Krebs Custom’s Interchangeable Muzzle System (IMS) features a flash suppressor base onto which other devices can easily be mounted/removed without the need for tools.
June 09, 2022
By David M. Fortier, Senior Field Editor
Muzzle brake or flash suppressor? Traditionally this is the question one must answer when deciding on what muzzle device to mount. Each has its pros and cons. Flash suppressors typically go on rifles intended for personal protection and muzzle brakes on rifles intended for recreational shooting and games. But what if you could have both? Enter the Krebs Custom Interchangeable Muzzle System (IMS) .
The foundation for the IMS is a four-prong flash suppressor which features external threads and a spring-loaded detent. All other devices thread onto this unit. Krebs Custom is well-respected for the handgun and rifle work, and their IMS is both well-thought-out and handsomely crafted. The IMS does exactly what its name suggests; it allows the shooter to easily swap out muzzle devices to fit his needs. The system consists of an effective flash suppressor which acts as a mounting base for a family of muzzle devices. The flash suppressor remains firmly mounted on the rifle. Different devices can then be quickly attached or removed to/from the flash suppressor to tailor performance as desired. Most importantly, all this can be done without the need for tools.
Included with the flash suppressor is a compensator which helps to reduce muzzle movement. It spins on over the flash suppressor and locks into place. The foundation for the IMS system is an open four-prong flash suppressor. This is 2.9 inches long, adds 1.95 inches in length to the rifle and weighs 4.2 ounces. It is machined from 4150 steel and heat-treated to 40 Rockwell. What is unique about this design is it features 24x1.5mm external threads and a spring loaded detent. This allows you to thread on another device by hand over the flash suppressor, and securely lock it into place. To remove you just have to depress the detent and spin it off by hand.
Included with the flash suppressor is a simple compensator. This weighs 1.7 ounces and has an overall length of 2.46 inches, adding just .22 inch to the base unit. It threads easily onto the device and features three oval ports at 9, 12 and 3 O’clock. It is notched at the front to allow a cleaning rod or similar device to be used to aid in its removal if badly fouled. When installed it aids in reducing muzzle movement while keeping the flash signature to a reasonable level.
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The Short Muzzle Brake is made from US Grade 5 Titanium and is a two-baffle design which noticeably reduces felt recoil and muzzle movement. A better option, in my opinion, is to add an effective muzzle brake. Krebs offers two interesting designs as accessories. Both are made specifically for the IMS system and both are machined from US Grade 5 Titanium with a black cutting-edge TB-41 diamond-like coating. The “Short” brake weighs 1.9 ounces and adds .36 inch to the overall length of the flash suppressor. A two baffle design it sports a large and small port at 3 and 9 O’clock. The “Long” brake weighs in at 3.1 ounces and adds 1.4 inches to the overall length. This impressive looking piece sports five baffles and features four large and one small port at 3 and 9 O’clock. Both are handsomely finished, nicely knurled and appear very well made.
The Long Muzzle Brake is also made from US Grade 5 Titanium and sports five baffles for impressive recoil reduction. This device kept the muzzle very flat! Performance wise, the system works very well. The base flash suppressor was tested in low-light and no-light conditions with multiple calibers and different loads. Flash suppression is very good, not the best flash suppressor I’ve ever used, but solid performance. This base unit is very nicely made, looks good and mounted easily. Downside is it’s on the heavy side at 4.2 ounces.
The included compensator works acceptably well at reducing some muzzle movement. However, switching to the short muzzle brake noticeably reduces recoil and muzzle movement. Testing on a selective-fire 5.45x39mm AK showed a noticeable increase in control on full-automatic. The long muzzle brake greatly reduces recoil and muzzle movement and makes the rifle very flat shooting. Recoil reduction was highly noticeable on both 7.62x39mm and 5.56x45mm rifles.
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Krebs Custom offers their IMS with three different threads, 1/2x28, 5/8x24 and 14x1 and in .22 and .30 caliber so it can be fitted to a variety of firearms. Adding or removing muzzle devices from the base flash suppressor is very quick and easy. The IMS system is offered with 1/2x28, 5/8x24 and 14x1 threads so it can be mounted onto a variety of models and calibers. Price for the base flash suppressor with the included compensator is $90. The Short Titanium muzzle brake is $91 while the Long Titanium muzzle brake is $99. Also offered is a Blast Can for $56 and a Thread Protector for $15.75. In addition Liberty Suppressors also makes an adaptor to interface their sound suppressors to work with the IMS system. For more information visit www.KrebsCustom.com and www.LibertyCans.net
If you have any thoughts or comments on this article, we’d love to hear them. Email us at FirearmsNews@Outdoorsg.com .
About the Author: David M. Fortier has been covering firearms, ammunition and optics since 1998. He is a recipient of the Carl Zeiss Outdoor Writer of the Year award and his writing has been recognized by the Civil Rights organization JPFO. In 2007 he covered the war in Iraq as an embedded journalist.
