Just did a little tune on my Standard...

[Shed tuner]

yup, will bring it to the bash tony..

silva, just made a 5.5 dia, 13mm long steel plug, slightly tapered, with a 2.8 mm centre hole, and tapped it in with a bit of glue ( not really needed for security due to the taper, but it fills the voids).

.Rgds - JB

[TonyL]

yup, will bring it to the bash tony..

.Rgds - JB

Marvellous; thanks JB.

[greenwayjames]

In an early 20th century article in a gun trade magazine (Arms and Explosives?) The factory described a series of experiments made developing these old rifles complete with results. Light pistons, heavy pistons et al. BSA also used to make a point, it could have been the same article, of saying that the barrel and cylinder were made in one piece and then rifled. This may explain the bore sized transfer port?

[Shed tuner]

BSA also used to make a point, it could have been the same article, of saying that the barrel and cylinder were made in one piece and then rifled. This may explain the bore sized transfer port?

Definitely, yes, and with the tap fitted then reamed through, alignment would also be absolutely perfect.

[slow_runner]

silva, just made a 5.5 dia, 13mm long steel plug, slightly tapered, with a 2.8 mm centre hole, and tapped it in with a bit of glue ( not really needed for security due to the taper, but it fills the voids).
.Rgds - JB

Hello JB. I assume that the insert is fitted from the cylinder with a stepped rod to guide it into position before tapping it home?
I will be interested to see what results follow as you alter the transfer port.

[Shed tuner]

Hello JB. I assume that the insert is fitted from the cylinder with a stepped rod to guide it into position before tapping it home?
I will be interested to see what results follow as you alter the transfer port.

exactly that.. just turned down a bit of rod with a ~2.5mm spigot left to stick into the inside of the insert, guided it home and then a couple of gentle wallops to seat. My guess is around 3.0mm will be optimal, as there is a fair bit of lost volume in the tap, behind the pellet

[Shed tuner]

final update on that port...

After about 50 or so shots, the power had settled down to around 8.3 FP and the spring had taken a small set.

Stripped it down carefully, and reamed the port out tapering 3.2 - 3.0 (parallel would have been fine, but I have a taper reamer). Upon reassembly, after a couple of dozen shots, it's now nudged up to 9.1 FP, so a worthwhile if not dramatic increase of 0.8 FP. This confirms my initial premise, and I think this is probably about optimal now, so I'll leave it alone. Firing cycle is a fraction better too, presumably because the piston is bouncing back a little less. So job done, very happy.

For those wondering, I've no doubt that with a slightly stronger spring or more preload, the power would come up very nicely, without wrecking the shot cycle, but with open sights at my eyesight-limited max range of about 25 yards, 9 FP is plenty, thanks