We have been trying out a borrowed kurzziet (spelling may be wrong) which uses IR instead of light screens. Can be attached to a computer and works quite well but it's about £700.00. This is a lot if you shoot it! Following this have looked at Magneto speed which attaches to the rifle and looks quite good. I think somebody on here is the uk agent? This was going to be the purchase choice but having seen the Haugland blog (sierra645 on you tube) the Steinert may be a better choice for us. I think they are around the same price £250ish. Other than that there are a few for around the £150 mark which rely on sky screens. I must stress the we have only had hands on the expensive one and are relying on Internet info. We need accurate velocity for ballistic programmes as the published velocities are not always what we are actually getting. For ease of use, no tripod requirement and less chance of shooting your kit, the magneto speed would seem the best choice