. when looking at the data led me to notice powder options ( mostly faster than i have on hand ) and have some questions for any of you that may have already went through this

this rifle is a 24" 1:10 & should stabilize anything that will fit in the magazine. i would like to put the heaviest bullets i can in there

hodgdon data has "308 win" and "308 win service rifle" the service rifle only does mid weight bullets and faster-ish powders .. is that because those pressures are good for cycling ? or is it because that what hodgdon has tested to meet 7.62x51 nato pressures??
so my questions are when using the slower powders is there issues with over/under cycling gassing pressure issues .. where an adjustable gas block would be required / useful ??

and next question would be about bullet choice . id like to get as much distance outta this 308 win as i can. i think larger than the 168's is where id like to start... its not intended to be a hunting rifle but if i can achieve a little room in case by doing a sp .. i haven't measured throat yet so not really sure if i have any room to spare there anyways . maybe the 175 custom competition ??

just thinking ahead .. not trying to waste a bunch of components if i don't have to

another thing , would be progressive loading and ball powders you've have luck with .. for a separate load work up
 
Last edited:

mtwarych

Well-Known Member
Joined
Aug 16, 2013
Messages
358
Location
Stevensville MT
My son and I started with 165gn Nosler Ballistic tips and CFE223 powder chasing speed and accuracy. The results of the combination were dismal.

We then started working with H4895 with the same bullet and hit the jackpot with accuracy but the speed was a little slow, we decided that the accuracy was the most important part we wanted so we stayed with H4895 and the 165gr Nosler Ballistic Tips and haven't looked back since.

We are planning on trying out the 165gn LRAB this coming summer, it will be interesting what we can squeeze out of them.

As of right now, my son is shooting 42.5gn of H4895 under a 165nbt in military brass with a #41 primer to start things off.

I am loading 40gn of H4895 under a 165nbt in military brass with the same primer.

My sons rifle is a DPMS GI LR308 and my rifle is a DPMS GII Hunter.
 

mtwarych

Well-Known Member
Joined
Aug 16, 2013
Messages
358
Location
Stevensville MT
We decided to forgo the 175 to 180gn bullets because we are using the AR's to hunt with and we got what we needed from the 165's. Also, try to stick with service rifle loads due to you and the rifle taking a beating from loads meant to be fired in bolt actions. The loads meant for bolt actions may lead to other problems like overgassing and failures to extract and eject due to the bolt opening before the chamber pressure is low enough and the bolt travelling too fast to function properly.

One other powder I will work up in the AR's this coming year is AR-COMP. I use this powder in my 6.5 Grendel loads and it is so accurate I would like to run it in the 308's if I can find a better load than the H4895.

As a matter of fact, now that I think back on the load work ups, my son's rifle is marked with 308Win and my rifle is marked 7.62X51, which may be the reason my son's rifle runs 2.5gns more powder than mine. His velocity is about 70fps higher than mine also.

I see no reason why you would have any trouble loading the 175's and the 180's. All I will suggest is not loading to full 308 bolt action loads. Stick with the middle of the load ladder and you should be fine.

My GII came from the factory very overgassed and the rifle didn't function or shoot very well. (The rifle beat the hell out of me and had troubles with bolt-overs and my brass was beat to $#!t) I installed an adjustable gas block and a 10oz heavy buffer. What I have now is a well behaved, very accurate gasser that is a pleasure to shoot. I recently installed an Omega 300 suppressor on it and believe it or not, the rifle shoots more accurately than it did before, I can't wait for pinecone hunting season to open when the snow is off the mountains, If I can see them, they're in trouble.
 

rsmithsr

Well-Known Member
Joined
Oct 29, 2019
Messages
455
Location
phoenix
the service rifle data is typically m14/garand based. those limits do not really apply to ar10s. I shoot berger 175 as a base bullet in 24" armalite 10t. 1/2 moa is normal, I have shot some smaller.168 is a 300 yard by design bullet. I shoot 185 in a bolt gun, also 1/2 moa to 600 yards.

try to find a bullet that will get you close to the lands from 2.83(typical max mag length)
or get a bbl based on your needs.
as far as a progressive, you need to find a load WINDOW that is a couple of tenths wide, so the progressive can still produce match quality ammo. the alternative is to add powder individual ON THE PROGRESSIVE PRESS. YES I have loaded 600 yard match ammo on a progressive(Dillon).
 

mtwarych

Well-Known Member
Joined
Aug 16, 2013
Messages
358
Location
Stevensville MT
rsmithsr,

what are your suggested powders? I would like a little more speed but want to keep my accuracy. I don't have a progressive, I just do my reloading one stroke at a time.
 

Toddxusmc

Active Member
Joined
Jan 16, 2019
Messages
26
Location
WI
As RSMITHSR stated service rifle data mainly really only applies to the M1a/M1 Garand type rifles but not exclusively. The reason being is that class of rifle was designed for a port pressure of 12K psi to run the action. Anything much higher and you start bending and breaking op rods. The slower the powder the longer the pressure curve, this leads to higher port pressures, heavier bullets typically need a slower burning powder to manage chamber pressure and maximize velocity. While not as big an issue on the AR platform, you can still overgas and damage the action. Therefore you may want to go to an adjustable gas block, with which you can shoot pretty much any loading you wish. You should be able to load a 190SMK to magazine length with no problem. In my M1a I run a BERGER 190 vld with Win 760. I have an adjustable gas plug and a Sadlak grooved piston. While I would never shoot this from an un modified M1a, with the adjustable gas plug I can without worry of damage, I open it up completely and adjust until the action just cycles reliably.
If you don’t plan on running an adjustable block, you can call the mfg and see what their port specs are, they should also be able to give you a recommended bullet weight and load parameter(although you may void your warranty as no mfg recommends handloads). Another indication would be the caliber stamped on the barrel, if it’s 7.62x51 you might want to stay with service rifle data; if it’s stamped .308 you should be ok with any load for a .308. Also when loading keep in mind that brass thickness and internal capacity can differ between headstamp and mil vs commercial brass.
 

stirner

Well-Known Member
Joined
Mar 10, 2012
Messages
97
Location
Helena, Mt
You will find that the magazine is the limiting factor for COAL. I have yet to find a mag that will let me load a round long enough to come close to the lands, unless I use a round nose bullet. Some things that will help are to use ball powders, cup and core bullets, and rout the magazine. If the mag is a double-stack, you can cut out enough of the mag to accomodate about 4 cartridges before the mag starts to bulge, and becomes difficult to insert into the rifle. The way I did it was to load 4 rounds in the mag, and mark the front of the mag just a little wider than the bullet tips and a little deeper than the 4th round. The idea here is to remove as little metal as possible to allow loading a bullet longer than a closed mag would allow.

I have built a few ARs, and put an adjustable gas block on all of them. There's no sense in developing a fast, accurate load, only to not be able to properly cycle the rifle. Been there, no fun.

I have found that ball powders offer high load density. One of my favorites is Leverevolution. W748 and A2520 work well too.
 

Blackdirt Cowboy

Well-Known Member
Joined
Dec 9, 2018
Messages
484
Location
Texas
I haven’t tried the real heavy bullets in my ar10, as I’m using it primarily for hunting. My rifle has a 16” 1:10 twist barrel. I’m loading 168 grain Barnes ttsx over ArComp powder. Muzzle velocity is just under 2600 FPS. I wish it was a tad faster, but it shoots this load 1/2 moa. I hunt hogs between my cattle, so I’m more concerned about accuracy than speed. I need to know that bullet is going to hit exactly where I’m aiming.
 

rsmithsr

Well-Known Member
Joined
Oct 29, 2019
Messages
455
Location
phoenix
buying a 16" bbl and wishing for more velocity is pretty much dreaming.

I haven’t tried the real heavy bullets in my ar10, as I’m using it primarily for hunting. My rifle has a 16” 1:10 twist barrel. I’m loading 168 grain Barnes ttsx over ArComp powder. Muzzle velocity is just under 2600 FPS. I wish it was a tad faster, but it shoots this load 1/2 moa. I hunt hogs between my cattle, so I’m more concerned about accuracy than speed. I need to know that bullet is going to hit exactly where I’m aiming.
 

Blackdirt Cowboy

Well-Known Member
Joined
Dec 9, 2018
Messages
484
Location
Texas
You’re right. And velocity was one of the things I was willing to give up for maneuverability and accuracy. This rifle is suppressed, so I didn’t want a long barre with a 6” suppressor hanging off the end of it.
 

Primary

LRH Assistant
Here are some related products that LRH members are talking about. Clicking on a product will take you to LRH’s partner, Primary, where you can find links to LRH discussions about these products.

 
 
Top