Velocity climb on RT

[hmudd13]

Actually, it's an Emag micromag valve on a regular mag. On/off is .710 Level X
Problem is, when I rapid fire the velocity climbs big time.
Starting at 280 fps, it'll climb to 320 fps. During non string shooting the velocity is pretty constant.
This happens when I fire over 15 bps. I've had the marker to 23 bps.
Any help will be greatly appreciated.

[Piranti]

Just means you are not Chronoing a Mag properly, although 40fps seems a tad high of a climb. The increase is a function of the RT valve design, the air slamming into the valve heats up, and you know what heat does to a gas? makes it expand therefore more energy is available for a short period, during rapid firing the next shot wil occur while that gnome energy is available increasing your velocity.

To properly Chrono your RT valved mag you need to pull the trigger hold the trigger down release and rapidly pull it again for the chronoshot. If done right you will get a much better chrono though single shots will be at a bit lower fps but at speedball ranges wont matter much really. I am sure someone can explain better than I can.

[athomas]

Your velocity climb is higher than normal. Whats the pressure output from your tank? If you can lower the tank output value, it will reduce the velcity climb. Another thing that could help is to use a longer on-off pin. It will act as a throttle to the air recharging the front chamber and keep the temperature down thus keeping the upper and lower pressure ranges more stable. This will also keep the velocity more stable since they are tied together. Another thing is to use the longest bolt spring that will work in your system. It will keep the chamber operating pressure as high as it can be so the pressure differential between tank and valve will be less. This will reduce the heating effect as well.

[hmudd13]

Output is about 1000
I'd hate to turn it down because it rips at 23 bps.
I'll try the longer bolt spring first, then the on/off pin.
Thanks for the help. :)

[athomas]

Its the 1000psi tank output that is responsible for your velocity climb more than anything. If you are going to use all the other methods to throttle the recharge rate, why not just adjust the tank psi down first. It will do the same thing. That way you can use any tank on your gun with the same effect.