Why are accurate 308 loads slow

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by startrek1761d, Dec 29, 2013.

  1. startrek1761d

    startrek1761d Well-Known Member

    Messages:
    176
    Joined:
    Mar 27, 2011
    If we accept that the 308 can be loaded within 100 fps of a 30/06 with bullets under 165 gr then why do we have to accept the fact that most of the accurate 308 bolt action loads move a 168/175 gr around 2550/2600 fps. I have several rifles in 308 , a 5R and M1A NM, but am starting to question why we must lose 250 fps to make the 308 accurate, IMR 4064, Varget and even FGM are all very slow in an accurate load based on published match loads with the exception of some of the old military match ammo. It would be nice if we could get the full velocity potential and accuracy out of the 308, no kidding I have Chrongraphed some 30/30 150 gr factory loads that match 42.5 grs of Varget with a 168 gr SMK in velocity. Granted the long range ballistics are not comparable but the muzzle energy is almost identical.
     
  2. Greyfox

    Greyfox Well-Known Member

    Messages:
    4,348
    Joined:
    Jan 21, 2008
    I run 45.3gr. of Varget with a 165 Ballistic Tip, Lapua brass, 210M primer. I get 2800FPS, and .5MOA. My rifle is a 308 Milsec.
     
  3. Remington5r

    Remington5r Active Member

    Messages:
    33
    Joined:
    Dec 20, 2013
    I do not necessarily agree that slow loads are the only accurate loads. I do believe that out to long range a heavier bullet will be more accurate due to their ability to buck the wind. I have seen a custom remington model 7 shoot both 168 grain bullets going 2700 fps and 125 grn ballistic tips at 3100 fps very well.
     
  4. startrek1761d

    startrek1761d Well-Known Member

    Messages:
    176
    Joined:
    Mar 27, 2011
    I guess I am just a little bummed out to have a CZ 550 in 6.5x55 Swedish that has more energy at 500 yards than my 5R, I bought the 5R to hunt with but am thinking of have something built in 6.5 caliber. I never even took the 5R out this season, used the 6.5x55 instead and I love it.

    [​IMG]
     
  5. J E Custom

    J E Custom Well-Known Member

    Messages:
    8,125
    Joined:
    Jul 29, 2004
    Not all rifles like slow loads to be accurate. Some barrels like hot loads. (The hotter the better).

    Try different powders in your rifle like H 4064 and 4895 and some others almost the same burn rate.

    My best load is IMR 3031, Fast and accurate.(My rifle likes hot loads but I keep them within reason and get 3 or 4 loadings before I trash the brass).

    In the M1-A you have to watch the port pressures but the powders normally used are 42 grains of 4895 and 168 SMKs.

    Varget should also work.

    J E CUSTOM
     
  6. MudRunner2005

    MudRunner2005 Well-Known Member

    Messages:
    12,271
    Joined:
    Oct 13, 2008
    We don't accept that fact...I have insanely accurate 168/175 loads in the 2,775 range, and sub-1/2 MOA 210 Berger VLD load that's rifht at 2,400 fps...
     
  7. MudRunner2005

    MudRunner2005 Well-Known Member

    Messages:
    12,271
    Joined:
    Oct 13, 2008
    Very similar to mine...I run 44.0gr and reach 2,775 with my 168 loads out of my 24" 700 5R MilSpec. I also use Lapua brass, Fed 210 primers, and I only use Varget powder for my .308. :D

    I went to the range today and a bunch of black powder guys were out there (never seen any there before, being a private range), and I can still smell the burnt powder smell in my nose...Nothing like the smell of burnt powder. :D
     
  8. benchracer

    benchracer Well-Known Member

    Messages:
    1,503
    Joined:
    Dec 18, 2009
    I don't know why having a 6.5 Swede that outperforms your .308 is a bummer. The fact is, the 6.5x55 handily outperforms the .308, especially when the 6.5x55 is loaded to modern pressures with low drag bullets. I once shot my 6.5x55 side by side with a friend of mine and his .308 F-T/R rifle out to 600 yards in gusty cross winds. My Swede was spanking his .308 at that distance. If your Swede DOESN'T outperform your .308, something is wrong.

    As far as accurate loads from a .308 being slow, I don't buy into that either. Take a good look at .308 loads with Varget and 155 grain SMK Palmas. They outperform the traditional 175's past 1000 yards.

    I have had a Swede and a 6.5-284 built. I love my Swede. I don't feel the 6.5-284 was worth the trouble. I bought a recent production .264 Winchester Magnum Winchester Model 70 off the shelf. If this rifle had been available a few years ago, I would have never built the 6.5-284 to begin with. In fact, I am considering having my 6.5-284 re-chambered to .264 WM to take advantage of the tighter twist and shoot Matrix 160 grain VLD's. The .264 WM responds well to being downloaded to 6.5 Swede velocities, yet retains the option to go full throttle and get 3150+ with high bc VLD's. IMO, there is no better option in an off the shelf 6.5. You can build a rifle if that trips your trigger, but you will be taking the long way around for very little or no gain, IMO.
     
  9. startrek1761d

    startrek1761d Well-Known Member

    Messages:
    176
    Joined:
    Mar 27, 2011
    would you mind telling me the load your using to get 168 grs that fast?
     
  10. Gunpoor

    Gunpoor Well-Known Member

    Messages:
    435
    Joined:
    Apr 28, 2007
    Startrek, I have the same issue with my Browning A-bolt in 308Win. My accuracy load for it runs 2450 ft./sec. with a 165 grain bullet but will shoot bug holes at 100 yds. Every attempt to speed it up opens the group up exponentially. I have shot steel pigs at 500 mtrs./555yds. with ease so I don't mind the lack of speed and if I want something to get there faster I can haul out my 270Win, but I really expected both accuracy and a little speed from the 308. I don't know if it is the luck of the draw, so to speak, meaning a slow barrel compared to a fast barrel in the same cartridge or what. I load 308 with Winchester brass and have never tried another brand but I really don't see what difference that would make, but who knows unless tried.
     
  11. MudRunner2005

    MudRunner2005 Well-Known Member

    Messages:
    12,271
    Joined:
    Oct 13, 2008
    Refer back to this post on the first page...

    You must also remember that my 5R MilSpec has a 24" barrel, with an 11.25" twist...It's gonna be slightly faster than a 10" twist, and the 24" barrel gives it more velocity over a 16" to 22" barrel.

    Also remember that every rifle is different...What works great for mine might not work so well for yours.

     
  12. Greyfox

    Greyfox Well-Known Member

    Messages:
    4,348
    Joined:
    Jan 21, 2008
    I think im addicted to the smell of black powder. At the other extreme of LR shooting and hunting, my other passion is shooting traditional flintlock long rifles,
     
  13. MudRunner2005

    MudRunner2005 Well-Known Member

    Messages:
    12,271
    Joined:
    Oct 13, 2008
    Yeah, there was an a-hole shooting one of those directly to my left about 2 booths down.....Everytime he shot it flint shards would hit me in the face while I was trying to shoot! If he hadn't looked like such a little pansy I would have said something. He enunciated his words, and dressed preppy, was kind of excitable (peppy and talkative), and about 5'-4"...He kind of reminded me of a tall leprechaun without the funny hat and green suit. No lie, his flintlock was as tall as him. So my guess is probably a doctor, or lawyer, or something professional and not manual labor, who would try to sue me if I had threatened to shove his flintlock up his "powder horn" sideways if he didn't move down further... LOL

    But I never said anything, just kept to myself and he eventually took a break and went off to talk someone else's ear off (someone who might give more of a crap than me, which shouldn't be hard to find...) to show off his exuberant knowledge of black powder rifles... :rolleyes:
     
  14. Michael Eichele

    Michael Eichele Well-Known Member

    Messages:
    3,865
    Joined:
    Jan 6, 2003
    A lot of factory loads are designed around 22-24" barrels. Shorter barrels generate more muzzle blast which kicks the crap out of the bullet. It takes less powder to see the accuray.

    Longer barrels not only allow for more powder but slower to boot. 26" barrels can fire 178s between 2750-2850 FPS accurately. Deadly accurate.