Wife got me a v3 magnetospeed for my birthday while back. Finally got it out to the range today with the 308win. This is 5 shots but was amazed at the low sd on it. Tried it on the ar and it was all over the place. Finally was getting code 4 readings that it couldn’t read the bullet. Is that because I had it to the side and not below the rifle and it was picking up blast from the muzzle break?