Tuning Umarex Notos has arrived.
- Thread starter pnwairgunner
- Start date
If you drill out the hammer and remove 3mm of material you can get fps ranging 550-800fps depending on the pellet. A 3/8 endmill fits perfect for the hammer slot/hole
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I detuned one Notos to the 460-490FPS range with CPHP.
I have detuned another Notos to about 600 FPS.
I am sure I could have gone even lower if I wanted to.
I did not touch the regulator which comes at about 2000PSI from the factory.
I only used a weaker spring purchased from Aliexpress: https://www.aliexpress.us/item/2255800219014836.html
I bought the spring with 9mm OD, 1.2mm wire, 100mm length.
I cut the spring and ended up to about 4.8mm-5.5mm length.
You need a chrony to know when to stop cutting.
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Back in post 848, I mentioned a charging lever handle meant for another gun.
I finally got one & attached it with 2 small screws. Clears the mag. Swings out no further than the end of the lever. Simple mod.
I finally got one & attached it with 2 small screws. Clears the mag. Swings out no further than the end of the lever. Simple mod.
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Nice job. I was thinking of something similar. I've never used the lever does it make loading faster.
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The link seems to show it has 1 center hole.....did you drill and tap 2 holes in the aftermarket part?
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Yes, yes & no. I drilled 2 pilot holes through the Notos lever and into the handle's plastic spacer block. Then, countersunk reliefs into the back of the Notos lever so the screw's heads could fit flush. The holes were drilled diagonally above & below the center hole, so as to not weaken the metal Notos lever.
I used screws with more aggressive threads to better grip into plastic. They self-tapped into the plastic spacer.
The center threaded hole and its supplied setscrew are for securing the handle onto an Air Arms rifle lever that it was intended for.
I used screws with more aggressive threads to better grip into plastic. They self-tapped into the plastic spacer.
The center threaded hole and its supplied setscrew are for securing the handle onto an Air Arms rifle lever that it was intended for.
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I hope this helps anyone looking for some spring information. I revisited the hammer spring that I replaced originally from a softer 1.0mm wire diameter to a stiffer 1.2mm x 9mm OD x 50mm spring along with a Tamiya 5x9mm bushing as a spacer and turned the adjuster 3 turns in from flush. If I were to back the screw out flush, there is a small amount of free flight. At 3 turns in there is preload for some wiggle room. It’s putting out Norma GTFT 17.6g at around 640 fps for about 35 shots before it encounters the off-reg bell. Additionally, I did a 5 pellet string with CPHP and those were 699-700 fps.
Attached is the string with the Norma pellets.
And here is the link to the spring.
*Edit #2: Uploaded a revised chart with FPE graph removed because it’s basically the same curve as FPS. Also had to change the weight to 17.6g from the incorrect 17.1g oops.
Attached is the string with the Norma pellets.
And here is the link to the spring.
*Edit #2: Uploaded a revised chart with FPE graph removed because it’s basically the same curve as FPS. Also had to change the weight to 17.6g from the incorrect 17.1g oops.
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While I wait for a barrel from @Firewalker i took the time to put all the pieces together I have. Plenum and complete buck rail kit.
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I have just tuned one of my Notos with the Norma 17.6 pellets too.
Like you, I get 5 magazines but in the 680-685 FPS range (about 18 FPE).
I start right under 4000 PSI (slight overfill) and go down to the 2000 PSI (factory regulator setting).
I have posted the Aliexpress spring I have been using in many posts so far, just search for it.
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Its cool but that grip fitment on those lowers is real bad.
I hope BR starts making a longer rail option. Seems the plenum is standard procedure for the Notos at this point.
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Those 17.6g Normas are pretty decent. For whatever reason my particular Notos doesn’t like the 15.9g…at all lol.
I opted for the pre-cut lengths because I prefer coil ends to be squared or squared-ground for consistency and reduced chance of buckling (messed with a lot of springs in my rc car racing days).
I just put the softer 1.0 x 9mm x 50 spring with 10mm of spacers back in a will do a string with that and post the raw data.
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I made a blunder removing the factory moderator. I figured the barrel was more sturdy than it was. I cut it with a rotary tool on a vice. I was trying to set it free with a little arm torque and some channel pliers. I ended up bending the barrel. I reached out to @Firewalker and he had one he could sell me and took my barrel. He has a project in mind for it.
Lesson #1: Take your time.
Lesson #2: The Notos barrel can bend pretty easy, I'm not a gym guy.
Lesson #1: Take your time.
Lesson #2: The Notos barrel can bend pretty easy, I'm not a gym guy.
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I forgot to mention that with the setup above my Notos became quite accurate, enough to consistently hit my 1.6" spinners at 50-55 yards.
Previously with CPHP I almost never hit those spinners.
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Here is the data using a 1.0mm x 9.0mm OD x 50mm length spring with 10mm worth of spacers and adjustment screw half a turn counterclockwise from bottomed out.
Started at 3600 psi and stopped 65 pellets later after it dropped off the reg, climbed, then matched starting velocity. Trigger weight, bolt handle effort, and report were noticeably reduced. Feels like a mellow setup.
Link to short soft spring
Started at 3600 psi and stopped 65 pellets later after it dropped off the reg, climbed, then matched starting velocity. Trigger weight, bolt handle effort, and report were noticeably reduced. Feels like a mellow setup.
Link to short soft spring
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I was always amazed at how many consistent shots, a detuned/lower powered Notos can give you.
I am not aware of any other air gun in this (less than $300) price range that can do that.
Detuned, the Notos is the perfect plinker.
The velocity spike when it falls off the regulator is documented in several places, like this one: https://hardairmagazine.com/ham-columns/tuning-regulated-pcp-airguns
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