Lowering FPS on a hi capa pistol?

[truckinthumper]

I have an SRC Baba Yaga Combat master. Awesome pistol and I really like the way it shoots. 

Only problem is it is a bit to hot for the field I shoot. 

Filed limit for pistols is 300 FPS @.20 bbs 
This thing lets loose with 310-315. 

I cannot find any info on what mod to do in order to get at or below 300 fps. 

Any help?  

[BigStew]

What gas you using? That would be your first start if you are using green gas drop to 144a. After that lighter springs in the trigger mech. Have to say this is the 1st time I have heard of a pistol fps limit other than the legal limits.

[Alimcd]

I’d say the best way, that won’t affect your blowback, would be to glue a sliver of material to the front of the rocket valve so it shuts fractionally earlier. That ought to bump you down to site limits 

 

Try a 1mm plastic washer or similar 

[truckinthumper]

I dont think I have access to 144a in the States 

 

3 hours ago, BigStew said:

What gas you using? That would be your first start if you are using green gas drop to 144a. After that lighter springs in the trigger mech. Have to say this is the 1st time I have heard of a pistol fps limit other than the legal limits.

P.S. 
would that rocket valve be this? 

[Alimcd]

You’re exactly right. A little bit of material on the front side of it will allow it to close earlier, reducing the output power a bit. It’ll be very sensitive to the size of the shim used, so start small and see what the results are

[Rogerborg]

4 hours ago, BigStew said:

Have to say this is the 1st time I have heard of a pistol fps limit other than the legal limits.

 

US sites, they seem to like 1.48J / "400fp" limits for AEGs with a 10' or 20' MED and bang rules, with only pistols to be used for point blanking each other in the face and kicking off IRL fights.

[truckinthumper]

2 hours ago, Alimcd said:

You’re exactly right. A little bit of material on the front side of it will allow it to close earlier, reducing the output power a bit. It’ll be very sensitive to the size of the shim used, so start small and see what the results are

Front as in muzzle or as in hammer end? 

P.S. Learning to tune one of these is reminding me of tuning a real steel CZ75. LOL. 
CZ maybe easier to do. 

[truckinthumper]

Actually, I may be good to go. 
The chrono I was waiting on showed up today. 
Charged and used. 

Full gassed mag. KWA green gas. 

first 5 shots are 306-310 
The next 15 rounds were 299 to 295. 
I will just chrono after the first 5 shots and call it good. LOL 

Plus I think the kid running the chrono did not know the rules. 
I had to go back and reread them to make sure. 
Pretty sure he told me 100' limit on my M27, which would mean it is shooting 500FPS.... I am betting it is max 400. 
I will chrono everything now, so I will have better game play 

now, I can storm some buildings. 

[Cr0-Magnon]

Does seem strange to have a 300fps limit on pistols. Was it that one kid at chrono saying that or is it officially stated?

 

However I would say rules are rules. Let's not let any of this "I'll use a half-empty bulb for chrono, I'll put my hop right up then drop it down" mentality creep in. I'm hearing it more and more recently.