January 11, 2011
When I was a youngster, a neighbor showed my dad and me his new rifle and how he handloaded the belted 7x61 Sharpe & Hart magnum rounds.
The bolt-action Schultz & Larsen Model 54J was one of the few original factory rifles chambered for the 7x61 Sharpe & Hart cartridge.
When I was a youngster, a neighbor showed my dad and me his new rifle and how he handloaded the belted 7x61 Sharpe & Hart magnum rounds. That fascinating occasion was the first time this kid was exposed to any firearm touting the magnum mystique. I never forgot it. Many years later, when my knowledge of guns and shooting had grown (and I achieved substantially more financial flexibility), I eventually purchased the first (and, I believe, only) factory rifle chambered for that round.
At the time, you could still purchase Norma's improved 7x61 Super ammunition and brass. However, I recently noticed that the Norma product catalog no longer lists them. I had a pretty good stash of both ammo and brass, but it pays to think ahead and plan accordingly. To that end, I acquired a set of RCBS form and trim dies to convert 7mm Remington Magnum cases into 7x61 S&H.
Of course, because both rounds are the same caliber; similar in size and shape; and share a common, belted case head, reforming the parent brass is a rather simple task. However, the final S&H shoulder turns more abruptly into the neck than the Remington Magnum. And the S&H case length is nearly a quarter-inch shorter, so the reformed neck and shoulder will be located where the Rem. Mag.'s shoulder and upper case body are. I suspected I'd have to anneal the reworked brass--hopefully after reforming it.
I began experimenting with some several-times-fired, mixed-headstamp brass that I had on hand. I found that if I carefully swaged the brass incrementally--and paid attention to how I lubed the case shoulder/neck--I could achieve satisfactory results. I also reformed cases both before and after annealing. Either way works, but it's probably easier if you anneal the brass first. Of course, if you're using new brass, you can get by without annealing initially and wait until after you've loaded and fired them a couple times.
I acquired a few boxes of factory ammo along with the rifle and scope package, but the M54J barrel indicated the rifling twist rate was 1 turn in 12 inches. The 160-grain factory loads generated 2,900 fps average velocity with minimal data dispersion. However, the heavy bullet's less than stellar speed and overall length apparently preclude any chance for them to properly stabilize, and my groups failed to meet my minimum standards of acceptable performance.
The best handload I've tried so far is 63.0 grains of IMR-4350 behind a 150-grain Nosler spitzer boattail bullet and sparked by vintage VihtaVuori Large Rifle Magnum primers.
I've used original Norma and reformed brass in my handloads with similar results. As you may know by now, this engineer likes to experiment, developing loads for off-the-beaten-path, obsolete, and wildcat cartridges. Handloading for the 7x61 Sharpe & Hart helps satisfy my need, and there have been no mishaps or surprises.
All components except cases are readily available, but 7x61 Sharpe & Hart cases can be formed from 7mm Remington Magnum brass using RCBS form and trim dies.
The Annealing Procedure
My research on how to properly anneal cartridge brass turned up a couple of obvious fallacies. Several sources directed me to "heat the neck with a propane torch until it turns (cherry) red and then drop it (flip it over) into a pan of water€¦." One continued with "€¦be sure to change the water often--if it becomes too hot, the annealed case can't cool properly€¦."
In the first place, a glowing-red condition will make the case neck dead soft, i.e., it's essentially ruined and can't be salvaged. In the second place, water actually boils at 212 degrees Fahrenheit, or well below the temperature at which an annealed case is properly quenched. So much for those oft-repeated "expert" recommendations.
Actually, Designing and Forming Custom Cartridge Cases by Ken Howell includes an excellent treatise on when and how to properly anneal brass. Obviously, when reforming cases, you probably should anneal them, too. Howell suggests you may do so before or after reforming, depending on how severely the case neck and shoulder are reworked.
The 7x61 S&H's very sharp shoulder coincides with the 7mm Rem. Mag.'s upper case body, so I decided to experiment both ways. I successfully reformed a few nickel-plated 7mm Rem. Mag. cases without annealing them before reforming. Then I annealed and quenched a mixed batch of freshly tumbled brass with a propane torch and a bucket of water.
I have a sink in my shop with a worktable on one side, so I rigged up a cardboard shipping box on the table to securely hold the gas bottle with the nozzle suspended over the sink. I lit the torch and adjusted the blue flame so it was about 1.5 inches long. I held the case by the lower body (with my fingers--no gloves) and submerged the neck in the tip of the blue flame, tilting slightly away from the nozzle. I rotated the case back and forth so the flame evenly heated the neck.
Howell suggested using a temperature indicator (special crayon mark on the shoulder that melts or changes color at about 650 degrees). That's not absolutely necessary because if you turn the neck in the flame consistently, you'll see the surface sheen and color begin to change to a dull bluish appearance starting from the case mouth and traveling down the neck and shoulder.
About the time the discoloration turns down the shoulder, your fingers will be exchanging messages with your brain and concluding it's time to drop the case into the bucket of water.
The same process can be applied to simply annealing case necks of your favorite brass when it shows the first signs of excessive hardening. I found one exception when I tried to anneal some .25 WSSM brass. The case length is, of course, abbreviated, and the neck walls are much thicker than most. My fingers automatically released them before the neck and shoulder could completely change color.