I mean, yes. Your threatened range would be 30 ft between Improved Snap Shot (Greater is unnecessary.) and Combat Partol at level 20. It's going to be a long road to get there though, you're looking at doing almost nothing in the early levels.
As a Fighter you'll have 20 feats? 1 per level + 1 if human or another bonus feat race.
Combat Patrol is 4 feats (Combat Reflexes, Dodge, Mobility) and minimum level 5.
Greater Snap Shot is something like 6 (Improved Shap Shot, Snap Shot, Weapon Focus, Rapid Shot, Point-Blank Shot) with staggered level requirement of 6/9/12.
Disruptive has an entry level of 6 and of course locks you in Fighter (which isn't a bad thing, but it means you can't skip any requisites with a class like Ranger with free bonus feats).
I'm not familiar enough with Mythic tiers to know exactly how it'll expedite things, I know that you do get bonus mythic stuff at certain tiers though.
Not to mention the basics like Precise Strike to make a ranged build viable without penalties to to nines, Rapid Reload unless you're using a long/shortbow specifically (Exotic Weapon Proficiency if you're trying for something like the Hornbow). The action economy on the trick as well will be garbage needing to devote full actions into Combat Patrol rather than firing arrows at anything and everything.
Basically there's not a lot of reasons to get Combat Patrol or Disruptive at all before Snap Shot, and Snap Shot is level-locked and prerequisite locked, so you have a lot of "just buying up prerequisites" levels where you aren't improving.
I'm the king of far from perfect builds. I love off-meta archtypes in particular.
I presume you mean Improved Snap Shot not Greater, as you won't qualify for Greater without it (and greater is just a boost to Attack and Damage).
You however, are a 1st level Wizard followed by a 3/4ths BAB class. You do not qualify for regular snap shot before your BAB becomes +6 at level 8 (9 with your multiclassing). Your Myrmidarch is also eating your level 6 (7) Magus Arcana, so Disruptive is locked behind your level 9 (10) Arcana. And Improved Snap Shot is locked behind level 12 (13).
I would probably cut the Myrmidarch out, simply because using a gun without specific enchantments means you can't really use the multi-spellstrike which is the only thing I can see that Eldritch Archer isn't giving you already. None of the feats you've selected beyond Disruptive require Fighter so the better fighter level equivalent isn't worth the diminished spellcasting.
You also still need Weapon Focus (Any Gun if you're the Champion Mythic Path since you can take the Mythic Weapon Training) in order to qualify for Snap Shot.
Speaking of, if you're only taking Spellslinger for Firearm Proficiency, Mythic Weapon Training from the champion path would give you that proficiency, and it's available Tier 1. You could go pure Eldritch Archer and probably have a better time getting your prereqs, and having the higher BAB to apply for things earlier.
So here's my problem with this:
First, you use Snap shot so that you threaten 5 feet. Great, nice feat.
Second, you get Improved Snap Shot to increase your threatened range to 10 feat. Marvelous.
Finally you take Combat Patrol to increase that range even further ... by using up your full round action. The whole Schtick of a magus is that you can cast spells and attack at the same time, which you're appareny no longer doing? Also the whole point of an archer is that you can full attack every round, which - again - you're no longer doing. I almoat can't imagine a scenario where Combat Patrol would actually give you more attacks than just Full-Attacking and taking AoO's to foes who come within 10 feet. Even in those scenarios it's hard to imagine that those few extra attacks are worth more than a spell you could cast.
But let's say you go with it, and you're surrounded by mooks who come marching in to die by the thousand. What does Combat Patrol give you?
At level 15 (when you take Combat Patrol) your BAB is +10. You get +10 feet of threatened space, increasing it to 20 feet. And from there it never gets better. You hit +15BAB at character level 21, so unless you're going into epic levels you'll never see that 30 foot threatened area.
For my money, go Snap Shot and Improved Snap Shot and you'll love your life. If you really want to mess with a wizard just ready an action to shoot him (with a ranged spellstrike even). It takes a standard action rather than a full-round action, so even though it's not perfect it's still way better than Combat Patrol.
Just noticed you took Rapid Shot before taking Rapid Reload. You can't make Use of Rapid Shot if you can't reload quickly, swap those 2 feats.
Mr. Charisma is very right on both counts. Again, I'm not 100% sure what you want from Myrmidarch, (I realized midway through making the guide that Burrowing Shot required Weapon Training, which was an "ah that's what you want" moment. With extra Mythic Feat chances, I think it would be better to just grab Martial Focus instead, because you're weighing 1 feat versus 3 Magus Arcana, one of which slows down your build progress by 3 levels) but still keeping what you want to do. I think this would be a better path. Mythic stuff will be labeled M1-M10 since I'm not sure where you're starting from there. Frats marked with * require an ability chouce or feat from Mythic. I also assume you're using a pistol cause if not... Well it's not a fun time trying to get multiple attacks in unless you're a Musket Master. ** Is something from Mythic that obviously needs the regular first.
Human Eldritch Archer 20
Mythic Path Champion Tier ??
1) Point-Blank Shot
1) Precise Shot
3) Rapid Reload (Pistol)*
3) Free Arcana Pick
5) Weapon Focus (Pistol)*
5) Rapid Shot
6) Disruptive (From Magus Arcana)
7) Combat Reflexes
9) Snap Shot
9) Reach Spellstrike (Arcana)
11) Dodge
11) Deadly Aim
12) Free Arcana Pick
13) Improved Snap Shot
15) Combat Patrol
15) Free Arcana Pick
17) Martial Focus (Firearms)
17) Burrowing Shot
18) Free Arcana Pick
19) Free
M1) Mythic Disruptive**
M1) Mythic Weapon Training (Firearms)
M2) Ever Ready (Path)
M3) Free
M3) Free Path Pick
M4) Free Path Pick
M5) Free
M5) Free Path Pick
M6) Free Path Pick
M7) Free
M7) Free Path Pick
M8) Free Path Pick
M9) Free
M9) Free Path Pick
M10) Free Path Pick
You can use any of your free Mythic feats to sub in some of your prereqs early, however most of your necessary feats are limited by your BAB. So you could get say, Deadly Aim, Martial Focus (assuming you have proficiency from Mythic Weapon Training) and Dodge/Mobility early. I would use most of your free feats though towards metamagic options to round out actually being an effective Magus (I've built 2 so far and find metamagic a more fun investment than raw combat ability). Then of course you've your Path picks to be a better ranged character, and Magus Arcana to do more Magus (the on the fly metamagics are nice, since as a firearms user you don't really need the to-hit ones).
Of note, Pistol range is too low to use the super far ranged Spellstrike stuff, you're better off just getting reach for more options (which I slipped into the build path), and you'll get 25/30 ft for your Disruptive threaten on the rounds you've got nothing better to do than Combat Patrol. You have so many more options as a Mythic character though that the extra threat range is going to very rarely be the good option for a turn. In an Antimagic Field though, it wouldn't be a bad one. You'll also need Alchemical Cartridges for Rapid Reload to hit Free Action, but thankfully Mythic Weapon Training will apply your single weapon feats to all from the group so if you can nab an advanced firearm later Focus and Reload still apply.
@ Isaac Zephyr. Looks good.However my one problem is The GM(S) yes we have to Gm are picking are Mythic paths. It all part of the story of 3 heroes from other worlds being summoned to save the world we'll be in
But I can assure you they won't just stick us with crap we can't use.
They Asked us to Make 4 to 6 legendary feats are heroes have done in there life time and there choosing are paths Base of of them
Hmm... Well backup plan: though Champion does work best for the more archery-y build, Archmage could be cool too. The 5 Mythic Feat opportunities are just part of base mythic, so those are always available.
If you don't end up with the Champion path, then just swapping your Tier 1 feat with Exotic Weapon Proficiency (Firearms) still subs out the need to multiclass and lower your BAB/spell slots. You can then also as a human slip in Martial Versatility to apply Focus to all firearms you might get, and Mythic Rapid Reload to apply your Rapid Reload to all firearms, as well as giving you the option to spend mythic points to reload without provoking AoOs.
I can't really see giving a Magus a path other than one if those two. One is better with the gun, the other is better with the spells. If you get Archmage, I'd probably invest the feats for Combat Patrol (still keep Combat Reflexes for Snap Shots) into more metamagic just because the Archmage focuses on bigger mythic spells, and this will make Spellstriking the option you'll prefer most rounds.