I use the low Harris Bi-pod on my bolt guns, and on my AR.I forget what the model number is.I prefer the non-swivel model.I have used the swivel model and found that you have to be consious about canting the rifle while shooting.There is also a shorter model of the bi-pods.I think they are called the benchrest model.For the AR, the bi-pod height will be determined on what size mag you use.You should be ok with the low model if you use 20rnd mags, but if you use 30rnd mags, you may have to go up one size. HTH.
Skullboy