Oh, that.
Yeah I get it, not that this handguard is anything like rigid, being just a piece of plastic and tin; but the original M16 bi-pods clamp right to the barrel. It's gotta be better than that.
(How else would you mount one anyhow?)
you have a good point about the M16 pod.
The reason it really doesn't matter is that I do believe you are using the pod as they intended the M16 pod to be used and that is simply a rest .
The M16 running full auto would benefit from something like that and when running 800 rpm precision is out the window....well how you and I think about it, there is what is considered full auto accuracy standards.
If you use a bipod for a rest it helps your accuracy.
Then there is using a bipod as a true accuracy shooting aid by preloading it so that it returns to the same point . When you preload a pod it has some serous torque. Hooked to your barrel would kill any precision....you might retain accuracy but repeatable precision, forget it. Hooking it to your less than stable HG, that is hooked to a stable plate that is hooked to your barrel is just all around frowned on for precission....most of precission is repeating things exact.....hard to do with that set up.....
As the barrel heats up, it gets way worse.
Believe it or not just shooting prone, not trying to preload can do it because your body weight just resting on the rifle.
From a bench, just using it as a rest, your fine.....your rifle jumps, you reset it , get all situated and shoot again. .....in a hunting rifle or fighting rifle or anything where a follow up shot might really count, that is no way to use a bipod.....you would be better off resting on a car hood or something as you will be about as accurate and can reset faster
Then you got the different torques uneven ground puts on the whole works....
How would i attach it ?.....well frankly I wouldn't. That there is a carbine sir.
I think from my interaction with you, that you would be extremely pleased with an SPR set up. Something 18-20", free float, bipod, with magnification, a comp, a 10 round mag full of 77gr SMK's
But I could be wrong, the cool thing is a couple wrenches , a few bucks and you can make that one into whatever you want.