Building the Little Thumper .500 Jeffries

“Who in their right mind needs a .500 Jeffery rifle anyway?” was the question I asked myself over and over. Yet here I was, searching for one in all the usual online auction houses. I got lucky and ended up getting one from a friend for a reasonable price. It was a CZ 550 Magnum.

After watching Tim Sundles whack two Cape Buffalo with his custom .500 Jeffery, it just made sense. Everyone needs a dangerous game rifle capable of “stopping” near 2,000-lb. mean critters dead in their tracks — with one shot from said rifle!

Besides, it’s always interesting handloading new and exciting cartridges, especially one with history. The .500 Jeffery had both — and it was my first name.

History

The 500 Jeffery was originally introduced by the August Schuler Co., a German firm, calling it the 12.7x70mm Schuler, or .500 Schuler around 1920. Schuler wanted the most powerful cartridge a standard-sized ’98 Mauser could handle, and the .500 Schuler fit the bill.

When famous British company, W.J. Jeffery & Co offered the gargantuan cartridge, they renamed it, calling it — what else — the .500 Jeffery. Remember, this was after WWI and English sporting men weren’t real keen on anything German so a more English-sounding name would be better for sales than the German .500 Schuler.

CZ? Easy!

It was fall and I had a hankering for fried perch, spicy chili and a cold lager beer. The best I’ve experienced is 8 hours away in a little bar in Michigan called the Adair Inn. Master gunsmith and friend Ken Kelly of Mag-na-port introduced me to this hole-in-the-wall hangout in Michigan’s big woods. The walls are adorned with deer heads, perch, bass and walleye, a true outdoorsman’s place to refuel, tell tales and warm up from a day’s hunt or fishing trip.

Of course I brought the CZ 550 with me for Ken is one of only a few men I’d trust to do the work my gun needed. In factory form, CZ seemed to think 25″ barrels were necessary for their Magnum rifles. Sure, the long tom barrel ramps up velocity but it also makes the gun cumbersome and unwieldy, especially in tight quarters.
I wanted the barrel cut-down to 21″. A simple job, but I wanted to keep the nifty and traditional barrel-banded front sight the rifle came with. Ken would work his magic to make this possible.

First things first, Ken performed a severe circumcision of sorts, cutting off the last 4″ of barrel. Ouch! I cringed as the band saw blade quickly cut through the barrel. No turning back now! He then applied heat from a torch to loosen the soldered front sight and its barrel band. Thankfully, the whole slid off without a hitch. Ken then went to the Bridgeport milling machine to administer a perfect barrel crown for the newly made carbine.

Next, Ken honed out the barrel band so it would slip snugly in place onto the thicker portion of the tapered barrel. Once this was accomplished, he skillfully centered the front sight, marking where he would drill and tap a hole so the barrel band could be screwed onto the barrel.

The hole was hidden under the front sight. Combined with JB Weld and the barrel band design, the front sight is now locked solid and the barrel didn’t need to be re-blued, saving time and money.

NECG

I replace the front sight with a gold-faced patridge style sight from New England Custom Gun. A little file work was necessary on my part to make it fit. Matched with one of their aperture “peep” sights mounted onto the recessed scope dovetail, I have faster target acquisition, especially with the shortened barrel and longer sight radius.

I removed the stylish fold-down rear sights, which were dovetailed into the bridge of the rifle barrel. Now I needed a slot blank to give the rifle a finished look.
I thought of Special Editor Roy Huntington. He’s a master at shaping metal things and I sent a detailed drawing on a napkin, via texted photo, along with the folding rear sight assembly so he could make an appropriately sized blank.

A few days later I received a package in the mail with my perfectly sized blank. A few coats of cold blue and the metal matched the rifle. The blank was installed with just enough resistance to provide me confidence it will never work free, even from the raucous recoil of the 500 Jeffery.

Trial By Fire

I’d assembled handloads to test fire and sight-in my modified marauder. Using RCBS dies, Hornady .510″ 570-grain DGS bullets, Varget powder and a Winchester Magnum primer, I assembled a dozen cartridges. The first shot showed windage was dead-on but shooting low. A few turns of the aperture screw, and we were dead-on at 50 yards.

Now I have a proper dangerous gun, tweaked for my needs and preferences with the satisfaction of having a hand in the works. Now I just need to introduce my Custom CZ to something big and dangerous.

Subscribe To GUNS Magazine

Purchase A PDF Download Of The GUNS Magazine December 2024 Issue Now!