Currently, bolt action rifles are too expensive to be a realistic option for the marksman class. The Mosin Nagant and M24 both cost 2 supply points. The greased bolt, essentially a mandatory upgrade, costs 3 more. For this same cost you can get the Mk. 14 EBR or the SVD, which both have almost the exact same kill potential while having a higher capacity and much faster firing time. The only reason to take a bolt action rifle currently is for fun -- which is great, I love using subpar guns to have a good time. But they can't stay the same cost.
At the minimum, the price of the bolt action rifle and the greased bolt both need to be reduced to 1 supply. This would make it 3 supply points cheaper to get this(not counting an optic) than it would to get one of the semi auto rifles for marksman.
But I think we can go further to bridge the gap of balance. The semi auto rifles are so far ahead in the meta that the bolt action rifles have a chance to shine in a niche role as a budget option.
You could make the bolt action rifles 1 point or even free. And more importantly, remove the Greased Bolt upgrade. Make the rifle's default cycling speed be what it is when someone has the Greased Bolt equipped. It's already essentially mandatory, why not attach it to the weapon? This would make bolt action rifles much more attractive. They would be cheap but require precision to get kills, as you can't land follow up shots quickly and you have very limited close range versatility. You could spend the extra supply points on a sidearm or grenades.
Long story short, bolt action rifles need to be cheaper.