I just finished firing about forty of my reloads and six would not even chamber. The other 37 showed signs of pressure spikes with one round reaching 3508 f.p.s. on an average 85.8 grn. of RL22. I full-length sized all these rounds and was wondering if the pressure spikes are really due to insufficient headspace or the chrono. sitting too close to the muzzle giving erroneous readings. I backed the chrono off about two more feet on the last ten and got more consistent readings but that doesn't explain the rounds that would not chamber. BTW the OAL is less than 3.6"" Can Insufficient headspace cause velocities to reach these levels? I have a headspace gauge on order and should not be full length sizing w/o it but thought the die instructions would be sufficient to set headspace. Any advice would be appreciated.