Monsoon shot string

The "other" semi-auto airrifle from FX.

Monsoon shot string

Postby mikewh on Fri Apr 03, 2015 9:21 am

image.jpg (102.27 KiB) Viewed 4367 times
Hi all
Have now sorted the failing semi auto action, lubed carefully the bolt. No fire failures now.
However shot string curve is awful
74 fps extreme spread over 36 shots
200 bar fill, .22 using jsb's 15.9 ( new tin ) bench rested through chrony chronograph. End pressure appx 130 bar.gun seemed noisier last 6 shots. Gun is new, less than 100 shots
There seems to be no sweet spot. Normally I believe, a power curve should be much flatter with no massive drop. Any ideas what is wrong?
Ps sorry about poor photo, first attempt
Last 4shots on graph are
Other shot strings posted on web are much flatter.
Waiting for my dealer to respond on submitted data.
Posts: 3
Joined: Sat Mar 28, 2015 10:08 am

Re: Monsoon shot string

Postby Guipago on Mon Apr 06, 2015 2:54 am

Only thing I could suggest is to remove the stock & check if any of the grub screws are leaking air when it is fired, you could put talcum powder on them, replace the breech o-ring, it may be damaged.
On the miss firing, a problem I had that sounded similar was the wire arm at the l/h rear of the breech was juuust touching the stock when it rebounded stopping the trigger from cocking sometimes but loading a pellet, on the stock there was a tiny shiney spot where it touched, relieved that area on the stock & never had the problem again.
Posts: 51
Joined: Fri Nov 26, 2010 11:58 am
Location: OZ

Re: Monsoon shot string

Postby mikewh on Tue Apr 07, 2015 4:28 pm

Thanks for your input

I don't get any fire failures now since lubing the bolt.
The shot string is the problem and will try your method re possible leaking air. Breech O ring seems fine.
Have arranged with dealer to return gun who accepts shot string is poor.
Will post his solution and fix, hopefully.
Would have thought FX / dealer would check functioning properly prior to delivery! Like buying a v8 with only 7 working.

Happy shooting
Posts: 3
Joined: Sat Mar 28, 2015 10:08 am

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