Custom made durable breech seal made in our shop for the FWB 124-127 with the larger oring-Serial numbers 5,000 and upward-Meaning most current 124's and all Beeman models.
We had to custom make the seal because of variances on 124's and the oddity of the seal itself.
Push seal into groove smartly-Just like the factory seal, it may seem oversize-This is necessary in a 124 to seal.
Use a flat object like an end of a screwdriver handle or a piece of wood-While holding the barrel so to avoid a mishap-press the flat end onto the breech seal to set the seal in its groove. Its not really easy as if it just drops in, it will not seal. Once installed it will contour to your gun.
You may also fit the ID. of the seal and use your fingernail to tuck in the OD while pushining it down with your thumb or flat object. The cut out at the bottom of the oring cavity is there to allow the oring to squeeze in and the excess can go out the slot-just like old factory units.
In the end it will appear just like the factory unit. Minor break in will occur during the next several shots. Some guns are easy to refit the seal-others are harder-especially older ones.
If you get droop on test firing. Let the seal go for a few hundred rounds if possible. If not simply sand the seal to thin it. Sand the face that you do not see. Re install and test. There are many slot variances in these guns so some minor work maybe required.