AA/CZ T200 PCP Rifle - Chrony Results: Explanations Please?

[Shed tuner]

A leak ?

[Aimstraight]

A leak ?

Hmm, what like a weak shot at the start of the string, then it improves seals towards the end of the string, then repeats after the interval when changing the mag?

Interesting thought. If the peaks are joined up, the trend is in the right correction (reducing velocity/power), but the saw tooth ramping velocity up while pressure in the cylinder reduces is counter intuitive.

[Shed tuner]

i'd shoot a mag. leave it an hour. shoot another mag. if a massive drop, you have a leak.

there may be other things going on, but try the simple stuff first..

PS it also look a lot like a dodgy regulator (leaking through), but you said you haven't got one ?

the real throught process here, is is the sawtooth drop time related ? If time related, something will be leaking - either out of the gun, or through a reg/prechamber, or somesuch.
I can't see how the mag change per se could affect it - unless the gun is blowback. Other option is single load, and chrono every 3rd / 4th/5th shots to save boredom - the other shots can be target practice, plinking whatever. is it a smooth decay ?

I like a challange - much better than .177 vs .22 or TX vs HW

[Aimstraight]

Will do next time I have the Chrony set up, also could try on single shot to see what goes on. I may well include in target practice rather than just wasting pellets.

Yes, it is an interesting one, it looks like I made that graph up! I did not really spot it from the raw numbers, but the graph really shows it up.

[air-tech]

How bizarre. I am not familiar with the 10 shot conversion, but is it the typical probe through the mag affair, with the probe finally sealing within the breech block/barrel itself? If so, it ought to make no difference to sealing which shot number in the magazine it happens to be, also the major drop between mag changes coupled with a gradual increase does not sit well with the possibility of poor sealing, I would expect more erratic behaviour.

[Aimstraight]

How bizarre. I am not familiar with the 10 shot conversion, but is it the typical probe through the mag affair, with the probe finally sealing within the breech block/barrel itself? If so, it ought to make no difference to sealing which shot number in the magazine it happens to be, also the major drop between mag changes coupled with a gradual increase does not sit well with the possibility of poor sealing, I would expect more erratic behaviour.

Yes, the probe/o-ring just pushes the pellet through the mag (all 10 pellets are held by a single large o-ring), which seats in the breach just like the single shot system. The results are certainly weird.

[Aimstraight]

Bollards! Operator error. The F1 Chrony readout of 'stored values' shows the last shot first, and the first shot last. So reverse all the reading and the graph makes a very nice curve!