Reloading .308 AR-10

[Stats Shooter]

I am about to start developing a load for a Ruger SR 762. I was curious if anyone out there has either reloaded for the SR 762, or used the projectile I have settled on. I am using the Sierra 165 grain BTSP (it will be a hog load.) My gun appears to like 165 gr bullets. I'll try CFE 223, IMR 4320, and Benchmark. I am a bit new to precision semi-auto reloading. I'm not sure how much I can safely vary the jump/jam on an AR-10. Historically I have seated to the cannalure for my ar-15 and ak-47. In fact my saiga .308 loads shoot sub moa out of my Ruger.
Any information would be appreciated, thanks

[Quentin2]

Sorry, I can't help you since I've only used cheap M80 in my new ArmaLite AR-10 but I'm sure you'll get many answers.

I must compliment you on your very clever signature. I've never heard it put that way before, so simple yet indisputable. Is that your original quote?

[Stats Shooter]

Quentin, the signature is something my dad taught me.

[CarJunkieLS1]

My Dads DPMS. 308 Tactical shoots sub-moa (3shots) with a 125 grain Sierra Pro-Hunter using Benchmark powder and shows promise using IMR8208.

I have an old .308 Semi Auto that prefers bullets heavier than 150's this old rifle (54 yrs old) LOVES the Speer BTSP and a minimum charge of IMR 4064.

As far as varying seating depth and such just oset them to mag length and if you need to seat the bullet .005-.010 deeper until the groups start to shrink. Also using a lead tip bullet don't put much faith in measuring COAL to the bullet tip they aren't very consistent. Measure to the Ogive and keep it +/- .003 and that's gonna be good enough.

[Stats Shooter]

Thanks car junkie, seating depth can matter more than power sometimes. My .300 WM wants just about everything .005 off the lands. It will shot clover leaf groups if seated long. If seated to book COAL, you are lucky to shoot 1.5 moa.

[CarJunkieLS1]

Yeah my 300WM will shoot it tightest groups with .030 jump (208 Amax) if it's any shorter than that the rifle will string shots horizontally, any longer and they string vertically.

[snolden]

In my semi .308's I load to mag length for best accuracy. It also slightly increases powder capacity and at the same time is not on the lands. Thus helping me keep the pressure spike to a minimum.

2.805" in a FAL mag, feeds 100%. That would be my starting point for an AR10.

[Stats Shooter]

Thanks snolden.
Usually when I start developing a load I adjust jump/jam first since my experience has taught me that the best COAL doesn't really change when you adjust powder. Then I find the most accurate powder charge and crony it.

One other question, with semi's do you still check chamber length using a gauge or just assume if it fits in the mag that it will safely chamber?

[Reloadron]

The powders I like best for my AR-10 and my M1A are IMR 4895, Hodgdon 4895, Accurate Arms 2495 all used under 168 grain and 180 grain match bullets. I size my brass and always trim to 2.005". Since most of the 308 Winchester I load can end up in any of several rifles I really don't seat a specific distance off the lands but go with the bullet manufacturers load data for a C.O.A.L. Anyway, in the gas guns the three powders I mentioned are my go to powders. Since I don't hunt with the rifles my bullet choices are generally Sierra, Speer and Nosler match type bullets.

Ron

[snolden]

Pretty easy to check if the round will fit in chamber. Load a dummy with no crimp to mag length, then chamber it. If it bumps back some or doesn't chamber its too long. Feel free to "soot" the bullet to check for lands' marks, but I bet you won't see anything. 2.005" trim every time and use an RCBS X-die if you can. Semi's put more stress on the brass when extracting than a bolt gun does.

Don't load your load too fast either. Magnum speeds allow the gas system to start cycling too early and put more stress on the brass while it is still stretched from firing. I run just within 20-50 fps +/- of mil spec velocity.

[ocharry]

Hi Mississippi,, you are gona love this rifle

My SR7.62 really likes 168MK over varget powder,,,i have had really good results with varget in my 308 rifles

I load them to 2.800 and my rifle will keep this load in 1"-1.5 at 100,,,it is amazing

i was just starting to really play with the loads for my rifle and it go to hot here so,,,i will resume testing when it cools down this fall,,,,but i have had some really good results with this rifle so far and varget,,,,it is my go to powder for 308

i love this beast,,,and it looks like it will be a shooter,,,,i also want to see what it like for factory loads,,i have about 6 different loads stacked up to test with the heavier bullets,,,165-180gr. lots of fun at the bench with her to come when it cools down,,,been 90+ for a while with the index 100+ for a while,,ac is working OT

but i am looking forward to getting back to the bench and shooting soon

ocharry

[Jimro]

There is an actual reloading section on this forum

But, here is the load data from Hodgdon for a 165gr Hornady Soft Point.

CFE 223 .308" 2.750"

45.4gr 2,649fps 46,700 PSI
48.3gr 2,839fps 61,500 PSI


IMR 4320 .308" 2.750"

43.0gr 2,536fps 46,900 PSI
46.5Cgr 2,730fps 58,400 PSI


Benchmark .308" 2.750"

38.5gr 2,438fps 40,200 CUP
42.5gr 2,647fps 50,500

Barrel length is 24" listed, so it looks like CFE223 is your best bet to get velocity. Odds are IMR 4320 will be the best bet for accuracy if you fine tune the charge and seating depth.

If you just want a I good hunting round that hits about one minute of angle, I recommend doing an OCW load workup with the CFE223 with the bullet seated to the cannelure. Crimping or not is your choice, but odds are it would be a good thing for getting a consistent bullet hold (sometimes semi-autos can do bad things to uncrimped bullets like unseat them or shove them back into the brass a little which plays heck with velocity standard deviation).

Hope this is helpful.

Jimro

[TMD]

I have a SR762 even though I haven't seen it in over a year since my son borrowed it. Anyways my two pet loads for it is a 180gn SST loaded with 43.5gn of Varget. It chronos at 2450fps and groups about .75". My other load is a 165gn Nosler Ballistic tip with 44gn of Varget. It chronos just shy of 2500 fps and groups @ .5". Both loads have a col of 2.780".
Oh and before everyone jumps on the bandwagon about low velocities remember the SR762 only has a 16" barrel.

[Stats Shooter]

Thanks for all the info so far guys. When I reload I always trim to the recommended case length to ensure consistency and my primer of choice for .308 is CCI 200's. I chose CFE.223 as it had solid velocity numbers. It may not be the most accurate for this gun/bullet combo, but I have found that you can get sub moa with any bullet/powder combo in .308 as long as you stay within 172k - 178k RPM and adjust the seating depth. Which is why I wondered about seating.

[NBK]

To Anyone still out there,

I'm new here, this reply is based on my reloading stats for my F-1 AR10 308 semi auto.

new starline brass
factory trimmed @ 2.005
Hornady 200 grain ELD-X boat tail
CCI #34 primer
Varget powder
OAL 2.700" (Hornady reloading data)
39.0 grains (starting load, Hornady reloading data)
42.0 grains (Max load, Hornady reloading data)
My Specs; (actual)
OAL measured to the ogive:2.035"
OAL measured to the tip of bullet:2.691
measurements fit in magazine without touching and ejects smoothly

I still have not shot rounds yet, still need to zero in new optics.
My Firearm spec;
F-1 BDR 10 308
16" contour stainless barrel
200 grain Hornady ELD-x
1-10 right twist (twist is designed for shooting heavier bullets)

Note: I've also made ammo shorter, and used a case length gauge, Forster Ultra micrometer bullet seater (dead accurate). when I chamber a round the bullet still goes into the lands. My rifle has a heavy duty buffer spring that slams round into chamber.

I'll return with results after zeroing of optics. Hope this stirrup some conversation, ideas, suggestions, or comments welcome.

[Mobuck]

If it were me, I'd be using a powder with a burn rate slightly on the faster end(4064 or 4895 rate)as a compromise. Likely will make the gas system happier.