Cutting a spring to lower FPS
 

Hi there.

So I've got a sniper rifle, but its shooting a bit too hot. As I am a "do it yourself" kind of person ( read : cheap ), I thought about cutting the spring a little bit, to lower the FPS.

Now, I see no problem that could arise from this, but just to be sure I'd like to ask before doing it :p Good idea or not? Anyone ever tried it?

NO this is not a good idea, the spring is that length for a reason. Get a new spring, they cost $10.

Itll work alright if youre stuck, at a game or something, snip a coil and test fps until you have her where you want but youre better off doin it right and throwin in a decent spring first time.

You'd spend more on decent bag of .36s.

Alright, thanks.

Yea for the cost of a spring put a new one in, your already taking apart the the gun to do it, may as well do it right.

It really depends on what rifle you have.

If you have a clone L96, cut the coils until you have the right FPS.

The reason for this is that you would need to change the piston and spring guide if you want to use a spring that will shoot 450fps.

Best trick I can give you: Cut the coils until your gun shoots a bit over (10-15 fps). Then heat the end you just cut for half a coil, red hot. Press the spring agaist a metal object to flaten it. It will remove a few FPS and prevent damage to your piston/guide.

Funny thing, I cut a length of spring some time ago when I had a PTW.

The stock spring with shooting at 495FPS on average with a string of 10 BBs, so I cut the length to 75% of the stock length and I had an increase to 515FPS with a much higher ROF.

That makes no sense.

your brain asplode now

I had something weird happen in that fashion some time ago: an AEG that refused to shoot anything between 315 and 390 - strong spring would consistently go above 400 with no problem, weaker spring would never give anything above 315.

As said, cut off a coil or half a coil at a time, reassemble and chrony. But if you cut off too many coils, your spring will end up too short and you'll have to buy a new one (not that much, $25 or so). I cut my Laylax 170SP spring down (was getting about 585fps) and with tweaking other parts now have my rifle sitting at 400fps and love it. Went many years running it at around 500fps, and had tried 430-440fps, best I've seen is the state it's in now.

Thanks.

Did you "flatten" (like Kos Mos said) the spring or did you just put it in like that?

The ROF makes no sense to me. Cutting coils would make the spring stiffer and speed up the piston. You have to think of any coil spring as a long uncoiled spring or torsion bar. the longer and thinner the weaker, the shorter and thicker the stiffer. Progressive springs use tighter windings in places that will compress first and stack, effectively shortening the spring and raising the rate when they do.

Ya, deburred and flattened each time using my Dremel with a reinforced cut off wheel.