Good afternoon everyone and welcome back to TFB’s Silencer Saturday brought to you by Yankee Hill Machine, manufacturers of the YHM Turbo K rifle suppressor. I’m Austin R. and I’ll be your guest host for the week. Last week looked at a no-win scenario for Form 1 makers, and this week we take a look at B&T RBS or Reduced Backpressure Suppressors.
Designed with low back pressure and the shooter’s health in mind, the B&T RBS is certainly no slouch. Initially designed for military use, the RBS design is overbuilt focusing on being extremely durable to accommodate prolonged firing schedules. With these silencers coming to the American market very soon, I had the rare opportunity to test the durability of the original Swiss B&T RBS on a belt-fed FN MK46. Let’s see what happens when we turn up the heat.
B&T RBS & B&T @ TFB:
The last time we looked over the RBS was at SHOT Show 2022 where B&T showcased a massive silencer lineup for everything from handguns to submachine guns. For those familiar with B&T, this won’t come as a surprise as they’re currently the largest silencer manufacturer worldwide.
If these silencers have existed for years, why haven’t I seen them? Well, current U.S. import laws make it extremely difficult for silencers to be imported. Rather than ignoring the U.S. market, B&T has decided to expand bringing their Swiss-born silencer designs and manufacturing equipment stateside to accommodate the rapidly growing U.S. silencer market.
With the U.S.-made RGS silencers rolling off the production line, this was the rare opportunity to look at the original RBS and the updated RBS for both the European and U.S. markets.
Before you ask, yes the U.S. silencers are being built using the same tooling to the exact same spec. Even the raw materials are being imported from Switzerland so they’re exact 1:1 clones. B&T has spared no expense.
While the materials and construction haven’t changed, small tweaks have recently been made to the RBS. Specifically, a new end cap design (see above photo) with additional forward-facing vents. This tweak allows more of the gas to vent forward and away from the shooter and helps mitigate flash. For this test, I’d be using an RBS with a legacy front cap designed for the FN Minimi.
Health and safety are the primary focus of the RBS silencers, and here’s B&T’s product description for the RBS from B&T’s Swiss website.
When using a suppressor, the gas blowback in the face of the operator is not only disturbing but also a health risk, especially on indoor ranges. The new RBS suppressor significantly reduces the amount of combustions gases from the ejection port and charging handle.
As sensible as the use of silencers is in police and military applications, the escape of the retained gases from the ejection port and charging handle has various disadvantages. With the new RBS suppressor B&T addressed these issues. The new low-pressure chamber design allows to absorb a significant amount of gasses thus reducing the back pressure, which makes the RBS a great choice for semi-automatic carbines, assault rifles and machine guns.
While normal suppressors will increase the speed of the bolt up to more than 30% due to the backpressure, measurements have shown that with the RBS the increase is only about 4%., which will reduce wear and tear on the gun. This is due to the special design of the first expansion chamber, which cuts the pressure in less than half the time and thus avoids backpressure. A further advantage is the significantly reduced fouling of the system.
The new design only minimally increases the size and weight of the suppressor compared to conventional silencers, while muzzle flash and noise are suppressed similarly well as with the proven B&T suppressors.
The RBS is available in calibers 5.56 (.223) and 7.62 (.308) each in a direct mountable version (DM) for various muzzle threads as well as with a newly developed quick release (QD) fitting all NATO A2 muzzle flash hiders.
There are three models of the B&T RBS in both 5.56 and 7.62. The 5.56 lineup shown above features the RBS 5.56 DM or direct mount, RBS 5.56 QD NATO that mounts to a NATO Spec A2 flash hider, and the RBS 5.56 ROTEX-SF (not pictured) that mounts to both SureFire and B&T Rotex mounts.
For this 1,000 round test, I’d be using B&T’s FN Minimi direct mount RBS. The Minimi has the same 9/16x24LH thread pitch as this MK46 provided by Park City Gun Club, making it a perfect combination. With the suppressor hand tightened snug, tighten the screw on the collar and you’re ready to shoot.
There are three baffles suspended within a series of chambers in the RBS. This does an excellent job of reducing gas for the shooter while also providing excellent flash reduction. At this point in the above photo, the RBS has been subjected to a couple of hundred rounds of safely paced bed-fed fire. It’s when I went 150 rounds of continuous fire (from a 200 round belt) that things changed dramatically.
With unburned propellant particulate now passing through a superheated RBS, all it needed was an oxygen source. Then as they’d say at the Kennedy Space Center, “We have ignition”. A sudden flash accompanied by a loud bang erupted out of the front of the silencer. It was then decision time.
With only a quarter belt remaining, I decided I could safely finish off the belt in controlled bursts. At this point, I’m amazed that I’m not surrounded by a toxic gas cloud. Something that’s all too common among suppressed open-bolt belt feds.
Now it was time to stop. Not because I was told to, but because I’d rather not risk ~2,000° F shrapnel flying around, a runaway machine gun, or just setting the gun on fire. With the gun cleared, it was time to take a closer look at this now forbidden popsicle.
With the lights turned up slightly, the combination of Inconel and stainless steel in the RBS glowed purple as the can started to cool down. I would wait just long enough for the can to stop glowing, and continue this firing schedule until all 1,000 rounds of belted Striker 5.56 had been fired.
When the gunfire finally ceased it was time to remove the RBS Minimi to see how it’d held up. The end cap showed no signs of wear or damage, but it’s the blast baffle that I was really curious to see.
Much to mine, and everyone’s surprise, the blast baffle looked as good as new. There were no signs of erosion, and even the internal threads were clean. During testing, the RBS never moved, and it was just as easy to take the can off as it was putting it on.
The B&T RBS exceeded my expectations on this FN MK46. These silencers are coming to market very soon and will be a welcome addition to the U.S. market. As for the other silencers pictured, I’ll have a full in-depth review of those in the coming weeks. So stay tuned.
Special thank you to Park City Gun Club for hosting this event, Chris M. from B&T for flying out with these suppressors, American Marksman for supplying the ammunition, and James Rose for his help getting all these incredible photos.
Be safe, have fun, and we’ll see you back next weekend for another Silencer Saturday.
Silencer Saturday is Sponsored by Yankee Hill Machine
DEALERS: If you want your link to buy YHM suppressors included in future Silencer Saturday posts, email: [email protected]
Belt Fed Brutality with the B&T RBSThe Firearm Blog is written by Austin R for www.thefirearmblog.com