I have a M&P15T on the way (early next week hopefully!). I am looking to get a bipod for it and am curious what height I would need?

Right now all I have are the long-ish 30-rd PMAG magazines. I am looking around for some of their 20-rd, but haven't got any yet. So, I am trying to find out what height of a bipod would let me shoot from bench rest using the 30-rd magazines.

Thanks!

Something 9"-12" works well on a bench. I use a Harris bipod with notches, rather than fuss with adjustments. That gives you enough reach for a 20-30 round magazine to clear the table. It's also short enough to fold out of the way (toward the muzzle).

A tripod is better for hunting, where you might be seated, kneeling or standing. A loose bipod that tall offers very little stability.

For me, bench rest/bipod/30 round mag was a combination that did not work. I found the 6" - 9" bipod height worked for bench and prone shooting; however, the 30 round mag was a little too long for those positions. Since shooting position is more important than the additional 10 cartridges, I went with 20 round mags and the 6-9 inch Harris bipod.

Alright, sounds like 6-9 if I can actually get ahold of some 20-rd magazines, 9-12 if stuck with 30s.

One followup question. While looking at the Harris bipods, I've seen a couple variants. One of models similar to "1A2", ex:
Amazon.com : Harris Engineering 1A2-BR Hinged Base 6 - 9-Inch BiPod : Gun Monopods Bipods And Accessories : Sports & Outdoors@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41Vocmg4ysL.@@AMEPARAM@@41Vocmg4ysL

Others are "S-...", such as:
Amazon.com: Harris Engineering S-BRM Hinged Base 6 - 9-Inch BiPod: Sports & Outdoors@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41m816Y8nBL.@@AMEPARAM@@41m816Y8nBL

The "1A2" models seem to be generally at a much lower price point. Is this a case of different generations or something?

If you are wanting a QD for that bipod, LaRue offers a combo package with their QD mount and Harris bipod.

The QD mounts you are gonna find on Amazon, suck big time.

Harris Bipod 9-13" LM-S and LT706 QD Swivel Mount Combo | LaRue Tactical

Hmm, I haven't thought much about mounting yet. I know the bipod itself describes as connecting to a QD swivel stud. How quick is quick on that? If I just leave the mount itself attached to the rail and separate the bipod from the mount when I want to remove it.

Although, I feel like I don't really need it to be all that quick. If I'm in a hurry for whatever reason, I'll just fold the legs up and keep on going.