Lil Gun Hot Weather Chrono, just checking
Posted: Thu Jun 23, 2022 9:15 am
150 grain Hornady fmjbt. CCI small rifle primer. WW Super 222 Rem converted case. 15.5 grains Lil Gun. COAL 2.066 inch.
98 degrees F, full sun (if that matters) 78% relative humidity.
Shot ten rounds while sighting in both irons and a scope so shooting was not fast at all, at least two or three minutes between shots with a very long unexpected break in the middle to help a new shooter. In other words barrel/chamber heating was not an issue.
If I throw out 3 chronograph readings which are WAY out of the expected range, for the remaining seven shots I have an average of 1904 fps, 115 ES and 42 SD.
But, I have one shot that read 2794 fps, another that read 2460 and one that read 1289.
Magnetospeed Sporter chrono. It has always worked reliably and provided believable data. In fact this day I also used it on another rifle and data was consistent and believable.
Here's my question; am I right to discard those three readings as errors? I really don't think that 2794 fps would be possible. Or is it possible I really had that much velocity swing in hot weather with LG?
Some of the rounds did fail to lock the bolt back, and some did seem to be “hot” but other than that brass shows no major pressure indications.
98 degrees F, full sun (if that matters) 78% relative humidity.
Shot ten rounds while sighting in both irons and a scope so shooting was not fast at all, at least two or three minutes between shots with a very long unexpected break in the middle to help a new shooter. In other words barrel/chamber heating was not an issue.
If I throw out 3 chronograph readings which are WAY out of the expected range, for the remaining seven shots I have an average of 1904 fps, 115 ES and 42 SD.
But, I have one shot that read 2794 fps, another that read 2460 and one that read 1289.
Magnetospeed Sporter chrono. It has always worked reliably and provided believable data. In fact this day I also used it on another rifle and data was consistent and believable.
Here's my question; am I right to discard those three readings as errors? I really don't think that 2794 fps would be possible. Or is it possible I really had that much velocity swing in hot weather with LG?
Some of the rounds did fail to lock the bolt back, and some did seem to be “hot” but other than that brass shows no major pressure indications.