Umarex Notos CRK Review

[Squirrelhunter2002]

New Handguard for the Umarex Notos designed by Bravo3d. 7 Mlok slots with one on the bottom. Quick and easy install. Its a one peace design so you just heat it up with a blow dryer and slide it over the tube.
If you would like to pick one up or learn more please check out www.bravo3d.com

[kbstingwing]

Cool 

[bronzehammerhead]

Be warned, the grub screw under the hex head screw that holds the picatinny rail is complete carp! You will want to pull it out and replace it ASAP. I was able to reassemble the Notos but just a few pounds of torque rounded out the hex cup.

New member here. I found this forum after searching online for how to set up my new Notos. Firewalker, you have provided a tremendous service for everyone. I am appreciative of the time you have spent sharing your knowledge.

This is not the first time that I've heard bad things about the grub screw that holds the barrel assembly in. It's pretty clear that it's pot metal trash.

Any idea on where to get a quality replacement grub screw? Or at least the length/diameter/thread pitch so I can start looking?

[2A Georgia]

Be warned, the grub screw under the hex head screw that holds the picatinny rail is complete carp! You will want to pull it out and replace it ASAP. I was able to reassemble the Notos but just a few pounds of torque rounded out the hex cup.

New member here. I found this forum after searching online for how to set up my new Notos. Firewalker, you have provided a tremendous service for everyone. I am appreciative of the time you have spent sharing your knowledge.

This is not the first time that I've heard bad things about the grub screw that holds the barrel assembly in. It's pretty clear that it's pot metal trash.

Any idea on where to get a quality replacement grub screw? Or at least the length/diameter/thread pitch so I can start looking?

Really pleased with these guys
https://monsterbolts.com/
You'll need to know you size and pitch and such and probably order a 10 or 25 pack...good quality bolts IMHO

[bronzehammerhead]

Thanks for the reply. Truly appreciated. Will order from those guys when I figure out the size and thread pitch.

[shaky2]

M3 x 10mm is what you want for trigger adjustment...For the barrel grub screw its M4 x 4mm

[2A Georgia]

Be warned, the grub screw under the hex head screw that holds the picatinny rail is complete carp! You will want to pull it out and replace it ASAP. I was able to reassemble the Notos but just a few pounds of torque rounded out the hex cup.

New member here. I found this forum after searching online for how to set up my new Notos. Firewalker, you have provided a tremendous service for everyone. I am appreciative of the time you have spent sharing your knowledge.

This is not the first time that I've heard bad things about the grub screw that holds the barrel assembly in. It's pretty clear that it's pot metal trash.

Any idea on where to get a quality replacement grub screw? Or at least the length/diameter/thread pitch so I can start looking?

After swearing I would plug and play (no mods) the Notos, I took it apart to slug the barrel and am in the tedious process of trying to clock the barrel.  Going to order some quality M4x4 grub screws and does anyone know the size of the two barrel o-rings?  This transfer portless TP is driving me nuts not lining up.  As much of a PITA getting the barrel back on is, I might as well stuff the plenum kit on whilst I have my no mods AG in pieces.....argh

[TorqueMaster]

I haven't dug in that deep personally, but my research on them shows:

transfer port oring size SPA 0.8 x 10.2 (0.031" x 0.402" x 0.465 OD = almost exactly  1/32 x 13/32 x 15/32)
also have been used:
1.0 x 9.0
1.0 x 10.0 turned on lathe

[elguapo99]

I ordered the barrel o-rings from Aliexpress in the 0.8 x 10.2 size and they fit perfectly. It was the only place that I could find that size. https://www.aliexpress.us/item/3256802493229253.html?spm=a2g0o.order_detail.order_detail_item.3.4019f19chKsPXX&gatewayAdapt=glo2usa

[2A Georgia]

Thanks for the link!
O-rings ordered

[2A Georgia]

M4 grub screw, barrel/TP area o-rings and plenum kit ordered.
Time to start disassembly....
Questions for those who have gone before me;
Does anyone know the length of the factory exhaust valve stem (considering TR Robb again like my pp800r build)?
Anyone going loud-n-proud with no shroud or moderator after the plenum swap?  I hunt and have started to work 25yards at the LGR so may not need BY friendly...
Here are my options for post plenum moderator no particular order but love to hear opinions experiences
1. Loud-n-proud.  Cover the 1/2UNF threads and rock on dude :-)
2. $35 Buck Rail moderator.  Same size/shape but concerned about the Neanderthal and 3D parts...
3. Pay the gentleman who had free moderators his fair price.  I'm sure the performance is wonderful, same concerns for hunting durability....
4. DonnyFL Tanto $99 smaller diameter 1.25" shorter and machined from solid metal....might survive Neanderthal use.....
5. DonnyFL Tatsu $130 slightly larger diameter and 2" shorter...could be nice for stomping through brush.....

Looking forward to strong opinions/experiences....

[bronzehammerhead]

M3 x 10mm is what you want for trigger adjustment...For the barrel grub screw its M4 x 4mm

Shaky, thanks much for the info. Just ordered them up.

I still haven't shot mine yet.

I've been waiting to clean and possibly polish the bore (I know that some say that this is overkill. I know that when doing this, a lot of people take substantial steps to protect the crown of the barrel. The most common way I've seen this done with other guns is by removing the barrel, putting the crown against a block of wood, and working from the breech end. Obviously, that can't be done here because of the non-removable moderator.

Does anyone know the exact distance from the crown to the end of the moderator?

If anyone had advice on how to do the clean/polish, I would be appreciative. Do I remove the barrel? Or just work from the moderator end? Also, any advice with regard to how to do this would be appreciated.

[avator]

I don't know why but for some reason I checked the muzzle end of my NOTOS and noticed the barrel was loose. It twisted freely about 1/8" in either direction. I took the screw out of the picca rail and got to the allen screw under it. Sure enough, it was loose.
That is strange because I've never had the barrel off of this gun. I just never noticed it being loose before. I wiggled the barrel as I tightened the grub screw to center the barrel as I tightened it. Once tight there was no more movement in the barrel.
I checked and accuracy was not affected.
Just strange to me.

[2A Georgia]

I don't know why but for some reason I checked the muzzle end of my NOTOS and noticed the barrel was loose. It twisted freely about 1/8" in either direction. I took the screw out of the picca rail and got to the allen screw under it. Sure enough, it was loose.
That is strange because I've never had the barrel off of this gun. I just never noticed it being loose before. I wiggled the barrel as I tightened the grub screw to center the barrel as I tightened it. Once tight there was no more movement in the barrel.
I checked and accuracy was not affected.
Just strange to me.

When I slugged my barrel I had a devil of a time clocking the barrel and it wouldn't seal.  I have a 10 pack of o-rings so if you need me to stick 2 (or 4) in the mail just DM me.

[avator]

I don't know why but for some reason I checked the muzzle end of my NOTOS and noticed the barrel was loose. It twisted freely about 1/8" in either direction. I took the screw out of the picca rail and got to the allen screw under it. Sure enough, it was loose.
That is strange because I've never had the barrel off of this gun. I just never noticed it being loose before. I wiggled the barrel as I tightened the grub screw to center the barrel as I tightened it. Once tight there was no more movement in the barrel.
I checked and accuracy was not affected.
Just strange to me.

When I slugged my barrel I had a devil of a time clocking the barrel and it wouldn't seal.  I have a 10 pack of o-rings so if you need me to stick 2 (or 4) in the mail just DM me.

Thanks but I don't think it's leaking. I plan to shoot it some more today so I'll have a closer look.

[Martin_T]

The images below show my best effort at extended inserts (similar to what Dave tested) designed to fit the unmodified Notos "can". 

I scaled the retention pin positions from the images in this thread, and applied a human trait:  When there is no clear reason to choose fractional dimensions, most designers default to full units.  So, the pin to pin spacing seems to land 8 mm away from the centerline, and thus 16 mm center to center, placed in the 32 mm OD casing.  I did something similar for the pin placement from the casing shoulder.

You may need to sand down the rings I added to the insert OD to ensure it is not loose in the casing.  The rings are 0.002" taller than the surrounding OD, so not very aggressive.

The pin holes should print close to 2 mm in diameter.  You may need to chase them, but decide that after fitting the insert OD to the casing ID.

The STL print files are attached, below.  One for the long snout version; the other for the short snout. 

Both inserts will have a cavity ahead of them that Umarex designed as primary expansion chamber, ahead of the muzzle.  The difference between the inserts is how far the pellet has to travel in that primary chamber before it is shielded from turbulence by the first air stripper.  Will there be any meaningful grouping ability difference between the two versions?  I hope someone prints either or both to find out.

This may be my last contribution on this topic for 5 weeks.  I am going walkabout in the Southern hemisphere, imminently.  I need to do my taxes and a few other things before I am ready.

As I recently got me a Notos as well, (been eyeing it on and off for the last 6 months, and when Ted endorsed it, I finally gave in!) I found this thread in my search for info on mods on the Notos. So I want to thank both Firewalker and especially Subscriber for the awesome work done, and making it freely available for the Notos owners!

So I printed me a long snout moderator, and it works super! The only drawback is that the gun is now slightly longer, but there's no free lunch...

I always test all my moderators with a digital sound pressure meter, and measure on a 45 degree angle from the bore/moderator end at a distance of 1 meter (3.3 ft)

This got me the following data: (std unmodded Notos, doing 232mps/761fps with Crossman Hollow Point:)

Without the red OEM factory insert        113.7 dB
With the red OEM insert:               avg.  100.5 dB  (7 shots measured, low 99.9 high 101.3)
With Subcribers Longsnout insert: avg.   96.1 dB  (7 shots measured, low 95.3 high 96.9)
Measured at 10cm from my ear:              90.6 dB

A tremendous reduction in sound pressure! But 90 dB at the ear is potentially still quite damaging... (it doesn't SOUND damaging at all though...) Unfortunately I did not get the "quieter than a fingersnap" result that Firewalker got, in order to get that magnitude of sound pressure reduction I guess we would need to resort to a really large can (big soda bottle size type).

There is this gentleman offering a 3D print called a "deciball" online, and he claims a 15dB reduction in sound. But this thingy is suspicously small, (and unsightly looking) so I think the number is a comparison from using no factory insert at all and his design. Which would make it just about as good as the factory insert. (it could change the pitch so it could be perceived as being quieter). I do not believe the claimed 15 dB reduction is the difference between the factory insert and his. (thay would be miraculous for such a small volume) There are not many user reviews, and the ones that are are not very conclusive, other than that it does work at least some.

So to get the Notos noticeably queter than out of the box, I fully endorse Subscribers moderator, a measured 4 dB reduction from the stock Notos!

Thank you again Subscriber for making your work public! 

[tennx]

I have one of the mentioned inserts and I agree there is some reduction..I did buy the machined kit that allowed for 1/2x20 moderator….but decided I didnt want to tackle removing the factory set up…most all my guns have some sort of moderator…but its now a mute point as I dont worry about the neighbors anymore…lol…like most I really like this gun…but its long since quit being light ……good luck

[smythsg]

M4 grub screw, barrel/TP area o-rings and plenum kit ordered.
Time to start disassembly....
Questions for those who have gone before me;
Does anyone know the length of the factory exhaust valve stem (considering TR Robb again like my pp800r build)?
Anyone going loud-n-proud with no shroud or moderator after the plenum swap?  I hunt and have started to work 25yards at the LGR so may not need BY friendly...
Here are my options for post plenum moderator no particular order but love to hear opinions experiences
1. Loud-n-proud.  Cover the 1/2UNF threads and rock on dude :-)
2. $35 Buck Rail moderator.  Same size/shape but concerned about the Neanderthal and 3D parts...
3. Pay the gentleman who had free moderators his fair price.  I'm sure the performance is wonderful, same concerns for hunting durability....
4. DonnyFL Tanto $99 smaller diameter 1.25" shorter and machined from solid metal....might survive Neanderthal use.....
5. DonnyFL Tatsu $130 slightly larger diameter and 2" shorter...could be nice for stomping through brush.....

Looking forward to strong opinions/experiences....

Charles, as you know I have a Donny FL Tanto on my Escape UL and it has served me well over a couple or three years now. It has held up to all the thick brush hunts I have been doing. 

[2A Georgia]

M4 grub screw, barrel/TP area o-rings and plenum kit ordered.
Time to start disassembly....
Questions for those who have gone before me;
Does anyone know the length of the factory exhaust valve stem (considering TR Robb again like my pp800r build)?
Anyone going loud-n-proud with no shroud or moderator after the plenum swap?  I hunt and have started to work 25yards at the LGR so may not need BY friendly...
Here are my options for post plenum moderator no particular order but love to hear opinions experiences
1. Loud-n-proud.  Cover the 1/2UNF threads and rock on dude :-)
2. $35 Buck Rail moderator.  Same size/shape but concerned about the Neanderthal and 3D parts...
3. Pay the gentleman who had free moderators his fair price.  I'm sure the performance is wonderful, same concerns for hunting durability....
4. DonnyFL Tanto $99 smaller diameter 1.25" shorter and machined from solid metal....might survive Neanderthal use.....
5. DonnyFL Tatsu $130 slightly larger diameter and 2" shorter...could be nice for stomping through brush.....

Looking forward to strong opinions/experiences....

Charles, as you know I have a Donny FL Tanto on my Escape UL and it has served me well over a couple or three years now. It has held up to all the thick brush hunts I have been doing. 

Pretty much what I theorized.  I've been in thick brush with you and our micro-machetes.  Tanto will get purchased before August.  It's almost gonna be unfair to have Notos accuracy and subsonic suppressed tree rat headache medicine....

[2A Georgia]

BTW Steve, next woods walk I'll bring you some 19.4gr NOE Hunters and some Monster 35gr MPmolds 5.55mm slugs.  My Notos actually grouped the 35gr slugs better than the NOEs but of course about an inch lower at 15 yards.  Kinda makes the Notos a psuedo-mortar cannon