[1tonne]

That is a hard one. Really it is just a trial and error thing. It also depends on your inner barrel length. With a heavier bb, you will want a shorter inner barrel and a bigger spring.

 

[1tonne]

That would sound about right. May vary a little though.

 

[1tonne]

It is really just trial and error as some springs are thicker that others as well as longer than others.

 

[1tonne]

I would use the M160 and put weight on the piston. That is way better than cutting a coil off.
To put weight on the piston, just wrap solder around it and the hold it on with a layer of electrical tape.

 

[1tonne]

I don't understand?

 

[1tonne]

Oh. I thought you had some way of reducing fps with adjuster rings.


Yes, they are fine to use to increase fps. If you make some, just make sure not to make them that long that the trigger sear will not catch. Also, make sure that they will fit into the piston nicely.

 

[1tonne]

It is an approximation. It depends on brand of spring and barrel length too.
The fps rating are pretty accurate though. Normally you multiply the M number by 3.28 and that will give you the fps when new (give or take 20fps). So 492fps. Then once it has settled it will be less. But it is not an exact science as longer barrels will give you more fps and shorter barrels will give you less fps. If you have a barrel of about 360mm, that would be about the average.

 

[1tonne]

It may give you about 10fps extra.
Add weight to the piston to bring the fps down. Wrap solder around it and hold it on with a layer of electrical tape. Then oneday when the fps does drop too low (Once worn in), you can take off the weight and the fps will go back up. So you get twice the life out of your spring.

 

[1tonne]

You can cut sniper springs.
But in your situation I would not. Just purchase some solder and wrap it around the piston to slow it down. If you take 2 coils off of an M150 you will most likely end up with only around 450-460fps. Just add weight to the piston. Then once the spring has worn in, take the weight off.

 

[1tonne]

You can do that but don't make the wash/spacer too long otherwise the piston sear will not catch onto the trigger sear.

 

[1tonne]

Use them on the spring guide. Cheers

 

[1tonne]

I tried linear and non linear in JC builds thinking that one would be better than the other but in the end, I found no difference. Both produced similar JC.
What have other people found?

 

[1tonne]

That is a little high but not unexpected. Different springs can have slightly different outcomes. Also, if it is new, it will wear in to about 510fps