Your best bet would be to swap out the stock forend for a 4 rail design. Like this one from Midwest Industries, that will replace a standard Delta Ring forend. They are well made, easy to install, and don't move around or rattle. From there you can attach the mount and bipod of your choice. There are literally dozens. They come in Carbine, Mid Length, and Rifle length, (20").
Cheap route is the Harris HB5 adapter for the factory plastic handguards on M4 rifles. Or you could use a Magpul handguard, which has MLOK attachment points, in which case you could use any one of the hundreds of MLOK bipod adapters.
Magpul handguard with MLOK adapter by IWC
Ok, I didn't explain myself well. Sorry.
This is what I meant. Bi pods with LEG notches and those without. The ones with leg notches have 1 inch increments. Without, the legs travel smoothly to your desired length. Was wondering what most were prefer.
I disagree. How rigid does a bipod and stud need to be on a .223 rifle? Those studs are more than adequate for bipod use.
It's not the caliber. That has nothing to do with it. It's the fact shooters apply a lot of front to back lateral motion to a bipod, as they tuck the weapon into the shoulder, setting up the shot and acquiring the sights on target. Depending on the make of the bipod, this pushing and pulling applies a lot of leverage, that transfers the load from the bipod legs, to the small stud attached to the forend with just a tiny screw. I've seen nice Walnut stocks split along the point where the stud is screwed in from this. (Those cheap plastic forends don't offer any better support). Having a 4 rail metal forend, with an Aluminum Picitinny rail type clamp, (most are at least 1" long), or else a bipod that clamps directly to the rail itself, like this one does, gives the whole set up far more rigidity and strength.
I would agree that a free floated aluminum rail, with a heavy duty mount and heavy duty bipod, would certainly be more stable and heavy duty. BUT, a person with a $399 AR15 rifle is not going to add a $350 Geissele rail, A $280 Atlas bipod, and a $85 Larue bipod adapter to have the most sturdiest, best built bipod for his first National Match rifle shooting competition at Camp Perry. My advice was tailored to the apparent (assumed) budget of the op. The bipod mounts I recommended are acceptable for those on a budget and are not going to snap off or break at the range when he takes his gun to the range once/twice per year.
.....BUT, a person with a $399 AR15 rifle is not going to add a $350 Geissele rail, A $280 Atlas bipod, and a $85 Larue bipod adapter to have the most sturdiest, best built bipod for his first National Match rifle shooting competition at Camp Perry.