Expected Velocities for Regulated AT-44 QE .22 Short

[Kopfjaeger]

Hello all,

I am brand new to the PCP world...about a month into it and I'm hooked!!  I recently installed an Air Superiority regulator in my .22 cal AT-44 QE Short.  I have the regulator set at roughly 158 Bar and have the hammer spring screw turned in clockwise about 7 turns from stock position....probably not proper settings   The gun loves Crosman Premier Ultra Magnums 14.3 gr.  3/8"- 1/2" groups at 30 yds. 

For a ten shot string with regulator I average 918.4 fps at a full charge of 200 Bar, with a high of 922 fps and a low of 913 fps.
Are the velocities I am getting with the current regulator setting "normal"?  The reason I ask is I cleaned the barrel when I first got the gun and noticed there was half an O ring stuck in the air inlet port of the barrel.  I of course removed it and checked out the schematic and it looks like it is one of the O rings for the air transmission bushing.  I haven't disassembled yet to find out. 
Just was wondering if the stock velocities are "normal" also....
before I installed the regulator and no adjustments to hammer spring and a full charge of 200 Bar for each test:

Crosman 14.3 gr Premiers avg. 960 fps.
JSB Jumbo 15.89 gr avg. 900 fps.
JSB Jumbo Heavy 18.13 gr avg. 885 fps.

What would be the max velocities possible with the regulator installed?

Thanks in Advance!!

Rick

[zandrew]

Hello all,

I am brand new to the PCP world...about a month into it and I'm hooked!!  I recently installed an Air Superiority regulator in my .22 cal AT-44 QE Short.  I have the regulator set at roughly 158 Bar and have the hammer spring screw turned in clockwise about 7 turns from stock position....probably not proper settings   The gun loves Crosman Premier Ultra Magnums 14.3 gr.  3/8"- 1/2" groups at 30 yds. 

For a ten shot string with regulator I average 918.4 fps at a full charge of 200 Bar, with a high of 922 fps and a low of 913 fps.
Are the velocities I am getting with the current regulator setting "normal"?  The reason I ask is I cleaned the barrel when I first got the gun and noticed there was half an O ring stuck in the air inlet port of the barrel.  I of course removed it and checked out the schematic and it looks like it is one of the O rings for the air transmission bushing.  I haven't disassembled yet to find out. 
Just was wondering if the stock velocities are "normal" also....
before I installed the regulator and no adjustments to hammer spring and a full charge of 200 Bar for each test:

Crosman 14.3 gr Premiers avg. 960 fps.
JSB Jumbo 15.89 gr avg. 900 fps.
JSB Jumbo Heavy 18.13 gr avg. 885 fps.

What would be the max velocities possible with the regulator installed?

Thanks in Advance!!

Rick

You need to find out where the o ring is from. There is an O ring where the barrel goes into the breech but you should feel a pfft in your face when you shoot if its gone. Your velocity is fine, especially for a short. What type of shot count you getting before the velocity drops off?

[Bwalton]

@158bar that is the norm...

[Kopfjaeger]

Thanks for the replies guys!!  The O ring is not the one from the barrel, I'm going to disassemble and see if anything is damaged or missing.

As far as shot count to when velocity drops-
second shot string: shots 11-20 High of 926 fps to a low of 886 fps...about shot number 16 is when velocity starts to drop with every shot.
third shot string: shots 21-30 High of 883 fps to a low of 818 fps.

I was messing with the hammer spring preload and noticed that the hammer was turning when I tried to adjust the spring tension....
so that means it is still in the stock position,  would that be why I'm only getting about 15 consistent shots??

Also, was shooting a bit tonight and the velocities increased to avg. of 933, for the first ten shots.....no adjustments to anything.
Do regulators have a break in period?

[jeff76]

you have to hold the hammer still when adjusting it.  the stock will have to be removed to do it.  there is a hole in the bottom of the receiver where you will see the hammer.  it has a hole in it too.  just stick a small allen key in that hole to hold the hammer still while you make your adjustments.  and you can also drill a hole in the stock so you don't have to remove it in the future to make adustments.

[Kopfjaeger]

you have to hold the hammer still when adjusting it.  the stock will have to be removed to do it.  there is a hole in the bottom of the receiver where you will see the hammer.  it has a hole in it too.  just stick a small allen key in that hole to hold the hammer still while you make your adjustments.  and you can also drill a hole in the stock so you don't have to remove it in the future to make adustments.

I did that. I turned the screw in, clockwise, 2.5 turns.  That was as far as it would go.  It made quite a difference, was able to get 50 shots before it got to 100 Bar.  What do I need to do to flatten the curve?  The shot string started at 803 fps, rose to a high of 869 fps, then the last shot, number 50, was 783 fps.