Crosmsn 2240 tune for more shot count

[picto007]

Hi all just a quick question? has anyone ever tuning one of these Pistols for more shot per C02 bulb I'm quite happy with the power output. As pistol will be for my son just would like to maximize shot count as the price of co2 quickly adds up

[gingernut]

You can fit a power adjuster at the rear of the pistol.
This changes the tension on the hammer spring.

Have a look at GMac Crosman site and/or talk to them.

And buy your co2 in bulk from our sponsor JS Ramsbottom.
Most shops charge silly money.

[picto007]

Hi tanks for the reply I was thinking of the evilbay for the C02 as for the tune I was thinking less spring tension/compression more flowing may be a light hammer if thing start to creep

[eyebull]

As well as either replacing the hammer spring or adjusting its preload, you can also change the spring in the valve for a slightly more powerful one.

As a rule, the hammer spring should be just strong enough for the trigger to 'set' halfway through the cocking motion. So, without fully cocking it, you should be able to pull the trigger and hear a tiny little click as it releases the hammer under tension.

If you open the valve up (a collett is recommended for this so you don't damage it in the vice), you can either change the spring for a stronger one, or add some preload to the existing spring. If you wanted further efficiency, you could possibly fill part of the transfer area with some sort of plastic filler, but I would be inclined to see how you get on adjusting the spring first.

Bear in mind that because the bulb is pierced by actually firing the pistol, rather than the capsule being pierced by the action of screwing the cap on (a la QB78), there is a minimum strength that you can have the hammer/valve springs set up to.
However by balancing the power of the two springs you should eliminate most of the 'hammer bounce' - most notable for the farting sound it can make - which is where a lot of gas gets wasted.
Another thing to take into account is that how it sounds when you fire it without gas is not how it will behave under pressure, so just because the hammer buzzes when you dry fire doesn't necessarily mean that the hammer will be bouncing when it is full of gas.

You will have to waste a few capsules, and tear down and reassemble a few times, before you get it spot on.

If you have any more questions or run into problems, by all means ask away.

[picto007]

Thank for all the info I was think about modifying the probe ,opening up the transfer port, angling the transfer port ,replacing the cylinder to barrel seal with some air line, polishing the inside of vale and angling the vale pin and then lighting the hammer and leaving all the spring stande .The lighter hammer bringing it all back in line 6ftld and with the lighter hammer improve the firing lock time what all think or its to much watch work for little improvements to shot count

[eyebull]

Thank for all the info I was think about modifying the probe ,opening up the transfer port, angling the transfer port ,replacing the cylinder to barrel seal with some air line, polishing the inside of vale and angling the vale pin and then lighting the hammer and leaving all the spring stande .The lighter hammer bringing it all back in line 6ftld and with the lighter hammer improve the firing lock time what all think or its to much watch work for little improvements to shot count

Maybe be careful with opening up the transfer port, as it's not that hard to get these going above 6 ft/lb in .22 caliber. Those are more things I would do with a stock 2250 to squeeze a bit more power out of it.

Bear in mind the more volume you create inside the valve, the more gas it will use. The internal volume and the valve return spring are the main factors controlling efficiency and gas use. Adjusting the hammer spring on its own will change power, but will not necessarily give you more shots per fill.
Also a lighter hammer spring will give you a slightly longer lock time.

The 2240 I have just finished modding is getting 35 to 40 (I haven't shot it to empty yet so it may well get a few more) 5.01ft/lb shots from a cartridge, in .177 caliber.
I was going for a good compromise between efficiency and power.
That has the springs set up like I outlined above, with a wider transfer port (because .177 is less efficient I wasn't worried about it going over) and balanced valve and hammer springs. It also has a steel breech with a hollow probe, which further increases efficiency, but the cost of this part would buy quite a few CO2 capsules!

[harvey_s]

....would like to maximize shot count as the price of co2 quickly adds up

If at a penny a shot, Co2 costs are an issue - I'd suggest buying an HW40 instead