Swordmaster dedication: Martial Exercise

[HumbleGamer]

Can this be used with a gunslinger using a combination weapon?

Taking the gunblade as example, given the Martial Exercise feat, by lvl 10 the gunslinger will be master with the sword group and by lvl 13 legendary with the sword group.

Am I reading this right?

[Onkonk]

Single Expertise wrote:

You have particular expertise with guns and crossbows that grants you greater proficiency with them and the ability to deal more damage. You gain a +1 circumstance bonus to damage rolls with firearms and crossbows.

This intense focus on firearms and crossbows prevents you from reaching the same heights with other weapons. Your proficiency with unarmed attacks and with weapons other than firearms and crossbows can't be higher than trained, even if you gain an ability that would increase your proficiency in one or more other weapons to match your highest weapon proficiency (such as the weapon expertise feats many ancestries have). If you have gunslinger weapon mastery, the limit is expert, and if you have gunslinging legend, the limit is master.

You can't use features that boost the proficiency of other weapons based on your firearms with Gunslinger.

[HumbleGamer]

Neat.
Thanks!