Low fps in my kwa sr12

[Miracle]

Have you changed mags by any chance from one day to the other? KWAs are notoriously picky about what will feed in them. My KWA just barely poops out bbs if I try and use anythin but VFC, MAG, and KA mags.

Also if you are slamming your mags in to make sure they're seated, you may have created a little space between the hopup and the mag and you'll lose compression that way.

[Toan]

Have you range tested? And are the velocity changes actually noticable when you fire? It might be the chrono itself... Gotta think about every factor.

well the chrono tests on all my other guns are good except the sr12

[xKingSizex]

When I say to see if your barrel is straight, I wasn't referring to your hop up unit being on correctly. I am speaking of the actual shape of the barrel. Take it out to make sure it does not bend, you can roll it on a flat surface to make sure. A crooked barrel can cause a decrease in fps. Just a thought...

[Minerva]

Not a significant one though. I think you should invest in a new spring

[Toan]

When I say to see if your barrel is straight, I wasn't referring to your hop up unit being on correctly. I am speaking of the actual shape of the barrel. Take it out to make sure it does not bend, you can roll it on a flat surface to make sure. A crooked barrel can cause a decrease in fps. Just a thought...

Ive tried it with 2 different barrels and still got the same results and i know for a fact both of them are not bent in anyway.

[Toan]

Not a significant one though. I think you should invest in a new spring

I put my old sr12 spring in it and it still shot the same, I had the old one sitting in the sp140 bag, so it wasnt compressed for about a year. Could it be that the battery I'm using? Idk just a thought, right now Ill take anything that makes the gun shoot into consideration.

[Minerva]

No. Electrical currents do not impart any additional velocity or stress. If its not your spring its likely a compression issue. It could also be an engagement problem with your piston however.

EDIT: Take a look at your O-Ring as well

[Toan]

No. Electrical currents do not impart any additional velocity or stress. If its not your spring its likely a compression issue. It could also be an engagement problem with your piston however.

EDIT: Take a look at your O-Ring as well

I'm gonna buy a #14 o-ring tomorrow and try again. I know this has been asked about a billion and one times but, when I just shoot the gun and looking at the air nozzle, is it suppose to reseat itself in the fully out position? Cause when I shoot in semi, it looks like the tappet plate pulls back the air nozzle each time as if the spring is compressed and there is no play in the nozzle, but in full auto it sometimes seats the nozzle without any tension on it so I can push it in and out with my finger.

[dom186]

The air nozzle should reset itself to the rear before each hot on semi. On fully automatic, sometimes the gun is stopped half cycle, which would explain why the air nozzle is loose. The air nozzle cycles forward each time to chamber a bb in the hop up and to seal the compression area between the hop up and the air nozzle, invade you didn't know. The types of magazine should have no effect in the kwa since the lower half of the hop up is screwed into the body. Electronics have nothing to do with the compression other than it is used in a motor to cycle the piston back. On some extreme cases, the battery has caused a lower fps because it is so powerful it cTches the piston half cycle before it is able to compress completely, which would only happen on automatic. Not semi. Hope this helps.

[Switchback]

You can lose air seal between the magazine and hop-up unit. Try to get a good seal on that.

$0.02

[Jester316]

Actually, if your gun is functioning properly, you won't loose air between the hop up and the magazine, because the air nozzle pushes into the bucking PAST the feed tube. So, unless you have a broken air nozzle or something drastically wrong, you won't loose air there.

Switchback, remember when I said don't post stuff you don't know about? Yea, this be one of those times...

[MillerSA15]

It could be the spring that sits on the top of your hop up assembly and makes sure it sits in the right place, nice and tight up against the gearbox. If that somehow got bent and was no longer putting enough tension on it, that could be the problem.

[Jester316]

Note to self: 2 piece hop ups suck balls...

[dom186]

It could be the spring that sits on the top of your hop up assembly and makes sure it sits in the right place, nice and tight up against the gearbox. If that somehow got bent and was no longer putting enough tension on it, that could be the problem.

This might be my problem! I lost that spring when I took it out on my SR-10!! I'm almost done soldering to deans, just have to get my battery soldered, and I'll see if that's the case. I'll have to contact KWA to see if I could purchase that part.

[Toan]

It could be the spring that sits on the top of your hop up assembly and makes sure it sits in the right place, nice and tight up against the gearbox. If that somehow got bent and was no longer putting enough tension on it, that could be the problem.

That was honestly the first thing I checked cause I know that presses the hop up against the gearbox. The spring seems to be in good shape, theres no bends or anything in any of the sections of coil. Tomorrow I'm going to the local hardware store to pick up the o-ring, we will see if this fixes the problem. The stock o-ring seems like it doesn't really "line" up very well with the walls of the cylinder, it just sits inside of the head and doesn't touch the walls very much.