Different Brand Ammo (same grain) giving inconsistent target results?

Discussion in 'General Rifle Discussion' started by SubZero, Oct 30, 2012.

  1. SubZero

    SubZero New Member

    71
    0
    0
    I had 3 boxes of 300 WSM ammo at the range today. I had one Winchester Super X box of 20 and two Federal boxes (20 each) all 3 at 180 grain.

    I zeroed the Tikka T3 Lite 300 WSM to 50 Yards using a rest with front sandbag and two rear sandbags and the Winchester Super X ammo. Rock solid, dead center.

    But when I fired the Federal, it consistently seemed to fall about 1/2" to maybe 1" lower. I tried after the barrel was warmed up, then let it cool down and shot a final spread of 4 on a fresh target, a bit of a cool down between each shot, and while it was just fine left to right, it was indeed just below the bullseye in all 4 shots even though the reticle was smack in the middle of the bullseye.

    Is this sort of result normal?

    It's not a huge deal, but it just had me wondering.

    Even though the Winchester Super X is more expensive per box, I've had great luck with it, and only tried the Federal because it was somewhat less expensive. But given that 300 WSM is so expensive anyway, the difference is really not that big.

    Thanks in advance for your replies.
     
  2. Gatoragn

    Gatoragn Active Member

    3,937
    13
    38
    Very typical of switching between brands. Find the brand and weight of ammo you shoot best in your rifle and stick with it.
     

  3. gunnut07

    gunnut07 New Member

    944
    0
    0
  4. SubZero

    SubZero New Member

    71
    0
    0
    Thanks for the feedback.

    Got me wondering, does the change usually show in elevation and not windage? I did not notice any variance left to right, only up and down in this particular case.

    Thanks again.
     
  5. WhelanLad

    WhelanLad New Member

    124
    0
    0
    Thats generally because one is goin faster than the other?

    even though both 180gr, my Abolt 300wsm shot different with Win V Rem 150sp but Ones primers were flattened an one wasnt.. charts show a difference in Veloctiy..
     
  6. Intheshop

    Intheshop New Member

    210
    0
    0
    Each bullet maker has their "ideas" on whats appropriate WRT overall design.These differences show up downrange.....on paper as well as tissue.Will venture to say(don't know for absolute as its a pretty guarded)that jacket hardness is pretty much the same between manuf. in specific calibres.But little differences in the bullets shape can and does change how that "hardness" shows up.IOWs,two different manufacturer's could use the same jackets...but because their swaging dies,and resultant "shapes" are a touch different...they can behave differently.

    Little changes in a bullets design....and small variance's in construction(how they're assemble'd)....even though the nominal weight is the same can produce dramatic differences internally and externally.To a much lessor degree....even between two rifles/brrls of the same maker.

    Wish I was smart/experience'd enough to explain "windage" changes as it relates to bullet design.I've found bedding to be a much bigger windage "effect'er" than changes in bullet design.YMMV.
     
  7. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

    11,380
    1
    0
    Of course they will impact in different places, they are different loads. The bullets are different. The powder is different. The primer is different. The case is different. Even if you use the same EVERYTHING, but change powder manufacturers your POI WILL change.
     
  8. locutus

    locutus Well-Known Member Supporter

    16,578
    682
    113
    Even the same brand from different manufacturing lots will very.
     
  9. SubZero

    SubZero New Member

    71
    0
    0
    First, thanks to everyone for the assistance. I appreciate the replies.

    Well, that is kind of a bummer.

    Are there some brands that are more consistent than others when it comes to putting out different lots?

    I know for example in the computer world, Verbatim has a history of making very consistent, high quality optical media (CD-R, DVD-R, etc.)

    Maybe certain rifle ammo brands are more consistent than others.
     
  10. jpattersonnh

    jpattersonnh Active Member

    5,360
    5
    38

    Power is made from organic ingredients, not software. When I reload, if I find a lot that shoots well, I buy 8lb. Takes guess work out of it for a while.
     
  11. TLuker

    TLuker Active Member

    3,937
    2
    38
    You just have to try different ammo and see what your gun likes. Most brands are pretty consistent. If a brand shoots well then that brand in the same identical type will almost always shoot good. The trick is finding the one type that shoots good, and there usually isn't any way to guess which one that'll be. :)
     
  12. nitestalker

    nitestalker New Member

    6,489
    0
    0
    The heavier bullets will strike higher in most cases. The lighter rounds will impact lower with the same sight settings. The reason is lapse time in the barrels and muzzle rise. The slower bullet will remain in the barrel longer allowing the muzzle to rise more before exiting the muzzle. The lighter bullet will spend less time in the barrel and reduce the muzzle rise before it exsiting the muzzle.

    Flat primers are not going to tell you what the the pressures may be. This can be caused by a large flash hole dirty chamber improper headspace bullets to tight in the throat etc. The fact that the windage was not off has more to do with the stable factor of the bullets at a given pressure. They seemd to be OK reletive to twist and barrel bedding.;)
     
  13. SubZero

    SubZero New Member

    71
    0
    0
    It was just an example. I know that ammo is different. I'm not a total idiot.
     
  14. locutus

    locutus Well-Known Member Supporter

    16,578
    682
    113
    A good military commander has his troops re-zero their rifles every tie a new batch of ammo arrives.

    As Patterson said, buy 8 lbs of powder st a time (or more if you can afford it) and don't worry about lot numbers.
     
  15. nitestalker

    nitestalker New Member

    6,489
    0
    0
    No so Locutus. Bench rest shooters would never agree on that concept. There are many examples of difference in Lot numbers. The famous Ball C Lot number 2 was a legend. The later Lots Of Ball C just never did the job. There are many examples such as the orginal IMR 4831. For serious shooters Lot mumbers are damn important. :)
     
  16. locutus

    locutus Well-Known Member Supporter

    16,578
    682
    113
    Right. I guess my previous post wasn't clear.

    Lot numbers are critical. That's why I buy at least 8 lbs, or more from the same lot when I buy powder.

    When that stash is used up, I buy another 8 or more lbs, again from a single lot number, and re-work the load.
     
  17. nitestalker

    nitestalker New Member

    6,489
    0
    0
    ;);):) Now that is the way to buy powder.
     
  18. big shrek

    big shrek Well-Known Member

    1,832
    44
    48
    Even with the same weight bullets, the powder charge may actually be two different types...
    Winchester is likely using their favorite mix for 300WSM, while Federal is using theirs...
    or if they are using the same powder...they might be using one grain different charge...

    Heck, even different composition of bullets can make a difference...different alloys fire faster or slower...
    Chrono's show that fairly quickly...

    So many variables...
     
  19. SubZero

    SubZero New Member

    71
    0
    0
    I don't make my own, but I did buy 4 boxes each of Winchester Super X ammo.

    .270 Win 130 Grain = 80 shots
    .300 WSM 180 Grain = 80 shots

    I'm going to sight-in both rifles using a front rest and sandbags provided by the range, and then set the remaining ammo aside, with a note that to myself indicating they were the same lot as the ammo used to sight-in and a date of purchase. That way, I figure I'll have a good chance of being accurate when I really need to be, not taking any chances.

    Hope that works out for me. Lesson learned. :)