.308 'light' 155gn Load Data?

Discussion in 'Big Stuff -- 6.5mm, 7mm, 30 Cal' started by inuhbad, Aug 19, 2010.

  1. inuhbad

    inuhbad

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    I recently got my hands on a LOT of 155gn Berger Target bullets, and Sierra 155gn Matchkings dirt cheap!!!

    I did about 12 to 14 hours worth of some custom 1911 work on a friend's Colt. It turned out beautiful using the old 1908 Colt hand-bluing technique after all the parts were fitted. In exchange, he gave me 1000 Berger Target 155gn bullets, and 1200 Sierra 155gn Matchkings, and 200 Sierra 180gn Matchkings!

    My rifle really LOVES the new 168 grain SMK loads all of you gave me here a couple weeks ago! I need to do more shooting, testing, adjusting, and then I'll post some results & targets on those 168gn loads. The rifle LOVES those 168's, and it matches the ballistics of the Shepherd Scope on the rifle.

    However, these 155's will likely fly a lot flatter & faster... I'm curious to see what you'd recommend for a good 155 grain load??? I usually fire Federal GMM Brass, with CCI BR2 primers, and Varget powder.

    I suspect these could be some decent varminting bullets/loads, and I'll save the 168gn & 180gn SMK's for more serious distance shooting. I'm excited - the local range just opened up a new 500 yd lane

    Any advice on powder charge & overall length?

    It's a Savage 10 FCP-K 308.
     
  2. milanuk

    milanuk Team Savage Site $$ Contributor

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    Sounds good for the most part. The Fed GM brass may be a bit thick and soft compared to other options, but it'll work fine.

    Mmmm... a little bit backwards there. Unless those are the 'old' (15-20yr) S180MKs, they aren't really all that hot for long range (past 600yds). A 175 or 190 would probably work better. The S168MKs were originally designed as a 300m target bullet, but work beautifully out past 600yds... but there's a saying along the lines of "Friends don't let friends shoot 168s @ 1000...". That particular bullet tends to become unstable somewhere past 800yds as it slows down towards the speed of sound - the angle of the boat tail (13°) is sharper than on most bullets designed for long range (7-9°) which doesn't help it out any. 155gr bullets see a *lot* of use for long range (800, 900, & 1000yd) in the form of Palma (see the article on the front page of this site), Fullbore, and F/TR. Certainly more than the S168MK and S180MK do. That said... for 500yds, any of the above should work satisfactory.

    I'm guessing the S155MKs are the older (model 2155) version, which shoot very well but aren't quite as aerodynamic as the newer versions. The B.C. is actually the *same* as the S168MK, and you can push them faster to boot - generally a win-win situation. What flavor the Berger 155s are may matter some - there are the older Berger 155 BTs, roughly equivalent to the S155MKs that you have, or the 155 VLDs, which may fly a little flatter/drift a little less.

    Generally for the SMKs I'd seat them 20-30 thou off the lands, and if the Bergers are VLDs, I'd try 5-10 thou into the lands.

    The Federal brass is thicker/heavier than the brass most people use for long range ammo (Winchester or Lapua), and thus has slightly less case capacity. For Lapua brass I'd say start around 46gn of Varget and work up... for the Federale stuff I'd say back off another 1/2 gn at least and work from there.

    There in lies the crux of the issue... with the barrel length on that thing (24? 26?) you may not be able to get the full advantage out of the 155s without skirting pressure problems. A heavier pill like a S175MK, B185BT, or 190gn bullets from either company might be a better option - but again, thats assuming you're trying to drive them hard enough to perform @ 1k. For 500yds... don't sweat it, load em up and go shoot ;)

    Good luck,

    Monte
     
  3. ChrisNZ

    ChrisNZ

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    As for a load, most NZ NRA shooters use 45-46grs of Varget (ADI-2208) behind 155s.

    If as your post suggests you're after a light load, maybe start at 44 but going much lower may not produce acceptable accuracy.

    Chris-NZ
     
  4. 40X Guy

    40X Guy Site $$ Contributor

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    My .308 loves the Berger target 155's just touching the lands over a charge of 44.5 grains of IMR4064, very accurate combo in my 24 inch Brux barrelled Remy. I had started off lands about .020, then .010, with decent results, then touching lands was far and away the load my rifle loves. You will have to experiment with seating depth and as already mentioned, the Bergers seem to like it best into the lands.
     
  5. 2506

    2506

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    If those Berger 155 VLD's are the older ones they are what is now called the HUNTING VLD. These are the bullets that Berger recommended I use in my 308 Win and 30X47 HBR for white tail deer. They blow GREAT BIG HOLES through deer. In the 308 Win 43 to 44 grs IMR 4895 is what shoots with these bullets for me. Berger's will shoot backed waaaaay off the lands also. They don't have to be jammed.
     
  6. CJ6

    CJ6 Site $$ Contributor

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    With 155.5 Bergers , 43.7 grs XBR, Fed 210, -.01 lands , 12 twist. XBR has shrunk my groups .3 MOA from my previous Best load useing Varget. The PPC guys might not like it But it's (XBR) has shown it's worth in the (mine at least)308.
     
  7. inuhbad

    inuhbad

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    Thanks for the great information, guys!

    I've got a decent load starting to show promise.

    I'm using 45.2 grains Varget, CCI BR2 Primers, Federal GMM brass, and seating them about 0.015" jump.

    I'm going to load 20rds of 0.010", then 20 of 0.005", and see what happens!

    I can't get much more precise than ~0.002" to 0.003" with my basic FL 308 RCBS die set for bullet seating, so I'm going to have to play around a bit to find what works best.
     
  8. camac

    camac Site $$ Contributor

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    As a rule of thumb 45-47 grains of varget behind a 155 and 20 thou off the lands has worked well in every 308 I have seen - fine tune from there with seating depth. Go to the range and generally 45.5-46.5 seems very common and the "go to" load over here.
     
  9. milanuk

    milanuk Team Savage Site $$ Contributor

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    If your seating depth is inconsistent, you'll probably be better off jumping more rather than less. The longer the jump, the less it matters if you are 'right on'. Up near the lands, that variation could put you at 0.005 or 0.002" off the lands - right where things get touchy and may lead to inconsistent behavior.

    By comparison, I use a lot of Berger 155.5 BT Fullbore bullets, and jump them ~45 thou. Does it matter if they are jumping 45 or 48? Not really... they still go where I aim 'em...

    I'd say move the other way... 20-30 thou instead of 5-10.

    YMMV,

    Monte
     
  10. Steve Blair

    Steve Blair Site $$ Contributor

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    Monte's point is well taken. One of my .308s shoots the Berger 155.5 FULLBORE exceptionally well seated .020 off the lands. In Lapua brass with 55.7 gr H2O capacity, I load 45.4 grains 8208 XBR for 2990 from a 26" barrel. I shot the attached target prone from a bipod with no bag. The first seven shots were .852 during a lull and then my old enemy, the wind, had his way with me on the last three. :(
     

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  11. inuhbad

    inuhbad

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    Thanks again for the excellent advice here!

    I played around with a few more batches with different seating depths recently.

    I tried the following seating depths:
    ~0.018"
    ~0.015"
    ~0.011"
    ~0.009"

    I also increased the powder load to 45.6 grains as recommended here.

    Then after helping my father move his company into their new office building, we decided to hit the outdoor range. Since this was his first time shooting the 308 after finally getting some education on breathing, trigger, and shooting techniques, I decided to let him try out the loads & see what works best for him.

    There was a 10 to 15 MPH inconsistent wind coming from the right, so it took us 2 shots before we got the Shepherd Scope dialed in for the windage, but once it was dialed in okay we got some decent groups!

    The top two holes were from the first two shots getting the scope adjusted better for the windage.
    [​IMG]

    We learned that the two best loads we shot were seated at 0.018" and 0.011"! When we got any closer to the lands, as Monte noted above - the shots were starting to hit all over the place!

    Let me preface this - my father had NEVER shot precision rifles accurately in the past. He usually wound up getting 3 MOA groups with a sub 0.5 MOA rated rifle. After getting some training, and after we tested some of our own hand loads he was absolutely SHOCKED to see this above shot grouping!

    A VERY inexperienced shooter, finally learning some precision shooting techniques, and finally starting to appreciate accurate, precision loaded ammunition with match-grade components... This grouping measured about 0.42" to 0.43" at 100 yards (Center to Center) with about 10 to 15 MPH 90 degree cross wind with occasional gusts up to 20+.

    He was EXTREMELY excited that he was able to produce this shot grouping! So much so he started Emailing it off to all of his friends! After the life he's lived thus far, my father had become a fair bit cynical in his nearing-retirement age, and no matter how hard he tried - he couldn't seem to find much of anything that can put a smile on his face! But he sure as heck was grinning ear to ear like a 10 year old kid after producing that shot grouping!

    We proceeded to produce several more good shot groupings on Saturday, and the 0.011" seating appeared to produce just SLIGHTLY better groupings than the 0.018", but about 1 out of every ~15 shots produced quite a WILD flyer. The 0.018" didn't produce any notable flyers, but the shot grouping wasn't quite as small.

    I'm thinking that either of the two seating depths COULD produced even more dramatically improved shot groupings - if I get more meticulous & systematic in my brass preparation. That's an area where I'm not quite sure I'm being as precise as I possibly could. I'll have to find out how to go about measuring case capacity & consistency as well.

    In the meantime, I'm still quite happy with nearly about 90% of my groups hitting under 0.5" at 100 yards!

    Soon we'll start pushing our loads out to greater distances & see how they perform. The range we shoot has lanes out to 500 yards, but we'll progress out that direction slowly.

    Thanks again for the great information & advice!
     
  12. Steve Blair

    Steve Blair Site $$ Contributor

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    Good results. Don't get too hung on seating depth with the FULLBORE, it is pretty tolerant. I just seat them .020 off and they work well. Eric Stecker of Berger Bullets said the following in a 2006 post.

     

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