New Ammunition from Grizzly Cartridge Co.
    by Matt Zietlow

    Mike Rintoul is a devoted husband and father of 10 children, and an instrumentation engineer by day. I believe it’s safe to say that might make for a pretty full schedule already, wouldn’t you think? As an engineer myself with a couple little ones running around the house I know that I certainly would. And still, a little over a year ago Mike felt there was a need for more choices in the premium ammunition market, and with the blessings of his wife Jeanne, Grizzly Cartridge Company was born.

    Pick-up a box of Grizzly Cartridge Co. ammunition and you’ll appreciate right away the attention to detail. The cartridges are packed individually in styrofoam trays housed in attractive cardboard boxes bearing the Grizzly Cartridge Co. design. Inside, you’ll find highly polished and consistent ammunition, each loaded by Mike himself with the precision you’d expect from an engineer.

    I’ve had the pleasure of trying out some of Mike’s offerings these past few weeks in .454 Casull, 45 Colt +P, and .44 Magnum, and I am pleased to say they shoot as well as any factory ammo I‘ve come across, and better than most. A quick perusal of the Grizzly Cartridge Company website at www.grizzlycartridge.com will show that Mike pretty much sticks to relatively large-caliber offerings, and you’ll find an excellent selection of choices in an array of calibers. Handgun offerings range from the .357 magnum up through the mighty 500 S&W, and rifle chamberings run the gamut from the venerable 30-30 up through the 444, 45-70, and even the 50 Alaskan. Several bullet weights in both jacketed and cast are offered for most calibers.

    For this evaluation, Mike had sent examples of both jacketed and cast loadings in .454 Casull and .44 Magnum, as well as some cast loadings in .45 Colt +P. Please take note that the .45 Colt +P ammunition is only to be used in strong modern firearms such as Ruger Blackhawks and old-model Vaqueros, Freedom Arms revolvers, Colt Anacondas, and TC single-shots. They should not be used in Colt or Colt clone single-actions, Ruger new-model Vaqueros, or Taurus and S&W double-action revolvers. I used a S&W Performance Center M-629 to test the .44 Magnum loads, and a Freedom Arms Premier-Grade revolver on both the .454 Casull and .45 Colt +P offerings. Both handguns were scoped, with a Weaver 4x riding on the S&W M-629 and a Burris 2-7x astride the Freedom Arms revolver.

    It didn’t take long for me to find that these loads would shoot. My very first 5-shot group out of the S&W .44 Magnum registered a snug 1 1/8" at 25 yards, that being with the 275-grain Hawk Bonded Core FP loading at a nominal 1300 fps. A subsequent 5-shot group at 50 yards wasn’t much larger, that one measuring a tidy 1 7/8". The 300 grain cast loading was even better in terms of accuracy, registering 25 yard groups averaging a bit under 1" and 50 yard groups well under 2".

    The .454 Casull loads behaved in a similar fashion, with 5-shot groups at 25 yards grouping consistently around 1 1/4", and 50 yard groups around 2". Interestingly, the very best performing load of all those I received proved to be the 45 Colt +P when fired from the Freedom Arms revolver while still using the .454 Casull cylinder. This particular load launched a 300-grain cast LBT-style flatnose bullet at well over 1200 fps, and consistently turned in groups under 1" at 25 yards and hovered near 1 ½" at 50 yards. Darn good accuracy for premium heavy hunting loads any way you look at it.

    Mike Rintoul is turning out some superb ammunition at Grizzly Cartridge Company. If you’re looking for top-quality heavy hunting ammo for your handgun or perhaps a big 45-70 levergun or single-shot, you might give him a call at (503) 556-3006. Mike even offers an ammunition development service specific to your gun if you so desire!

    Freedom Arms Revolver; .454 Casull; 7 ½" barrel with Burris 2-7x scope

    Grizzly Cartridge Co.


    Average Velocity

    Standard Deviation

    25 - yard accuracy

    50 - yard accuracy

    45 Colt +P

    300 grain LFNGC





    454 Casull

    260 grain Hawk FP





    454 Casull

    335 grain WLNGC






    S&W M-629 PC Revolver; .44 Magnum; 6 ½" barrel with Weaver 4x scope

    Grizzly Cartridge Co.


    Average Velocity

    Standard Deviation

    25 - yard accuracy

    50 - yard accuracy

    44 Rem. Mag

    275 grain Hawk BCFP





    44 Rem. Mag

    300 grain WFNGC





    Note: All groups shown in the above tables were fired from a sandbag rest, and reflect the average of three 5-shot groups.