ok lets leave out the DMR for a sec.
The BR is a great weapon for short to mid-long range. It doesn’t function well at long range due to its 3 burst functionality, and its recoil. It takes 13 bullets to kill ( 5 shots) you can miss at most 2 bullets to get the kill
The carbine is a very good weapon that for short to medium range, it doesn’t work as well at long range because of the size of the reticle, but it does kill faster that a BR if you can land all 8 bullets.
The Light Rifle is a very good weapon for medium to long range, when scoped in it is a single shot, 4 shot kill, when unzoomed it is a 3 shot burst, 5 shot kill. Its unzoomed version kills slower than a BR but its zoomed kills faster than anything else.
Now lets put in the DMR It is a great weapon for short to long range. It really has no range limit. It kills faster than any other weapon (accept maybe the Light Rifle but im not shure) and is arguably easy to use.
If you put the DMR in this it is the most versatile, and powerful primary weapon of all time.
To fix the DMR I would say either make it a 6 shot kill or nerf the fire rate to be out matched by the BR when shooting perfectly.
Now for the boltshot
This weapon is like a mini shotgun in your pocket, It has a pretty fast charge rate and has two charged shots per clip, enough said.
to fix this just nerf the range and damage of the weapon, and maybe the clip.
With these implemented the games weapons are nearly perfectly balanced