Asg Bren Spring

[strykerles]

So I recently purchased a brand new ASG Bren

Was double firing on an 11.1v lipo and going full auto with a slight trigger pull in semi

Power was around the 280fps mark when it did fire singly

So I gutted it

Fitted a gate titan, 16:1 gears, silent piston head, 3/4 cylinder

Good air seal, good aoe, shimmed correctly

Using a 7.4v lipo

Put in a M105 spring (ASG) I had and it turned out 370fps

Put in a M95 spring (ASG) and it turned out 365fps

Put in a M90 spring (SHS) and it turned out 382 fps

Any suggestions? maybe 1/2 cylinder? I'm at a bit of a loss as it's the lowest power spring I have. Looking for an M80 but having trouble atm

thanks for looking

 

[Speedbird_666]

Put in a M105 spring (ASG) I had and it turned out 370fps

Put in a M95 spring (ASG) and it turned out 365fps

Put in a M90 spring (SHS) and it turned out 382 fps

Any suggestions? maybe 1/2 cylinder? I'm at a bit of a loss as it's the lowest power spring I have. Looking for an M80 but having trouble atm

Therein lies the rub - each manufacturer has a different idea of what they should label their spring power as, and two supposed identical springs from the same manufacturer can yield different results due to manufacturing tolerances. The quality of the steel and the coil pattern are also additional variables.

As taking apart a CZ Bren can be a bitch to replace the cylinder, I would use the quick change mechanism and source either a weaker spring, or even consider cutting one down .

Personally, I would put the ASG M95 spring in  @~365fps and shoot a 1000rds or so through it. There's a good chance that the the FPS will drop to sub 350fps as everything beds in.

 

[Adolf Hamster]

you got thrust bearings on both the spring guide and piston? if so i'd pull the one from the piston, will give a little fps drop (and lessen pme).

could be a shell thing, i know asg m95's are normally pretty damn close to 1j with a single thrust bearing in quite a lot of guns, but perhaps the bren has a little more preload than normal.

 

[strykerles]

Yeah it has bearing both ends of the spring but ideally I didn't want to take it apart again lol

I'll try and source another spring and if that fails I'll cut a ring or 2 off one that I have