As a linguist by profession, this is particularly interesting to me. The "
Any caliber 5.6 mm (.22”) rimfire pistol chambered for Long
Rifle cartridges may be used," in the rules (8.4.3.3.)
appears to be unambiguously structured, even if the sentence structure is awkward.
"
any" is a determiner that here refers to "pistol"
"
caliber 5.6 mm (.22") rimfire" is adjectival and here also modifies "pistol".
"
chambered for Long Rifle cartridges" is a limitation that imposes a restriction on the pistol itself, specifically its chamber dimensions (not permitting, for example, a Walther Olympia chambered in .22 short).
"5.6 mm (.22") ... Long Rifle" is, of course, a specific cartridge that is defined by the C.I.P.
"
may be used" refers back to the head of the noun phrase, in this case "pistol"
The rule would probably have been clearer if it were phrased differently, such as: "
Any pistol may be used provided that said pistol is chambered for the 5.6 mm (.22") Long Rifle rimfire cartridge." or "Any 5.6 mm (.22") rimfire pistol that is chambered for the Long Rifle cartridge."
However, if we think about the implications of that rule for a while we might note that it gets even more complicated. We observe that ISSF is talking about
the pistol and not about
the cartridges used by a particular shooter in a match. We said no Walther Olympia is allowed if it's chambered in .22 short, but what if we want to shoot a a .22 short cartridge through a Hämmerli 100? So to take care of that possibility ISSF has a separate rule for ammunition (8.4.4.) (¡there sure are a lot of rules for "free" pistol, eh!). For 50m pistol, under "Other Specifications", ISSF rules require that the ammunition be "Rimfire Long Rifle".
So we have the Illocutionary Meaning of the ISSF rule on the pistol itself: the ISSF's intended meaning probably is to only allow .22LR ammo in .22LR pistols. Then we have the Perlocutionary Meaning of the same rule: the fact that competitors and judges are generally conditioned to think of only using .22LR ammo in .22LR guns. However, the Propositional Meaning of the rule (~ the 'literal' meaning) is more interesting. Even though 8.4.3.3. says nothing about what cartridges shooters choose to use in their pistols as long as those pistols are
chambered for .22LR, rule 8.4.4. does, in fact, say that ammo must be "Rimfire Long Rifle".
Interestingly, as currently written, the rules
do allow for an extremely wide range of different loads with bullet weights anywhere from 20gr to 60gr and muzzle velocities anywhere from slower-than-a-typical-air-pistol to screamingly-fast-supersonic (e.g., Aguila Colibrí, CCI Stinger).
After a lengthy debate about a gentleman using .22 shorts in all levels of competition here (Greece) I was informed by a member of the national shooting federation that they emailed ISSF and the answer was that they can allow him to use the .22 short ammo as it offers no real advantage. I was further scolded that the most important part of being a Judge is applying your own judgement.
I can't speak to this authoritatively since I don't have access to the original message from ISSF to your national shooting federation member, but it appears that what ISSF is saying to him/her is basically something like 'don't worry about that rule, it doesn't really matter'. Essentially this means that with regard to .22 shorts, that 'they' (= your matches in Greece) 'can allow' (= don't "have to" follow the rule book) because they (ISSF) don't think it matters. It seems like ISSF's response is not so much about the rules
per se but rather about (1) allowing some level of local autonomy in local matches, and (2) not taking the rules too seriously unless there is some kind of competitive advantage.
It's too bad that you were scolded for this because it sounds like what you did was indeed to apply your own judgment in a very logical and reasonable manner (and even in agreement with the rules, so there's that...).
To my cries that the rules say "must be .22LR" so no personal judgement required, the answer was that in the English language, "must be" is more of a suggestion, while "has to be" is the definite wording to disallow something......
"Balderdash" (as we say in the English language). That's just plain wrong. In no variant of English of which I am aware is "must be" anything less than "has to be" in the context of a rule book. In this case, all the different types of meaning are the same. It is clear: It must be a .22LR pistol (and not something else, like a .22LR rifle held with one arm), it must be chambered for .22LR (and not something else, like .22 Short), and the ammunition must be Rimfire Long Rifle (and not something else, like .22 CB). Since you're in Greece, I will assume that at least part of the issue is that one or more other people (e.g. that national shooting federation member) must have one or more translations of "must be" available to them in Greek which may vary significantly from the original meaning. For example, see
http://biblesuite.com/greek/1163.htm for a whole bunch of possible translations of a somewhat similar lexeme in biblical Greek. But anyway, in the context of a rule book, "must be" indicates obligation or necessity in English - it's not a suggestion.
TL;DR
ISSF rules for 50m pistol only allow .22LR ammo in .22LR pistols.
Language is extremely complex. Guns are, too. And so are rules. And when that all collides...wow!