Interesting observation of Webley Mk3 and Airsporter loading taps

[craig7]

I have recently been looking at the loading taps on Webley Mk3 and the BSA Airsporters inspired by the various MK3 versus Airsporter discussions on boards like these.
Results
They both have their advantage and disadvantage. It appears that the Mk3 must have had its tap drilled through and line broached from the transfer port as it is exactly the same size and displays identical broach marks. The advantage of this process must have completely eliminated possible errors for alignment for Webley. The pellet fired into lard reveals absolutely no clipped edge to the pellet skirts.
However, i recently noticed an article in Airgunner which details transfer ports upto a max of 4mm being ideal for power. It also details why the Anshutz 335 was never as powerful as its competitors due to a transfer port above 5mm because they mistakenly thought it would be more efficient.
At 12ftlbs limits, 3.8mm is suggested to be the optimum for power.
Its interesting therefore that the relative massive transfer port of a .22 MK3 of 5.6mm (that allowed line broaching through the 5.6mm tap) probably reduces the guns performance by a good 1ftlb to 2ftlbs and can even cause the pellet to fall from the tap into the transfer port when shooting upward into the sky as noticed by one poster on this board.
The Airsporter with its 4mm transfer port having some 2ftlbs lbs more potential power.
Also interesting is the tiny damage clippings to one edge of the pellet of 3 Airsporters i looked at under microscope.
Conclusions.
The Mk3 has to be potentially the more accurate gun with little or no chance of tap alignment issues.
To get to this perfect alignment we however lose 2ftlbs potential power due to the transfer port having to match the tap diameter and thus breaking the 4mm golden rule for diameter .
The Airsporter is ideal for power but you either get a good one or bad one in alignment/accuracy terms because alignment would be hit and miss based on the usual limits and fits tolerance system inherant in the manufacturing process.
My next tests will be run on the indoor range (chrono and target)