Umarex notos -Longer barrel, less speed?

[Luckyfro15]

Bone stock Notos and as my first mod I did the FX 500mm barrel kit. I chose the superior heavy liner as I plan to mainly shoot slugs. I haven't touched anything else but the barrel swap.

So I was shooting 15.4 gamo pellets @740ish and 23gr NSA slugs @ 650ish. After the 500mm kit I lost quite a bit of speed. The 15.4s are 660ish now and the 23gr are 550ish.

Any one have an idea as to why? More curious as to understanding why the loss in speed.

I plan to fully port and big bottle/reg swap too along with custom spring and hammer stuff too at a later point. So I know I'll pick up speed at a later point.

 

[nervoustrig]

I haven't touched anything else but the barrel swap.

Assuming it was adjusted for reasonably efficient use of air with the short barrel, it will need more hammer strike to produce more valve dwell to take advantage of the longer runway.

 

[Rizz01]

You are running out of air before the pellet leaves the barrel. The Notos is VERY low on power. Most folks actually start off with a bottle/plenum mod first to get a decent shot count and velocity.
Look up a member here named Firewalker. He offers help and will mod your Notos if you ship it to him (for a fee, of course). He's a good guy and knows the Notos inside and out.
Good luck!

 

[Luckyfro15]

You are running out of air before the pellet leaves the barrel. The Notos is VERY low on power. Most folks actually start off with a bottle/plenum mod first to get a decent shot count and velocity.
Look up a member here named Firewalker. He offers help and will mod your Notos if you ship it to him (for a fee, of course). He's a good guy and knows the Notos inside and out.
Good luck!

Yeah that's kinda what I was thinking but wasn't sure on how to remedy it. This is my first regulated gun other then an inline reg on a big bottle. And yeah I got eager and pre-ordered slugs when I ordered the gun and the 23gr did not like the stock barrel at all so did the 500mm kit to get the slugs to fly right. Good news tho I guess, the 23s are same hole at 30 going this slow.

 

[Rizz01]

The stock barrel is actually pretty good.
It's a 1:22 twist which makes it so accurate with 18.1 gn pellets or less. But, due to the low power It's appreciable range is about 40-50 yds max. I don't shoot it much because it's so underpowered and my desire is to shoot farther.
Firewalker actually has a Notos "tricked out" with a 500mm barrel and power upgrades shooting at around 900 fps. Since I mentioned him, he will most likely respond to this thread today.

 

[Firewalker]

You are running out of air before the pellet leaves the barrel. The Notos is VERY low on power. Most folks actually start off with a bottle/plenum mod first to get a decent shot count and velocity.
Look up a member here named Firewalker. He offers help and will mod your Notos if you ship it to him (for a fee, of course). He's a good guy and knows the Notos inside and out.
Good luck!

That's me!

I've been working with c88machining to develop his kits to be as efficient as possible but with a stock Notos, you don't have enough air being released to overcome friction, thus you get slower speeds.

Herd is my kitted out 700mm FX barreled, fully ported Notos, shooting 14.39gr at 1050fps.

 

[Luckyfro15]

That's me!

I've been working with c88machining to develop his kits to be as efficient as possible but with a stock Notos, you don't have enough air being released to overcome friction, thus you get slower speeds.

Herd is my kitted out 700mm FX barreled, fully ported Notos, shooting 14.39gr at 1050fps.

View attachment 480678

Yeah i was wanting to try the 700mm or even an 800mm based off his kit but after thinking it over I'll just do alil bit to this one.

So what kind of mods are you doing for the hammer and springs?

 

[Rizz01]

That's me!

I've been working with c88machining to develop his kits to be as efficient as possible but with a stock Notos, you don't have enough air being released to overcome friction, thus you get slower speeds.

Herd is my kitted out 700mm FX barreled, fully ported Notos, shooting 14.39gr at 1050fps.

View attachment 480678

When I get around to it I may do some mods to mine. Currently trying to save up for a new .25 cal gun. Sent the Rainson I recently got back since it was just awful. Pretty sure I'm going with Daystate.

 

[Star7]

How stiff is the barrel mounting in the NOTOS? I would think that a long barrel would start inducing flex.

 

[Luckyfro15]

When I get around to it I may do some mods to mine. Currently trying to save up for a new .25 cal gun. Sent the Rainson I recently got back since it was just awful. Pretty sure I'm going with Daystate.

I've been saving for the 35 FX dynamic. Needing a doe management airgun. Picked up the Notos for a small neighborhood airgun but can't resist the itch to mod these things. So here I am....

 

[Luckyfro15]

How stiff is the barrel mounting in the NOTOS? I would think that a long barrel would start inducing flex.

I have the kit by c88 n it uses a carbon fiber tube that goes over the barrel housing. The way it works it seems to act like a barrel tensioner so I don't think it'll flex too much. 500mm doesn't seem to move anyways

 

[Firewalker]

Yeah i was wanting to try the 700mm or even an 800mm based off his kit but after thinking it over I'll just do alil bit to this one.

So what kind of mods are you doing for the hammer and springs?

Frightening that you can ready mind!

I'm evaluating springs and slip-in weights next week.

The 700mm kit is for sale if you're looking. It's 1 MOA.

 

[sb327]

I have the kit by c88 n it uses a carbon fiber tube that goes over the barrel housing. The way it works it seems to act like a barrel tensioner so I don't think it'll flex too much. 500mm doesn't seem to move anyways

Does it pull tension against the single grub screw? That’s not really ideal if that’s the case, of course a single grub screw is not really ideal in any application, imo.

Dave

 

[Stubbers]

If its possible, increasing hammer travel may work in itself over increased hammer weight/spring, but that is a big if and would need someone familiar with the notos to confirm if there is room for such a modification. Quite a few ways to skin that cat too.

After that I'd consider a peek poppet with .02" sealing margin over the stock poppet to crack the valve open easier.

Then if it needed more hammer weight/spring I'd consider, these are just my opinions/inputs as to keep the guns action more tame.

-Matt

 

[sb327]

@Stubbers,

It’s has a really strong valve spring, angled poppet seat, and a relatively large stem. It’s a great design for short barrels (short dwell) but needs some tweaking for the longer barrels. That’s part of the reason I went to my own valve design (simple flat peek poppet with smaller stem). I haven’t changed the valve spring…yet.

Dave

 

[Luckyfro15]

Frightening that you can ready mind!

I'm evaluating springs and slip-in weights next week.

The 700mm kit is for sale if you're looking. It's 1 MOA.

Eh idk about it. Lol if I go beyond this 500mm I'll prolly jump straight to the 800mm. I just can't find it in just the liner yet. All that's available are in a barrel swap kit. So instead of $100 it's $400 . May just have to wait it out and see what becomes available. Also trying to save up for that Dynamic

So I was think of doing a tungsten hammer. I had one made for my 457 texan way back before covid. And then playing with some springs. Just curious as to what's been done before....

 

[Luckyfro15]

@Stubbers,

It’s has a really strong valve spring, angled poppet seat, and a relatively large stem. It’s a great design for short barrels (short dwell) but needs some tweaking for the longer barrels. That’s part of the reason I went to my own valve design (simple flat peek poppet with smaller stem). I haven’t changed the valve spring…yet.

Dave

I'd be interested in looking at your valve if you care to share.

 

[sb327]

I'd be interested in looking at your valve if you care to share.

I have some pictures in this thread starting at post #34. And other mods through that thread.

Umarex - "Umarex Notos Update HUGE power Upgrade!" Or is it?

Which size bottle is that and did you sand it to a matte look? Most Alsafe bottles are high gloss epoxyt. That is a .36l bottle. No, I did not do anything to the bottle. That’s how I received it

www.airgunnation.com

Dave

 

[Firewalker]

How stiff is the barrel mounting in the NOTOS? I would think that a long barrel would start inducing flex.

As stiff as carbon fiber. Here is a group ay 100y with a bag under the bottle, no support on the stock, just shouldered.

 

[Trucker3573]

Assuming it was adjusted for reasonably efficient use of air with the short barrel, it will need more hammer strike to produce more valve dwell to take advantage of the longer runway.

I agree with this . I think you are completely wasting your time venturing down the slug route with that setup. It will never push them hard enough to reap any benefits. I get it people are obsessed with slugs.