Who actually puts the handguard or barrel directly up against the barricade? I lean against them slightly with my support hand and then usually hold the forearm of the stock with a combination of thumb and forefinger or all fingers depending on the nature of the barrier.
If you torque even a thin ALG type tube enough to flex the barrel Mount and thus the barrel you are putting huge amounts of lateral pressure on it, far more than I could ever envision in barricade type shooting.
The old trope about flexing hand guards and 3moa point of impact shift was largely due to people doing CMP type shooting with super tight slings. Not to say that GIs first learning to shoot couldn't put excessive pressure on it, just that it's not a thing lately.
In a world where people who will see combat are routinely monopodding on magazines (which I can't bring myself to do) rail flex is a pretty extreme concern. And monopodding is something GIs are often taught lately.
This wouldn't be that hard to test in a controlled environment. Upper receiver firmly held in a vice. Increasing amounts of weight applied to the end of the handguard. Or the middle where most people would hold it. Rough math a 16-in barrel would need to deflect .013" to yield a 3 moa shift, easily measured on a bench.
Also remember that a more rigid handguard is just going to allow more torque to be applied to the barrel nut and extension. A tube that flexes slightly will absorb some of that torque. So I can make the argument that a more rigid handguard is actually worse for this potential issue.
The above unless you're using one of those BCM skinny rails design for men with girly hands. :-) in that case all bets are off!
I typically also don't really use barricade stops, but this is more of a function of range limitations more than anything; if I really bear into it, the barricades at the range will definitely flex and move. However, when using actual vehicles or inside a shoothouse, I've definitely just jammed my light or sling mount into the side of the barricade, and could definitely see the doing that with a VFG.
The issue of deflection isn't an issue of the barrel itself moving to shift zero (which I have also seen, with my friend on his KAC LPR and loading the bipod), but the handguard itself flexing, and thus the MFAL on it also moving and thus now being off-target. This is why this issue of handguard rigidity is really only discussed in the context of NODs-oriented guns, since we are concerned about the POA/POI shift due to the laser moving, so this is not an issue during the day when just using optics on the receiver.
Last edited by Defaultmp3; 03-30-22 at 14:49.
Plus ça change, plus c'est la même chose.
老僧三十年前未參禪時、見山是山、見水是水、及至後夾親見知識、有箇入處、見山不是山、見水不是水、而今得箇體歇處、依然見山秪是山、見水秪是水。
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I was wondering this about some of my Long handguard carbines. I can grab the muzzle device and the rail and flex the two. Is it the barrel/upper receiver flex? Or just the handguard? Or both?
I know from the guys who mad the VLTRO MUR that there was measurable upper receiver flex with standard flat top receivers.
"What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v
Ran across this write up researching rails to laser up, thought I'd share. I was particularly surprised the Geissele MK16 preformed rather poorly compared to other handguards like the BCM MCMR and Midwest Industries (see page 12)...
Understanding Handguard Flex and Point of Impact Shift for Laser Aiming Devices
Gettin' down innagrass.
Let's Go Brandon!
There's always the Easy Button... just get an Arisaka Mossie Mount and rack a LaserMax Uni-Max or similar compact laser or light/laser on it. Your laser is structurally connected to the barrel through the FSB, handguard is taken completely out of the equation.
<><><><><><><><><><><><><><><><><><><><><><><><>YOU IDIOTS! I WROTE 1984 AS A WARNING, NOT A HOW-TO MANUAL!--Orwell's ghost
Psalms 109:8, 43:1
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