Although 20 preformed cases have been included with your .375 Renner English Sporting Rifle, you may wish to have more on hand. Making the .375 Renner cartridges is simplicity itself. Begin with .45-90 Winchester cases which are available from Midway USA (for smaller quantities) and from the source, Starline. Simply anneal the case to within an inch of the head. Then lube them sparingly and slowly work them into the sizing die which was supplied with your RJ Renner English Sporting Rifle.
Begin by setting up your reloading press with the .375 Renner sizing die and shell holder as if you were reloading any other cartridge. Work the .45-90 cartridge case part way into the sizing die then retract the case slightly and give it a quarter-turn. Then push it further into the die and give it that quarter-turn each time you retract it. Repeat the process until the whole case has been formed.
If needed, trim the case mouths, but not too much, just enough to square them up. The overall case length should be 2.445-inches. Once the cases are formed, then you can fire-form them to your rifle's chamber. I like to use a 255-grain lead bullet and 24 grains of IMR 4198 for this purpose. This load will produce about 1300 fps and pressure enough to complete the fire-forming of the case. Once completed, load the cases as you would any other cartridge, being sure to observe all safety practices relative to reloading ammunition.
Please note that I do not accept ANY liability for the results of your handloading processes, nor for the information and load data that is listed below regarding the loading of the .375 Renner. Please remember that when you contracted for the production of your .375 Renner English Sporting Rifle, you accepted ALL liability and responsibility for ANY result of loading of ammo and your use of the firearm.
Following are loading charts that were composed on the excellent Quick LOAD© V.3.9 program which I highly recommend you purchase and use for load development of your .375 Renner. The loads listed are intended for the .375 Renner English Stalking Rifle in consideration of its 7-pound weight. Heavier rifles can be loaded to higher levels of performance, but beware that recoil increases significantly, too.
For the most fun and economy with your .375 Renner English Stalking Rifle, keep bullet velocities below 2200 feet-per-second and save your shoulder for serious hunting loads over 2200 fps - IF needed.
Enjoy your .375 Renner, but above all else, be careful in your loading and think before you shoot.
The information presented in the charts above is provided to indicate the potential of the .375 Renner cartridge when chambered in the .375 Renner English Stalking Rifle. When chambered in a heavier rifle, loads can be increased carefully and incrementally to achieve the full potential of the cartridge. It is strongly suggested that you purchase the Quick LOAD© program and use it for further load development.
Again, please think carefully when loading ammunition.
Making and loading the .375 Renner cases is easy!
Some hunting opportunities may require the 300-grain sledgehammer and the .375 Renner will handle them with ease.
While the bullet listed is Hornady's FMJ solid, the same data can be used for 300-grain expanding bullets, as well.
Loading the .375 Renner
Chambering the .375 Renner is accomplished using a standard .375 H&H reamer (most every gunsmith has at least one) to cut a short chamber of 2.445 inches. Then cut the cartridge rim recess into the barrel breech. It's that simple. Of course, you'll also have to cut the relief for the extractor.
This is an example of the potential loading the Speer 235-grain Hot Core bullet driven to 2423 fps by 54.0 grains of IMR 3031. This velocity provides a very good balance between power and recoil in a lightweight rifle.
The chart above is a calculation of the excellent Quick LOAD© program. The bullet is the Sierra 200-grainer that is intended for the .375 Winchester. Sierra suggests keeping the velocity to 2200 fps. However, it sheds speed quickly and pushing it to 2400 fps at the muzzle provides just under 2200 fps at 100 yards.
And, let's not forget lead bullets. When loaded with TrailBoss, the .375 Renner is economical and great for small game hunting and just plain plinking fun. Lighter-weight cast bullets are available from www.ReedsAmmo.com
Chambering for the .375 Renner is easy!
Here is another good load of 55.6 grains of H335 under the 235-grain Speer Hot Core bullet producing 2401 fps.
Keeping velocity of this bullet to about 2400 fps in our .375 English Stalking Rifle helps keep recoil manageable.
Since the genesis of the .375 Renner I have been urged by friends and customers to release the .375 Renner cartridge into the public domain so that others could work with it and help develop its full potential. As its creator, it's difficult to give up control of one's brainchild, but they were right because I simply don't have the time needed to explore the full potential of this cartridge. So, the .375 Renner is now free to use by anyone competent enough to do so - so long as credit is given to its source.
A very useful bullet for bigger, tougher game is the excellent 270-grain Speer Boat Tail bullet. This is a good long-range load for the .375 Renner cartridge in the .375 English Stalking Rifle, the bullet having a slippery ballistic coefficient of .429. While loading to higher velocity is easily accomplished, the increased recoil must be considered.