Unusual groups - 150 partition loads

[cutthroat]

I was sighting in and practice shooting with a buddy this weekend. He had built up some loads for a Kimber 308 Mountain rifle using 150 grain partitions. I was stunned at the poor performance. While there was wind blowing, we were still shooting groups inside the box using 22-250s, 30.06, 300 win and 300 WSM. The 15O partions, however, are all over the map.

I can't figure out what happened. Jim is a carefull loader. In fact he is a perfectionist. When he switched to ballistic tips or other bullets, the 308 was back to driving tacks.

Any thoughts what might be going. I undertand that the groups using partitions might be a little wider than with other bullets but I was stunned. He was using I4895 as powder and the loads were not compressed.

 

[Guest]

Well, it all depends on the wind, as well as some 'intrinsic' factors regarding the rifle and load. Was this load the only non-tipped load y'all shot? If so, it might just be the lower BC causing problems with the wind drift. Or, perhaps this load was worked up at different environmental conditions, and doesn't fare well with the change? Also, did a new lot of primers, powder, brass, or bullets make it into this loading? Any of these could explain the issue. Or it might be just one of those odd gremlins of inconsistency. Unfortunately it means your friend will have to make another trip to the range after doing some more handloading. Hate it for him...

 

[FOTIS]

She just do not like them, simple.
A powder change can fix this usually but not guarantee.

 

[Powerstroke]

+1 With POP,
You may go through ten other powders before you find a combo that works with them.

 

[longwinters]

My Sako 308 loves Reloader 15. It does not sound like your buddy loaded up several different combinations of powders etc... to shoot the Partitions. I don't think it is the bullet.

Long

 

[cloverleaf]

Reloading is funny- I went up 1 grain of H4350 and my groups went from perfect "cloverleaf's to a 2-3 inch spread. Unfortunately I shot up the last of the lighter load so I cant go back and check it out. I'm going through all te other variables trying to straighten it out 'till I can get some more reloads. It may even get me loking at a new scope I am my own marketing department....just a bundle of insecurities Your in the right place for some good advice as long as you dont listen to me!! Good luck!! Let us know what you figure out. CL

 

[FOTIS]

I personally do not "trust" these loads that go from rags to riches by adding or subtracting one grain.
In my way of thinking what would happen if the temperature varies by ten to thirty degrees? Velocity goes either up or down (regardless of Extreme powders or not) and your literally one grain off up or down.
My perfect load is one that shoots well but if you go a grain up or down there is a small diff in accuracy and any difference in velocity is acceptable---usually it is not that much anyway .....50-75 fps.

 

[dw06]

I personally do not "trust" these loads that go from rags to riches by adding or subtracting one grain.
In my way of thinking what would happen if the temperature varies by ten to thirty degrees? Velocity goes either up or down (regardless of Extreme powders or not) and your literally one grain off up or down.
My perfect load is one that shoots well but if you go a grain up or down there is a small diff in accuracy and any difference in velocity is acceptable---usually it is not that much anyway .....50-75 fps.

I agree.Good advise.