Buckshot Shotgun is the only commonly available marine weapon that deal with fast, but squishy castes. Buckshot in this scenario is Scissors and Runner/Lurker (yes, if you have problem with 1vs1 marines as runner, you will have as much problem when you are lurker) are paper. That is a big simplification, but overall this works this way. The only commonly viable counter. That was already nerfed couple of times. There is no replacement for that, no bolt cutter option, no knife option etc. Each and every other commonly available marine weapon (and ammo) can't reliably deal with those benos, because they don't do enough burst damage to kill super fast castes.
There is many variables why is that and they all were listed trough forum and gitlabs. You can only see 7 tiles in each direction. Runner can move those 7 tiles in less than a second. Here. This is why each and every other commonly available marine weapon (and ammo) can't be considered a "counter" against fast benos. There is so much you can nerf buckshot, before you will hit this magic number, where runners won't be able to be punished. Right now even if player is god-like runner/lurker, he can be struct down with a well placed buckshot/s. At some point of beno cries, it will be deleted. In that case beno who doesn't make mistakes won't be able to be killed, the opposite of marine who doesn't make mistakes, because there is multitude of abilities and benos who can punish group of said god-like marines who doesn't make mistakes.
In short: https://gitlab.com/cmdevs/ColonialMa...-/issues/10656
Check it out, there you have offical Bancrose response. If no marinemain can convince you, then head honcho has to.