I haven’t tested or ran the numbers, but stayed at an Holiday Inn express last night.:laugh:
Last year I was in the market for a 7.62 multi-cal can, and after some heavy research, settled on the Surefire RC, and so I’m familiar with Surefire suppressors QD mechanism - and here are just some of my observations when comparing the two. Although Gemtech Halo and Surefire 556-RC mount interface may initially seem like two entirely different systems, with one essentially an upgraded thread-on, while the other a true QD, the two actually use the same method of retention - compression force on the rear of the muzzle device to hold the suppressor in place. Both use the retaining collar to clamp onto the muzzle device via threads. However Surefire’s threads can’t be seen, as the retaining collar is integrated into the suppressor, with the latch/teeth only functioning to lock the retaining collar in place, whereas the Gemtech retaining collar is a separate part entirely, requiring two hands to mount and is thread on. Surefire was able to integrate the retaining collar onto the suppressor by using a cam lock design - the retaining collar only needs to be turned about half a rotation to be fully locked. So both may not function or look the same, but fundamentally both apply a compressive force on the rear of the muzzle device. It’s hard to describe in words, so here are some diagrams that I saved back when I was doing research - trying to understand how the Surefire QD mechanism functioned.
http://www.google.com/patents/US20100313743
For load paths, here’s a quick run down in tension, compression and torque. In tension, for either suppressors to be pulled off, the external threads on the suppressor body or internal threads on the retainer collar would have to fail - assuming necking of the thin walled outer tube, and core containing the baffle stack doesn’t occur first. In compression, as if used as a “meat masher” to strike someone in the face, the Surefire muzzle device has a taper surface that mates with the interior wall of the suppressor, and that engagement surface area will carry load assuming the baffle stack and outer tube don’t buckle first. I’m unfamiliar with Gemtech interior engagement surface so can’t comment there. In torque, the Surefire can was designed to be timed, so that the suppressor is mounted consistently each and every time, via the pin extrusion on bottom dead center on the muzzle device, so suppressor cannot rotate and the pin/tongue will carry load. However, I believe the Gemtech suppressor can rotate around the bore axis, as the retainer collar and suppressor are brought together, so if enough force is applied you could rotate the suppressor.
For durability, I assume you mean the number of times the can is mounted and unmounted. Durability of the mount would be dependent on selected pitch, thread and materials with respect to strength, propensity to cross thread or gall. Though Gemtech threads are exposed when unlocked it’s a non issue. But Surefire does feature a locking mechanism to prevent the retaining collar from backing off. So for the locking latch to work loose, either the teeth or spring will need to give. Even if they did, the latch and springs look easily serviceable. But let’s also look at it from a larger perspective, I’m speculating (Garin will have to say what the latch is officially rated at), but let’s say conservatively the latch spring or teeth is rated only to say 100,000 compression cycles, my guess it’s in the millions, but assuming you mounted and unmounted the can, and fired just one round each time, that be equivalent to say 50,000 rds fired per two compression cycles on the latch, and if barrel life is rated to 10,000 rounds, you’d have to re-barrel 5 times, before having to replace the spring. Let’s go further and cut the rated cycles by half, spring only rated at 50,000 compression cycles, then that’s what, 25k rounds, so 2.5 barrels?
In short, I wouldn’t loose any sleep.
