Velocity Increase Is this possible

Jump to latest Follow Reply
B

bubblerboy64

Member
Jul 25, 2018
2,413
94
Pa, United States
Yesterday I was shooting my new cricket rifle at my favorite pigeon hunting spot. I've got a lot of shooting there and it's challenging. 68 yards from my spot just inside an equipment shed. I miss plenty at that distance. If there is any change in wind direction it's tough. But it's what I enjoy.

Now here is my question. I started out with the gun fully charged with air and as I shot I had to keep dropping my elevation adjustments which reason would indicate my velocity was increasing during my shooting. I know there are plenty of variables coming into play but not knowing exactly how regulators and things work in these guns is it possible that MORE air could result in lower velocities over the first number of shots from a freshly filled air chamber ?

Reason would seem that as you shot and bled off air your velocity would drop requiring that adjustments would be required UP not down. 

Like I said I know other variables involved my question is only relative to the gun itself. 

I do have a chronograph so I can test but just wondered if any one else has experienced this 
 
Yesterday I was shooting my new cricket rifle at my favorite pigeon hunting spot. I've got a lot of shooting there and it's challenging. 68 yards from my spot just inside an equipment shed. I miss plenty at that distance. If there is any change in wind direction it's tough. But it's what I enjoy.

Now here is my question. I started out with the gun fully charged with air and as I shot I had to keep dropping my elevation adjustments which reason would indicate my velocity was increasing during my shooting. I know there are plenty of variables coming into play but not knowing exactly how regulators and things work in these guns is it possible that MORE air could result in lower velocities over the first number of shots from a freshly filled air chamber ?

Reason would seem that as you shot and bled off air your velocity would drop requiring that adjustments would be required UP not down. 

Like I said I know other variables involved my question is only relative to the gun itself. 

I do have a chronograph so I can test but just wondered if any one else has experienced this
Click to expand...


Sounds like you're describing a bell curve, starts out a bit lower then raises then lowers again as the pressure decreases. At the beginning of the tank/bottle the hammer is opening the valve but there's more back pressure so less velocity, as the back pressure decreases you get a increase in velocity.

Like so.

1541606214_1000551155be30b469a3048.38779300_bell curve.gif


If it's a regulated gun then something must be off with the regulator would be my guess.
 
Upvote 0
It sounds like your hammer spring may be set too light. Try this if you are interested. Using a chronograph, take a shot then start turning the hammer spring adjuster in (clockwise) a quarter of a turn and repeat the shot. Do this observing each next shot will be higher in speed than the previous shot.

At some point you will notice that the speed will not change with increase in hammer tension and will start to fall. At that point back the adjuster off counter-clockwise an 8th to a quarter turn back to the highest speed before it plateaued. Now the hammer is in sync (harmony) with the regulator and you should have consistent shots with the lowest extreme spread.

Hope this is the cause and hope this helps.

KP 
 
Upvote 0
It is possible, but it looks to me like you're filling the gun to in excess of 240 bar. I know it says 300 bar on the side of the gun, but too high a pressure causes the reg. to actually regulate at a lower pressure, so your velocity would decrease. Then as you passed through 250 or 240 bar, it would return to "normal" and should be VERY consistent from 235 or so all the way down to about 140 bar. The stock Cricket regs. are as good as they come, every bit as good as a Huma regulator.

You should NOT have a "bell curve" with a well and properly regulated gun. It should be very flat in the design regulated region. The .25 Cricket that I just sold was flat and within 7 or 8 FPS for the entire shot string from 225 bar all the way to 130 bar and got about 45 full power shots (960 FPS with .25 JSB Kings). These results are not unusual for a properly tuned Cricket with the stock regulator.
 
  • Like
Reactions: Mike_Lenardon
Upvote 0
I'm not over filling. I'll have to follow thru on some of this. As far as my shooting. I know there are a number of factors which could cause this BUT I am suspicious that it was the gun. I ask the question and the answer as I read it is "yes it could be". So I'll have to chronograph . If I have a string and there is little or no variation in velocity then I have to look elsewhere. I'll be back when I have more info. 

Little more info. Dead calm shooting at concrete silo 68 yards measured by rangefinder. I could sight in by shooting at "marks " on the concrete . I'd get right on . Had a starling land nailed him and that's a small target at that distance . Couple mins later a pigeon lands and a carefully placed shot goes over him. Sight in on the concrete again and I'm two inches high. Adjust the scope down a couple minutes of angle pigeon sticks his head out over the rim of the silo ( they're starting to get educated) nail him (my best shot) and this goes on . What I then did which I probably should not was to fill the gun. So anyways I've got to do some more scientific testing rather then this antidotal stuff. BUT I can shoot. No world class shooter but not without some experience.

Shooting at pigeon heads at 68 yards ? That's a hoot.
 
Upvote 0
Im just throwing this out there but could it just be that your shooting at different angles at that distance and due to gravity the pellet will hit at different spots. Your poi will be different shooting up or down as compared to shooting level. Just something to think about.
Click to expand...


Bingo.

The other variable:

Edit: I'm giving away all my secrets. lol

Shooting in Ambient outdoor conditions at those ranges, I severely doubt that there is anything wrong with your regulator. A 4mph wind from 180 degrees will make your projectile hit high. Add into the equation of constantly changing angles. And the wind never blows exactly the same. I could add more to this. What I have noticed here is that the regulators get blamed a lot. If not that, the scope is second in line for the blame. Never the user. It seems in every single case, the user is a crack shot who cant possibly miss a penny at 50 yards. No matter what condition they are shooting in.
 
  • Like
Reactions: steve-l
Upvote 0
Yes I have some info from Charlie at 40 yards and chronograph read outs. The groups are OK . And I know I'm shooting at very long range. I understand all of this. I'm not condemning the gun. I just wanted to talk about the possible variables that could be gun related. And I FULLY understand that one range or shooting session proves nothing . My impression right or wrong was the velocity was increasing. It very well may not have been. It could very easily been an updraft of air at the silo. Like I said more testing required. And also a difference of a couple yards at that distance is a lot. I understand and you guys have helped . I appreciate 
 
Upvote 0
Im just throwing this out there but could it just be that your shooting at different angles at that distance and due to gravity the pellet will hit at different spots. Your poi will be different shooting up or down as compared to shooting level. Just something to think about.
Click to expand...


Bingo.

The other variable:

Edit: I'm giving away all my secrets. lol

Shooting in Ambient outdoor conditions at those ranges, I severely doubt that there is anything wrong with your regulator. A 4mph wind from 180 degrees will make your projectile hit high. Add into the equation of constantly changing angles. And the wind never blows exactly the same. I could add more to this. What I have noticed here is that the regulators get blamed a lot. If not that, the scope is second in line for the blame. Never the user. It seems in every single case, the user is a crack shot who cant possibly miss a penny at 50 yards. No matter what condition they are shooting in.

i agree completely Remember I said I was suspicious of the gun . Did not say it was the gun. Trust me I know I can miss . BUT when you miss consistently high then it makes a guy think. Right?
Click to expand...


 
Upvote 0
If you're filling to 300 BAR, that's your problem. Charlie Freer says it's not a good idea to make a habit of filling to such extreme pressures, no matter that is what the gun is rated for. Pressure gauges are not accurate, and you could be filling to well over 300 BAR even if your gauge reads 300.

I fill my CF-tuned .25 Cricket bullpup to 250 BAR (habitually), and get 52 CONSISTENT shots (over the chronograph) with 33.95 JSBs at 915 FPS and 63 foot-pounds. I just reduced the power to 890 FPS / 57 FP and got 66 shots (on a 250 BAR charge). You can't beat that kind of performance, and furthermore don't need to. 
 
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu