Umarex Notos Moderator is loose

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Geezerhood

Geezerhood

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Aug 16, 2022
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Southern, Utah, USA
I am now on my 4th Notos - Two for me and two for family members. I noticed that on one of them the moderator will rotate fairly easily but only very slightly in both directions with a firm stop at each end of the travel. Maybe a total of about 3 degrees? What could be causing that?

I haven't shot it yet but it doesn't seem to be loose as far as bore alignment goes, just that strange circular movement.

All the others did not show any movement of the moderator. So far they all like CPHPs and H&N FTTs, outshooting several of my airguns that I paid a LOT more $$ for.
 
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Sqwirl57 said:
Is there a set screw that maybe loosened up a smidge?
Click to expand...

Not that I am aware of and nothing is visible. The guts are held in the outer moderator tube by two pins near the muzzle. I don't know how the tube is held on to the shroud / rail on the gun. I am looking for some videos / instructions on how to remove the moderator, but haven't found one yet.
 
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That happened to me
It's the whole barrel inside the housing moving because the barrel grub screw is loose.
Remove the allen head bolt in the pic rail and tighten the smaller allen hidden underneath.

Edited to add - moderator can only be removed in a destructive manner, jerks molded it on there
And PP750 videos are a good reference for the rest of the gun
 
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Geezerhood said:
Not that I am aware of and nothing is visible. The guts are held in the outer moderator tube by two pins near the muzzle. I don't know how the tube is held on to the shroud / rail on the gun. I am looking for some videos / instructions on how to remove the moderator, but haven't found one yet.
Click to expand...

NOT pins, C-clips.

Lathe, then thread the barrel. Message me if you want me to do the work for you.
 
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When I took mine apart, I found the barrel grub screw loose also. I could see that the barrel had been slightly moving, and the transfer port orings were both damaged. Wondering if this could have caused my accuracy problems from the beginning. I’ll know for sure when my parts come in. I’ll replace the orings, install a second grub screw for the barrel (there’s already a threaded hole in the action for it), cinch then nice and tight with a drop of blue picture, and test again. All after polishing the barrel of course.
 
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Firewalker said:
NOT pins, C-clips.

Lathe, then thread the barrel. Message me if you want me to do the work for you.
Click to expand...

Thanks for the offer. At the present I am OK with the stock moderator. I was just trying to figure out how to fix the rotating moderator which turned out to be a rotating barrel. My understanding is that the pins hold the front plate of the moderator in place, which is what I was referring to.

madeintheuk said:
When I took mine apart, I found the barrel grub screw loose also. I could see that the barrel had been slightly moving, and the transfer port orings were both damaged. Wondering if this could have caused my accuracy problems from the beginning. I’ll know for sure when my parts come in. I’ll replace the orings, install a second grub screw for the barrel (there’s already a threaded hole in the action for it), cinch then nice and tight with a drop of blue picture, and test again. All after polishing the barrel of course.
Click to expand...

Good to know about the 2nd threaded hole. I will be adding an additional set screw there as well. Thanks!

One thing that I think is needed on the breech is a more rounded feed area into the chamber an possibly a bit wider of a chamfer. All 4 of mine have a very sharp corner that sometimes catches the nose of pellets when chambering.
 
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madeintheuk said:
When I took mine apart, I found the barrel grub screw loose also. I could see that the barrel had been slightly moving, and the transfer port orings were both damaged. Wondering if this could have caused my accuracy problems from the beginning. I’ll know for sure when my parts come in. I’ll replace the orings, install a second grub screw for the barrel (there’s already a threaded hole in the action for it), cinch then nice and tight with a drop of blue picture, and test again. All after polishing the barrel of course.
Click to expand...

You will need to drill an access hole on the shroud / Picatinny rail to be able to access the additional threaded hole for a 2nd barrel retaining grub screw. Should be easy enough. It could be countersunk like the existing one, adding another round headed screw to beef up the connection of the pic rail to the receiver. Or, if you wanted to ditch the shroud assembly, you could chop the Pic rail off and add the second mounting hole.

I am guessing that the shroud doesn't really contribute to accuracy since it has a fairly loose fit overall. A short section of Picatinny rail could be screwed down to the receiver using those same two holes like it currently is held in place with one screw, eliminating the shroud / rail if desired. I have some extra Pic rail pieces laying about, so I might give it a try some day. There is an 11mm rail under the shroud connecting area that would accept a dovetail to picatinny adapter if you could find one that just happened to be the same height as the rear one. (unlikely).
 
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Geezerhood said:
You will need to drill an access hole on the shroud / Picatinny rail to be able to access the additional threaded hole for a 2nd barrel retaining grub screw. Should be easy enough. It could be countersunk like the existing one, adding another round headed screw to beef up the connection of the pic rail to the receiver. Or, if you wanted to ditch the shroud assembly, you could chop the Pic rail off and add the second mounting hole.

I am guessing that the shroud doesn't really contribute to accuracy since it has a fairly loose fit overall. A short section of Picatinny rail could be screwed down to the receiver using those same two holes like it currently is held in place with one screw, eliminating the shroud / rail if desired. I have some extra Pic rail pieces laying about, so I might give it a try some day. There is an 11mm rail under the shroud connecting area that would accept a dovetail to picatinny adapter if you could find one that just happened to be the same height as the rear one. (unlikely).
Click to expand...
The shroud isn’t in the way at all. You would need to remove the top pic rail to access, which is easy now I cut off the factory mod. Now it will slide off after removal of the screw on top. Then both barrel screws would be accessible. Any extra screws on the barrel are worthwhile, especially bc the factory screw is a very small grub screw.
 
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madeintheuk said:
The shroud isn’t in the way at all. You would need to remove the top pic rail to access, which is easy now I cut off the factory mod. Now it will slide off after removal of the screw on top. Then both barrel screws would be accessible. Any extra screws on the barrel are worthwhile, especially bc the factory screw is a very small grub screw.
Click to expand...

I agree on the benefit of the extra screw. Poor choice of words on my part - by "you" I meant "I" or anyone who like me has no plans to remove the factory moderator.

One of the biggest positives for me on the Notos is that it shoots extremely well out of the box with inexpensive pellets (CPHP and H&N FTT) and I don't need to buy another moderator or really anything else for it other than some sights or a scope and rings. I don't think I will be making any changes to the 3 stock guns we have other than adding that extra setscrew and a hole in the pic rail to access it, sling studs and a place to store the allen key so I can remove the single screw holding the stock on the grip for carrying the gun in a backpack.
 
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Geezerhood said:
I agree on the benefit of the extra screw. Poor choice of words on my part - by "you" I meant "I" or anyone who like me has no plans to remove the factory moderator.

One of the biggest positives for me on the Notos is that it shoots extremely well out of the box with inexpensive pellets (CPHP and H&N FTT) and I don't need to buy another moderator or really anything else for it other than some sights or a scope and rings. I don't think I will be making any changes to the 3 stock guns we have other than adding that extra setscrew and a hole in the pic rail to access it, sling studs and a place to store the allen key so I can remove the single screw holding the stock on the grip for carrying the gun in a backpack.
Click to expand...
I’m glad yours shoots well. If mine did, I would have left it alone. I was getting terrible accuracy at 35yds with cphp. I bought the gun specifically for these, to shoot low power at rats and such. I was not impressed with the accuracy, so for the price, instead of returning it, I decided to play. This will include removal of mod, polish of barrel, adjustment of power, polish of trigger and hammer components, and a kit I found on eBay with a mod adapter and power plenum. We’ll see how it does.
I have high hopes. It’s a very nice to hold and shoulder platform, and I actually enjoy the left hand cocking.
 
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