New 6mm 115gr DTAC from David Tubb
August 22, 2016
The RBH Cartridge Family
May 21, 2019
Show all

RBH Cartridge Lineup

This project actually started back in 2008 when a customer contacted me wanting to build a 7/338 Norma Improved. He had a reamer print design in mind, so we tweaked it a little and put the proper throating on it and chambered up his rifle.  Performance was decent but we knew that brass seemed to be the limiting factor, or so we thought.  Fast forward 10 years and several barrels worth of data between us, not to mention becoming very close friends and hunting partners, we have learned a lot.  Now, we aren’t the only one’s wildcatting the 300/338 Norma case, but we do have a fair amount of experience and data over the last 10 years.  With the development of better brass over the last couple years I decided it was time for a new lineup of cartridges.

On a recent bear hunting trip with my hunting partner Robert, we started brainstorming ideas on what would make the ideal hunting cartridge setup. So many people are focusing on the ELR market lately with their wildcats, but our focus was hunting applications.  This isn’t to say that these cartridges won’t work for ELR, because they will very well, but they were designed for hunting and to optimize todays heavier for caliber bullets, yet be able to be setup in a repeater platform.  Taking what I have learned over the last 10 years of shoulder angles, body taper, neck length and overall case design, I set out to design the RBH series of cartridges.  The goal was to duplicate full size RUM cartridge performance in a shorter OAL package that would stay a repeater even with the heaviest of bullets.  It’s pretty common knowledge that we are 7mm fanatics, so it was only natural that the 7 RBH would be the first out of the gate.  Taking what I learned with the original version back in 2008 I set out on redesigning it to make it better and up the performance.  I used the original platform for testing which is built on a Remington 700 with a PTG bolt.  This would give me pressure indications long before the Rogue action, so it made sense to use if for “proofing”.  Lapua and Peterson brass were fireformed and the testing began.  Before anyone starts to ask, I was not accuracy testing, but mainly looking for velocity at this point.  Velocities were impressive for the initial workup with 180’s running 3350 and 195’s running 3200.  These were not max loads, but I was happy with the results.  I continued to run the 180 load to finish barrel break in.  7 full power firings on the brass and primer pockets were still virgin tight and no web growth. These velocities were out of 26” barrels and using conventional powders.  Case capacity ended up with 109.8gr of H20 capacity.  Happy with the results, we will now look for the velocity max, but the results we are seeing at this point make this a solid hunting rifle.

There will be a 300, 338 and 375 RBH as well. The 338 and 375 versions are slightly different since they are designed more for critters with sharp teeth, but they are still proving to run right with their full size RUM counterparts.  The 300 is simply the 7 RBH necked up.  Based on the data of the 7 so far, the 300 will be pretty much identical if not a little beyond the 300 RUM.  Again the goal of these was to be able to keep the rifle a repeater.  We will be continuing to test and update things as we move forward.  Brass is already in the works and I am hoping to have it available by the end of 2019.  In the meantime we will be hydro forming the 7 and 375 RBH for guys.  The 300 and 338 are as simple as firing the 300 or 338 Norma in the rifle.  We may end up doing hydro forming for them as well until brass is ready.

 

 

Now for the rifle system….I will be renaming the Carbon Hunter to the APEX Series. Sounds funny to rename these, but we never really had a designation for them.  The RBH calibers will be setup a little differently however.  We have specially designed BDL that allows 3 rounds in a stagger feed.  This allows smooth feeding and a flush floorplate rather than the canoe style that a single feed box requires.  It also allows 3.82” of OAL, which is long enough for the heaviest of bullets in the RBH lineup.  The APEX Series will consist of:

Apex Alaskan Hunter

Apex Hunter (formerly Carbon Hunter)

Apex Sheep Hunter (coming soon)

 

Now before anyone starts asking, I will not give out any reamer dimensions or details. These are proprietary to R Bros.  I may eventually rent out reamers, but for now it’s staying in house.  We will continue to collect data and will end up having a RBH page on the website to give guys an idea of performance.  Also, let’s not bring in the question of barrel life.  We should all understand that this level of performance does come at a cost.  The original 7 did last 8-900 rounds with proper care, so I expect this one to be about the same.  Realistically, we should expect RUM barrel life or slightly more since the case if more efficient. This may not be for everyone, but some will find it interesting and like the performance.

 

Travis Redell