Pumping a Gamo Urban

[cbourbeau32]

For those who own an Urban and fill it with a hand pump. How many pumps did it take to fill it to full the initial fill and how many pumps to refill it after shooting?

[Nomadic Pirate]

The refilling after shooting is directly linked to how many shots you take and at what power your gun is set at.

[EdinGa]

There's a lot of information out there on this rifle. If I remember correctly, it's between 150 and 200 pumps to fill it from empty. I think you'll find that there's no need to fill it all the way to its 3365 psi max though. The sweet spot in the shot string actually starts lower than that. Do a little reading and research and you'll save yourself good bit of work and time. I've got mine tuned to shoot heavy slugs, and I shoot 2 magazines and refill. It takes 35 to 40 pumps to top it off each time.

[CraigH]

There should be air in the rifle from the factory.   If not it leaks.

[Xraycer]

Add Craig mentioned, there should be some air in the gun when you first take it out of the box. Also, it's always a good idea to do no more than 50 pumps at a time, with at least a half hour break. This let's the pump's o-rings cool down, thus cuts down on the wear and tear.

[cbourbeau32]

Thanks for the replies everyone!

[moorepower]

Reading between the lines, yes they are a good gun to use with a hand pump.

[Xraycer]

Reading between the lines, yes they are a good gun to use with a hand pump.

When I need a quick, sure shot, my Urban is my weapon of choice. Just ask the big muskrat that had decided to make the bottom of my raised shed it's home.  Let's just say it was "evicted" this past weekend.

[Ribbonstone]

Urban...small volume,but high presssure.   Not hard to pump-fill, it's only 105cc's and you're likely only refilling for about 1000psi (assuming you stay in the typical sweet spot).

PCP's use to ship empty or nearly so.Recent yeqrs, usually come with at least some pressure.  Change in shipping regulations?  Just common sense (they stay sealed up better with some pressure in storage)?  They actually pressure cheack them and it'seasier to NOT de-gas them?

Even with a choice,will normally pump-fill the Urban. Something like 65-75 pumps to refill (something like 2000 to 3000psi).

IF you do have to fill from empty....more like 3X that number of pumps (putting in 3X as much airas a refill).,,,maybe 3 1/2X as hand pumps really hate starting from zero.

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I really like the little Urban. Likely becasue I wanted what the factory specs./reviews were getting out-the-box.  Didn't buy it to make it into something else,thought the name "Urban" pretty well matched what it was designed to do.

[Airnut]

My shot strings show that with my tune optimum fill pressure is 2800 - 2900 psi. Not a problem for a hand pump.  One other thing that I found is that after filling shoot off one shot in the ground before using. I dont know why after filling the first shot is useless. I have read about others having the same experience.
 

[Ribbonstone]

No proof....but come to think it's the pulse-pressure doing a  "rap-rap-rap-rap...." on the valve stem/poppet of refilling vs. the "clean" valve stem cycle of shooting.

[CraigH]

PCP's use to ship empty or nearly so.Recent yeqrs, usually come with at least some pressure.  Change in shipping regulations?  Just common sense (they stay sealed up better with some pressure in storage)?  They actually pressure cheack them and it'seasier to NOT de-gas them?


I really like the little Urban. Likely becasue I wanted what the factory specs./reviews were getting out-the-box.  Didn't buy it to make it into something else,thought the name "Urban" pretty well matched what it was designed to do.

All my PCP's have arrived with around 1000 - 1200 psi, except a SPA that was about 2500 psi.

Ditto on the "Urban" name - rather quiet, relatively compact, relatively light, respectable 800 fps rating.   The rifle is easily tuned (really adjusted) between 700 fps and nearly 900 fps by mere hammer spring preload and starting pressure set to support the desired fps.

[Airnut]

No proof....but come to think it's the pulse-pressure doing a  "rap-rap-rap-rap...." on the valve stem/poppet of refilling vs. the "clean" valve stem cycle of shooting.

I always thought that is was just an attribute of a self regulating valve?
What ever that is!

[CraigH]

No proof....but come to think it's the pulse-pressure doing a  "rap-rap-rap-rap...." on the valve stem/poppet of refilling vs. the "clean" valve stem cycle of shooting.

I always thought that is was just an attribute of a self regulating valve?
What ever that is!

All our typical PCP poppet valves (in non-regulated guns) are "self-regulating".    It refers to the manner in which the pressure in the tube/tank,  which begins at a particular high level and is reduced with each successive, will effect the string of valve opening events during each shot.   If the gun is well-tuned to a nice, relatively flat bell curve, the first shots under influence of the higher pressures, will be of a bit lower fps as the hammer strike cannot open the valve as much as will occur with later shots.   Shots in the middle of the curve, the "sweet spot" so to speak, have a particular balance of hammer strike to tube pressure.   Later shots are with less pressure in the tube/tank, and so the hammer strike will open the valve more (higher and/or longer) therefore using more air volume that has less air pressure.

Short version - the gun is not regulated.