Think I would be inclined to make a brass threaded sleeve and glue that in.
A bit in between.
I've just put together a project Beeman R1 in .22" calibre. At this stage, the internals are pretty standard apart from the spring, as I've dropped in a 14.5mm i/d spring with a bit more pre-load. Currently running at full stroke length, she's at 11.7ft/lb with FAP, but a bit harsh on cycle. The problem lies, I think, with the transfer port; measured at 4mm. I'm not sure if this was US spec' or if someone had previously tweaked it up. So, I'm thinking of a tp reduction to 3mm. Do I:
A) drill out the tp and tap it to add a drilled out grub screw and glue it in? I've done this before with an HW80 with good results.
B) get a sleeve made and drift it into the existing tp?
Think I would be inclined to make a brass threaded sleeve and glue that in.
A bit in between.
Repariere nicht, was nicht kaputtist.
You don't need to thread it. Close fitting and thread lock will be fine as they don't really get much force on them. You want the cylinder side to have a bit of a curve into the hole and the barrel side to be square (or slightly proud of the face of the breech.
Full power HW80's have smaller ports than 4mm.
Could the 4mm port be an attempt at reducing bounce in a 12fpe gun?
I've used brass tube and red thread locker on a Diana 35 transfer port and I worked well.
Ora
yeah, as BB said the forces relative to the area for glueing are very low.. so make the brass sleeve a tight fit and glue / loctite it in. Just be sure to degrease thoroughly first.
I'd go with 3.0 - 3.2 - I've just reamed my 80 TP to 3.1 and it shoots very nice at 11 fp - but this is going to be running near 16 when I export it. 4mm is too big for any power level.
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.
Yes thats the wonderful things about theroies. Often let down by reality
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I sleeve and glue them, don't bank on the 4 mm hole being a very good one, I tend to open them up with a ream and make a sleeve to suit, as mentioned 4 mm way too big , had a 97 comp tube with a 4 mm port last week, I sleeve them back to standard 2.8 and go from there.