interesting problem !!!

poff6401

Sergeant
Full Member
Minuteman
Oct 26, 2007
125
0
39
Columbus, Ohio
a buddy asked me to put this on here to see if anybody had any thoughts

winchester model 70 action
krieger 1-8.5 twist chambered in 260
hs precision stock

all work performed by krieger

loading 42.5 gr. of H4350
against lands

it was shooting 5/8" groups with no signs of pressure. now the groups have opened up to 2.5" and the primers are being pierced. he is doing nothing different since he got it
 

oneshot onekill

Gunny Sergeant
Full Member
Minuteman
Jul 29, 2008
1,952
7
58
DeBary, Florida
Re: interesting problem !!!

Weigh the projectiles. I bought a batch of 168 SMK's once only to discover some 190's mixed in.
NOTE... This was an opened batch I bought online so it was just the seller's mistake.
 

Wheres-Waldo

Gunny Sergeant
Full Member
Minuteman
Nov 2, 2008
1,607
443
Tallahassee, Fl
Re: interesting problem !!!

Ide chrono the load to see how much faster its shooting. Its going to be something in the reloading process. An odd batch of powder, some bullets with an unusualy long bearing surface...ect...
 

bigwheeler

Sergeant
Full Member
Minuteman
Oct 18, 2008
451
0
65
montana
Re: interesting problem !!!

Carbon ring in the throat or case necks stretching into the throat and getting
pinched if it's a tight neck chamber.
 

matt2143

Gunny Sergeant
Supporter
Full Member
Minuteman
  • Dec 4, 2009
    1,926
    74
    Northern, VA
    Re: interesting problem !!!

    First a visual inspection and secondly I would have him chrono a few shots, that will be the fastest trouble shooting he could do if he has loaded every bullet he had from the batch already.
     

    Cascade Precision

    Sergeant
    Full Member
    Minuteman
    Jun 23, 2008
    868
    20
    44
    Klamath Falls, OR
    Re: interesting problem !!!

    Also, what is the temperature difference? A hot load at 10 degrees F is going to be way too hot at 90F. Not likely the issue since it is december and cold...
     

    steve123

    Lt. Colonel
    Full Member
    Minuteman
    Mar 16, 2008
    9,141
    1,631
    none of your business
    Re: interesting problem !!!

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: poff762</div><div class="ubbcode-body">a buddy asked me to put this on here to see if anybody had any thoughts

    winchester model 70 action
    krieger 1-8.5 twist chambered in 260
    hs precision stock

    all work performed by krieger

    loading 42.5 gr. of H4350
    against lands

    it was shooting 5/8" groups with no signs of pressure. now the groups have opened up to 2.5" and the primers are being pierced. he is doing nothing different since he got it </div></div>

    Are you using Lapua brass? They have thicker necks than other brands of 260 Rem causing excessive pressure problems because the neck cannot expand enough to release the bullet correctly.
     

    TRAAV

    Full Member
    Full Member
    Minuteman
    Apr 15, 2010
    1,643
    19
    43
    Santa Claus IN
    Re: interesting problem !!!

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bigwheeler</div><div class="ubbcode-body">Carbon ring in the throat or case necks stretching into the throat and getting
    pinched if it's a tight neck chamber. </div></div>
    +1
     

    steve123

    Lt. Colonel
    Full Member
    Minuteman
    Mar 16, 2008
    9,141
    1,631
    none of your business
    Re: interesting problem !!!

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: steve123</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: poff762</div><div class="ubbcode-body">a buddy asked me to put this on here to see if anybody had any thoughts

    winchester model 70 action
    krieger 1-8.5 twist chambered in 260
    hs precision stock

    all work performed by krieger

    loading 42.5 gr. of H4350
    against lands

    it was shooting 5/8" groups with no signs of pressure. now the groups have opened up to 2.5" and the primers are being pierced. he is doing nothing different since he got it </div></div>

    Are you using Lapua brass? They have thicker necks than other brands of 260 Rem causing excessive pressure problems because the neck cannot expand enough to release the bullet correctly. </div></div>

    Oh and I had ran out of a older 8lb jug of H-1000 and bought a new one. The new jug was giving excessive pressure with the same powder charge as the old. Bolt was very sticky.