338-300 PRC... Sherman Improved!

Got out and tested the 225 McGuire CR's. As hoped, this combination is working out better than the H4350.

Ran my pressure ladder up untill I hit pressure at 76 gr of N550 with a bolt click & slightly heavier bolt. Shooting all charge weights at 100 yards, it started stacking together at 73/74/75/76 gr where I stopped. 74/75/76 gr charges were all nearly touching. Pretty typical of what I've seen with the McGuires.

Loaded up three rounds of each charge weight 73/74/75 gr of N550, staying one full grain off of 76 gr where first signs of pressure were. Here's where we landed!



I'll load up a few more at 75 gr of N550 coming in at 2950 fps to go verify it repeats!
Scrubbed my barrel, loaded up a few more, fouled it back in and checked my load again. Here is what I'm going forward with!


This combination is shooting great. Shot some 5 shot groups as well and its holding sub moa. Next up will be putting the NXS 2.5-10x42 back on till after the spring bear season. It's looking like I'm taking the 225 CR's from McGuire Ballistics to Alaska in a couple weeks for some field testing.

Loading up a few more to zero, get drops, & verify BC. For my intended use it will likely be a 200 yard or less shot, 300 at most but it's good to know and get the practice in 🤙🏽.
Range trip to get the NXS re-zeroed. This thing is just drilling. Somehow I'm shooting just as well or even better off the Hatch Bipod than my Phoenix Bipod that I use for load dev, AND with the 10x Power NXS. I think it makes a guy try harder!



Next up, some long range testing to verify drops and get more practice on the NXS.
Sam at McGuire modified a magazine for me also. The McGuire Ballistics mono's have a pretty unique tip design, and with the larger magnums they've created a solution for magazine fed setups to prevent tip damage. It's working pretty slick so far. This is the first Hawkins mag modified so it's a "rough in" if you will.


Quick "long range" day to verify drops & true a BC with the 225 Copper Rose load.


225 CR
2960 fps
.600 G1 (estimated starting point)
100 yd zero

Started with a 100 yd zero check:
(Disregard that beautiful little 3 shot group from the other day 😁)


Next out to 400 yds. Had a 10-15 mph left->right wind, hence the horizontal. Vertical looks pretty good! Note the copper splash marks on the steel.


Next out to 600 yds, first couple shots below, again noting the copper splash:


Approximately .2-.3 moa low with the .600 G1 BC. Again, pretty good crosswind (holding 3.0 moa left), but very little verticle. Corrected to a .550 G1 and shot two more at 600:


Pretty easy day! I'd love to geek out a little more on the BC's when time allows but I would suspect that most everyone will land between a .550-.600 G1 BC on these. At 600 yards that is literally only the difference of ONE 1/4 moa click on the scope. Next outing, if wind cooperates a little better we'll stretch it a bit more! For the rifles intended use of sub 600, and for big stuff in Alaska we'll call that good to go! Time to load up the rest of my ammo and pack a bag for spring bear!
Drumroll... the 33 Sherman Magnum worked out flawlessly in Alaska this spring season! I was fortunate enough to take a great bear AND with the new prototype 225 gr McGuire Ballistics CR's. The rifle was an absolute joy to carry, experienced no zero shift through all commercial/small airplane/bush flights as well as being carried around for 25 days in field. I'll say mission accomplished on this build 😁