Berger 155.5 fullbore ?? Help

Discussion in 'Reloading' started by ramp, Jul 28, 2011.

  1. ramp

    ramp Well-Known Member

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    I've been shooting 168 smk out of my factory Remington 308 getting .5 moa.
    The Guys at the club shoot berger 155.5 and said I should try them.
    The 168 smk is seated .040 off the lands.
    When I measured for bergers to the lands only the boattail was in the neck and no bearing surface.
    If I seat it to the same amount as the smk I have .150 jump to the lands.
    From what I've read the bergers like to be touching or close.
    How much bearing surface do I need in the neck to be safe?
    Has anyone had any luck jumping the bergers this far?
    Should I just stick with the smk's?
    I know out of a factory rifle I cant ask for much better.

    Thanks
    Ramp
     
  2. Buffalobob

    Buffalobob Writers Guild

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  3. ramp

    ramp Well-Known Member

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    Thanks Bob I'll check it out.
    Whats the least amount of bearing surface in the neck I can get away with.
    I only use this rifle for target matches.

    Thanks
    Ramp
     
    Last edited: Jul 28, 2011
  4. Broz

    Broz Well-Known Member

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    I have shot Berger VLD's in many Weatherby chamberings where the freebore keeps you way back off the lands. .200" in some cases. I also worked up loads for a 7mm-300 and ended up .115" off the lands. Accuracy was good in all instances and I am talking 1/2 moa or better.

    Jeff
     
  5. Buffalobob

    Buffalobob Writers Guild

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    I don't know. A lot would be how careful you are handling them and feeding them into the chamber.

    A lot of people are shooting 185s in FT/R. You might consider them if you can't get the Fullbores to jump well.

    As Broz said, many of us have shot factory chambered Weatherby's for years and jumped all kinds of bullets but the short bearing surface ones don't always come out of the barrel with competition required accuracy. I used to shoot some 115 HPs in a 7mm Wby at ridiculous speeds and moderate accuracy at groundhogs but I seldom killed any over 350yds away with that combination.
     
  6. milanuk

    milanuk Well-Known Member

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    I normally jump the B155.5BT about 0.045-0.050" in my 12 F/TR. With the factory Obermeyer chamber (and a little bit of wear on the throat) that currently leaves me with just under 0.100" of bearing surface still in the case neck - but it does shoot *very* well...

    The general rule of thumb I'd always heard was to try and keep at least 1/2 caliber worth of bearing surface in the neck, i.e. about 150 thou minimum for a .30 cal. Obviously not a hard and fast rule as per above, but I'm dealing with relatively delicate target rounds on a flat range, not something used in the field.
     
  7. ramp

    ramp Well-Known Member

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    Thanks Milanuk.
    If I seat 1/2 bearing surface into neck I have .194 jump.
    1/4= .117 jump.
    I think im going to start at .117 and work my way back.
    Unless someone tell's me it a bad idea.
    Thank's for the help folk's.

    Later
    Ramp
     
  8. nfhjr62

    nfhjr62 Well-Known Member

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    This is all good info as i'm waiting for a box of bullets #30416 155.5 gr. called yesterday are backorder will have to wait.
     
  9. ramp

    ramp Well-Known Member

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    Hey guys
    I loaded 30 rounds starting at .117 from the lands and worked my way back.
    5 each @ .117, .127, .137, .147, .157, .162
    The 168 smk's shot good with 42.0 gn RE-15 so I thought I would try that.
    I havent messed with the powder yet but I think these bergers are going to shoot great.
    This is at 100 yd's. .147 off.

    Thanks for the info.

    Ramp
     

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    Last edited: Aug 14, 2011
  10. milanuk

    milanuk Well-Known Member

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    Yep... they do work pretty well :D

    I was doing load testing for a new barrel (12 BR barrel screwed on a 12 Palma action/stock) Friday/Saturday mornings... when I went to shoot a confirmation test @ 300yds yesterday morning (using a 6" shoot-n-c for an aiming point so I could see my shots in the mirage) first shot, okay, see it. Second shot... where the heck did it go. Third shot where did that one go? Fourth shot... same. WTF?!? Finally pumped the fifth shot into the dirt berm beside the target to make sure they were actually making it to the target (this particular tube has a slightly faster twist than the F/TR or Palma), yep, big puff of dirt. Wrote that one off as 'weird', and continued w/ doing load testing.

    At the end of the day, I wound up back down at the same charge weight and everything, and had a *very* flat group - albeit w/ the wind playing hell with the actual group size. Very tight vertical, which is what I want to see. I drove down to the targets (finally) to take a closer peek and admire the view... when I 'found' the missing shots from that first group of the day. Turns out they all were in one little hole - not 'touching', one dime-sized hole. The hole *had* looked a little big for one bullet hole @ 300 thru the scope, but four? Too bad I screwed it up by pumping that last round into the berm :D

    Now if I could only do that regularly, on demand <sigh> Granted, the conditions were unusually stable and all, but it was an eye-opener!

    I'm thinking load development for that particular combination is *done*, save for a cursory run over the chrono.

    FWIW, this particular barrel didn't seem to like the 45 thou jump that my past tubes (4 12 F/TR, 2 12 Palma) have... after the initial testing didn't pan out very well, I went back and went from 45 to 25 to 15 to 10 to 5 thou jump, and 15 seemed to be the magic number for this barrel. This seems to be consistent with what I've heard from a number of other people - their barrel either likes them around 10-20 thou jump (15 being common) or 45+ thou jump.

    Monte
     
  11. ramp

    ramp Well-Known Member

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    Dont you wish you could shoot like that all the time.
    We have a monthly fun match at the club.
    It's only 200 yd's prone. I've only been shooting in it about one year.
    Never shot prone before but its lots of fun. I've deer hunted all my life.
    Kinda hard to get prone 20 foot up in a tree stand.

    Later

    Ramp
     
  12. ronas

    ronas New Member

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    Aug 7, 2011
    I'm shooting the 155.5 Berger out of my factory mil-spec rifle, a TRG-22.

    With a dummy round jammed, and I mean jammed into the lands I computed the length with a Sinclair comparator to be 3.2529". So my loaded rounds that produce the best accuracy are loaded to 3.1700" Measured base of case to ogive. So that means I'm .083" from jammed into lands. Not positive exactly were lands start, but I figure and this is a guess that the bullet jumps about .068" to .078".

    The bullet is a great one. It only takes 3.2 mils to 600 yards and 5.5 mils to 800 yards. I've shot groups as small as 9.5 cm at 800 yards and even tighter groups at 600. I do have to say this was with really good condition, like little mirage and almost no wind.

    Today I tried some 175 SMKs at 100 yards rifle shoot a 10 shot group of about 2.3 cm. Load was 44.5 gr. of Varget seated .015 off the lands. This bullet shots excellent to at least at 100 yards. I can not imagine it shooting as well at 800 yards but maybe so.

    I like the 155.5 but with little bearing surface to hold the bullet I'm concerned they will not take rough handling very well.

    So I've order some BIB bullets in 155 gr. They have a flat base and should offer more bearing surface to seat bullet closer to lands. It will also depend where the ogive is located.