german 300 wby loads

[jdl420]

I'm working up loads for an older mark v german 300 wby. i've tried imr4831, 4350, h870 and finally imr7828 without much success. i'm using an AccuBond 180gn and instead of trying different charges i've started using a couple of grains less than max and varying the seating depth by 0.007 ie 91gn h870 is fixed and just changing the seating depth for 4 rounds then another 4 rounds 0.007" further out. i started with the listed OAL of 3.56". Any help/ideas would be greatly appreciated. Or am i just being impatient this is about the 5th box of reloads with nothing less than 1.5" groups. Thanks, John

 

[SevenShooter]

Start by altering powder charges methodically to find a load that is decent. Then do the tweaking of the COL to wring the best out of that load that showed potential. Just picking a charge and hoping that it will eventually work with some COL risks wasting a lot of effort.

 

[baltz526]

try a bullet closer to what the rifle was designed for, 220gr Partition, 200gr Partition. a 180gr is light for case capacity in the 300 weatherby, in my opinion. nosler #5 lists fed 215 primers and i have heard these are required for good accuracy in the big weatherby cases. sometime developing loads with a particular bullet if futile, switch bullets and the rifle comes right to you.

 

[Alaska]

IMR 7828 @ 84.5
Fed 215 GM Primer
180 gr Nosler AB
COL: 3.560"

1:12 Twist......should be very accurate with 180 and lighter!

 

[jdl420]

Thanks for the input, i did originally start out trying different powder weights but went through 5 boxes using starting charges and working up from there, then switching powders. i've always used cci 250's but i get a box of the federals and see if this helps. thanks again, john