CP1-M pistol first impressions

[nervoustrigger]

Pretty sure I ordered them from Amazon but just PM me your address and I'll put some in an envelope.

[cobalt327]

Pls disregard/

[imadunatic]

Jason,
Do you have a source for the silicone 50 durometer -113 o-rings for the valve buffer mod? I could find silicone in 70 or Nitrile in 50 but not the silicone in 50

Thanks

Stan,

I'd give it a whirl with any 113 o-rings you can find to start. I ended up with 2 70 duro 113 and 1 70d 016 nitrile o-rings to get mine in the sweet spot. These pistols seem to all respond differently. I searched to the end of the earth for the silicone o-rings also and figured I'd just try it with what I had, worked great. Much better than anything else I'd tried.

[WhatUPSbox?]

Good point on the variability and tolerances.

What speed numbers did you settle on? Mine will be for paper punching so low 400's is OK

[imadunatic]

Good point on the variability and tolerances.

What speed numbers did you settle on? Mine will be for paper punching so low 400's is OK

At 56 degrees, mine was running 420-430ish. I could get over 70 shots above 400, and shot 84 was the first one under 300 FPS using 7.9gr CPHP pellets. I haven't re-checked it since it's warmed up here in the north, but it is definitely a blast to shoot when it's 75 degrees out, seems to go on forever.

Mine is also just for paper punching (and those little metal spinner resettable targets that you can get for $20, it's JUST enough energy for that at 20 yards).

[Wildcatter]

I'm hoping to get mid 400's using the 5.5 GTO non lead.  Just hoping they group, you know?  No pistol yet

[WhatUPSbox?]

So I decided to look at the trigger assembly....

The good news was that the grub screw was in there...on the other hand they installed it from the top so it was trying to cookie cut into the sear.

Some smooth and polish, flip the grub screw, round and polish, lube

Using my DIY trigger gauge, the pull dropped 4 oz. to 1lb, 10 oz.

I set the grub screw about .030" proud. Has anyone played around with that number, or tried the dual grub screw 2 stage mod?

[cobalt327]

Some discussion of the CM1 trigger HERE.

[imadunatic]

I did add the second screw to mine, I didn't measure it after I was done though. I do like it better (I have an affinity for short final break triggers, single stage or 2 stage) and I'd recommend it if you have the tools. I used #6-32 set screws for everything and even retapped the metric screws to #6-32 just to keep everything cohesive. 

[WhatUPSbox?]

I was trying to figure out if you can set the grub screw height so the trigger transitions from the grub to the edge of the trigger to break. Might need a ball tip screw to make that more controllable. A bushing on the pin would set the first stage travel.
Otherwise I'll add the second grub screw like you did.

Mark, thank you for the link

[WhatUPSbox?]

I did some more tinkering with the trigger. I tried a couple of bushings on the pin and a couple of heights on the grub screw.
First tried a .045" wall bushing and a .034" grub screw height. This is too much and the sear does not hold.
Then dropped the grub screw height to .012" This had almost no travel.
Switched to a .025" wall bushing and the .012" grub height. I think I feel a first/second stage so I'll shoot this for a while, with maybe a few more tweaks.
One interesting note, the trigger has a lighter break on the grub than on the back edge by some 6 oz.I think most of this is due to the geometry. So using the grub is an easy way to get some reduction even without changing the spring.

I think I'll get another grub and try to shape it into a dome for better adjustabilty. Though I may end up with the 2 grub approach for staging

Having fun with this gun

[WhatUPSbox?]

Just to close out on my trigger ramblings. I've been using the 5M match targets and range http://www.gatewaytoairguns.org/GTA/index.php?topic=36.0 to see if things are improving.
So for a new pistol, relatively novice shooter, two handed, I started in the low to mid 130's, typically pulling a handful of shots.
After the trigger tweaks, I shot a couple of sheets, they were in the low 140's with much fewer pulls.
For a little bit of time and one bushing invested, I'm happy with the change.

Though I'm sure I'll tinker with it some more.

[cobalt327]

Wish I could average ~ 9.5 per shot for 15 shots with mine.

[Wildcatter]

You know, I ordered my pistol on 5-24 and it still hasn't arrived.  I'm bumming - was really hoping to get a chance to use it this weekend, but knowing my luck it won't show up today either

[cobalt327]

Mine took 13 days.

[WhatUPSbox?]

I think mine took about 11 or 12 days to get to CA

[Wildcatter]

I got excited; I thought I saw a couple folk got theirs in 3 days and 5 days...it is what it is...

[Bizill]

I feel your pain.  Especially when you miss out on an entire weekend to get to play.  For some...most of us, that's the only prime time we have to give to our hobby.  It doesn't help for me to say but I think it will still be worth the wait.  I took aim at a sparrow...about...18-20 yards up high atop a palm tree and didn't think I'd even get the pellet close enough to scare him when all the sudden he went twirling downward to his demise.  I'm diggin' this little bugger more and more and it's been only a couple of days. 

[Wildcatter]

I got it!  Played Friday night with it.  Pretty accurate with the 5.5 grain GTO pellet.  The loading cycle is HARSH and I can't figure out how to use the magazine...single loading only.  Really like the grip and it LOOKS purpose built.  Not bad for less then $100...

[nervoustrigger]

The loading cycle is HARSH

There were a couple of things that remedied the harsh loading on mine.  Firstly, the bolt has a sharp edge where it steps up to the full diameter.  That was chewing up the O-ring in the barrel each time a pellet was loaded.  I chucked up the bolt in my drill press and spun it while gently touching the sharp edge with a rubber Dremel polishing wheel.  Just enough to break the sharp edge.  That type of polishing wheel left a cloudy finish so I stepped over to the cloth polishing wheel with a fine polishing compound and put a mirror finish on it.  Then I replaced the O-ring with a 90 durometer Buna-N and I've since put about 1000 pellets through it and the O-ring still looks good.  Mine's a .177 and I didn't have a M1.5x4.5 so I used a -008 with the outside diameter abraded down until it fit neatly into the barrel recess.

The other issue was that wadcutters would hang up when loading...

Wadcutters were hanging at the leading edge of the receiver, which I noticed first while using the single shot tray.  I went ahead and addressed it before I had even tried the magazine.  Once I did try the mag, I did not have to make any mods to it.
 
The way I beveled it was with a small ball-shaped carbide burr.  I think it was a 3/8" diameter (mine is a .177 cal but I suspect a 3/8" ball would work just fine for .22 cal as well).  Just pressed the ball against the receiver opening for the bolt, spun it at slow speed in a handheld drill and it made quick work of the soft aluminum.