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.308 gas gun load

bm11

Gunny Sergeant
Full Member
Minuteman
Jun 18, 2010
2,562
13
40
Maine
Hello,

Interested to hear what's working for you guys for a .308 AR. I've been working on this for a bit now, and am still struggling a bit.

Thanks,

-Bob
 
Sierra Matchking 175 Vhitavuori N150 42.5 Federal Match 210M Lapua, Five, Annealed 1.622 2450 AVG 0.68
Hornady Match BTHP 178 Varget 40.5 CCI 200 Lapua, Five, Annealed 1.622
Sierra Matchking 175 Varget 41 CCI 200 Lapua, Four 1.625 2450 AVG 0.58
Hornady Match BTHP 168 XBR 8208 40 CCI 200 Lapua, Three 1.625 2457 AVG 0.60


Whats worked for me so far..... Gap 10 308 18", Still working....
 
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Sierra Matchking 175 Vhitavuori N150 42.5 Federal Match 210M Lapua, Five, Annealed 1.622 2450 AVG 0.68
Hornady Match BTHP 178 Varget 40.5 CCI 200 Lapua, Five, Annealed 1.622
Sierra Matchking 175 Varget 41 CCI 200 Lapua, Four 1.625 2450 AVG 0.58
Hornady Match BTHP 168 XBR 8208 40 CCI 200 Lapua, Three 1.625 2457 AVG 0.60


Whats worked for me so far..... Gap 10 308 18", Still working....
Thanks for the input. Everything I have tried has been in the 43-44g of Varget range with a 175 and 178. I have heard that semi auto's prefer a lower charge weight. I'm going to give it a try today.
 
I've been doing a little bit of load development with mine. So far its preference has been 42.5 gr Varget, CCI 200, Fed case, 175 SMK, COAL 2.800". I've still got too small of a sample and the barrel is too new to know if this will be the go to load.
 
168gr SMK
43gr IMR 4064
LC Brass
CCI BR2 primer
2.80-2.81 OAL

These are shooting 3/4 MOA 5 shot groups in my (now sold) AR-10T, and my dads standard AR-10. Both 20" barrels.
 
Thanks for the input. Everything I have tried has been in the 43-44g of Varget range with a 175 and 178. I have heard that semi auto's prefer a lower charge weight. I'm going to give it a try today.

Glad I found this post. Was having a problem with my bolt gun loads in my DPMS REPR. Gun shoots the Factory FGMM 168 and 175 SMK loads well, but my standard load was blowing primers. I use a Dillon step case gauge for headspacing (interestingly, factory brass sits a few thousandths LOW in this gauge), trim brass to 2.005" with a Giraud VLD trimmer, use FC cases, F210M primers, 168 grn SMKs at 2.810" with 46 grains of H-Varget. This load gets me out to about 900 yards reliably, accurately, about 12.5 MOA at 600 yards (IIRC) with my Rem PSS, but the gas guns (two) just don't like it. Now that I think about it, that load gets the 168s moving close to 2700 fps. Factory is a little less.

I'll revisit this now that I've read through this thread, check my numbers and get some range time.

Factory ammo's too freaking expensive.
 
I try to duplicate the LC M118LR load.

175SMK
43.1 gr Reloader 15
210M Primer
LC LR Brass
2.805 OAL

2630 fps from 20" barrel Blackhole Weaponry 1:11 Barrel .308 AR
 
Sierra 168 Gr HPBT MK
Win Brass
Fed 210 Primer
H4895 42.2 grains

SUB MOA out of my POF-308 20", .438 MOA 3 shot group at 300 yards, this was with the gas on, operating semi.

R/
Chris
 
I've been working hard to find the best load for my 20" Lilja Mega MKM. With the total vacum of Varget available I have only been able to work with XBR8208, TAC, Benchmark and now Power Pro 2000MR which I have not yet shot. So far this is what has worked best.

LC brass
CCI BR2
Benchmark 41.2g
2510 FPS

LC Brass
CCI BR2
XBR8208 43g
2630 FPS

LC Brass
CCI BR2
44.5g TAC
2690 FPS

All these loads have been pretty accurate at maximum sub MOA at 100. Have not got a chance to stretch them out yet but I'm sure they will do good at distance with the velocities. All of them have done as well as my old Varget load of 44.5. I have loaded a ladder with 2000MR starting at 44 going o 48 in .5 increments that I will test this weekend. I have high hopes for this powder based on what I have been reading. It supposedly nets 150 FPS over other powders with mid 2700's out of a 20" tube at 47g with no pressure signs. I have a bunch of Lapua brass that I will work up a final load once I decide which powder I will settle on. The great thing about the .308 and these powders is they all work great in .223 which is the only other rifle round I shoot. My Seekins DMR build is not picky about powerder so nothing will go to waste.
 
Danco-
What bullet are you using and at what distance from lands? Looks like something in the 168/175 range from the loads posted, but you'll have to advise further.
 
Thanks for the input. Everything I have tried has been in the 43-44g of Varget range with a 175 and 178. I have heard that semi auto's prefer a lower charge weight. I'm going to give it a try today.

Varget likes to be compressed and performs best when so done.

168g Amax moly
a lot of Varget (my load book is at home)
2.815 OAL
Fed 210M
~.5
Armalite AR10T 24"

My next load to develop will be 208g Amax, I just got some in.
 
Since you are struggling a bit, it would help us help you if you told us more about your setup. loading procedure, gun, components, etc. Cartridge assembly is critical.
 
I've come back from a second range session of the day, and seem to have further vetted a charge my older GAP 10 with 11.25 twist Schneider 21" barrel seems to really respond to:
Both Winchester and Hornady Match brass, properly prepped.
Fed 210M primers
44.9 of two different lots of 8208
155gr Sierra 2155, Sierra 2156's and 155 Amax's
Avg velocity 2750-2775 depending on bullet, with low ES/SD
No 5 round group exceeding 1", most around .6-.7. 97 degrees.
 
Is there much difference in reloading data for .308 for a gasser vs. a .308 bolt gun load?
 
Yes, depending on the gun gas gun there are some extreme variations on a bolt load vs a load for a M1A for example, then you can play with an adjustable gas block to refine even more. On a bolt load development is pretty straight forward.

Is there much difference in reloading data for .308 for a gasser vs. a .308 bolt gun load?
 
Ok, I guess I should have been more specific with the platforms. I'm trying to see how the load data for a 700 would do in a GAP10 or a JP LRP07. If the load I have for a 700 is around 43.5-44gr should I back off the grains a little for a gas gun? I hope that makes sense.
 
I'm shooting an old fashioned M1A. Here's my favorite load.

Bullet: Nosler 155 gr. HPBT Custom Competition
Powder: Hodgdon H4895 43.0 grs. (02 May 13 Lot #5161)
Primer: Winchester Large Rifle
Case: Lake City 64
LOAL: 2.780 (2.196 Base to Ogive with Stoney Point)
Average Velocity: 2800.68 fps
Extreme Spread: 29.05
Standard Deviation: 11.61
 

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Would you expect there be much difference between the loads for a gasser vs. a piston?
 
Well, the AR10 isn't as powder sensitive as the M14/M1A. I've seen guys shooting loads through AR10s (with no problems) that I wouldn't ever try in my M1A!
 
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168smk commercial case, win lr primer, 41.5 grains h4895 or IMR4895, COAL 2.8inches. Very accurate out of my M1A or a friends LR308.
 
Just tried some 43.5gr varget, 2.800 OAL, 168smk, Win LRP, and winchester brass. I got a good group with that load out of a 18'' JP.
 
Bullet :Sierra 155 Palma Match
Powder: Varget 42.5gr (if I go much over 43gr I start having issues)
Case: Misc military
Oal: 2.80
Primer CCI

I shoot this load in my Armalite Ar10 22'' barrel I get consistent sub moa groups at a 100 and have used it with decent results out to a thousand yds. I shot a 2 man sniper match this weekend at 300-600yds and was scoring consistent Xs-10s. I also use this load in my 7005R because I have so many rounds loaded up and haven't had a chance to do load development for the 5R yet but 44gr Varget and 175 SMKs shoot well from 300-600-1000.
 
I finally got my large frame AR to shoot after a ton of work and bumps in the road. Today I was able to shoot a few 1/2-3/4 MOA groups at 200 yards with 175 SMK, 42.0 grains of IMR 4064, Lapua Brass, and CCI #200 primers.

It’s got a 20 inch barrel with a brake and I’m getting 2505 FPS average velocity with a SD of 10.

Photo is 6 shots @ 200.
 

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Fed/Win/Rem brass, F/L resized
175SMk, 2.815" OAL
CCI BR-2/Fed210M
42.2gr IMR-4064

This has been my goto 308 LR load, semi and bolt for going on two decades.

In a hurry, distances to 800yd, IMI 168 Semi-auto Match.

Greg
 
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Lapua brass

110 vmax
47.5 gr h335
Win lr primers

155 gr eldm
45.5 gr varget
Win lr primers

Both loaded to mag length
 
178 amax
Lclr brass
fgmm primers
39.9 Tac or
39.6 Varget
Both loads are consistently under 1/2 moa @ 100 yards
Shot out of a
20" wilson combat SS barrel
and 3/4 moa out of a Ballistic Advantage 18" "premium" heavy profile barrel.
Side note - The Wilson Combat barrel is possibly the most accurate barrel I've ever owned. Absolutely ridiculous accuracy. Which is the only reason I reload.
 
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Fed/Win/Rem brass, F/L resized
175SMk, 2.815" OAL
CCI BR-2/Fed210M
42.2gr IMR-4064

This has been my goto 308 LR load, semi and bolt for going on two decades.

In a hurry, distances to 800yd, IMI 168 Semi-auto Match.

Greg

Anything around 42.0gr of IMR 4064 and 175gr; you really can't go wrong.

I have since switched to Varget and found 42.6 works very well without beating the gas rifle up.
 
Thought I'd share some additional load data that I worked up over the last year in addition to my previous post. The rifle is a home built large frame AR in 308 Win with Aero Precision M5 receiver set, a 24-inch Criterion Barrel from Fulton Armory, and a Toolcraft NiB bcg.

41.7gr IMR 4064 / 175gr SMK / LC Brass / F210M / 2.805" - This is my current match load. It gets me 2752 fps with a SD of 9. I'm going to run this load until I run out of 175 match kings. Once the SMKs are done, I'll work up a load with 178gr Hornady BTHP bullets with RL-15. The Hornady bullets are almost $10 cheaper per 100.

You are not making 2750 FPS with that load. Bullshit.
 
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GAP10 w/ 20" barrel
6.5 CM
123 scenar
Hornady brass
H4350 43.6gr
2815 fps

Mega Build 6.5 CM
20" Carbon Proof barrel w/ +2" gas system
140 Amax
Hornady brass
2.820 OAL
H4350 42.5gr (43.0 was better accuracy but started to really chew up the brass)
210m
2670 FPS
 
KAC M110
175 SMK
LC-LR brass
43.2 Varget
210m
2.815 OAL
5/8 MOA at 100y and MOA out to 600y

KAC Mk11 Mod0 (most accurate gas gun I've ever seen)
175 SMK
LC-LR brass
210 m
2.810 OAL
43.8 Varget truly shots 3/8 MOA and 3/4 MOA out to 600y
(44.6 was better accuracy but I had moderate pressure signs with LC brass)
 
KAC M110
175 SMK
LC-LR brass
43.2 Varget
210m
2.815 OAL
5/8 MOA at 100y and MOA out to 600y

KAC Mk11 Mod0 (most accurate gas gun I've ever seen)
175 SMK
LC-LR brass
210 m
2.810 OAL
43.8 Varget truly shots 3/8 MOA and 3/4 MOA out to 600y
(44.6 was better accuracy but I had moderate pressure signs with LC brass)

Just a question, are you shooting any of these suppressed? Because whenever I shoot any loads much lighter than the ones you posted, I get some pressure signs early on. I use LC and IMI 7.62 match brass. I have a batch of LC-LR but never wanted to waste it on a gas gun. When I shoot those same loads suppressed, I cannot use the brass again. ( I get flat primers, expanded case heads, and primer pockets are blown out after one firing) I shoot an LMT MWS with 18" SS barrel. It's a precise gun, sub MOA with lighter loads, but I'm getting flat primers at 4 grains below what most are shooting. I've used Varget, XBR, and 4064. Now, I've never seen ejector swipes, but the loosening primer pockets especially suppressed is what's worrying me. (I've also use the 16" CL barrel and I have the dual-ejector bolt and same symptoms) Looks like my chamber is cut fairly loose. Should I up the load somewhat and maybe get better sealing? Also, this rifle is overgassed so that may be why it beats up my brass.
Thanks,
 
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