How to decide

Hi, Art,
And welcome to the obsession-probably best to run very fast while you still can, lol! As to your scope, try googling 'how to set up a scope'-there are a lot of things going on that are not obvious. If I remember right Archer Airguns has a couple good videos on how to set up a scope- here's one: https://www.youtube.com/watch?v=ot5wz_3vZS0&t=85s 
You should be able to shoulder the gun naturally with your eyes closed and see clearly through the scope when you open them without having to move your head forward or back.
I'd encourage you do some research and shoot your gun a lot before you fall into buying a lot of stuff. PCPs are cool and easy to shoot well-BUT you need an air source and that will cost you. 
Good luck,
John
Here's an overview of the different types of airguns:
http://www.crosman.com/connect/which-airgun-powerplant-is-right-for-you/

1st the only dumb question is the one that's not asked,
You don't need a tuned pcp to take care of pigeons and do some good target practice.
Here is the deal, A PCP is basically easier to shoot, but that being said I am sure you have seen the review done on our last contest guns which are springer's and decently accurate.
It is really a matter of preference and budget I have an Air Force that has not been tuned and I am perfectly happy with it, The same goes for the Benjamin Bulldog I recently sold. There are a lot of really good mid range PCP Air Rifles on the market that will provide you a great starting platform.
What you are asking about is a regulator, or regulated air gun, the purpose is as you described it simply provides a consistent fps from fill to the point that the tanks supply falls below the regulated amount at which time the power starts falling off giving more shots per fill due to less waste. 
Non Regulated PCP Air Rifle will usually have a slower FPS at full fill, then as you drop the pressure the spring and hammer is able to overcome the tank pressure better and open the valve longer as this happens there will be what is called a power curve climbing to a peak this peak can last anywhere from 5 shots all the way out to 15 or 20 shots depending on the caliber of the rifle and the size of the tank, then the power curve will begin to fall again.
Both Regulated and non regulated air rifles has a power curve the difference is that the curve is flatter in a regulated gun than a non regulated gun.
Here are two good choices in starter PCP Platforms I would choose a .22 caliber due to the pigeons simply because I do not know what your backstop is (barn silo???) 
Benjamin Marauder, Non Regulated but a lot of aftermarket tunes and upgrades including regulators. The Marauder has been around a good while with a lot of data online on how to do all kinds of tunes and mods so it is a good platform if you want to buy a gun that you can perform your own work on and learn from. Price point $500.00 
FX Streamline
Internally Regulated See the review done on AGN for more information Price point $1000.00
Both guns from the box will provide a great shooters experience again its a choice as to where your budget is. If you don't have to worry about backstops I would consider a .25 caliber but must warn you that it will blow right through a pigeon and hit whatever is behind it with enough force to punch a hole in it.

PS.... I posted this and then watched the recent AEAC review on the Gamo Urban It sounds like it has a lot of potential, and a pretty darn good price to

What are you upgrading from? I was very impressed with the gamo urban shown in an AEAC video, in fact I ordered one. Should be great for pesting and general use. A Hawke airmax scope and hill pump and you'll be set 

depends on your budget though, this is is around $850 with scope and pump 

.

I would suggest a 3-9×40 AO scope like the Nikon EFR or a Hawke airmax, both are rated for springers. If you zoom out to 3x, they have easy-to-use eye relief and fine depth of field. I got the Nikon at Amazon. The Hawkes are available from airguns of Arizona or pyramydair. Either should be around $160

But I would be sort of reluctant to put a good scope on a spring rifle, those days are long gone for me. I have a HW-50S spring rifle that I keep with open sites only, same with a low power IZ-61. I only scope pre-charged and CO2's

I would recommend a 22 Benjamin Maximus Hunter direct from Crosman using the AGN discount code for $164.99 and free shipping on Fridays with a Hill Pump purchased elsewhere and TKO (or similar LDC) or probably find a used 1/2 unfx20 LDC for a reasonable price. Very easy to pump to 2000 psi and normally gets 25-30 shots straight out of the box or just over 40 if you back the power down and is reasonably consistent being a non regulated gun. The "Hunter" edition includes a free Centerpoint 6x scope with AO and mounts with a threaded barrel adapter and is the same price as if you buy the Maximus by itself. If you want to upgrade the scope, I would suggest the $149.99 (Before discount) UTG compact 3-12x44 mildot side focus which is so good enough that the Hunter FT guys use it.The Maximus has a longer barrel than the Discovery so you can shoot more efficiently and suggest you back the power down to shoot at 20-21fpe. Hill pump for ease of use and has a system to minimize moisture from getting into your gun when pumping. Great thing about Crosman is their warranty if you ever need it and they offer to send a pick up ticket so its of no cost to you. I have a 22 Discovery (shorter barrel) shooting at around 20-21fpe 800fps with cheap Crosman Premier Hollow Points (WEIGHED+SORTED!) and consistently average between nickel to dime sized groups at ranges betwen 55-60 yards with the factory Crosman barrel and the factory trigger. I had it upgraded to a BNM multi shot breech and bull barrel shroud which is near silent now after the warranty was finished and the 3 trigger screw mod. Final stage will be to fit a Gen1 Marauder lighter adjustable trigger $48 to it with a Nitro Piston rifle trigger guard $2 and some change and $11 trigger spacer riser or make one using PVC pipe as suggested on the Crosman forums. Matter of fact I like it so much I recently bought one in 177 with BNM multishot breech and bull barrel shroud from a respected member here and am more anxious than anything to receive it! I would personally wait a bit before buying a new 22 Marauder to see if their barrels have improved or buy a proven accurate used one from a credible and respected seller and besides that, there is a significant increase in effort to pump from 2000 to 3000 psi. 
AJ 

I like AJ's idea, have one in the house right now purchased just like he said. Outstanding value for the money, pick on the lack of finish on this one if you like but still a great value.
The scope ( while not great - I like the old bushnell - ) it is decent and the best I( have ever seem in a "bundle" package , not like the old Gold Finger special deals on Beeman's gone by. 
Just need to chrony it and may well get the marauder trigger group ( AJ thanks for the nitro piston trigger guard tip) but as is out of the box at pidgon at 50 would be an easy shot, light weight & low psi charge needed and the AGN coupon makes it a must have even if you might have better rigs already & if you don't you need one.
John

Borrowed this thread! Check it out!

http://www.airgunnation.com/topic/cutting-the-cards/#post-175994

"spysir"I like AJ's idea, have one in the house right now purchased just like he said. Outstanding value for the money, pick on the lack of finish on this one if you like but still a great value.
The scope ( while not great - I like the old bushnell - ) it is decent and the best I( have ever seem in a "bundle" package , not like the old Gold Finger special deals on Beeman's gone by. 
Just need to chrony it and may well get the marauder trigger group ( AJ thanks for the nitro piston trigger guard tip) but as is out of the box at pidgon at 50 would be an easy shot, light weight & low psi charge needed and the AGN coupon makes it a must have even if you might have better rigs already & if you don't you need one.
John

Click to expand...

Specifically a 2 bucks Benjamin Trail trigger guard b180011a and 48 bucks Gen1 Marauder trigger assembly 1763a105. You will need to provide these part numbers when you call Crosman to order.
I don't think the AGN discount applies to parts orders since you have to call them and order over the phone. You will need to either fabricate a spacer so the sear does not get hung up and damaged or buy one for 11 bucks from Airgun Lab.

AJ