Because it is a large bayonet that straps onto your barrel — this can shift your point of impact while it is attached. It can also mess with your rifle harmonics and open or close your groups oddly. MagnetoSpeed V3 Been testing Vectan SP3 powder and 10.5grains behind a 17grain vmax kranks bullet is giving an average of 3690 fps but still got work to do to find lowest SD and best accuracy been up to 11.00grains then getting 3805 fps average.

If you do not wish to do this, or your manual does not have the nescessary data for your needs, you can visit our Reloading Data Section for manufacturer advice. From cheapest to most expensive, here are the chronographs I’ve tested hands-on! 1. Caldwell Ballistic Precision Chronograph But if you took the first reading on Monday and the second reading on Friday, the gap between them might be a little more… iffy. Although really, not by much. A shooter that reloads their own ammunition can’t look at the side of a box of factory ammunition to gauge the velocity of the round, they need to gather the data themselves. MagnetoSpeed Bayonet Sensor – The sensor itself is manufactured to withstand a muzzle blast, so use on shotguns and firearms with muzzle breaks isn’t a problem.Each range session it will be accurate to itself. If one bullet reads 1000 fps and the next one reads 1200 fps, it’s very likely that there was a 200 fps difference between the two.

Clamps such as the QD throw lever or a Picatinny rail clamps are sold separately (Any Atlas style clamp is compatible) PLEASE NOTE: This item is no longer available, but the MagnetoSpeed V3 Ballistic Chronograph in Hard Case is available!Get to know your chrono and this won’t be a real problem. And if nothing else, the readings will get you very close.