Specna Arms Spring Change Issues?

[danlangster9721]

I have a SA-E11 Edge, gun has been great so far!  The spring fitted (M90) was on the low side of FPS, getting around 295-310, so I swapped it for the 'factory' spring (M110). Now the FPS is a little hot, consistently shooting around 370-375. 

 

I bought a ASG M105 spring to try hit the sweetspot... Fitted the spring and ran it through the chrono. Gun was shooting perfectly at 343-345 FPS! The day after I attended a skirmish at my local site, took the gun to chrono station and it wasn't working correctly. Looked like it was over feeding BB's, some shots wouldnt go past 10 meters, BB's were dropping off horribly. FPS was going from 190 up to 300, horribly inconsistent! 

 

Took the M105 out, checked it and put it back in... still the same issue!  Then put the M110 back in the gun and it worked fine (but was too hot for the site)? I did notice the M105 was maybe 3-4cm Longer than the M110....

 

Does anyone know why the M105 might be causing the issues I had? 

 

[Rogerborg]

That's a bit peculiar. Is the M105 the same diameter as the Specna springs?  I'm wondering if it's either sticking to the spring guide, or has too much free play.

[Adolf Hamster]

3 hours ago, Rogerborg said:

That's a bit peculiar. Is the M105 the same diameter as the Specna springs?  I'm wondering if it's either sticking to the spring guide, or has too much free play.

 

that's my thinking too

 

they can expand under compression, so even if it goes in smooth it can still bind when compressed during the firing cycle.

[danlangster9721]

6 hours ago, Rogerborg said:

That's a bit peculiar. Is the M105 the same diameter as the Specna springs?  I'm wondering if it's either sticking to the spring guide, or has too much free play.

Just had a look, maybe the ASG is 0.8mm bigger in diameter. Could that be why? 

I'm tempted to take out the M110 and just compress it more or cut a spring off as I know it works with that in the gun.

[Adolf Hamster]

16 minutes ago, danlangster9721 said:

Just had a look, maybe the ASG is 0.8mm bigger in diameter. Could that be why? 

 

it's possible, depends how tight it is against the piston/spring guide.

 

it's a tricky balance as you don't want it too loose either lest it kinks.

[L3wisD]

I use the ZCI M100 Springs from @ak2m4 in all my Specna rifles and they are all happy in the 330-335 sweet spot.

[danlangster9721]

17 hours ago, L3wisD said:

I use the ZCI M100 Springs from @ak2m4 in all my Specna rifles and they are all happy in the 330-335 sweet spot.

Ill go check them out! Thanks!