Well-Known Member
Mar 2, 2002
Central Minnesota
I bought a Weatherby Mark V Accumark .30-378 Wby Mag and I'm looking to handload for it. I decided to do this mainly because the cost of factory ammo. I already know what I will use for hunting, but I want a super accurate load for shooting on the "off season." I want to use the Sierra Matchking and I'm wondering what grain bullet to use I'm looking for the most accurate, the longest range, and the most energy I can get. Also I'm wondering which powder to use. Can anybody help? Thank You


Well, you have a nice rifle. However the weatherby rifles have never been known for their accuracy because of excessive freebore. The bullet jumps to the lands and the distance it jumps in a weatherby is totaly to much for an accuracy stand point.
Some do shoot well but a factory weatherby with a factory barrel will not get you what your after.
Some may disagree but I have never seen one shoot moa or even sub moa with the best loads and best bullets.
You may be able to use it as a single shot because youll have to seat the bullet out so far to engage the lands that the magazine well will not hold them but I doubt it as the bullet shank is short on sierras and the likes, but if you used say berger, jlk, or lost river ballistic bullets you may just be able to touch thoses lands.
Your twist will determine a lot of what will perform in your gun also. Heavy bullets do well with faster twists, and the reverse lighter with slower twist.
This 30-378 is a barrel burner from what Ive been told and read about but since you have a weatherby you may see a few more rounds than a custom barreled rifle would because of the freebore distance.
Try this link may help you out a bit.
accurate reloading


Well-Known Member
Dec 16, 2001

I have been working with the 30-378 Mark V since Christmas. Out of the box as is no trigger adjust, nothing. I have found the most accurate loads to date (last Sat)to be 220 grain Matchkings with H50BMG. I am at 2 grains under max listed on Hodgdon's web site for the caliber. At this load in my rifle the brass is showing ejector marks. But as a side note with the first box of factory shells I put through the gun I saw similar marks on three of the 20 cases. This was my first testing with the H50BMG. I had only five rounds each in 1/2 grain increments but at 200 yards this set printed the first 4 at .9 and the overall 5 at 1.5. The previous set at 1/2 grain lighter was only a three shot due to a scope adjust from 180 grain bullets but they mingled right in with the 5 shot for a total of 8 at just under 2 inches.
I hope this helps. I felt sick after getting mine and then reading that in order for it to shoot I had to have it rebarreled. I am feeling much better now. Will let you know if interested what they will do at double the distance after next weekend.


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