Vortek Springer Kits

I have been doing some chronograph on my RWS 350 Magnum Diana claims 1000 FPS here is my results. This is why I am wonder about the Vortek Kit along with calming the firing cycle.
With chronograph set at about 18 ft away 
Benjamin Ultra Magnum 14.3 gr 10 shots average 635.60
H&N Barracuda Green 12.35 10 Shot average 691.60
JSB 15.89 10 shot average 645.90
 
The 1000 fps claim is likely achieved with ultra lightweight alloy pellets. This is a ploy used to get people to buy their guns based on the fps numbers. In the real world with lead pellets the numbers are substantially lower. Usually the chronograph is around 3 feet from the muzzle.
Having said that your numbers may be a little slow for a 350-I'd expect something like that from the milder model 34.
 
I would like to be around 800 FPS with 14.3 pellet and slightly slower with the 15.89 after watching several Y tube channels on my Caldweld Chronograph they say you should set the graph at a minimum of 10 ft to get accurate consistence reading.Also this gun really rocks a rolls a lot was wonder if the vorteck kit would calm it down some. I have gotten pretty accurate with it but still can be a real frustrating sucker about the time I think I have master it kicks me in the nuts :*)