the paper i linked states on page 119 that " 57 mm lvzonrör är f n i produktion och rörets storlek
skiljer sig inte mycket från ett normalt anslagsrör. Figur 8 visar den
relativa storleken av rör av 50-talets generation, av 60-talsmodell
och av en tänkbar 70-talskonstruktion. "
and translated:
“57mm antiair-proximityfuze is currently in production and the fuse size does not differ by much compared to a normal fuse. figure 8 shows the relative sizes of fuses with technology from 50’s, 60’s and a future imagined 70’s construction.”
nothing to do with French navy, this is the Swedish developement talked about.
Its the Swedish Bofors company. i don’t know about a “trinity” program.
There is a document from 1975(or 1977?) (“ammunitionskatalog, data och bilder”) given out by the Swedish defence ministry showing all the in service ammunition, how they work, their dimensions and how they look.
i’m trying to find it again as i’ve lost it but it shows 40mm with proxy fuses.
Edit:
so far i found this:
saying that 40mm proxy became available 1975 and an upgraded mark 2 became available 1983.
The L/70 and L/60 Does NOT use the same casing the have the same callibre sure but the casing got changed to the more powerful 40 × 364R than the older 40 × 311R.
The original acquasition plan was for deliveries between 1966 and 1968. There’s no indication that HE-VT shells would have been ready by this point. HE-VT ammunition may have been under development at this point, but there is no indication that they were specifically being developed for the VEAK 40. The first Swedish 40 mm HE-VT shells of the 1970s are significantly different compared to the 3P ammunition used by the Lvkv 90s
You are correct that the timeframe where the first VEAK 40 would have been delivered would have been before the wide implementation of 40mm proxy fuses.
BUT since it’s a prototype vehicle and we have found evidence of 40mm proxy fuse tests during the same time that the VEAK 40 project was ongoing and being done by the same company it is extremely likely that they did tests with proxy and VEAK together.
And having a prototype vehicle in WT with prototype ammo would not be in any way weird (in my opinion).
I’m currently searching for better evidence of this as at the moment we only know both existed at the same time in the same company.
Sure, my main concern is with finding out to what degree this HE-VT was actually functional and whether data could be found. If it’s a purely experimental projectile that was being iterated upon until the 1970s, that may be very difficult. Given that it’s a case of a 2nd hand source, it could also be somebody confusing it with a 57 mm HE-VT round so more data would really be needed.
In terms prototype ammunition there’s also the 40/24 mm slpprj m/49 APDS round that could be added to either the lvkv 42 (lvkv fm/49 and yes it used an L/70) or VEAK 40 that we know for sure existed, although again in the form of prototype ammunition
Another topic to discuss with regards to the VEAK 40 would be its stabilizer which afaik it didn’t have historically, been thinking about making a report on that but I guess that people here wouldn’t be too happy about that :D
Lvakan 48 exists as both L/60 and L/70 as far as I understand it.
Here is the ammo for both, note that both have the m/48 designation but the casings are different lengths:
Edit:
I might have misunderstood this… I’ll double check when I have access to a PC later today…
Yeah, i was wrong about this one. Mixed it with the fm/43.
The basic 40 mm lvakan m/48 is the 40 mm L/70 in Swedish service, but I believe at least some models could be equipped with L/60 barrels for training and some L/60 platforms acquired late may also have been entirely designated m/48 too, possibly the m/48E. It’s very clear in documentation that the lvkv 42 is equipped with an L/70 barrel however, Bofors even marketed it as 40 mm SP anti-aircraft gun L/70
I think you’ve confused lvkv 42 and fm/49. It was originally designated lvkv fm/49 for 1949, but with the designation reform of the 1950s it was changed to lvkv 42 as the 2nd 40 mm SPAA. An SPAA from 1942 wouldn’t have the L/70 but the lvkv 42 is a post-war vehicle tested in the 50s, hence why it might be relevant to give it APDS
