The spell slot progression for the Spell Shot is really weird. It does not play nicely with multiclass spellcaster rules. It gains spell slots up to 7th level just as fast as a full caster, but it also caps out at 7th level. And then it doesn’t gain any spell slots at all from 14th - 18th level.

Magic Arrows could benefit from some clarification. I’d change “arrows” to “pieces of ammunition,” since you’ve established that crossbows and blowguns are part of the archer’s kit. I’d also clarify that you cause the ammunition to become magical, and that the benefit lasts until the ammunition is used to make an attack or until the next time you use this feature.

Intense Impact is bonkers, both in terms of battlefield control and damage output. At 6th level you get Extra Attack. Are you okay with a sniper having 70 foot knockback per turn? Or 8d4 (average of 20) bonus damage per turn? Without expending any resource other than ammunition?

Full Metal Jacket is the 20th-level feature right? It doesn’t mention the level.