POI change on coldbore shot

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Ultramag45, Nov 29, 2013.

  1. Ultramag45

    Ultramag45 Well-Known Member

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    Hey guys, for the life of me I cant figure this out...I shoot a custom 338 RUM.. it is a real tackdriver....shoots well into the 1/3 moa to 600 yards...Never really pay attention to it since I shoot a fowler everytime i shoot steel...well this hunting season I was humbled...Hunted with a fouled barrel shot a buck at 588..10 inches right....No wind.. shot again and hit perfect...Got home cleaned gun went out and shot...fouled barrel...proceed to shoot a 2 inch group at 500... last week went to shoot again before another hunting trip...same fouled barrel (5 shots)...1st shot10 inches right at 500...then 4 right on top of eachother in under 2 inches....Thought it was me.. went home cleaned gun.. fouled barrel..waited an hour and shot cold bore shot again 10 inches right, and 3 dead center....Just went to colorado on deer hunt and this was wagging the back of my mind the whole time...lined a buck up at 614, and actually gave him 2 minutes left( his brisket). and hit about 4 inches back of his shoulder..killed him dead...approx 10 minutes later, just for fun.. found a volleyball size rock at 720 and pouded it twice...So what is the deal here..Cant go around shooting my gun every 10 minutes while I am hunting .shooting 225 gr accubonds with 98.5 gr of h1000 going 3175 fps....28 inch benchmark barrel...thanks and look forward to a response...hopefully Jeff ( BROZ) has an answer for megun)
     
  2. Mikecr

    Mikecr Well-Known Member

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    Well it sounds like you've prepped for pissing around.
    If you've decided now to hunt, you'll need to prep for this instead.
     

  3. Ultramag45

    Ultramag45 Well-Known Member

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    so you are saying WHAT,,, CANT REALLY PREP FOR 10 INCH MOVEMENT...IS IT BEDDING..STOCK IS FREEFLOATED..RUNNING OUT OF ANSWERS....WHEN I SHOOT AND HUNT I DONT PISS AROUND...ALL BUSINESS..WHERE I HUNT IN WY AND OTHER WESTERN STATES,,90% OF PEOPLE WOULD NEVER MAKE IT IN THERE..ALOT HARDCORE...JUST LOOKING FOR LOGICAL ANSWER
     
  4. Mikecr

    Mikecr Well-Known Member

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    Your focus needs to shift to one shot-one kill.
    Ever heard of cold bore accuracy?
    Grouping walked and/or preconditioned into steel isn't it.

    How ACCURATE is the gun producing single cold bore shots at 200yds?
    IMO, you shouldn't be shooting at big 600yd animals until you can pull out a gun & hit a 2" dot at 200, exactly as you would in the field. One shot, off a bipod in the dirt, etc.
    For small varmints, a 1" dot at 200, and you should be able to do it over & over with an hour or two between each shot.
    ~10min followup shots will probably bring out the worst consistency in your gun. It does with a couple of mine. And while my worst isn't good enough, I won't use it like that with hunting shots.
     
  5. TOM H

    TOM H Well-Known Member

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    Well your no strange to the 338 RUM guess you got the other custom sold. My deer/elk rifle I keep fouled from my last range trip just before hunting season.

    I'll do some cold bore shooting after I get a load and it's just to shoot one shot and I'll use same target 4/5 range trips @ 200/300yds and I don't clean when I doing that. I'm not sure where your hunting here in Co but DOW has some rifle ranges might want to check see if one close by next time and take couple shots before opening day.

    You been shooting 338RUM since joining have you had this problem with other rifles? My last build use a Mike Rock barrel haven't tried Benchmark.

    Glad you got your buck here.
     
  6. Ultramag45

    Ultramag45 Well-Known Member

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    No never have had this problem before...had 3 other Ultra Mags...A Defensive edge that was great... a Mcworters that I still own that is great..And reload for several others...all 1/2 moa guns...I understand making adjustments for that coldbore shot..But that much... and yeah I can shoot a 2 inch dot at 300 everytime...just strange why it is off that much...I usually clean all guns after 15- 20 shots... and send 2 foulers through, and it is ready to hunt with....But this gun coldbore is consistently off to the right everytime.. perfect for vertical...though.. after that shot, it stacks em right on top of eachother...the same with 225 and 300s...never seen that much difference before.. a couple inches maybe...even with some of my 30 cal.. not that much difference.. if there is anything I should try let me know...Gonna bug Kirby I think... Hes building me a 338 AX right now....gun)
     
  7. TOM H

    TOM H Well-Known Member

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    You should get hold of Kirby. Hard to say why it's off that much be interest to see what Kirby comes up anyway good luck.
     
  8. Jcub

    Jcub Well-Known Member

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    Your rifle is not zeroed for your cold bore shot. It's zeroed for a warm bbl.
     
  9. deadlift

    deadlift Official LRH Sponsor

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    Hey Ultramag45,
    Call me at the shop, 360-652-2594
    Talk soon,
    Chris
    Benchmark Barrels
     
  10. Jcub

    Jcub Well-Known Member

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    I wish I had been paying attention and read this response, pretty much the same thing I wrote. Guess my observation wasn't needed haha.
     
  11. rooster740

    rooster740 Well-Known Member

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    If I am not mistaken the fella is not asking a stupid question about his zero. He is asking what may be causing this big of difference between first and second shots? I know that many of you experts only take one shot, but some of us idiots need more then one shot.
    He clearly stated that the barrel is free floated and is a consistent difference between first and second shot.
    I have a 300wm with a octagon Lilja on a m70 action currently in a piece of junk manners gat stock that i hate! It is pillar bedded and free floated. Very similar issues.
     
  12. bigngreen

    bigngreen Well-Known Member

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    Anyone who tells you it's OK to have a POI change that much and all you need to do is change your zero is full it!!
    The last thing a guy needs is a long range rifle that walks around, if your wind call is a little of and you need a second round the very last thing you need is to be trying to figure out how much to compensate for the second round.
    Or like I do as often as I can shoot a couple animals while their standing there wondering why one of them just laid down, if I get on a pack of wolves the only thing I'm doing is cycling my bolt not worrying about my POI changing from my first shot!!
    A POI change that you have to compensate for is unacceptable!!!!! IMO :)
     
  13. Mikecr

    Mikecr Well-Known Member

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    You're right, it is the last thing to think about there. The first thing should be why you missed, and next should be what are you going to do about that.

    And yet reality
    ~10" at 600yds sounds like a big problem to me -to notice at 600yds. It wasn't noticed closer I guess.
    But even once he's fixed the issue, he will still likely have a POI shift from cold to hot barrel. Even the best in BR guns shift a bit from cold and it can be seen at 100yds.
     
  14. rooster740

    rooster740 Well-Known Member

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    A genius Has spoken!
    Two elk tags filled, five wolf tags in my pocket, three deer tags ready for soup, two antelope tags not drawn!
    The 300wm gets shelved until the cold bore issue is solved. We did not kill any elk further then 300 yards this year so it was no real issue. With the size of the kill zone shrinking from a 24"x24" elk to a 6"x6" area on a wolf. Its time to put my 243 in the saddle scabbard, 300rum big iron keeps its place on the pack horse, with the addition of the trapping panniers!
    So is it gun smithing, the barrel, the bedding, or the nut on the reloading press and trigger?