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220 grain for 308

Maggot

"For we wrestle not against flesh and blood"
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Full Member
Minuteman
  • Jul 27, 2007
    25,932
    29,225
    Virginia
    Someone told me that with a heavy bullet the 308 could reach out ot a mile.

    Fact of fiction?

    Seems like you'd have to up the powder too much for safety.
     
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    You aren't going to be able to push a 220gr fast enough out of a .308
    What you want is one of the high end VLD solid copper LR bullets running at a decent speed if you want to stretch the .308 out as far as it will go.

    Now if you step up to something like a .300 PRC or a .300 Norma you are really having fun with 220gr stuff.
    You could do a modern hotter load 30-06 with it as well, but still you won't be going as fast as it really needs.
     
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    You'll most likely require a bullet that maintains stability during transonic flight. I've heard one is the Sierra 175MK. The new Berger Tactical rounds might also achieve this in some cases.
     
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    Nothing magical about 220s, but they are probably WAAY to heavy for 308.

    Long range shooting comes down to "How do I keep my bullet the most stable for the longest time" There's a lot to unpack there and lots of competing factors:
    (1)"Most stable" aka get a bullet with high bc. Given a fixed diameter, higher BC generally means longer bullets. Longer bullets weigh more thus the quick "Shoot a heavy bullet"
    (2) Longest time: The longer a bullet stays supersonic, the better. So shoot it FASTER. More speed = more supersonic flight. Aka pack more powder into your case.
    (3) Transonic transition: All bullet design

    As is evident, these two things "compete" with space in the cartridge. There are tricks of more energetic powders and loading long, but eventually your bullet gets so long that you run out of powder space. Problem being you need more powder to get that bullet up to speed.

    Eventually your bullet is so large, that any gains for better BC are killed because you velocity is suffering. Larger bullets= slower velocity for a fixed charge of powder.

    I like to do a lot of modeling, back of the enevelope calculations. Back a while ago, I took the known "good" 223, 6, 6.5 bullets (sorry I personnaly hate 7 and pefer 7.65 because FUDD) and scaled it up to 30 cal. Turns out the prefered bullet size would be around 200-220 grains. But here's the catch--you need to be going 2800-3000 FPS to be equivalent. What 308 Load gets a 220 Gr bullet at 2800 FPS?

    There isn;t one: You need a 30 magnum of some sort

    But that doesn't tell you if you can get to a mile. TLDR: Get a good ballistic 308 round 175 Federal GMM or the 185 Berger and send it. Some F-Class guy will be along to say they shoot 190s or 200s but they use longer barrels and aren't shooting to a mile.

    You need Speed AND BC. Or be like me and go play with ballistic calculators.

    These folks have you covered:


    Load in the video or similar (to 2k yards)
    Ammo hand loaded 175 grain Berger LR HPBT in Lapau brass with Federal gm primers and AR2208 powder (max safe load).

    I dunno what AR2208 is, as they are Aussie, but usually its just a different name for one of ours.
     
    Nothing magical about 220s, but they are probably WAAY to heavy for 308.

    Long range shooting comes down to "How do I keep my bullet the most stable for the longest time" There's a lot to unpack there and lots of competing factors:
    (1)"Most stable" aka get a bullet with high bc. Given a fixed diameter, higher BC generally means longer bullets. Longer bullets weigh more thus the quick "Shoot a heavy bullet"
    (2) Longest time: The longer a bullet stays supersonic, the better. So shoot it FASTER. More speed = more supersonic flight. Aka pack more powder into your case.
    (3) Transonic transition: All bullet design

    As is evident, these two things "compete" with space in the cartridge. There are tricks of more energetic powders and loading long, but eventually your bullet gets so long that you run out of powder space. Problem being you need more powder to get that bullet up to speed.

    Eventually your bullet is so large, that any gains for better BC are killed because you velocity is suffering. Larger bullets= slower velocity for a fixed charge of powder.

    I like to do a lot of modeling, back of the enevelope calculations. Back a while ago, I took the known "good" 223, 6, 6.5 bullets (sorry I personnaly hate 7 and pefer 7.65 because FUDD) and scaled it up to 30 cal. Turns out the prefered bullet size would be around 200-220 grains. But here's the catch--you need to be going 2800-3000 FPS to be equivalent. What 308 Load gets a 220 Gr bullet at 2800 FPS?

    There isn;t one: You need a 30 magnum of some sort

    But that doesn't tell you if you can get to a mile. TLDR: Get a good ballistic 308 round 175 Federal GMM or the 185 Berger and send it. Some F-Class guy will be along to say they shoot 190s or 200s but they use longer barrels and aren't shooting to a mile.

    You need Speed AND BC. Or be like me and go play with ballistic calculators.

    These folks have you covered:


    Load in the video or similar (to 2k yards)
    Ammo hand loaded 175 grain Berger LR HPBT in Lapau brass with Federal gm primers and AR2208 powder (max safe load).

    I dunno what AR2208 is, as they are Aussie, but usually its just a different name for one of ours.

    Good write up, Thanks Doc.
     
    Yes the 308 can shoot a mile...the Australian LR couple made 2 of 10 hits at 3200 yds on steel with a stock Rem police 26" barreled action, 200 .2 gr Berger bullets mounted in a chasis... on video.
    When I belonged to the Varmint Hunters club many years ago the record prairie dog was 2200 yds with a 308 Win and 220 gr SMK, 28" barrel Winchester action...held the record for a few yrs. I have the details if needed.
    Today with new powders and better bullets I'm shooting 200 SMK 2856 fps 230 gr SMK .8 BC, 230 Atips in 2620 fps 225 eldm 2675 fps, in 9 and 8 twists. 30" barrel long action in alum chasis.
    For a hunting rifle 22" Bartlein 9 twist 230 gr .8 BC SMK 2550 fps SA single load, even with LC brass. Very accurate in new hybrid cases, beating out Lapua Palma and Lapua LR brass. The Lapua Palma Brass was surprisingly the least accurate and largest S/D for this combination of rifle and components.
    A mile with a 308 a piece of cake, & already been done...in 1879 the Springfield Armory tested the 45-70 it was taken to 3200 yds in a military test, and the army proclaimed it to be good to 1900 yds for its mounted troopers, in 1879. Ladder sights graduated to 2000 yds or meters on militarily rifles for like 150 yrs. It's already been done even with black powder.
     
    I like these videos showing that a factory rifle with all its limitations, twist rates, hammer forged barrels, can still be used to shoot LR. Most are not shooting in competition so ya don't need the latest PRC cartridge in a custom rifle, with its high dollar barrel to hit a target at a mile.
    Proof posivitive you can use your factory hunting rifle to participate, or test the water to see if LR is for you...then add more precision if you think it's needed, or want to try competing, at higher level. So dig out those factory rifles regardless of caliber...and go long, have fun, learn.
     
    Back to reality.

    Whether or not you can use a 220SMK out to a mile will depend on your rifle’s twist rate and your scope’s adjustment range. You can lob anything out to a mile these days.
     
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