CP1-M pistol first impressions

[nervoustrigger]

Have you found what sizes are needed to service everything? I am assuming I can find what I need at the Oring store, I'd like to get a full set ordered and added to the collection if you already found the sizes.

Yes, I measured them:

.177 bolt O-ring (in the barrel):  4.5mm x 1.5mm (or -008 with the OD abraded down slightly)
.22 bolt O-ring (in the barrel): my guess is 5.5mm x 1mm
barrel:  8mm x 1mm
transfer port:  6mm x 2mm (looks like a -010 will work as well)
valve: 13mm x 2mm

By the way, my transfer port had an O-ring on only one side but looks like there should have been two so I'm going with two when I reassemble.

[rrdstarr]

Very interesting results~
I have the .177 and .22 but haven't played with them much other then altering the grip for the .22.  Thought about an LDC except they are much quieter then CO2 wasting 2240's.  Think I will dig mine out of the big safe as it is getting up to 12c during the days now.   I purchased my pair over a year and a half ago when they first came out!  Bought two spare magazines for each at the time, haven't tried them out yet!  I paid $129 each shipped for them.

[nervoustrigger]

Did anyone's else crown look like it was done with a lava rock?  Fortunately the rifling looks pretty good once it is given an opportunity to show itself:

[imadunatic]

Oh my. Talk about a chattery chamfering tool....

Now that I've gotten through the nice weekend, I plan to fully tear mine down and see what it needs, as well as do the 2 stage trigger mod and look into upping the efficiency. I definitely think it'll be getting a MDS hammer of some sort, they're not that tough to make and I think it could help.

It just feels wrong that my 2240 is putting out 465 FPE in one powerlet averaging 410 FPS and this is putting out ~184 FPE averaging 410 FPS. I definitely expect the .177 to put out less, but not that much less.

I'm wondering if I don't also have a leak somewhere. Time to get out the microscope I think.

[imadunatic]

So, I just pulled it completely apart, I figure it's time to get to work. My crown doesn't look nearly as bad as Jason's, but I'm still going to touch it up.

Couple things:

• Transfer port, exhaust port and barrel port all measure ~.140", breech port measures .125" and all have sharp corners. I'm thinking opening the breech port to .140", and lightly chamfering all the sharp corners to help the flow.
• Looking more closely at the valve, the CO2 has got to make a heck of a journey to get down to the actual poppet seat. I think there is enough meat in the valve body to open up down closer to where the white plastic poppet actually seals. This would open up the internal valve volume as well as help keep a larger volume of CO2 available at the seal off itself.
• I don't think this is a candidate for rounding off the exhaust port as it already looks dangerously close to the poppet seat, and I think there is a brass bushing for the poppet stem (it sure looks inserted to me)

My thought is if I can get it breathing better, I can use a lighter hammer spring and striker to get the power back down to roughly 500 FPS but hopefully bump the efficiency a ways. It just seems to me that this pistol has more to offer; but I'm a little leery to start machining on the valve because how would I ever buy another valve if I went too far? I don't think I'd want to count on MRODAIR for spare parts and I'm not aware of any other supplier that might offer them (anyone have any ideas???).

[flyingmachine]

My CP1-M is in transit.  Since I'm quite new to airguns, are there any required maintenance before loading up the first CO2 powerlet?

[dv8eod]

My CP1-M is in transit.  Since I'm quite new to airguns, are there any required maintenance before loading up the first CO2 powerlet?

Put a drop of chamber lube on the tip of the powerlet before inserting, and then maybe every 3rd one after.

Jason, did the numbers help you out?

[Ribbonstone]

Just clean it.  Long ocean voyage on a big container ship, and there seems to be some kind of skummy/sticky preservative inside the bore.

Other that that, will agree to a small drop of lube on the nose of the 12g. being used (small as in about flea sized)....if you want to only lube ever 2nd or 3rd cartridge, doesn't seem a problem, but I've not found any problem running mine a little "wet".

Haven't tried the power increase...actually working in the other direction, looking for longer good shot count and accepting the lower energy that requires.

[nervoustrigger]

Hi Terry, yes last night I finally imported your string into my spreadsheet and the total energy was impressive.  I plan to take a closer look tonight and post the numbers. 

[imadunatic]

Terry, are you also going to post the secret sauce?   

I did finish the all nylon lightweight MDS hammer last night (along with a few creature comfort mods) but I needed to pick up some short #6-32 set screws and the hardware was closed on my way home. Hoping to get it back together tonight for a string or 2 to see if it helped at all.

[nervoustrigger]

The way he explained it to me, it's bog stock.  So something must've changed along the way.  Too bad, really, because his is set up way more efficiently than ours.  I'd love to see them side by side to note the differences.
 
I will say this, I noticed on mine that there is just the very slightest bit of hammer spring preload (1 or 2mm) in the uncocked state.  Let's instead call it the "fired" state to represent that the spring is just barely leaning on the poppet once fired.  That is, it's not pressing with enough force to hold the valve open after the shot but when the poppet rebounds in the reverse direction, it may be imparting enough energy into the hammer to recompress the spring and produce a second (CO2-wasting) opening of the valve.
 
I could be wrong but I'm not inclined to think that simply clipping coils will make a dramatic improvement.  I mean, it's only 1 coil shy of being a free-flight hammer as it is.  So it would likely have to be cut back quite a bit to make a difference and at that point, the distance the hammer must cover in free flight gets ever larger and that's not good for the extreme spread and can produces a large velocity variation for steep inclined shots.  Granted, neither of those things is probably of any consequence for a pistol duty but...
 
I think you are on the right track with a lightweight hammer.  The throat is quite small so it shouldn't take a lot of energy to crack the valve open, and you don't want a heavy hammer (momentum) holding the valve open for long because the barrel is so short.  My one lingering concern is how the material will wear against this type of sear.  Maybe you can sleeve the face of the hammer to deal with that.
 
I don't have the stuff for a light hammer so I'm toying with the idea of an internal SSG.  If I'm thinking about it right, I can drill a clearance hole through the face of the hammer and pass a long screw through it, on through the hammer spring, and thread it into the spring guide.  Then I can just thread the screw in and out to adjust the overall length of the assembly.  With a little preload added, it should then be stiff enough that the poppet's rebound won't be able to recompress it a second time and send it snapping forward to reopen the valve.  So it gets rid of that form of waste, I'm just not sure it won't still have way too much dwell on the initial strike.

[dv8eod]

The numbers I sent Jason were totally straight out of the box. I ordered mine way back when they were first offered. The only thing I did after that string was recorded, was stretch the hammer spring for a little more oomph. The hammer was free floating.... I could tip the gun up and down and hear the hammer sliding back and forth. Not much, but still movement. Had I thought about it, I would have measured the spring before stretching. Not many people were interested in the cp1m almost two years ago when they cost more.

[imadunatic]

Terry,  sounds like yours had a sort of pseudo short stiff spring? Hmm...

Not enough time to get mine completely back together tonight. I did discover that the transfer port is about .020" too short and the o rings on it are about .010" too small for the counterbores even when installed on the transfer port. I made a .030" thick shim so they'll at least seal on the ends. This wouldn't effect shot count so much, but might explain why mine is a little slower than everyone else is seeing (even when correcting for temps). I haven't powdered it yet, I probably will if the fps doesn't come up.

Jason, I'm really curious about how it's going to wear also. I only have these hammers in my pistol and 2400 that both have the PROD drop seers. I'm thinking of doing exactly like you're saying with a steel top hat of a sort and riding on MDS so it can still run dry. I want to see if there are any gains before I go too far with it though. Hopefully tomorrow night I'll have my answer.

[nervoustrigger]

A graph of Terry's shot string...363fpe total over 109 shots inside of an 8% ES.   Good stuff!

[imadunatic]

I gotta say, I see one glaring difference between Terry's shot string and mine.



My shot count has all the signs of an overstruck CO2 valve, while Terry's was probably hitting just a little bit lighter than I would prefer (I would trade a few shots for a little more power at that level) at least at whatever temp he shot the string at (though I wouldn't mess with that setup if I could get mine to shoot like that to be honest!!! LOL)

I'm thinking about compression setting the stock spring and see if it creates the slightest of gaps. I also don't have a spring guide yet, so I should have a little less spring than everyone else already. This gives me hope.

[Bob Pratl]

Thanks Guys!  After reading your reviews I had to order one. For $90.00 I don't think that I can go wrong and It looks like it has a lot of potential. With the warmer CO2 weather coming it will be another FUN toy to modify and shoot, as if I have time. Bob
 

[Wayne52]

Did anyone's else crown look like it was done with a lava rock?  Fortunately the rifling looks pretty good once it is given an opportunity to show itself:

Jason how did you go about doing the recrowning job on that one?  I've never personally done a crown job myself but I see how a lot do it with the brass screw trick.

[imadunatic]

Bob,

I was a little apprehensive at first... But it's won me over, and now I've got my eye on the MK II/PP700-S (need a hand pump first though, my scuba is never full enough for something like that!) after working on this pistol.

I'm really surprised by the quality at this price point, I guess I probably just had my expectations set pretty low.

[Wayne52]

Bob,

I was a little apprehensive at first... But it's won me over, and now I've got my eye on the MK II/PP700-S (need a hand pump first though, my scuba is never full enough for something like that!) after working on this pistol.

I'm really surprised by the quality at this price point, I guess I probably just had my expectations set pretty low.

They're still available for $219 shipped, I recently got an email response from them, that was the night before last and they said the guns were in transit from China so it won't be long

[imadunatic]

They're still available for $219 shipped, I recently got an email response from them, that was the night before last and they said the guns were in transit from China so it won't be long

Wayne, I'm waiting for the first wave to go through before I buy one. I'm never an early adopter.