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harley · New Member

I took my new Phantom apart tonight and modded the piston to Quest 1000 size (approx 2" shorter) with longer slot and new trigger catch hole. Sanded/smoothed the piston, smoothed the spring ends, added 2 washers in the piston and cleaned it all up.
The power increase was massive. I don't have a chrony but it will sink a .22 pellet about 1/4" or deeper into a fir 2x4. Before the mod the pellet stuck into the 2x4 but did not even go in flush.

AirGunEric · Site Admin

Good work! You got it right- I just came in from my garage/workshop where I was disassembling the Phantom 500 and taking pictures and measurements.

Did you take a picture of your shortened piston with the new hole(s)?

As you found out- either just using a Quest/Phantom 1000 piston or cutting down the one in the Phantom will do the most amount of improvement- and allow you to retain the other stock parts. Using a Crosman 1000 spring or an aftermarket unit designed for that purpose would leave alot of slop between the spring and the guides- allowing for alot more 'twang'.

See my photos of the differences here:

http://www.airgunhome.com/agforum/viewtopic.php?t=491

I am going to be re-arranging my Phantom 500, probably tomorrow evening and will get to installing the Bob Werner (CharliedaTuna) GTX-III trigger soon after that as well.

harley · New Member

Never took any pics of the finished piston. Thought about it but it was getting late and I wanted to get it done. The tools I used were a chop saw, small angle grinder, 30000rpm rotary tool and a metal file.
Chopping was easy enough, rounded the ends and deburred it, Used the angle grinder to rough cut the trigger catch hole then actually used the file to get a good edge. Used the angle grinder to extend the slot and the rotary tool to smooth and final trim everything up. Rolled up sandpaper to deburr the inside of the piston and then sanded it all up till it was smooth as a babys butt.
If I ever take it apart again I will snap a pic of it and post it.
I used the instructions that "gunrunner" wrote up on another forum for the Quest.
I shot about 100 shots through the gun today and it is amazing.
Right now these Phantoms at $100 plus 2 hours of modding are an unbeatable value in my opinion.
I plan to buy another to have as a spare in case they sell out!

AirGunEric · Site Admin

Well, I put mine back together earlier using a Quest 1000 piston and got rid of that gummy almost wax-like red lube that the Phantom was filled with from the factory. Haven't had a chance to chrony it yet.

Had a bit of a problem- initially I used the Quest 1000 piston, a couple of thrust washers, top hat and lower guide and spacer with a Maccari spring- somehow this grenaded the trigger (stretched or broken spring in it now) and it wouldn't grab the piston to allow the gun to be cocked after about a dozen shots. Fortunately, I had a spare Quest trigger to put in instead and I will take apart the Phantom trigger later to sort it out. I put back in the 500-specific parts and only the Quest 1000 piston and a couple of thrust washers were added/changed.

Anyways, I would agree- just cutting down the stock piston in the 500 and using the same spring and other pieces- maybe adding a couple thrust washers, and a basic tune otherwise- makes this gun really perform well- for under $100.

Now my left arm hurts from cocking it!

pks203 · New Member

What is the purpose of making the slot longer? After the piston changes does the barrel have too be cracked farther to cock the gun?

AirGunEric · Site Admin

Yes, the cocking lever travels about 50% further once a shorter piston is used- the bottom of the skirt on the original, longer piston has the trigger catch hole 2" further down. The slot itself is so the cocking lever's tip can travel up and down without scoring the piston skirt.

AirGunEric · Site Admin

Well- I got the chronograph out today to test the modified Phantom. With only a Quest 1000 piston and 2 thrust washers behind the top hat, gun lubed with 30-weight non-detergent engine oil and a bit of moly burnishing on the piston, everything else exactly as it came from the factory, here's the result:

The lowest and highest shots have already been eliminated

720.7fps
725.3fps
726.3fps
717.7fps
718.9fps
716.9fps
713.9fps
723.5fps
711.8fps
722.2fps
712.9fps
724.0fps
715.0fps
716.1fps
723.0fps
720.7fps
716.0fps

Average- 719.1fps vs. the starting point average of 478.7fps- that's a 50.2% increase! Holy sh!t.

Now I'll go back and take the Quest 1000 piston out and return it to it's factory state and maybe install the GTX-III trigger and some PET plastic around the spring to reduce any 'twang' and see how that works out.

Oh, and re-lubing it made it feel a lot less "kludgey" when firing. Dieseling is long gone and I used some Crosman silicone chamber oil through the top to lube the piston seal.

2RCHA · Veteran Member

Who want's to earn a couple buck's,,,and work some of that magic with my sub-500 "Phantom",,,,I'm in Toronto,,,and would be pleased to have a "Phantom" with number's like "Eric's",,,Andy.

AirGunEric · Site Admin

The problem right now- as I'm sure most people are aware, Crosman parts in Canada are nonexistent until they sort out a new parts dealer.

Maybe Harley can go into business cutting down people's 500 pistons. Very Happy

daniel sheldon · Member

I just finished cutting down the piston on my phantom 500 .I work in a machine shop and could get some one to make me up a longer top hat.What would be max for length of a new top hat?

AirGunEric · Site Admin

Why do you want longer top hat? The washers put behind it are mainly for rotation- so the spring doesn't bind when being compressed- i.e. creating a torsional twist on the spring. Theoretically, the plain top hat should do this, but adding a couple of polished washers allows somewhat easier movement.

That being said- you are probably thinking about a taller base for the top hat-not an extended pin- so as to act as a shim to increase power (which the washers also do a bit by adding a small amount of space. If that's your aim- we need to come to a conclusion as to what the optimal added height should be, and whether or not any washers will be placed underneath that would also increase this spacing.

From a purely mechanical point-of-view, the top hat has to remain slightly shorter once it's installed with whatever other parts that it won't come in contact with the rear spring guide when the piston is pushed down and the spring fully compressed. An additional 1/4" of space might also be wise so that an over-exhuberant person cocking it won't slam the two guides together. How long should this be? I really have no idea- the gun would have to be out of the stock and an index mark put on the piston and gun's tube once compressed and measured once the gun is fully apart and the pieces can be measured as well- or duplicate parts laid out next to the tube, minus the spring to determine where the top hat and rear guide will contact one another, and then back out a bit.

Of course- if we think we could make a 1" addition to the length of the top hat without collisions- we then run into the problem of whether or not the spring can take this sort of pressure on top of what has already been applied to it by the piston change for any length of time before bending or failing outright. Another thing to consider might be how the gun in general reacts- it might become quite harsh with alot more shimming.

Really, this is a real 'trial and error' process. For experimentation purposes- washers could probably be used, temporarily. Then, what one person calls "harsh" another doesn't even notice. Perhaps really more of a personal taste idea.

But for reference, one person had told me they had achieved closer to 750fps with the 500 using a Maccari spring and 3 washers (washers approximately 1.5mm thick each)- but that was the spring, not the spacing so much. Typically, each additional 1.5mm washer in the B1x .22 caliber series guns only seems to add 5 or 6 fps using stock springs- so if that remains consistent and we want to try to achieve 750fps vs. the 720 I got with only 3mm of space- we need to add 20 more washers, or well over 1.25" of shim- which I bet already puts us over the threshold for guide collision- but maybe someone will actually measure this. If I get the gun apart again in the next few days (doubtful- too much other stuff to get done) I will try.

All that being said, if you have the materials and the tooling- you could probably add 5mm to the base of the top hat without causing any real problems I would think (and still use two 1.5mm washers for rotation).

AirGunEric · Site Admin

Maybe Daniel also has the ability to cut-down the 500 pistons for a small fee? There's at least a couple people wanting to get new pistons that I know of so far.

daniel sheldon · Member

thanks for that info.Ill try another 3\4" and Ill see what happens.

AirGunEric · Site Admin

If you could let us know what occurs- i.e. power increase and/or spring problems- that would be useful.

I was thinking about this a bit earlier- and my 5-6fps for every 1.5mm washer added might have been too low- it depends on how far compressed the spring is already- so that number might actually be higher (as in each washer might add more than 5fps).

daniel sheldon · Member

well i put two 5\16 washers infront of the top hat ,there a little less than 1\8 thick.Now the spring is fully compressed .Still shoots good.A little hard to cock the gun because the trigger just catches the piston when the spring fully compresses.Guess 3\4" would have been way too much.Wonder if theres anything else I could do to power this baby up.