Newbie question of the day

[Randy]

I took my Remington .22 NPSS apart, crosshatched the compression cylinder, deburred all the sharp edges, replaced the seal, lubed where everyone says to lube, and installed a CDT trigger. I haven't had a chance to shoot it yet so here is the stupid question part, should all of these improvements affect which pellet my NPSS likes? 

[uncle paulie]

Absolutely a possibility! Anything you do which affects the power(fps) of the gun can change the preferred pellet. Less power will delay the pellet leaving the breach and more will speed it up. Your rifle may now like a tighter or looser pellet as a result.

pv

[Brewerja]

Beware, the first 2 or 3 shots might go supersonic. Sounds like a .22lr if even a smear of that moly paste got ahead of the seal. Just like a diesel engine, the high compression air will deonate the oil and your likely to have the police knocking on your door shortl after!! For me, i shot the heaviest lead i own to keep it from sonic booming. 32gr eunjins dis the job in my NPXL after a rebuild. If you dont have nosey neighbors, disreguard my last. Heheh, good luck dude!

[Randy]

Alright thanks for the insight, I will be sure and take a pellet variety with me when I get the chance to shoot. I will also make sure to be ready for the loudness.

[stock600]

Id be interested to hear your findings from before and after. I'll be doing one soon myself and curious the same question. What did you use to crosshatch your comp. cylinder what is the diameter inside? Thanks Also who's seal did you use and where did you purchase it? Im looking at one now from mr. macarri. Thanks

Ryan

[Randy]

I used a 200 grit brake hone and then followed with the wood dowel rod idea and 400 grit. The inside diameter of the compression tube is around 1 1/8". The seal and the CDT trigger blade came from junkyspace here on the forum. The seal looked like a factory Crosman seal because it was identical to the original. I probably didn't need to replace it but I did because I had it on hand. The rifle is very well manufactured and assembled with no nicks in my original seal. Deburring the piston went fairly easy and the piston is thick walled and extremely heavy compared to my Gamo Whisper. Still haven't had a chance to shoot it due to work but hopefully I will get some time around Christmas to try it out.
 
The barrel pivot bolt seems odd to me on the NPSS because it will only let you loosen it about an 3/4 turn before it locks and then you can only go about 3/4 turn back to tighten and it gets tight. I wanted to remove it completely but gave up after my luck in stripping out the same bolt on my whisper. I adjusted it so it would keep the barrel snug during the opening and still provided a good solid lockup when closed.

I also noticed on the nitro piston that the paint was wore through on the external cylinder like the piston had been rubbing up against it, so I made sure to debur the interior of the piston to prevent further damage/wear on the metal.
 
One thing is to make sure the set screw holding the scope mount does not protrude into the cylinder. I tightened mine down and it stuck into the cylinder far enough to touch the nitro piston, I removed it and sanded the end of it off enough to keep it from sticking into the cylinder. After shortening the bolt I went ahead and used an epoxy to cement the entire scope mount to the top of the body (just follow the instructions on the epoxy tube).

Two things to watch for during disassemby is the cocking arm pivot pin, if you look real close you can see that it is smooth on one side and toothed on the other, drive it from the smooth side, the tooth side should be the first out and when you put it back together it should be the last in to grab the metal and not fall out. The other is the little spring you need to remove from the trigger assembly attached to the open breech trigger block (this is my name, not sure what else to call it), my spring was actually attached underneath the arm so it was tricky getting it back together.
 
While I was installing the CDT trigger blade I went ahead and polished the sear on the top and bottom contact points just for the heck of it. The CDT trigger install was definitely the easiest part of this and all went well.
 
Sorry this seems like a lot of rambling but this is what I found out about mine. When I did mine I wasn't really planning on writing all of this down but you did ask.

[stock600]

Hey thanks for the reply thats what I wanted to hear. Not 100% sure what you were describing was rubbing but I wonder if the GRS bushing would fix this for you? I plan to have the bushing/ washers, seal, and GRT trigger all here when I do the first tear down and do all the upgrades at once. I have a cronograph coming as well so I'll have before and after numbers to compair. Looks like Im going with the Macarri seal rather than a stock replacment though, not much money and suppose to be a nicer part and better seal. Well see. Thanks for taking the time to answer my questions

Ryan

[microsalmo]

good read guys - thanks.  i plan on doing mine soon too.

[daniel hagman]

randy ,  i am new to the sport and was wondering where did you learn to dissemble and refine your gun? is there anyone to teaches this skill.

[Randy]

Just absorb all the information on this forum, and any other site I could find (pay special attention to the oldtimers). I spent about 18 hours on here reading everything I could before I started.

[Randy]

Around the skinny end of my nitro piston (NP) there was an area about 1/2" wide and 3/4" long where the black paint was rubbed of and the metal cylinder of the NP was getting scratched. I inserted the NP back into the piston to see where this rub is coming from and on the piston cocking arm slot, there is a sharp edge on the interior it looked like it was rubbing there so I removed the sharp edge, hopefully it will stop rubbing.