Rifle: HS Precision Short Tactical (700 SA)
Ok I’m getting light primer strikes pretty consistently every 4-5 shots. I’ve tried multiple ammo types - Black Hills, FGM, LC M118LR and even some regular 150gr stuff. I’ve cleaned the bolt, firing pin and spring. My total round count on the gun is pretty low as well <500.
Figured I’d ask to see what else I can do before I send the rifle away to either a gunsmith or back to HS.
Have you checked your trigger? The sear could be dragging.
No I haven’t. I’m not too familiar with the way the 700 trigger works but I can take a look online. Can’t be more technical than fire control in the Abrams. 
What trigger is on it?
Stock HS Precision.
OK. I have had light primer strikes with Timney triggers that had the short sear on both my 700s SA
I have had light strikes in 556/223 with the otherwise excellent Remington 7 1/2. If you dont seat them all the way into the primer pocket you can get a light strike. the 7 1/2 is a small rifle primer so maybe not relevant to your situation.
In factory ammo, SSA 175 grain 308 will occasionally give me a light strike. I checked head space and that was not apparently the problem. I am using a titanium firing pin in my Remington 40X and that might be the problem, though no issues with hundreds of Black Hills 175’s.
Those light weight firing pins are notorious for light strikes. They are supposed to be faster, but are plagued with this issue.
Good luck.