FWB P70 has me stumped.

[wildcj5]

I have a thread on here somewhere about this P70Jr that belonged to an older FT club member.

I have replaced all seals, rebuilt the regulator and replaced the old cylinder. Gun shoots amazing and is accurate as can be.

My issue is I’m getting a sharp crack of air from the breech block to bolt. If I put my hand over the bolt section I can feel the blast and if I push down firmly on the bolt section I can reduce the sound.

I’m at a loss. The breech and barrel seals are new. Anyone know if there is an adjustment for the bolt tension? The rifle was stored with it closed for roughly 20 years.

 

[woogie_man]

Not sure if you can adjust the tension as it is probably set with the link bar. What about a shim under the barrel seal to push it back further?

 

[Richely]

Blue breach seal bottom, white breach (barrel) seal top? Seals fitted uniformly and with no crease, nicks, cuts? Genuine FWB seals have rounded ridge one side and flat other, perhaps try reversing if all else is good.

 

[Lewis]

Beautiful gun and built great!
It is too bad it is getting harder to find parts and services for. They are amazing!

 

[wildcj5]

Blue breach seal bottom, white breach (barrel) seal top? Seals fitted uniformly and with no crease, nicks, cuts? Genuine FWB seals have rounded ridge one side and flat other, perhaps try reversing if all else is good.

Yes, white on the barrel and blue in the bottom. The blue had the slightest of ridge but made no difference. But I did just add a thin oring same diameter under the blue. The blue one still seated and seems secure. No more pop from the breach. And with the big RAW LDC it is nice and quiet other than the normal P70 spring twang they all have.

Thanks for getting the old noggin thinking.

Maybe the blue oring was out of spec?

 

[silverstreak]

cant remember how they mount, but if the barrel can be moved back a bit, it might help pull the breech block down ?