Crosman 2240 hpa conversion question

[Hold_Over]

I have had my 2240 for years, and every now and then I tinker with set up changing various things looking to improve performance etc. This time I used a "safepac" style pcp conversion, and did some work on the valve port for improved flow. All things have gone fairly well, but now I need to get a stronger hammer spring. At a full air charge the chrony numbers start low as the current spring does not hit hard enough to release enough air against max pressure. After about 5 shots the numbers climb, the accuracy dials in, and then goes back the other way once the overall pressure in the reservoir drops. I see there are hammer spring kits with as many as 4 different wire guages. If any of you have been down this road, what spring did you settle as the ideal set up for complete release at full pressure? Thanks in advance

 

[dv8eod]

My first question is, did you pin your valve? There isn't much holding it back against the pressure.

I would suggest getting a power adjuster. Easier to tune with rather than changing springs each time. Either that or an SSG.

 

[Dr. Kralenstein]

My first question is, did you pin your valve? There isn't much holding it back against the pressure.

I would suggest getting a power adjuster. Easier to tune with rather than changing springs each time. Either that or an SSG.

Those safepacs screw into the valve and basically become a self contained cartridge.

 

[Dr. Kralenstein]

I have had my 2240 for years, and every now and then I tinker with set up changing various things looking to improve performance etc. This time I used a "safepac" style pcp conversion, and did some work on the valve port for improved flow. All things have gone fairly well, but now I need to get a stronger hammer spring. At a full air charge the chrony numbers start low as the current spring does not hit hard enough to release enough air against max pressure. After about 5 shots the numbers climb, the accuracy dials in, and then goes back the other way once the overall pressure in the reservoir drops. I see there are hammer spring kits with as many as 4 different wire guages. If any of you have been down this road, what spring did you settle as the ideal set up for complete release at full pressure? Thanks in advance

Definitely need a power adjuster, and I personally run a magnum airpower. 038" wire hammer spring and 2400 psi fill. Dial it in for best performance. Should get about 10 good shots on that setup. You can go 3000 psi and a .042 or .045 spring, but it gets more of a curve in the shot string. 6-8 good shots at a higher power basically. Barrel length will also affect the air usage and power level.

 

[Hold_Over]

Definitely need a power adjuster, and I personally run a magnum airpower. 038" wire hammer spring and 2400 psi fill. Dial it in for best performance. Should get about 10 good shots on that setup. You can go 3000 psi and a .042 or .045 spring, but it gets more of a curve in the shot string. 6-8 good shots at a higher power basically. Barrel length will also affect the air usage and power level.

Thank you, just the info I was looking for. Already have a power adjuster on there, not enough without a stronger spring unfortunately.

 

[Dr. Kralenstein]

Found some pics of the 2240 safepac mini rifle I made. IIRC, it got around 10 good shots in the 750s with cphp.
2400 psi fill and a slightly smaller transfer port @ .125 vs .140

 

[dv8eod]

This is my 2040 with a hipac, hence the statement to pin the valve. Right now, it gets 16 shots at around 500fps. Curve begins at 1800psi. Still have a couple of things I want to do to it, but it's doing pretty well as a short range pester so no hurry.

 

[Dr. Kralenstein]

This is my 2040 with a hipac, hence the statement to pin the valve. Right now, it gets 16 shots at around 500fps. Curve begins at 1800psi. Still have a couple of things I want to do to it, but it's doing pretty well as a short range pester so no hurry.

View attachment 443805

Is that the older hipac, or a safepac from Rob(Froggy)?

 

[dv8eod]

It's the older hipac with one extension. Safepacs weren't available back then. Never looked into them when they came out.

 

[Hold_Over]

Looking good, this is a pic of mine in its current configuration. On the high side it will send 8.3 g superdomes at 900fps. Found a different spring in my spare parts yesterday, haven't had it out to see if the consistency has improved yet. Am expecting about 8 shots within reasonable specs.

 

[airgunner53]

This is an interesting thread, I have disco tube pcp builds and have never ran a safepac or hipac. I just recently acquired a 2240 hipac build and bought just to rob the parts (multishot breech, roller trigger, power adjuster, ldc) for other Lego builds. Seeing the hipac just sitting there in the tube got me thinking of a no frills 2240 build. This tube has 3 screws in the valve and an added extension.

How safe are they?
Would it be worth it to reseal it or sale it?
My pcp pump fitting does not fit the hipac so what size fitting to charge it up?

Also, to the OP, you can order springs direct from crosman or you can take your spring out and go to a hardware store and search their bins of springs but be sure to take some micrometers to measure them
Helpful spring party numbers

 

[dv8eod]

I can't say about the safepac as I've never used one.
The hipac is safe to about 3k as long as the valve is pinned, which it sounds like yours is. There is a good chance for valve lock at that pressure so you'll want to have a heavy hammer spring installed before going that high. It's not good to work on one under pressure.
Not sure what size the fitting is.
If it needs it, I would just reseal it and shoot. Whoever you got it from may have already got the best tune dialed in for it.

 

[Hold_Over]

Got a new .042 spring installed today. Charge to 2400, dump the first shot, and I get 5 good shot with an average of 875 fps using crosman domed 10.5 g pellets. Spread could be tighter, but groups are solid, and poi is not an issue at the ranges I have tested so far.

 

[Genob]

Just updated my 2240 to utilize some accumulated parts I had laying around. Made an adapter to use Notos stock and pic rail. Made new plenum above the reg bottle adapter. Valve is attached directly to the bottle adapter, so no need to pin it. Using P-rod trigger. Tensioned Lothar Walther barrel 18" long. Currently set to 30 fpe @ 1800 psi. 0.5 liter bottle.

View attachment 453645

 

[Genob]

This 2240 I built together with my younger brother. He wanted one in .25 cal and laminated stock. Eastern block polygon barrel 24" long. Modified Exclusive breech, Remington trigger, carbon bottle and home made moderator. It's set @45+ fpe currently, .465" center to center 10 shot groups @ 40 yards. It's posted also on Air Rifle Tuning & Tweaking group.

 

[boscoebrea]

WoW, that's some nice work!

 

[aroundlocks]

Hi bud
Hats off to you and your brother.
The blue lam stock is superb and fits like a glove" not to let it overshadow the rest of the engineering work you have put in.
You gotta be grinning from ear to ear looking at your creation.
Polygon barrel is icing on the cake.
its people like you who make my day a whole lot better .
*****

 

[Genob]

Hi bud
Hats off to you and your brother.
The blue lam stock is superb and fits like a glove" not to let it overshadow the rest of the engineering work you have put in.
You gotta be grinning from ear to ear looking at your creation.
Polygon barrel is icing on the cake.
its people like you who make my day a whole lot better .
*****

Thanks for the kind words.

 

[Hold_Over]

This 2240 I built together with my younger brother. He wanted one in .25 cal and laminated stock. Eastern block polygon barrel 24" long. Modified Exclusive breech, Remington trigger, carbon bottle and home made moderator. It's set @45+ fpe currently, .465" center to center 10 shot groups @ 40 yards. It's posted also on Air Rifle Tuning & Tweaking group.

View attachment 454833

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View attachment 454839

Great work! Every time a 2240 mod post comes up someone pops up with 1 that is beyond the norm. You sir, win this round!

 

[aroundlocks]

Amen to that lol
Just when you think you've seen it all you ain't lol.
It's one god dam expensive budget gun though he he.