Author Topic: Under The Hood Of A Crosman NPSS  (Read 19941 times)

Offline Gene_SC

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Under The Hood Of A Crosman NPSS
« on: February 23, 2010, 11:10:45 AM »



First I would like to say "Dat A Boy Crosman". With that said I had time this afternoon to break down the NPSS .177.



First is the stock. Personally I have never like any of the thumbhole stocks that I have shot. Reason being my thumb knuckle does not fit right. Very uncomfortable for me.



The rubber comb pad is a nice feature though. The stock weight is much heavier than any synthetic stock I have held in its class. On my NPSS the stock screws were securely



fastened to the point of aching hands after I got them out..:) That is a good thing though. The stock feels well balanced once the scope is on.



The Centerpoint "4-9-40AO" scope is very nice that came with the gun. In fact I was a bit surprised at its feature with the lock down gimbals. This is another feature that



Crosman seems to be dealing well with. Selling a combo with a good scope. It is clear all the way up to 9 power. As some of you know I am not a Centerpoint or Leapers



fan..:), but outside of this Center Point being heavier than any of my 50AO scopes I own, it has good glass and a bargain at that.



The barrel is a bull barrel and on close inspection it looks like it can be removed. Did not try but you can see at the end of barrel you can use an allen wrench to turn the



end to remove it. I am not positive but that is what it looks like. The barrel is a steel barrel in the shroud, not a sleeve with plastic around it. Great quality there.
The barrel and breech has a common screw to hold and adjust the preloads. Another good quality and it all is steel and not plastic...:) I checked the barrel with a swab and I



have to say it was very dirty with oil. So remember to always clean your new gun barrels before shooting them to get the factory goop out of there...:)



One other note is that Crosman has increased the size of the chisel wedge pin. I took a picture of it so you can check that out as well.



The NPSS is made right here in the USA. Lets hope Crosman keeps that up..



OK now for under the hood of the NPSS.



First off you really need a spring compressor to relieve the pressure from the gas ram. Right away I noticed that the action tube was much larger than any Crosman, Gamo,



Chinese etc. air gun's in its class. Once apart it was very apparent that the size of seal and piston were big. Seal measures roughly 1.1375". About the same O/D as a RWS



350 Magnum.



I had a chance to compare some of the parts from a Gamo that I exchanged the gas piston for a spring. Have had a few of these because of complaints that the Gamo with the



gas ram was way to harsh, and I tend to agree. The gas pistons are the same shaft diameter, but the Crsman gas ram is shorter than the one's I have taken out of the Gamo's..



I have heard the NPSS referred to as a short stroke air rifle... Here is where Crosman is way ahead. The piston itself is one machined part which ways in at about 16 oz. Very



heavy one piece piston but shorter than the Gamo piston which is just stamped metal and it is two piece affair. Crosman also machined a hole in bottom of piston so the gas



ram shaft would fit and not be able to move, unlike Gamo which they just use the standard piston. There are a few other details that make the Crosman NPSS a winner like the



rear adapter for ram to the inside diameter of action fit. Also Crosman has use a solid piece of steel for the rear block. What I have seen so far makes the NPSS a very



solid built air gun.



Three Main Improvements. The larger action tube. Then new design of the piston and it's weight factor. The over all weight of the gun makes for a great balanced shooter.



Just the weight itself will help with hold sensitivity. All around great build. I hope that Crosman keeps putting out guns built like the NPSS.




Chrony numbers. After the deburr and new lubes along with cleaning the barrel bore. I run about 40 pellets through her. Then set up on the chrony.. Respectively with JSB



Exacts "8.3 grn" she was pumping lead out at an average of 932 fps which calculates to just over 16 fpe. I only run 12 shots through the chrony but the overall deviation was



14fps. That is a good as some high end springers get..:)



I have taken some pictures so you can actually see some of the differences between the parts.



Next will be my review on CBT Trigger change. And when I have time I will take some target groups as well. I hope this answers some of your questions. Feel free to ask me



what ever comes to mind on this review that I may have forgot to put down.



Also I will be buying a new Trail NP but will have to wait until the .177's are released.











THE ONES I SLEEP WITH: BSA Lightning XL, AA TX-200, AA ProSport, BSA Ultra, HW-97K, Crosman NPSS .177, FX Cyclone, HW-30 Nicle Plated, AA-S200, Crosman Marauder, CZ-634, R-9 DG, Webley/Scott UK Tomahawk, Benji Kantana, Benji Marauder, Benji Discovery.....
....

Gene\'s Tunz n Toyz
Springer Tunin

Offline longislandhunter

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RE: Under The Hood Of A Crosman NPSS
« Reply #1 on: February 23, 2010, 11:33:30 AM »
A good read Gene..... sounds like a very well crafted rifle.  Will be looking forward to part II  :)

Jeff
\"If it was easy it wouldn\'t be hunting, it would be shopping.\"

Offline ezman604

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RE: Under The Hood Of A Crosman NPSS
« Reply #2 on: February 23, 2010, 11:46:42 AM »


Many thanks for the eval Gene. Is that a Gamo piston and RAM you are showing as comparison?



What about cocking force?



I kinda like the snake skin looking finish of the stock.



Dave



Crosman/Revelation 760 PumpMaster (Vintage 1967)
Powerline 1000S .177 (semi-tuned by me)
Benjamin Super Streak .177/.22 (semi-tuned by me)
Benjamin Trail NP XL1500 (bone stock)
Benjamin Trail NP XL1100 (project gun)
TF89 .22 (tuned by Gene)
Winchester 1000WS .177 (semi-tuned by muwah)
QB57 (l

Offline shadow

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RE: Under The Hood Of A Crosman NPSS
« Reply #3 on: February 23, 2010, 11:50:33 AM »
Great first take on the NPSS and I can see where the power is coming from with that big piston seal and compression chamber. :) I got say bro I really like the look's of that shooter, stock and all cause you know I'm a thumbhole guy hehe. Now I'm looking at the .177 is that style lol and if your review of the gas ram shooter stays in the positive ..........I'm now drawn to the gas ram shooters now, darn addiction will get you every time hehehe. She's a sleek looking gal bro and the design on the stock is hypnotizing lol. Ed
I airgun hunt therefore I am... };)  {SHADOWS Tunes & Camo}  airguncamo@yahoo.com

Offline dk1677

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Re: Under The Hood Of A Crosman NPSS
« Reply #4 on: February 23, 2010, 12:02:30 PM »
Thanks for the info Gene! Great to know!
Hammerli 850, Beeman RS3 ,Gamo viper express,Crosman 180

Offline Gene_SC

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RE: Under The Hood Of A Crosman NPSS
« Reply #5 on: February 23, 2010, 12:23:28 PM »
The cocking force is shorter and smoother than the Gamo conversions.About half way through the cocking stroke it gets easy. Crosman has done there homework on this gun. They have actually designed the gun with the gas ram in mind. Cocking leverage is good.
THE ONES I SLEEP WITH: BSA Lightning XL, AA TX-200, AA ProSport, BSA Ultra, HW-97K, Crosman NPSS .177, FX Cyclone, HW-30 Nicle Plated, AA-S200, Crosman Marauder, CZ-634, R-9 DG, Webley/Scott UK Tomahawk, Benji Kantana, Benji Marauder, Benji Discovery.....
....

Gene\'s Tunz n Toyz
Springer Tunin

Offline SDale

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RE: Under The Hood Of A Crosman NPSS
« Reply #6 on: February 23, 2010, 03:52:24 PM »
Hmmm... Not really knowing the dynamics of how a gas piston gun gets it's power here. But would spinning off a millimeter or 2 from the piston adaptor and the retaining block add a bit more stroke? Pretty much setting the whole ram assembly back further in the tube. Possibly giving it a bit more power? Not that it doesn't have enough already though  :)

Also would taking a bit off the piston to make it lighter, lighten the recoil and lessen the hold sensitivity?



Offline chuckster750800

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RE: Under The Hood Of A Crosman NPSS
« Reply #7 on: February 24, 2010, 01:51:18 AM »
Great write up Gene. I always wondered what the inside of my NPSS looked like but I'm chicken to take it apart. I bought the CBR trigger from Charlie Da Tuna and I think it's a big improvment.  I have a question for ya?  After cocking mine the barrel will not stay at a 45 degree angle, it moves up and down freeley with no resistance at all. Do ya think I can tighten the pivot bolt or does it just have shims in there to take up side play. I did try to tighten it, but that bolt would not budge and I was affraid to force it. Thanks again for the great write up.

Charlie,

Offline Gene_SC

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Re: Under The Hood Of A Crosman NPSS
« Reply #8 on: February 24, 2010, 03:10:51 AM »
Chuck, yes you can tighten the screw. Just make sure you have a good fitting screw driver. Make sure that you can see some lube around the breech barrel pivot. Generally there are thrust washers in there with a bushing.
THE ONES I SLEEP WITH: BSA Lightning XL, AA TX-200, AA ProSport, BSA Ultra, HW-97K, Crosman NPSS .177, FX Cyclone, HW-30 Nicle Plated, AA-S200, Crosman Marauder, CZ-634, R-9 DG, Webley/Scott UK Tomahawk, Benji Kantana, Benji Marauder, Benji Discovery.....
....

Gene\'s Tunz n Toyz
Springer Tunin

Offline mvhunter

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Re: Under The Hood Of A Crosman NPSS
« Reply #9 on: February 24, 2010, 10:49:41 AM »
great read.  lots of good info.  thanx.. i was wondering if you new how loud it is compared to the whisper
whisper 22. gas ram
850 magnum 22.
Mrod 22.
Crosman 2300S

Offline Gene_SC

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Re: Under The Hood Of A Crosman NPSS
« Reply #10 on: February 24, 2010, 12:02:09 PM »
I would say a tad less. I do not own my Whisper any longer but they are close as far as noise goes. My hearing is not that good anymore but maybe someone chime in on this and can give you true noise comparison.
THE ONES I SLEEP WITH: BSA Lightning XL, AA TX-200, AA ProSport, BSA Ultra, HW-97K, Crosman NPSS .177, FX Cyclone, HW-30 Nicle Plated, AA-S200, Crosman Marauder, CZ-634, R-9 DG, Webley/Scott UK Tomahawk, Benji Kantana, Benji Marauder, Benji Discovery.....
....

Gene\'s Tunz n Toyz
Springer Tunin

Offline mackeralboy

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Re: Under The Hood Of A Crosman NPSS
« Reply #11 on: February 25, 2010, 01:42:20 AM »
I would agree with Gene and say the my NPSS is quieter than my Whisper.
Air Arms Prosport .22 cal
Beeman SS1000H .22 cal
Beeman P1 .20 cal
Benjamin Discovery .22 cal
BSA Lightning Tactical XL .22 cal
Crosman 1377 converted to .22 cal by Tim McMurry
Crosman Quest 800X .22 cal
Crosman Nitro .22 cal
Gamo 1250 .177 cal
Gamo 1250 .22 cal
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Theoben Eliminator .25 cal
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Offline magothy

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Re: Under The Hood Of A Crosman NPSS
« Reply #12 on: March 01, 2010, 11:55:54 AM »
Right interesting read, thanks for the in depth look at the gun.  I have almost 500 rounds thru mine, it's shooting well, way better than me.  I had an itch to shoot on a rainy day so I set up the 24' range in my shop and had a few groups of three that I was able to almost stack from a rest. It's a good in town gun as far as noise goes.  Seems to like the RWS Super-H-Points, they do well on the tree rats.  Again, thanks for the interesting review.

Offline CaptZippy

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Re: Under The Hood Of A Crosman NPSS
« Reply #13 on: March 16, 2010, 01:20:37 AM »
Gene...!   I need to tell ya, you're posts are fantastic!  I bookmarked this one and several others....Motivated me to take apart my Nitro to Lube Tune...and I'm so glad I did.  I felt an occasional 'grinding' when cocking before I took her apart and de-bured and lubed.  Now after de-buring and lubing per Charlie Da-Tuna's guidance in the Library, it cocks and shoots as smooth as silk.  Most of the parts were already de-burred as you indicated, but the cocking slot on mine was really rough.  Without your detailed review and insights, I probably wouldn't have taken her down to investigate.  Just thankful for your inquisitive personality, detailed work, and reporting here on GTA.  My Nitro is much better because of you.  I would post pictures, but I don't have any because  my hands were covered in Moly... I'll learn how to better control the mess next time so I can take some pictures.  Thanks for everything!!! Semper Fi Tom
If you\'re going to be a bear...be a Grizzly Bear

Offline Gene_SC

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Re: Under The Hood Of A Crosman NPSS
« Reply #14 on: March 16, 2010, 02:38:51 AM »
Well Tom I am glad the post gave you the rocks to pull your baby down and fix her up..:)  I should mention that the gas ram rifles are much easier to work on than your conventional springer. I have learned allot myself here on the GTA in the past three years. Many of us feel the same way. Bob and I really want to help the new air gunners the best we can and with the additional knowledge of the rest of the family we all can share our thoughts and ideas with others. Best of luck.
THE ONES I SLEEP WITH: BSA Lightning XL, AA TX-200, AA ProSport, BSA Ultra, HW-97K, Crosman NPSS .177, FX Cyclone, HW-30 Nicle Plated, AA-S200, Crosman Marauder, CZ-634, R-9 DG, Webley/Scott UK Tomahawk, Benji Kantana, Benji Marauder, Benji Discovery.....
....

Gene\'s Tunz n Toyz
Springer Tunin