WW1 'Periscope Prism company' sniper scope???

[lmg15]

Taking this line of thought a little further........if you look at the contract details (post number 65) - the entry dated 30/09/16 refers to a contract placed with Aldis Brothers to 'Fit Telescopic sights with Bartle fittings'. The contract size is 700. There is a second similar entry dated 18/10/16 for a further 700 units. So, if the 'modified PPCo rings' & the 'Bartle fittings' are one & the same, it would explain why the scopes turn up reasonably frequently.....
Immediately above the second entry is a further reference to Aldis for a contract for 2254 'sights telescopic' but with no further qualification. Although above the 18/10/16 entry, it is dated two days later.

Further, if the fitting of Aldis scopes using mounts supplied by J Bartle was carried out by Aldis Brothers themselves, they (Aldis) didn't really need to put their company name all over the rings, as it was already boldly emblazoned on the ocular lens housing. To add it again may have been seen therefore as unnecessary.

Terribly difficult to prove or disprove, but it seems very plausible. I wonder if there are still patent details extant for a J Bartle telescopic sight mount.....or if produced by Bartle at the behest of PPCo or the government, & as it is the same in principle, would it have been covered by PPCo's original patent of February 1915? Just thinking aloud....

Roger, your theory about Aldis fitting the dovetail mounts does sound feasible, but patent acknowledgement could be even more desirable when mix and matching Aldis and PPCo products, especially from PPCo's point of view if PPCo actually owned the mounts patent. Would they also be paying royalties for the German scope patents?

So who is this Bartle character? Is it possible that PPC only "designed" the scopes, and used a Bartle design for the mounts from the outset? Getting the patent details would be interesting, to see whether it is entirely credited to PPCo, or whether Bartle's name crops up as the designer. That would make sense if Bartle was then able to collaborate with Aldis for the contract.

The timing and size of the Aldis scope contracts is also a thing to consider, especially as it is so late in 1916. My own under-populated spreadsheet and rounding to the nearest hundred or so, you could get something like this:
66000 to 67500 made in 1915. Mainly No.1 and No.2 scopes
67500 to 70600 made in 1916 - Mainly No.3 scopes with a couple of No.2s at the beginning and a No.4 near the end.
70600 to 71600 made in 1916 - Almost all No.4 scopes with a couple of No.3s mixed in.

So in 1916, Aldis had made roughly 3000 No.3 scopes, plus another 1000 No.4 scopes, and I have not seen any Aldis sniper scope dated later than 1916. If the 18/10/16 order was for sniper optics, then they would have had to fit a lot of production into two months. PPCo also made optics for other guns as well, so maybe the 2254 scopes in this order were not sniper optics?

The other thing is that almost all No.4 scopes produced have the lateral adjustment prism fitted, implying fitting in a non-windage adjustable mount. Most of the No.4 scopes in my spreadsheet are fitted with the "PPCo" (Bartle??) dovetail mount from earliest noted scope serial 70889 onwards, but with Roger's possible overbore scope in that serial rage. Starting to make sense?

The only two scopes actually fitted with the overbore claw mounts I have seen are 1916 dated No.3s serials 70501 and 70533. I am not sure what can be read into those numbers. Possibly just that the next handfuls of scopes for the overbore job were sitting on the same section of storage shelf?

Brains are dribbling out of my ears now, must go.

ATB, D