VSR-10 upgrade spring size
 

I'm upgrading a VSR-10 and want to shoot about 490 fps. Canadian online stores seem to offer mostly army action springs. So my choice is a AA M-130 or a AA M-150. A M-150 may be too strong shooting over 500 fps until worn in. I'm also using a 6.01 inner barrel which probabaly ads about 15 fps.
The best option is to cut the M-150 spring. So my question is, how many coils should I cut? How much fps would you lose per coil?

Go with the 130 or find a 140. But those springs never guarantee FPS. It depends a lot on your airseal. So your nozzle, hop unit, hop bucking, R-hop (if applicable) and barrel will all affect this.

You could cut the 150 but sniper springs are often linear and unlike many AEG springs, they don't often allow much room for cutting. If you cut your spring too short it will not work properly, if at all. There's also no clear cut rule for cutting springs and FPS drop. You have to do a bit at a time, reassemble and test on a chronograph.

Besides, what weight of ammunition do you intend to use and have you done any upgrades to the hop unit yet? 90% of range come from efficient hop control, not FPS.

I have upgraded it with a Army Action Hop Up, 6.01 inner barrel and Maple Leaf bucking.I just received a Army Action Trigger today and spring guide in the mail. I can get a spring locally.
The Army Action M-150 is rated by the manufacturer @ 490 fps which I assume is after worn in. I figure if I cut two coils it would put me close to 480 fps after worn it.
I agree, every rifle has slightly different variations including air seals which makes a formula difficult.

Sounds like you've done most the work. Get the M150 and give her a whirl. You might find it does exactly what it says on the tin.

If it is a tad over, (like 520fps) then you can afford to cut 1-2coils off at a time. Just make sure you don't cut too much down that your piston goes slack.

:EDIT: Be aware of your joule creep though. If you're using .45's and running with good air seal and close to 500fps... You're gonna get pulled up.

Thanks
I am planning on going with .40's. The cost seems to almost double on bb's once you buy 4.3's and higher. I don't know if its worth it to get another foot or two of range or a very, very slight increase in accuracy using heavier than .4' bb's with a 480 fps limit.
I have been told to just cut one string at a time and reassemble and test but I find every time a I disassemble and reassemble my Bar-10, the screws strip a bit so I want to get the fps as close as possible on the first try.

I am just wondering if I should get a Army Action cylinder. I heard the Bar-10 stock cylinder is fine. But using a AA trigger set and piston with a AA cylinder may work better. There is also one video on youtube where the AA trigger set did not fit in the cylinder. I am assuming it was the stock cylinder, but I am also told AA fixed the problem. I guess I will find out this week when I install the trigger and piston.

I've always personally used .45 to .50g in my builds, but that's purely because the hop is magnificent or I rather accuracy over range. Each BB costs a cent or two but it's worth it.

Stripping screws is BAD. Are you referring to the screw head or threads? Or even the housing they screw into? Any case, it shouldn't take so long and once you've got it worked out maybe unscrew once more and add a dab of super glue or loctite to the screw threads...

If you're using 0.4's, remember it's a good idea to make sure your rifle isn't shooting over 353fps (on a 0.4g). Where I'm from, that'd give you an instant ban from 90% of sites.

My local field has a 480 fps limit with .2's. So once I install my spring I will chrono it with .2's. One online airsoft tech suggested I wrap the piston with solder to reduce the fps until the spring is worn in, then remove it.
Where do you find .45, .50's? Online? My local airsoft stores never carries them?

The VSR-10's are notorious for screws stripping. For me, mostly the head screws. Tried four different Philips sizes to try to get the perfect fit. Can't get the outer barrel screw in all the way without risking stripping it more. Some people have stripped the AA hop up screw that goes into the inner barrel.
My friends a wood builder says he hates Philipps screws and uses only Robertson square heads or Allen heads. I was thinking of finding matching sizes and lengths and replacing everything on my VSR-10 with Allen heads.

To be fair, I last used them in the UK. The 0.5's I had to import from Czceh Republic, made by BLS.
There are plenty of options available in the .40+ range.

The tech is suggesting you weight the piston. That can also have an unwanted effect to joule creep (the Ares Amoeba crew did this to the Striker a lot due to the tiny cylinder they have) I'd still go with cutting the spring a tad.

Eh, I've has screws strip all over. You gotta make sure you're using the right screw driver. I an a mechanic so I have a lot to play with! Poor quality Allen heads are easily the 2nd worst!! Haha.

I know, also wrapping solder around the piston may make it too tight in the cylinder causing other issues. Not sure if that is the best solution.

I went with a AA m150 spring and the fps was consistently 503 to 505.
I'm leaving it cocked over night and hope to lose 10 to 15 fps once worn in for a few weeks. If not, I will cut a coil.

Just finished my first VSR-10 upgrade.
It was so hard to get the stock piston out of the stock cylinder and afterwards I could not fit the Action Army piston in the stock cylinder so I had to buy a AA cylinder. Then the stock bolt cap would not fit on the AA cylinder, so I had to do a bunch of fine grinding and sanding to make it fit.

I tested the rifle and the range and accuracy were excellent.Then it started to slam fire after 40 shots. I took it apart and found one of the cylinder guide rings had broken, probabaly earlier on due to the stock cylinder being out of spec. Going to make a new guide ring today using UHMW tape.

Yes, I have two mechanics who work for me and on numerous times I have seen them messing with stripped nuts and bolts and cutting and heating them etc.

Upgrades

Bar-10
Action Army hop up
AA 6.01 inner barrel
Maple Leaf 70 degree bucking
Barrel spacers made from masking tape
AA 90 degree trigger and piston set
AA Spring guide
AA M -150 spring
AA Teflon Cylinder

Shoots about 504 fps with new spring so need to wear spring in or cut it to reach most field limits in Canada.
Range and accuracy 76 to 86 meters with .4 bb's. It may shoot farther, but I lose sight of the trajectory after 86 meters.

Does your local field make you chrono on .20s? Or the BBs you'll be using in game?

Update: Since I had everything apart I decided to cut the M-150 spring. I cut two coils off, sanded, heated , bent, and smoothed out. [See youtube video]
With just two coils cut it went from 504 fps to 468 fps. I may lose another 10 to 20 after worn in. My objective was 480 fps.

I recommend to anyone wanting to get in the 480 fps range to just cut one coil, or leave the gun cocked and take a couple hundred shots target practice before taking to a game. After wear it should be close to 480. If you field limits are higher than 480 fps, definitely do not cut. If you limits are in the 460-470 range, I would cut two coils. Anything lower I would just use a M-130 spring. This applies to Action Army springs which are easy to find in Canada. Using other manufacturers may yield different results.

After upgrades I took about 100 shots using .4 bb's. The gun has excellent accuracy 60-76 meters. I have not tested the range pass that yet. I lose sight of the trajectory after 76 meters. I will have to get someone to stand out there to test. There is little hop hitting 76 meters so I assume with a bit of hop, 90 meters plus should be obtainable.

Note: When you read or see videos on the Vsr-10 hitting 100 meters plus, it is usually in places like Europe where many areas have a 600 fps limit, so do not expect the same results in Canada where most fields have a 450 to 490 limit.