Co2 & COMBRO CB-625 Mk4 ????????

[ratmanbones]

Hi I am about to start some mods on a QB78 CO2 rifle and was wondering if anyone has used a COMBRO CB-625 Mk4 with Co2 powered rifles ? Question is will this crono work with a CO2 gun ?
If not what do you recommend.
Your input will be greatly appreciated.

[robinghewitt]

I may be wrong but I think there is a problem with the oily CO2 cartridges. If the second shot from a cold gun reads much slower than the first then you have to suspect something is wrong.

What happens is that on the first shot the bore is empty, on the second shot it is full of oily guck which comes out in front of the pellet in one solid lump and may trip the first optic before the pellet arrives.

The work around is to put something between the muzzle and the cb-625 entrance. Paper of masking tape works. The oily gunge cannot get through so the pellet arrives at clear optics.

You might fix it by simply increasing the separation between muzzle and chronoscope. A bit more can make a big difference because the guck will dissipate PDQ and cb-625 has a trick to discount muzzle blast.

If shooting through paper fails to improve things, there is always the possibility that your gun really is limp as a wet weekend

[speedthing]

I test my QB78DL quite often through my Crombro with no problems.

[splatfest]

As above,piece of tissue between muzzle and chrono,and/or tiltiing the gun down when firing.For all things 78 wander over to http://ukchineseairgunforum.myfreeforum.org/index.php

[ratmanbones]

Hi thank you all for the info, as I didn't want to buy a chrono and just be limited to using it on my springers and precharge . I would have bought one that I could use on them all instead of having two .

[short-carabine]

As Robin says, a bit of paper/masking tape does the job. Interestingly, if you have a mod on the gun you also avoid the problem, in my experience- must be down to the dissipation.

[Dragonboy]

There shouldn't be oil in the CO2 cartridges. As far as I am aware the aluminium case is dipped in liquid CO2 & crimped. Pretty much made to food and pharmaceutical standards.