.308 loads for M40A4
- Thread starter wboggs
- Start date
Liven The Dream
Gold $$ Contributor
Work up a load to 2750 + or -Start at 41.5 grains .
Be Safe ...........
Be Safe ...........
Bill Norris
Back in the Day
shoot4fun
Gold $$ Contributor
Bill Norris
Back in the Day
LOL, Right but I can't help it Bro.There you go showing off again!
Your twist rate says a 175 gr match bullet and a commonly used accuracy powder...In whatever that combination turns out to be. But your barrel may like 155s...
I run fast twist and heavy pointy LR bullets in my latest 308 bolt guns 9 and 8 twists 200 gr 2856 fps to 230 Atip 2620 fps...But I have the 12 twist that favors 155 gr at 2975 fps.
Have a ton of AR 10 loads ready in LC brass to see whats possible with every bullet from 110 gr to 225 gr eldm...in an 18" 10 twist AR 10.
The 225 gr .777 BC eldm has been accurate in the 8 an 9 twist.
Also well the new 200gr SMK 715 BC. in a 9 twist 22" barrel 7.75 lb hunting gun 9 shots into .782"
Or as an example:
AR 10, 18" LC brass 50.5 gr 2000MR 168 Speer 2690 fps 11S/ D 10 shots at 100 yds .972" On the old barrel...but the new Proof AR also 10 twist likes different loads better. Just threw some junk ammo in the new barrel with LC brass in the mag and it shot .374 5 shot group, and a following .450".... So I have to start all over, with the new barrel...they like what they like...some shoot cheap bullets really good. Some will like the match ammo everyone else shoots. I'm working on cheap or heavy bullets outside the box ammo with LC brass no prep AR 10 experiment ordered another 1000 cheap LC cases for this experiment...so far just decap, swage primer pocket, clean, (1st 500 shot dirty), size, load shoot. Shooting some .3 to .5 inch groups with mag feed non match ammo in an AR10. A mad scientist endeavor...110 gr to 225 gr got some chronograph results, laying in falling ice water soaked through my coat , the snow covered ground, on the side of a mountain... this ain't combat. It's supposed to be fun...too old for that ...need the weather to cooperate...waiting....
D-4297
Gold $$ Contributor
Dug in my books and found data for the original Federal Gold Medal Match round .
Case : Federal .308 LRP Brass
Powder : IMR - 4064 .....Starting load ..41.6gr GMM load was : 42.5gr
Bullet : 175gr SMK
Primer : 210M ..............Original Gold Primer not available
Approx. Velocity : 2680fps
Case : Federal .308 LRP Brass
Powder : IMR - 4064 .....Starting load ..41.6gr GMM load was : 42.5gr
Bullet : 175gr SMK
Primer : 210M ..............Original Gold Primer not available
Approx. Velocity : 2680fps
175gr SMK
43.5 Varget
CCI BR2 primer
2.832”
I suggest try the Berger OTM 175 with the same load. Another great powder IMR 4064 @ 44.5 Fed 210M
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Kurz
Silver $$ Contributor
Please read this for information only not as criticism:
That term 'mil-spec' gets thrown around frequently without the actual designation being used properly. Here's a couple of examples:
'Mil-spec' .30 caliber ammunition was designated 7.62x51 or later shortened to 7.62 NATO. As produced by Lake City, the cases were and are made a little thicker to withstand higher pressure better. This means that the case capacity of the 7.62 NATO is slightly less than commercial .308 Win. brass. In essence, carefully work up your loads watching for signs of pressure.
This is the most recent load information:
Cartridge, Caliber 7.62mm Special Ball, Long Range, MK 316 MOD 0 (United States): A 175-grain (11.3 g) round specifically designed for long-range sniping consisting of Sierra MatchKing Hollow Point Boat Tail projectiles, Federal Cartridge Company match cartridge cases and Gold Medal Match primers. The Propellant has been verified as IMR 4064 (per NSN 1305-01-567-6944 and Federal Cartridge Company Contract/Order Number N0016408DJN28 and has a charge weight per the specs of 41.745-grain (2.7 g).[15]
This replaced M118 Special.
https://military-history.fandom.com/wiki/7.62×51mm_NATO
This is only one reference so you can look up the original contracts to get the specifications.
The original M40 rifles used the Gary Schneider button barrels cut at 24-25" and left with the outside turning grooves created by the contouring. These came with the 1:12" twist rate which Gary's button created. The 1:11.25" twist is from Bartlein and makes for a terrific twist for multiple bullet lengths and cartridge combinations.
Testing loads and powder will establish your best combination. As stated above IMR-4064 is one of the best. I found that IMR-3031 and IMR-8208 XBR worked well for me in my rifles. One FTR rifle was especially accurate at 1,000 yards.
Enjoy!
for a guy with an eye on detail you missed a lot.Please read this for information only not as criticism:
That term 'mil-spec' gets thrown around frequently without the actual designation being used properly. Here's a couple of examples:
'Mil-spec' .30 caliber ammunition was designated 7.62x51 or later shortened to 7.62 NATO. As produced by Lake City, the cases were and are made a little thicker to withstand higher pressure better. This means that the case capacity of the 7.62 NATO is slightly less than commercial .308 Win. brass. In essence, carefully work up your loads watching for signs of pressure.
This is the most recent load information:
Cartridge, Caliber 7.62mm Special Ball, Long Range, MK 316 MOD 0 (United States): A 175-grain (11.3 g) round specifically designed for long-range sniping consisting of Sierra MatchKing Hollow Point Boat Tail projectiles, Federal Cartridge Company match cartridge cases and Gold Medal Match primers. The Propellant has been verified as IMR 4064 (per NSN 1305-01-567-6944 and Federal Cartridge Company Contract/Order Number N0016408DJN28 and has a charge weight per the specs of 41.745-grain (2.7 g).[15]
This replaced M118 Special.
https://military-history.fandom.com/wiki/7.62×51mm_NATO
This is only one reference so you can look up the original contracts to get the specifications.
The original M40 rifles used the Gary Schneider button barrels cut at 24-25" and left with the outside turning grooves created by the contouring. These came with the 1:12" twist rate which Gary's button created. The 1:11.25" twist is from Bartlein and makes for a terrific twist for multiple bullet lengths and cartridge combinations.
Testing loads and powder will establish your best combination. As stated above IMR-4064 is one of the best. I found that IMR-3031 and IMR-8208 XBR worked well for me in my rifles. One FTR rifle was especially accurate at 1,000 yards.
Enjoy!
7.62X51 did not get SHORTENED to 7.62 nato...THAT WAS A SPEC CHANGE, not just a name change.
m118 special was NOT replaced by mk316 mod 0.
m118LR was replaced by mk316 mod 0
AckleymanII
Gold $$ Contributor
169g Sierra match king
43g of xbr 8208
Fed 210
.003 off the lands
tiny groups
Lapua brass
168g Sierra MK
43.0g of IMR 4064
cci 200
seated .020 off the lands max
Lapua brass
43g of xbr 8208
Fed 210
.003 off the lands
tiny groups
Lapua brass
168g Sierra MK
43.0g of IMR 4064
cci 200
seated .020 off the lands max
Lapua brass
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