I just checked the stats and it looks like it will simply be a trade off of elemental protection versus raw defense, which will be greatly beneficial to me in this situation. The skill points are exactly the same.
Is there any downside? This is the first I've heard that caps/helms are interchangeable.
I've been fine up until now. It just feels like there is something wrong with my load-outs at this current moment. If my defense were 10%-20% better I would be fine with the monsters I'm up against. I get hit very infrequently, its just that the current balance of monster offense versus my defense puts me into a crisis situation (the healing death cycle I described in a prior post) after a single hit.
Helms are generally interchangeable yes, but it's not often that the skills are identical. Now if it's Narga armor or something where you're wearing it for evade skills then yeah it might be worth using the blademaster hat. I will admit to only using gunner hats for looks occasionally.
Armorcharm/armortalon are a substantial boost for gunners. Weapons with defense on them help too - the Najarala HBG for example. On monsters that I'm worried about one-shots, I eat for defense(L) and felyne moxie. But you will never be able to tank hits as a gunner - you're going to get hit once in a while so you just need to be able to deal with losing 2/3 of your bar. Try Mosswine Jerky - it recovers the red portion of your hp bar and for a gunner is as powerful as a mega potion. Cures Seregios bleeding too.
A simple fact of gunner life is that half the battle happens before you leave on the quest. If you're using the wrong items, ammo, coatings, or weapon then it could take you twice as long or worse. Proper armor skills can make a massive difference in clear times but then you need an armor set for each weapon. This makes them awkward to use in lower ranks because generally you're not spending a lot of time farming rather than doing keys and just pushing forward. You're not gonna make 3 different bows and sets between each urgent.
I'm not really a bow expert but this is why I stick to HBG versus LBG. It's a lot easier to make do with a general-purpose HBG, at most you need one for normal and one for pierce.