Unexplained velocity jump?

Hi guys!

It’s been so long since I posted here that I forgot my login info and had to re-join.

I was doing some chronoing the other day with a new air rifle and I figured why not see what my trusty Condor was producing with it’s current settings. Unfortunately I can’t say what those settings are but I don’t think that it has a bearing on this issue anyway. This is what I experienced…

I fired roughly 6 -7 shots over my 1980’s vintage “Shooting Chrony” and I was getting a consistent 876 fps with .25 cal JSB’s and then I fired a shot which was audibly louder than previous shots while the chrono showed 1048 fps. Another three or four shots over the chronograph with 876 fps and it happened again…1048 fps and a rather loud report even with Talon Shroud installed as always.

I’ve never known this rifle to do this and I shoot her allot. What do the fine folks here think would cause this?

BTW… A .25 cal. Condor shooting at 876 fps will do considerable damage to a 1980’s vintage “Shooting Chrony” at close range. Just sayin’. lol!