300 Weatherby Mark V Accumark New Barrel


Feb 6, 2022
I have a Weatherby Mark V Accumark chambered in 300 WBY. It shoots sub-MOA groups averaging around .88 in size. The accuracy is pretty good but I would like to get down to 1/2 MOA groups if possible. The rifle has the stock Criterion #3 taper barrel. I am considering purchasing a new barrel and having a gunsmith mount it on the gun but am not sure how to go about this process. I also want to have a RRS Arca plate mounted to the stock. I would appreciate any advice as to what would be a great barrel for this gun and if there are recommended gunsmiths that can do a good job changing the barrel. Thanks!
Barrel? I recommend Bartlein or Krieger.

Wyoming Gunsmithing.
There are a lot of quality barrels out there. The biggest decision is what is your goal for your rifle. Hunting , target or a mix of both. I replaced my 30-378 Accumark barrel with a MullerWorks cut rifled barrel matching the same contour but at 28”. I just recently finished a MarkV 340 Wby with a Krieger 28” Heavy Varmint contour , she’s a beast. Any reputable gunsmith will chamber your MarkV for you. I’m lucky mine is 26 miles away.
If want to run those long high bc bullets I would recommend a twist of 8 or 9.
Adjusting the seating depth you may be able to walk in that group to .5 MOA.
Getting a good quality barrel, although somewhat expensive, should get you to your goal of .5 MOA or better.
Krieger, Hart, Pacnor, Lija all offer match grade barrels. Selecting a larger contour will stiffen up the barrel but add weight. Getting flutes will make it lighter without sacrificing stiffness. You will also need to determine barrel length and if the barrel is threaded for a brake or suppressor.
Also consider having the action blue printed to ensure that it is squared up.
As for gunsmiths, I've used Rob Canze at Williams Gunsight in Davison MI. Rob does excellent work. He built my 280 AI with a Hart barrel and my 338 RUM with a Krieger barrel and both shoot well under .5 MOA. Also take a look at Twisted Barrel for fluting.

Did you ever do anything with this?

I’ve improved mine by doing a full action bedding, and of course with hand loads.
Of note, one of my 300s cut the groups in half when I started to use my new suppressor. It's now extremely accurate and would likely make your desired goal.