Gspec With a Possible Leak. Help Request.

[Groot]

Hello all,

I need your help hunting down the likely culprit causing a lack of efficiency 

I recently acquired a Gspec and it came with the following upgrades.

At least I am pretty sure they are in there. Seems like it but i haven't taken it to tiny bits yet. 

First PSS10 Tune Up Spring 170sp For Marui VSR-10 Series
First PSS10 Cylinder Head For Marui VSR-10 Series
First PSS10 Spring Guide With Bearing For Marui VSR-10 Series
First 6.03mm Inner Barrel for Tokyo Marui VSR-10 Pro Sniper Rifle G Spec (303mm) - Not sure this is in there as its a gold barrel but thats not an issue.
First PSS10 High Pressure Piston With Silence Shaft For Marui VSR-10 Series
First PSS10 Silencer Attachment For Marui VSR-10 G Spec
First PSS10 Spring Guide Stopper For Marui VSR-10 Series
First PSS10 Teflon Cylinder For Marui VSR-10 Series

Standard Hop and what looks to be a Prometheus Purple rubber.
Going to assume that the sheer is upgrade as well ( currently 45' but it is a smooth pull, so a 90' piston and trigger will come later when this breaks )  

Anyway back to the story. I am going to take it apart next weekend and rebuild it with a new AA hop and maple rubber.

It is too hot at the moment, kicking out 520 on 0.2's. However, as far as I know it is running a 170 spring.

This leads me to believe I have a massive leak from somewhere. A 150 should be more than enough and I want to save my arms

When i get the hop, it will be PTFE taped. Same with the cylinder head. I will clean the cylinder and re-lube everything.

Is there anywhere else that this power loss could be coming from? A 170 spring should be putting out around 600 on a sealed gun, afaik. 
I am guessing the seals on the piston would be a major suspect but again, this I will look at closer next week. 

Aside from fixing the sealing, is there anything else I should order to make the perfect sniper. 

Cheers

 

 

[leadly]

I've got an Action Army M150 spring in my G-Spec with all the other usual goodies and that sits around 400fps with the hop turned all he way off if I remember correctly. 

 

Once the kids are in bed I'll turn the hop down and get the chrono out and let you know what I get.

[Shaydee]

Quick and easy way to check air seal is to pop your finger over the end of the barrel sealing it firm, then fire. After a couple of seconds release and you should still have air escape, if not you should hear it leaking out - odds are it'll be hop unit seal but if it's old could be o-rings on the piston as well. Goes without saying to make sure it's unloaded before you try that 😄 Deffo strip it all down and rebuild from scratch.

 

Also pretty sure you don't have the Laylax barrel in place if it's brass, it's probably the stock TM one that has been thrown back in.

[Groot]

1 hour ago, Shaydee said:

Quick and easy way to check air seal is to pop your finger over the end of the barrel sealing it firm, then fire. After a couple of seconds release and you should still have air escape, if not you should hear it leaking out - odds are it'll be hop unit seal but if it's old could be o-rings on the piston as well. Goes without saying to make sure it's unloaded before you try that 😄 Deffo strip it all down and rebuild from scratch.

 

Also pretty sure you don't have the Laylax barrel in place if it's brass, it's probably the stock TM one that has been thrown back in.

 

Thanks, honestly i am quite happy the stock barrel is in there. I have never had any joy with TN barrels, I prefer wider. 

[leadly]

Hello again, 

 

437

437

436

437

437

 

That's with a G Spec length laylax barrel, AA Hop up turned all the way off, ML 60 bucking, Panthera nub, AA zero trigger.

 

I did the test without the silencer on, purely because there's all bits of string and camo tape dangling off it, making it difficult to get a consistent position in my chrono.

 

Hope that helps!

[Groot]

16 minutes ago, leadly said:

Hello again, 

 

437

437

436

437

437

 

That's with a G Spec length laylax barrel, AA Hop up turned all the way off, ML 60 bucking, Panthera nub, AA zero trigger.

 

I did the test without the silencer on, purely because there's all bits of string and camo tape dangling off it, making it difficult to get a consistent position in my chrono.

 

Hope that helps!

 

Thank you. Would you mind trying again with your hop on at what it would usually ( roughly ) be 

I get a massive difference between hop off and a tiny bit of hop. 

No Hop - 460
 

Some Hop - 520 

I have never been to a site that makes you chrono with hop fully off. Is this a new thing?

[leadly]

Your welcome. I only turned the hop off so I could get a base value of my spring and hop combo.

 

I had it set to 480ish, not a clue how far that would fling a 0.40g BB as I'm yet to skirmish the rifle and my garden is only 20m.

 

From memory it was just as consistent though. I'll wind it back up tomorrow and let you know.

[leadly]

Turned the hop back up, perhaps one full turn after feeling some resistance on the grub screw.

 

473

468

473

473

472

 

The best test is like Shaydee already said and hold your finger over the end of the barrel to make a tight seal! Obviously making sure your rifle and mags are empty beforehand!

[leadly]

Found this from when I was building my VSR from the Airsoft sniper forum.

[Steveocee]

I can't stress this enough. 500FPS isn't a target. It's a limit.

 

If you "tune" your VSR to 498fps with a 0.2, the moment you stick a heavier BB in then your 0.2 equivalent will be above what it should be.

 

Perfect example, my VSR that was doing 485 on a 0.2, once I stick shooting weight 0.43's in racked up 2.39J which equivalent put me over the 500fps mark. OK the site may not chrono me on shooting weight but firstly technically I'd be over the limit and secondly, I'm a human and shooting more powerful could potentially hurt someone at mid range. Said VSR has now been backed off to about 470 on a 0.2 but comes through chrono on a .43 at 2.28J