Playing the Battlefield 1 beta" Finding it a grind just to equip some of the weapons and equipment that are locked out until you’ve reached the appropriate rank in a certain class" Well, thanks to Reddit user “iamswain“, a Battlefield 1 beta exploit has just been uncovered that lets you equip any weapon and equipment that’s available in the beta provided you have the appropriate War Bonds (Battlefield 1’s in-game currency for unlocking items). 
Instructions on how to do this little Battlefield 1 beta exploit are listed below:

You’re able to obtain all weapons without levelling up a single class, by going to battlefield.com/career and purchasing them there. After you equip them, they’re also equipped ingame.
Edit:
Step 1: Go to battlefield.com and sign in
Step 2: Click on CAREER
Step 3: Select BF1
Step 4: Go to LOADOUT
Step 5: Buy whatever you want
Step 6: Go ingame
Step 7: Profit

Obviously this is a bug that has to be resolved in the final build of the game…

I tested it for erm, research purposes and can confirm that it indeed works! You can buy any gun and equip it even those sectioned off by DICE for the Battlefield 1 beta. As mentioned above, it’s obviously a bug, so don’t expect you’ll be able to do the same thing in the final game. 
Now you can equip the anti-tank missile for the Assault class ASAP, get the med bag instead of the pouch and so much more. 
[Source: Battlefield1 Subreddit...