Is the "Specna Arms SA-C25 - CORE PDW AEG" a good choice?

[Rogerborg]

4 hours ago, ModernTimes said:

Thanks. I'll pick that up but how does that help exactly? Doesn't the spring just make it more powerful?

 

Well, yes.  The spring (along with air seal, piston-to-barrel volume) limits your muzzle energy and muzzle energy is what ultimately limits your maximum range.  PatrolBase list the CA-08 at "Approx. 310fps ± 10%, using 0.20g BB" which is OK.  That comes out to about 0.89J, most site limits are around 1.13J (which they might phrase as "350fps with a 0.2g BB") and the hard legal limit for an automatic airsoft gun in the UK is 1.3J.

 

You won't have to change the spring, the stock M90 will be fine.  It's more a case of if you do want to chase site limits and every inch of range, a quick change system like that on the Specnas makes it much easier than taking the whole thing apart and opening up the gearbox every time.

 

And what matters much more is shooting effectively and consistently within the range you have, which brings us to...

 

 

4 hours ago, ModernTimes said:

Can't I just adjust that gear thing inside the gun when you cock it back? I saw the marshalls doing that when they were chrono'ing the guns before the matches and I figured since you can adjust the power that way can't I just do that instead of getting a new spring?

 

As Skara says, that's the hop up.  It will effect your muzzle energy, but indirectly, and that's absolutely not what it's for.

 

What it does it to add backspin to the BB, which through the science-magic of the Magnus effect gives it a straight-ish flight path.  Without applying hop, BBs will drop out of the air quickly and you'd have to shoot in an arc to lob them any distance.  With the hop spot on, they fly in a spookily straight line until they eventually run out of energy and drop abruptly out of the air.

 

This is a fairly decent video, although it makes the airsoft magic claim that "fps" (i.e. muzzle energy) isn't important.  Both are.  Hop gets you accuracy, and I'm agree that it's more important, but BBs do obey the laws of physics and energy is what determines how far they will ultimately go, whether straight or lobbed.

 

 

 

So: decide what weight of BBs you want to use.  Heavier tend to be more consistent and will go further.  This seems counter-intuitive, as a heavier BB will start off slower than a light BB (shot from the same gun), but the heavier one holds onto its kinetic energy better, is slightly less effected by wind, and ultimately goes further.

 

I tend to use 0.28g in AEGs, as a decent compromise between cost and effectiveness, many other opinions are available.

 

Set your hop as per that video above (you have a decent rotary hop unit which is adjusted like the G36 hop at 2:20) so that you get a nice straight flight with your chosen weight.  That'll be the best you can do with the spring and air seal that you've got.  Then you might (or might not) want to be think about chasing site energy limits.  Hop is much more important though. 

 

And there's really no need to worry about any of this stuff until you've played a bit and got a feel for how well your gun actually works.  Cleaning the barrel and hop rubber before use then feeding it decent BBs and getting the hop dialled in will mean you're competitive with most folk out there.