Hello & welcome!
Watch Cymas's M14 disassembly.

 

Yeah.... Good luck. The V7 M14 has a lot of it's goodies on the outside of the gearbox. My suggestion is you watch a disassembly video, OR JUST GET A DIFFERENT GUN. These M14s are pretty pesky to work on, and gearbox work is quite difficult. If you are set on just changing a spring, make sure you have an extra set of hands; there are multiple parts askew that need to be in place or compressed to get the shell back together. And with the heavier spring it's going to be even more fun.

 

okay, i really would like to keep the m14 line. Do yoi have any experience with the cyma m14 fps. some people say it shoots like 415 with .20 others say it shoots 350. which i think it shit for a ranged weapon.

 

I would suggest that you get the field limits from where you want to play, and then build it to that power.

400 FPS does kind of suck for a sniper/DMR role, but if you use BBs like .40-.48g in a 400 FPS gun you will have okay range.
But definitely try for higher FPS.

Also, Airsoft GI works on guns, so I'd suggest that you check them out before you buy anything or screw anything up.

 

0.4s and above are gonna feel like you're tossing rocks. Probably .36 and go accuracy by volume. The best way to test fps is to get a chronograph. They're essential if you plan to do any work to the gun. You can pick up a cheap xcortech for $55. I haven't used a Cyma M14, but I own a G&P one, which is essentially the same. Airseal was pretty bad, and fps was in the 350s range. Maybe 370. That was after changing the bucking though. Again, get a cheap chronograph.

 

@Uxorial do what SiliconeS suggested to you...
I wouldn't bother my self with a DMR in those (415-350) fps. Those fps are inadequate for the airsoft role of DM. Airsoft Assault AEGs (& yes a few pistols) will reach you...
Your range with 400fps using 0.48gr is gonna be nearly same with those of assault AEGs and your bbs will be too slooowww.
My best results, so far, in long range shooting (+60m top 70m) were with 0.25gr & 0.36gr. Hoping to test soon the 0.40gr & 0.30gr bbs...
DMR/Bolt Action Rifle must have at least ++450fps if you want to have some range advantage against assault AEGs. Keep in mind that we are talking only for range and not good accurate shots...

 

I would argue that even 450 is way too low. I played at Ballahack recently with 470, and it simply wasn't enough.

 

Eh... honestly I wouldnt build it into a DMR. I would keep it as a battle rifle. Aside from the gearbox being a pain to work on, your limited on your hopup from a hop unit and barrel standpoint.

The window cut on m14 barrels are half the size of regular AEG barrels, so you cannot use ML buckings at all. Rhop is the only real option to get more out of it, and even then its limited, as the hop up unit does not have enough give in it to do the job. They are also kinda picky with upgrades too. Mine was for sure.

Sorry to rain on your parade, but m14s are not that good of a gun. They can be made into one, but most do not have the stomach to do so.

 

@Plazmaburn I ran an ML in mine. Interesting, I'd have to check it again to see if it actually fit. It shot fine, though. Only issue is you need to cut the bucking short to fit the chamber.

 

Well mine is a cyma socom 16 m14. CYMA Sport SOCOM 16 M14 Full Size Airsoft AEG (Package: Black / Standard)

Perhaps it was just something with that one specifically.

 

Can't you just file the barrel window bigger?

 

How @1tonne ? By hand using a dremel? If yes isn't too hard to achieve symmetry?

 

I just use a small file. Be careful when doing it and you should be fine. Take your time

 

Unless you are going to R-hop, window symmetry doesn't really matter as the bucking should center itself.