been gone for a few days, so just getting back. I do not understand your question, I`m calling the poppet the brass piece with the seal and the stem on it. Maybe I am not using the right terms here. I cut off the aluminum tube to 3/8" to retain the O ring, and put the spring on the other side, retained by a washer and nut on the newly threaded stem.
the poppet and stem are one single piece, in fact I carefully chucked up the stem in the lathe and tapered the brass so as to allow better airflow into the valve. I also opened up the inside of brass valve body a bit to improve airflow. What you are doing here is instead of pushing the poppet against the seat from the inlet side, you are pulling the poppet against the seat from the outlet side.
I think @=S+S%^$# sells a replacement poppet for about $15, and there is a picture of it on their website. You may be interested to know that I just finished making a .260 breech riser, cut 3 inches off the barrel, and put a full length shroud on the gun. Nice and quiet now, it really barked before.
You are right, the poppet is pressed onto the stem, and the seal is pressed into the poppet. I did not stake mine and have probably shot it 500 times at least. The spring does not apply that much pressure to the stem, so it seems ok. Good point though, I will check it out next time I take it apart, which will be soon as I have a small leak in the transfer port. I`m post i pic of the qb with shroud, though the shroud is still in the white.
My aluminum ring on the front on my QB79 valve doesn't compress the O-ring at all, the gap is, if anything a couple of thou wider than the O-ring.... Air pressure alone causes the ring to seal in the corner between the valve and tube, like on a Disco....Bob
More will probably be fine, it will depend on the OD of the section of valve where the O-ring fits.... The larger that is, the wider the groove needs to be to provide room for the O-ring.... particularly during installation since you will be sliding it in, in place, not tightening it in afterwards....Bob