I've been using a Harris 13"-27" bipod for the last 12 years or so. I've taken shots with one extension out, 2 extentions out and all 3 extentions out. Even with all 3 out, they are very stable. My Dad missed a buck last year in Wyoming because his "cheap" bipod was not stable enough as the wind was pushing his gun around a bit. They have a fixed or swivel model. I use the swivel so you can shoot off of uneven ground and still get your gun level. I have 2 of them so I'll be taking the one off my .308 to give to my Dad.