05-09-2020, 01:26 AM
Klem Wrote:Correct, something is wrong. 178fps is too much for temp differences, even in double-based powders. That is not a hot load so you could have kept shooting for more data. My money is on the Chronograph. What type is it and how did you secure it? Any other indicators like where the cases were being ejected?
If you are shooting over a Chrony then this is not unusual as optical chonographs are notorious for errors if your bullets don't go exactly over the sensor; or the angle of light is not right, or there are shadows from clouds; or the battery is low; or it is moving; or not fully open, or not exactly parallel to the barrel.
I have a Caldwell optical chronograph that is attached to a tripod, no weights added or anything to hold it in place beyond that. The Caldwell app monitors the battery when its connected to my phone, but don't know how much I trust that feature.
I've had optical errors before, usually unbelievably high or low, but that did cross my mind. I did shoot 3 of my 27.7 and 27.9 which had a 153 fps and 97 fps spread respectively. I took my pistol out after that and was getting 50-60 fps at worse, which I attribute to not having the angle exactly the same each time. Having the rifle bagged up, I should be getting the same angle for each group I would think.
The brass is pretty beat up after 5 firings, but no fresh ejector or extractor markings. Primers looked good and recoil felt normal. I use a brass catcher so that I don't know. The brass is a bit of a mixed bag of what I collected shooting factory at first.