Cutting a spring advice

[FUBAR_444]

Hi guys,

Im planning on getting a Well L96 and the Action Army upgrade kit but the M190 spring will make it illegal at my fields (500fps limit).

My question is:

1. Is it possible to use an AEG SP150 spring in a sniper rifle?
2. If I cut a few coils off the M190, how many should I do at a time? (Like a group of 4 and test?)

I dont have a chrono but can get access to one after a lengthly drive

[RainyEyes]

Do not cut spring. Just buy another.

If you cut it wrong it will dig into the spring guide and cause issues. The spring is flat ended for a reason to allow the spring to expand and "spin" on the spring guide. Cutting it is not advisable for this reason.

You might be able to buy a chronograph off someone on the forums since it might not necessarily be an AV required item.

Some stores may have them so do some online shopping before you drive.

[FUBAR_444]

Originally Posted by RainyEyes

Do not cut spring. Just buy another.

If you cut it wrong it will dig into the spring guide and cause issues. The spring is flat ended for a reason to allow the spring to expand and "spin" on the spring guide. Cutting it is not advisable for this reason.

You might be able to buy a chronograph off someone on the forums since it might not necessarily be an AV required item.

Some stores may have them so do some online shopping before you drive.

Thanks, yeah I'd prefer not to cut it.

All stores near me sell springs (like the Guarder SP150) but it says they are for AEGs. They dont list any sniper springs specifically so was wondering if they are interchangeable or I need to find a sniper SP150 spring?

[Hectic]

You don't need a sniper spring. You need a spring for your specific rifle. VSR10 ,l 96, aps2 etc...
They are cheap. 30 bucks or less

[AnthonyG]

You can get an x3200 chrono on ali-express for under $70 shipped. Will take a while to arrive though.

Sent from my Nexus 5 using Tapatalk

[dmitril]

I cut my springs all the time, absolutely nothing to worry about, you don't even need to flatten the cut end. I see people talk about issues that can arise from "incorrect" cutting yet I have yet to see actual pictures of such damage.

[BloodSport]

New springs are cheap, bad advice is not when it goes wrong.

Check with some of the retailers they might be able to bring one in if it is not in stock.

[RainyEyes]

Originally Posted by dmitril

I cut my springs all the time, absolutely nothing to worry about, you don't even need to flatten the cut end. I see people talk about issues that can arise from "incorrect" cutting yet I have yet to see actual pictures of such damage.

I've done it before and I've done it wrong so I just chose not to do it again.

M10 spring cut down too much and I got 150 fps afterwards and a plastic spring guide got warped to shit.

It's just much cheaper and convenient to buy a proper spring and drop it in than cutting it and chronograph every time you need to reduce the spring length to estimate the proper fps.

[Zeroroaster]

First thing I would do is find a chrono...to save gas. hehehe.

Sure you can cut a spring, I do it often. I even warm up the cut end, bend it a bit to flatten out the contact area, then grind it flat so it will sit nicely on the spring guide. A bolt gun is way more forgiving than an aeg for spring work in that it cycles way slower and the spring has a moment to seat before letting it fly.

I also found in my L96 it was hard to find a spring that would get it to the desired fps, so after some tuning, we're around 480. Ideal for our field and the weight of BB's used. By trimming the spring you can zero in to your target velocity quite well....but I would only take off one coil at a time, check it for a few dozen shots so it seats in, then do it again. Time consuming, but good results.

[dmitril]

If one is looking for something exact cutting is the only realistic way. I cut my springs, many others do too and so far there is only speculation as to what might go wrong from guys who suggest against it. If you can provide an example of an actual problem you encountered then sure, until then it is bad advice to tell someone to spend extra money on springs they don't need.
Cut 4 loops first and check how much fps decreased. Next cut should be the same or less, the more you have cut off the more fps change removing an extra loop will result in.

Edit: I've been proven wrong, stuff can go wrong, I cannot imagine the mode of failure that leads to warped spring guide with a 150 fps cut spring when 500 fps unflattened cuts dont warp a thing for me, but it can happen.
Edit2: Mode of failure is likely not enough force from the spring to guide piston onto spring guide, I'm guessing this happened with an aeg.

[venture]

You can also retemper it. Heat it red hot and compress it a bit. It will be weaker when cooled. If you stretch the red hot wire it will have more fps.

[RainyEyes]

Originally Posted by dmitril

Edit: I've been proven wrong, stuff can go wrong, I cannot imagine the mode of failure that leads to warped spring guide with a 150 fps cut spring when 500 fps unflattened cuts dont warp a thing for me, but it can happen.

Well it's more of a beware/caution story. I was a complete amateur back then with 0 instruction and no chrony. People more experienced like yourself would probably have fewer or no problems doing this compared to someone like me just starting out.

The spring guide was plastic installed in an AEG btw and the spring dug into the crevice of the metal shim that it was seated in.

[Hectic]

I'm wondering why someone is seeking such and exact fps. Even the best tuned bolt actions will have a 2-5 fps variance. 480 or 500 isn't going to effect your range or accuracy by any measurable ammount.

[Zeroroaster]

In my case, Hectic, it was to remain well within the limits of our 500fps field limit for bolt guns. Regardless of temperature, hop settings, etc, I can rest assured that the gun will pass chrono. Last year I was really close to the 500 mark and one day when conditions were just right I chrono'd 502 on one shot and the gun was disqualified.

You're right, not much difference in performance between 480 and 500 so, better safe than on the bench...it passes every time now.

[freshblake]

I do it all the time. Blow torch, vise, pliers, cut off wheel and a bench grinder for a proper job.

Just don't cut so much you lose tension between the spring guide and piston.

I cut my VSR spring so it only compresses half an inch when I screw the cylinder head on. Combined with a pdi vacuum piston my rifle is dead silent because the piston doesn't hit the cylinder head with as much force as a full length spring.

I'm also only getting a +/-1 fps variation