Uragan II .25 600mm
So after receiving the U2 I was finally able to get it over the chrono and see about a few shot strings.
The very first thing I noticed was the loud report. It was much louder than the .30 Vulcan 3 which makes a lot more power.
A few strings showed around 17 es after 30 or so shots.
I wasn't trying to see where the regulator was set but get a baseline idea where to start on a tune if it needed one.
I noted that the thing seemed to be wasting a lot of air so I attached a digital gauge and found that 34 gr pellet going 880's was using 4 bar per shot.
Four bars per shot is a lot of air for such a modest tune so I started turning the hammer spring down to see how much velocity would drop.
To my surprise, none. I turned the hammer spring out about 4 turns (sticking out of the back of the receiver) and lost ZERO velocity.
I know it's a balanced valve but that actually means it only needs to open all the way and not be hammered.
After a few more shot strings the ES tightened up to about 6-7 fps, the report got much more quiet like it wasn't the same gun shooting, and most important, it's now using just under 2 bars per shot.
Averaging 888 fps with 34 grain pellets is likely just fine but I plan to shoot slugs with it so when I get some, I'll turn the reg up a but and see what it likes.
The stock, having the hammer spring adjuster protruding like it is now, doesn't allow the stock to fit closely and causes fitment issues so I used a dremmel and solved that as well.
I had read not to turn the HS out any more than being flush with the back of the gun but i suspect I know why now. Because the stock won't fit if it's not.
I had also read that the first few generations of valve poppets broke easily (I know the actual steel didn't go completely through in the first two gens) and I'm wondering even with that weakness to them, if it's because the hammer really whacks that valve turned in like that making a weaker area more vulnerable to breaking.
The point is, having read it's an air hog and loud might just be solved with a simple fix of not having the hammer drive so hard it wastes air also making it loud.
YRMV.
So after receiving the U2 I was finally able to get it over the chrono and see about a few shot strings.
The very first thing I noticed was the loud report. It was much louder than the .30 Vulcan 3 which makes a lot more power.
A few strings showed around 17 es after 30 or so shots.
I wasn't trying to see where the regulator was set but get a baseline idea where to start on a tune if it needed one.
I noted that the thing seemed to be wasting a lot of air so I attached a digital gauge and found that 34 gr pellet going 880's was using 4 bar per shot.
Four bars per shot is a lot of air for such a modest tune so I started turning the hammer spring down to see how much velocity would drop.
To my surprise, none. I turned the hammer spring out about 4 turns (sticking out of the back of the receiver) and lost ZERO velocity.
I know it's a balanced valve but that actually means it only needs to open all the way and not be hammered.
After a few more shot strings the ES tightened up to about 6-7 fps, the report got much more quiet like it wasn't the same gun shooting, and most important, it's now using just under 2 bars per shot.
Averaging 888 fps with 34 grain pellets is likely just fine but I plan to shoot slugs with it so when I get some, I'll turn the reg up a but and see what it likes.
The stock, having the hammer spring adjuster protruding like it is now, doesn't allow the stock to fit closely and causes fitment issues so I used a dremmel and solved that as well.
I had read not to turn the HS out any more than being flush with the back of the gun but i suspect I know why now. Because the stock won't fit if it's not.
I had also read that the first few generations of valve poppets broke easily (I know the actual steel didn't go completely through in the first two gens) and I'm wondering even with that weakness to them, if it's because the hammer really whacks that valve turned in like that making a weaker area more vulnerable to breaking.
The point is, having read it's an air hog and loud might just be solved with a simple fix of not having the hammer drive so hard it wastes air also making it loud.
YRMV.
Last edited:
