[Mosin91/69]

Hello, this is my first time cutting a spring and im just looking for some feedback. Unfortunately i dont own a chrono yet. I read the guide on choosing the right spring and making it work, it said one coil on an m130 would be about 20 fps. But my spring is an m120 and I'm trying to lower the fps by atleast 30ish. Does it look like I took enough off?

 

[Blind Sniper]

You should see a significant drop with that. I would just try and clean up/bend/flatten the cut end. 10/10 buy a chrono.

edit: if you don’t own a chrono then why did you decide to cut the spring?

 

[Mosin91/69]

You should see a significant drop with that. I would just try and clean up/bend/flatten the cut end. 10/10 buy a chrono.

edit: if you don’t own a chrono then why did you decide to cut the spring?

Thanks. Well I chrono at the field and I was over 400 fps, and the rifle is advertised to shoot 420. Trying to get it below 400 so I have less of an MED and can play more aggressive without having to switch to a sidearm

 

[Blind Sniper]

I don’t want to speak too soon but you may have cut too much off. Guess we will find out when you re chrono!

 

[Akami]

You took a bit too much I would say. Also flatten the end of the cut

 

[Mosin91/69]

That's alright as long as I got it below 400 I'll be happy with it. Thanks for the help.

 

[SiliconeSword]

You can gain a little power back by using washers to shim the spring forward on the spring guide

 

[Mosin91/69]

Thanks for the tip. How much fps you think I took off of it?

 

[Akami]

There's too much factor for the resultant of the fps, but if I have to take a wild guess, your fps should be around 370ish now

 

[RonSwanson]

I would have waited to you was at the field and just took some wire cutters/Dremel and some pliers and cut a bit and chrono'd, any good field wouldn't mind.

Also you need to flatten/bend that cut end smooth.

I would say you've cut more than 50fps off if I had to guess.

 

[Sodium]

If you want to tech, you need a chrono. It's by far the most important part of building a good rifle. For $60, you get to not have to wait like a month every time you make a change to see if it messed amything up.

 

[Doctor Jest]

As the other dwellers have said - a chrono will absolutely be your ally in any tuning you may undertake.

Secondly, file the cut end flat and you'll get more consistent readings with no possibility of snagging anywhere you don't want it to. I use a dremel but a good engineer's file, or even (if you feel energetic) some emery cloth and/or wet and dry paper will serve.You'll be fine, but there's no substitute for having the correct tools for the job ^