Accu-Tac HD-50, 50BMG Heavy Duty Rifle Bipod, Black Finish HD50-0000 The HD-50 was designed for the 50 BMG caliber platforms. This is their Heavy Duty and most robust bipod. The arm lock lugs are larger to withstand the heavy recoil of a 50 BMG. This bipod has the ability to cant and has a very sturdy throw lever. The lever allows you to adjust the tension and enhance the ability to lock the canting motion into place. The legs can be extended into nine different height options. Its wider center hub delivers more stability and strength to support larger heavy rifles.