I agree with meganoth that what you describe - for a single player, alone not in a party, at level 7 and presumably not much past day 10 - should be impossible. I'll be back momentarily with The Math. I gots a database which calculates odds for Item X at Level Y and such as.
While I get the numbers, can you check your current Gamestage?
Hey, I'm back. Alright so picking just one of your loot items - the Sniper Rifle - it sure seems pretty impossible in a vanilla game for a solo Level 7 player to find one of any quality, never mind a quality 3 rifle. Here's the nauseating detail.
1) The Sniper Rifle is only available from lootgroups "groupWeaponsRangedScaled" and "groupWeaponsRangedScaledTPlus". In both cases, the probability distribution "ProbT3" is used.
2) The first bit of ProbT3 looks like this, which means between level 0 and 88, the chances of finding an item which uses this distribution are zero. Naganna happen.
<lootprobtemplate name="ProbT3">
<loot level="0,88" prob="0"/>
<loot level="89,91" prob="0.04"/>
<loot level="92,93" prob="0.05"/>
<loot level="94,96" prob="0.05"/>
<loot level="97,98" prob="0.06"/>
<loot level="99,100" prob="0.06"/>
3) At Level 7, your Gamestage is capped at approximately 16. Therefore, without some other extenuating circumstance not described in the OP, it's impossible for a Sniper Rifle or any other Tier 3 weapon to be found. In any loot container. Even Tier 2 weapons are unobtainable at that low GS.
Edit to add: here are the ranged weapons you would expect to find at GS16 in a chest which pulls from "groupWeaponsRangedScaled":
Weapon
Probability
Primitive Bow
0.64%
Wooden Bow
0.007%
Iron Crossbow
0.007%
Blunderbuss
0.64%
Double-Barrel Shotgun
0.014%
Hunting Rifle
0.014%
Pistol
0.014%
AK-47
0.014%