Look it is like Power Armor. All the sources out there will state that X01 Power Armor starts appearing in game at round level 25, this is only a half truth.

In my current play through it started to appear about then, in another play through of mine it didn't start appearing until around level 60.

Basically, there is more to it than just what level you are. Difficulty setting of the game plays a part. How far along you are with the main quest can effect some items. It varies. Basically, when someone says you need to be level 25, the only correct response is, "Ok, level 25. Got it. What else?

you should be seeing a gauss rifle, there's a lady outside of boston, kinda to the south, not too far from the hardware store near fenway park, she's in a trailer and she sells high level weapons early on but its kinda a dangerous area early on to go to but she'll prob have one, also check the goodneighbor vendors often.

I am on Xbox one I like the idea of uninstalling except that I want to keep playing on this one a while until I start again from about the middle of the story, where your choices are open. I'll look into it in a minute to see if there's an option to uninstall like there was on 360

could you elaborate on this vendor so that i can find her or give a map location pic

Sounds like Cricket tbh. She is the only female merchant to travel near Diamond City. If so, she has the standard gear according to level, except the Spray 'N Pray unique.

ah yes i remember her bought pay and spray from her at the vault near there

Cricket is my favorite merchant. She is so... enthusiastic.

Cricket: "And THERE they are! Did your heart skip a beat too?"

SS:

My tier 3 weapons merchant started selling Gauss Rifles around level 40.

I like the Railway Rifle, I just wish I could find a Legendary variant.

yeah railway rifle is my favorite although ive never tried a guass rifle

Gauss rifles are in the airlines secret cache, though it needs master lock or a quest from Ness and i never ran across her myself, probably wont appear till after you could just pick the lock....

yea my next lvl i am going to unlock being able to pick master locks

Hehehe, yeah, she is something...something

above level 70, there is an option to buy one in Diamond City, I didn't do it because I already have 2 different legendary gaus Rifles.

Is Cricket the sister of that awful old lady in Sanctuary ? yeargh

I found a gauss rifle in a chest at the end of Nick Valentine's loyalty quest, exiting from Andrew Station after killing the final enemy. I was maybe level 30 or so. The chest was in a locked room that can be opened by pressing a nearby button on the wall.

Complete the Battle of Bunker Hill quest and you'll probably walk away with like 6 of them...lol

I did that quest and did not see a single one all I saw was a bunch or railroad hevies with some kind or rifles I was only lvl. 20 though