CA M15A4/M4A1

[walshy155]

I'm having problems with my gun what was meant to be a G&G CM16, but is actually a CA Sportline M15A4 (M4) it has alot of screws missing, alot of wobble and creaking, fires okay/accurate but has an FPS on 235, I got it from a swap and was used well for 2 years, has a new motor in it (I hope) and a tightbore (doesn't) the hop is still working pretty good, I think it used to be blowback, there are no trades on it, as the body has been replaced with a metal one, how is the FPS on 235 in a .2g, what is wrong?

 

 

Also how do I put the RAS ( I think it's 6 inches ?) rail on it, it also has a handgrip to go on the rail.

[walshy155]

How could the FPS be only 235 on 0.2g Blasters?

 

Maybe it's the spring, air nozzle?

 

How can I check what's causing the problem.

 

And how would I put the RAS rail on?

 

Please help guys, that be great.

[Grounded_Pilot]

How could the FPS be only 235 on 0.2g Blasters?

 

Maybe it's the spring, air nozzle?

 

How can I check what's causing the problem.

 

And how would I put the RAS rail on?

 

Please help guys, that be great.

I am surprised no one has answered this.

 

First off, you should have kicked the guys ass who described the rifle incorrectly! That's called false advertising and is fraud!

 

Second of all, As far as I am aware, Classic Army have made M15's... but not sport line models I think! And if it is the M15A4 sport line version, I know from experience it certainly isn't blow back.

There are no markings probably due to the nicely marked up CA one being replaced for a JG metal one...

 

If the gun is a little old and hasn't been given a once over for a while, that could be causing your low FPS. It should be around the 300fps mark.

 

First, try cleaning the barrel. If no improvement try:

Turning your hop unit OFF.

 

If still no improvement there could also be an issue with:

-Your hop unit- there could be an airleak. Often caused by a tired hop rubber. Simple solution, replace the hop rubber.

-Your piston and/or piston head- over time the O-rings on the piston heads degrade causing an air leak. Also, you could have broken the last few teeth on your piston (from use) causing the gears to loose contact early and create a too smaller airpocket.

-Your air nozzle- should be fine really, if it stops working/breaks you usually know about it pretty fast. I.e. You get lots of BBs feeding at once or it doesn't feed at all!

You dirty, dirty boy!...pardon the joke, but it could simply be a dirty gun/gearbox/both.

 

Those are the most likely issues. However there could be a whole host. The gun needs a full clean out, to loose any dirt/grime and to replace any broken/damaged parts, if there are any. But I would like to bet on your hop unit having the issue. It may look fine, but if the rubber is ruined, there's not much you can do but replace the rubber bucking.

 

The only other possible issues I can think of off the top of my head are:

- Spring is dead/dying...unlikely that anyone would reduce the spring intentionally, so it might have been left compressed in an unused gun for far too long... although that's a huge drop in FPS.

- Damaged barrel... had this issue once before on a swapped gun. Got a sniper rifle that was supposed to be firing 400fps, was just about managing 300... the barrel had been gripped by what looked like monkey wrenches and had distorted it somewhat, causing an airleak.

 

Either way, it needs looking at. If you don't feel confident enough to do it yourself seek the aid of someone who will do it for you! (PM me if you need help )

 

Also in regards to the RIS, do you know the brand? RIS's are a pain in the ass. Many need modification to fit, and some just won't! Make sure you've got the right brand for the gun!

 

Hope that helps!

Luke.

[walshy155]

I am surprised no one has answered this.

 

First off, you should have kicked the guys ass who described the rifle incorrectly! That's called false advertising and is fraud!

 

Second of all, As far as I am aware, Classic Army have made M15's... but not sport line models I think! And if it is the M15A4 sport line version, I know from experience it certainly isn't blow back.

There are no markings probably due to the nicely marked up CA one being replaced for a JG metal one...

 

If the gun is a little old and hasn't been given a once over for a while, that could be causing your low FPS. It should be around the 300fps mark.

 

First, try cleaning the barrel. If no improvement try:

Turning your hop unit OFF.

 

If still no improvement there could also be an issue with:

-Your hop unit- there could be an airleak. Often caused by a tired hop rubber. Simple solution, replace the hop rubber.

-Your piston and/or piston head- over time the O-rings on the piston heads degrade causing an air leak. Also, you could have broken the last few teeth on your piston (from use) causing the gears to loose contact early and create a too smaller airpocket.

-Your air nozzle- should be fine really, if it stops working/breaks you usually know about it pretty fast. I.e. You get lots of BBs feeding at once or it doesn't feed at all!

You dirty, dirty boy!...pardon the joke, but it could simply be a dirty gun/gearbox/both.

 

Those are the most likely issues. However there could be a whole host. The gun needs a full clean out, to loose any dirt/grime and to replace any broken/damaged parts, if there are any. But I would like to bet on your hop unit having the issue. It may look fine, but if the rubber is ruined, there's not much you can do but replace the rubber bucking.

 

The only other possible issues I can think of off the top of my head are:

- Spring is dead/dying...unlikely that anyone would reduce the spring intentionally, so it might have been left compressed in an unused gun for far too long... although that's a huge drop in FPS.

- Damaged barrel... had this issue once before on a swapped gun. Got a sniper rifle that was supposed to be firing 400fps, was just about managing 300... the barrel had been gripped by what looked like monkey wrenches and had distorted it somewhat, causing an airleak.

 

Either way, it needs looking at. If you don't feel confident enough to do it yourself seek the aid of someone who will do it for you! (PM me if you need help )

 

Also in regards to the RIS, do you know the brand? RIS's are a pain in the ass. Many need modification to fit, and some just won't! Make sure you've got the right brand for the gun!

 

Hope that helps!

Luke.

 

Well I have checked over the gun and it seemed to be the spring I replaced it for a what was supposed to be an M110 and now I get 285FPS on a .20g.

[RR01]

Well I have checked over the gun and it seemed to be the spring I replaced it for a what was supposed to be an M110 and now I get 285FPS on a .20g.

 

That is still way too low for an M110 spring unless your gun has a really short barrel (i.e. less than 250mm). That spring should be shooting at least 100fps more than what you are getting in an M4 lenght rifle. You definitely have other problems. The whole gun probably needs looking at to check everything is working as it should. If it was me I'd be having strong words with the person I did the swap with.