Umarex Notos lower the power down

If you can’t go any lower with the hammer spring adjuster you will have to decrease regulator pressure.

Depending on what your crosman 177 was, bring it down to the 4-600 fps range depending on pellet used. (those are the speeds I remember from my crosmans)

If you are using a Hollow Point pellet that will expand you may still be able to get a one shot humane kill without the full penetration. A heavy pellet will also move slower thus less penetration as well.
Edit:
If you have a test plank you can use to set the power this will help , and if the Notos is in .22 use a 25g pellet.
You want between 16 to 18 fpe to kill rat , but not go through a fence plank.
Testing on scrap wood is the best option if you miss rat it will not blow all the way through fence. OV.

OldVet said:

If you are using a Hollow Point pellet that will expand you may still be able to get a one shot humane kill without the full penetration. A heavy pellet will also move slower thus less penetration as well.

Click to expand...

My friends and I have done a little research on how little gun you need for backyard rodent head shots with weak antique guns ends up if you're within 10 feet or so 1.5 fpe can do it with a wadcutter. Then we went in the garage to see how powerful we could get the 150 yard guns

Drill out the hammer to remove weight/spring preload

cfs916 said:

Drill out the hammer to remove weight/spring preload

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This is a interesting concept as the lighter hammer won't open the valve as far , but for a novice like me being as a Notos has an adjustable reg what would happen if the hammer was too light.

OldVet said:

This is a interesting concept as the lighter hammer won't open the valve as far , but for a novice like me being as a Notos has an adjustable reg what would happen if the hammer was too light.

Click to expand...

You'd be buying a a factory one or doping the drilled one with welds or tungsten. I would recommend finding a factory one to play with the weight of and retain the original. Minimum spring rate and lowering the regulator would be my first course of action. If it doesn't play nice at the lower reg pressure, I'd then reduce hammer weight to match.

I'm not intimately familiar with the inards of the notos and would lean towards the least time consuming and least destructive methods first.

Nah...

Just open her up and turn down the reg to your desired speed. Just turn out the hammer spring cap all the way back and see where you are at after giving the reg a full turn out.

I've done a good dozen low-powered mods for those in regulated areas with great luck, 600 fps was the goal with 14.30 CPHP's, we got 580.