Arisaka Defense showed me their new MCX Spear 308 Zero Retention Clamp during the vendor day at last week’s USASOC Sniper Competition.
It’s the big brother to their popular MCX Virtus/Spear LT Zero Retention Clamp which is designed to prevent handguard flax and thereby reduce zero shift for lasers and iron sights that are mounted on the handguard of the MCX Spear.
The Arisaka ZRC consists of two sets of 7075 clamps that mount in the vent slots on either side of the handguard. The inner half of each clamp engages the extended upper receiver.
This new version is designed for the MCX Spear chambered in 277 Fury and .308 while the LT model is for .223, 300 BLK, and 7.62 x 39. You can tell the difference between the two clamps by the number of external lugs: three for the heavy and one for the light.
While I firmly believe that the MCX Spear was the best of the downselect submissions in NGSW, the fact that this issue is being addressed by the aftermarket and not Sig is a bummer.
I’d have liked to see Sig get out in front of this with a long term solution. I’d also be very interested to know if this was a known issue on their part (though I likely already know that answer); on the chance that it was not known, I’d love to know how they plan to change their internal testing procedures to catch stuff like this in the future.
Just going by what they’ve discussed, the MCX->Virtus->Spear->Spear LT has been a progression to address the issue. There’s a line there with weight and total redesign where the returns start to diminish, but a lot of times a fresh set of eyes can come up with a simpler add-on the wouldn’t have been acceptable for them to put on the rifle out of the box . Honestly, it’s something all rails do and it’s a matter of how much you’re willing to deal with.
So the current issued M4’s are still being issued with a non free floated rail with PEQ15’s usually mounted on 12 o’clock on the rail and surefire lights mounted on the sides is the units actually have them, my friends currently deployed to Africa have this set up. With a mixture of different optics mounted to the rifle.
The new Qual for the M4, you can see many soldiers bracing their barrels off the barricades, have barrel flex or rail deviation ever been a discussion?