Bumfuzzled by spring rates!

[G.I. Joel]

I'm looking into buying a spring for my KWA to bring it down from the blistering 400fps to a 340-350 range for use indoors.
I'm terribly confused as to what spring type to purchase. as far as I can tell, Most M100 springs will do that job well and others are too high. Im just worried about going over 350fps with them. Then again, some M/S90s are low like 300-320ish. What should I do?
Im in need of some good advice from a gun doc I guess.
Thanks for all your help.

[Lisa]

Check out Illusion's spring guide http://www.airsoftcanada.com/SpringChart.php Granted your gun is different so your results will not be exactly the same but you can see how a different spring will compare to one you've already got.

[m102404]

With the stock KWA (guessing M4)...I would guess (everything through the internet is a guess ) at putting in a Modify S90+ spring. Although the "strict" conversion of 90m/s only works out to 297fps...with the setup of that mechbox/AEG you'll probably hit closer to 340.

I've seen plenty of mid-upgraded (i.e. good piston heads, air nozzles, tightbore and bearing spring guides) that have shot 360-370fps w/ 0.20g bbs with a M100 spring.

If you want to be sure of being under the MAX limit (and it is a limit no an objective) of 350fps...err on the low side. For most indoor engagement ranges even 330 is plenty.

But buy a Modify S100+ as well...you never know for sure until you chrony it!

Tys

[coach]

http://www.airsoftparts.ca/news/modifyspringtest.pdf

bit of a hit and miss but if you follow modify's upgrades, you could get similar results.

I'm putting an s100 in my MP5 but it will be strictly used for outdoors. I have put in an s90 in my TM AK that is bone stock with a 229mm TB but will have to chrony it to see what it actually shoots.

[G.I. Joel]

Originally Posted by Lisa

Check out Illusion's spring guide http://www.airsoftcanada.com/SpringChart.php Granted your gun is different so your results will not be exactly the same but you can see how a different spring will compare to one you've already got.

Thanks I did look there, Thats where I thought A 100 spring would work best.

Originally Posted by m102404

With the stock KWA (guessing M4)...I would guess (everything through the internet is a guess ) at putting in a Modify S90+ spring. Although the "strict" conversion of 90m/s only works out to 297fps...with the setup of that mechbox/AEG you'll probably hit closer to 340.

I've seen plenty of mid-upgraded (i.e. good piston heads, air nozzles, tightbore and bearing spring guides) that have shot 360-370fps w/ 0.20g bbs with a M100 spring.

If you want to be sure of being under the MAX limit (and it is a limit no an objective) of 350fps...err on the low side. For most indoor engagement ranges even 330 is plenty.

But buy a Modify S100+ as well...you never know for sure until you chrony it!

Tys

THanks, Tyson. I thought a 100 would work well. I have a 6.01TB installed, so I guess I was throwing my guesstimates off with that in mind.
Well I've made up my mind then. Thanks for the Help....now to aquire a chrony...lol I was thinking that most stock AEG's have a 100 spring stock and shoot 330-375 with that.

[Schlyder]

PDI 140 worked good for me, right in the 340-350 range.
Stock CA mechbox, except for a bearing spring guide, and going through a 6.03 tight bore

[Crunchmeister]

With a 6.01 tightbore and bearing spring guide, a Prometheus MS90SP would bring you somewhere in the 330 range. With a 6.04 in my C8A2, I get a very consistent 325 fps. The tighter bore would add a few more fps to that. IMO, that's an ideal velocity for CQB.