Piston Rod to Bolt Carrier distance

[bonnie]

What is the maximum/minimum acceptable measurement from end of piston rod to the face of the bolt carrier for L1A1?

bonnie

[Peter Laidler]

I don't think that there was ever a set distance but from memory....., looking at one this lunchtime, the rear end of the piston sits just inside the hole by about 3mm or so. The front end of course sits up against the gas plug

[bonnie]

In my commercial inch pattern rifle the British piston rods measure to around 1.46mm. All these rods are same length.
The commercial Tapco piston rod is shorter and measures around 2.56mm inside the hole.

Have to use the commercial op rod for compliance reasons. Didn't know if shorter would cause any issues. Gun works fine.

Thanks,
bonnie