I did account for internal structure. But still more proof if we're going to truly solve this issue in a consistent manner we're going to also have to accept that infantry small arms might have to be massively reduced or even outright rendered ineffective against proper vehicular armor and that the current conversion system is not meant to work for mech scale weapons.
There is a difference already.
Looking at the entry for Rifle Cannons now and it says nothing about low muzzle velocity being the reason they get the -3. It just says lack of penetration power and not useful in space. I suppose you could interpret the not useful in space to meant that they have lower muzzle velocities than Autocannons and Gauss Rifles but that's only really by comparison and as others have stated most likely not the only reason even if true why they get the -3.
Monbvol, you're really trying hard to push that mushroom cloud back into the steel casing with infantry, aren't you?
It's been a little over twenty years since the late 1990s/early 2000's when they got all granular with Infantry weapons and put together the basic elements of the system we've got today.
and lots of people argued against it every step of the way, because somehow it was going to remove 'mechs as the star of the show.
It didn't.
It didn't with combat ops, it didn't with the House Books, it didn't with late BMR era and it didn't with Total Warfare/Techmanual/etcetera.
admittedly there WAS that hiccup with MWDA, but despite where the ownership sits and what gets periodically promoted, THAT DID NOT STICK and surprise! Battlemechs are still the star of the show.
even with people getting carbon-reinforced fingernails or longbow platoons with grenades for support weapons.
Now, we've largely got a system that works-it's worked for DECADES now in realtime, and that system lets infantry weapons do damage to battlemechs.
From a pragmatic perspective, when you have a system that WORKS, that your market can use, that your market DOES use, and there's a hiccup because of a new add-on, you change the add-on, not the system that's been working.
Why? because you want to keep your audience while attracting people, and this is gaming-make too many changes too fast or too drastically, and you lose that invested market. In the case of Battletech, that invested market represents how the game's survived three publishers going belly up, numerous staff changes, several economic recessions that have absolutely SLAUGHTERED older games and properties that at their height, eclipsed BT in all its forms.
YOUR solution means retconning something close to forty years worth of game materials, novels, sourcebooks, stories, tradition, and player involvement.
In doing so, you also have to engage in tens of thousands of dollars in new materials in the hope you won't lose the market that's been keeping this game alive for, at this point, generations of players.
Risk-assessment wise, your proposed 'solution' is a bad solution. It's a good way to end up being an aborted kickstarter sometime twenty years from now.
The Games-Workshop method only works for Warhammer, Monbvol, they dominate their niche (which is ever shrinking) so completely that adopting their policies (which was tried) will fail.
It's too late for the reset button, alright? it's in fact 30 years and 2 publishers too late for a hard reset to the original box-set's setting. It's hundreds of novels too late, it's metric tons of lore too late. The market itself has contracted so far that there's no room for a total reset and still keeping the lights on, and product coming.
simple fact: Physical attacks do damage. Infantry does damage. Infantry weapons (no matter how ludicrous) do damage.
That is the paradigm, that's the systems that have kept Battletech from being an also-ran only a few diehards even remember existed.
There were giant robot games where infantry were completely useless. guess what? they're not still being made. Battletech IS.
That's the paradigm. It's the market. BT has a niche that's strong enough to keep it alive-which a lot of niche games never achieved and didn't maintain.
In dealing with an engineering or mechanical problem with a prototype, the simplest, least invasive fix is usually the right fix.
so which is simpler/less invasive? Adjusting the damage on LRC's, or scrapping thirty years of evolution in the game mechanics and thousands of dollars in product, promotion, market penetration and development to satisfy a minority of players who don't like that infantry can hurt 'mechs?
You tell me, what's the simpler fix? Which adjustment generates the least amount of retcon, reboot, errata, and rules changes?
[Full discllosure here: MY solution is: if I don't like something, I don't bring it to the table, as opposed to asking for a major portion of the setting to be rewritten to exclude something I don't like, I just don't use it.]