Anyone ever use this combo? Varget is difficult if not impossible to find without giving up my firstborn.

Yes, TAC is a great choice for 308 and can give higher velocity than a lot of other powder choices. I've had good accuracy with it, depending what rifle and what bullet weight it likes. In my experience TAC performs best at or near max loads.

The best source of data for it IMO is the free Western Powders load manual (I think 8.0 is the latest version). Western owns Ramshot and Accurate powders, and their data is very comprehensive. Based on my experiences with those powder brands, I trust that manual more than any other for Ramshot and Accurate powder data. It's also one of the few sources for actual 5.56 loads (vs the 223 data everyone else provides), which TAC is also excellent for.

Thank you!!

I would encourage you to post your process and results if you do try these loads.

Of course! 8 pounds is on the way.

UPS is finally shipping my powder. In the meantime I have brass prepped! Prepping consisted of resizing, using RCBS Competition FL resizing dies, wet tumbling, trimming using a KWICK case trimmer, chamfering, inside neck cleaning with nylon brush and a drill, another quick wet tumble then a drying off by placing them in a cardboard box with an old hair dryer blowing into it.
All brass is LC trimmed to 2.006 +- .002

Hopefully when sizing, you measured shoulder bump relative to brass fired in that gun, and carefully controlled that? Correct (minimal, but enough for clearance) shoulder bump is far more important for accuracy than precise case lengths, or a number of other things people do. A general rule of thumb is .001"-.002" bump for bolt actions, and .003"-.004" for semi-autos, although that can vary depending on several factors. And for clarity, that bump is measured between fired brass from that rifle (finding the longest measurements), and the same brass after sizing.

Cleaning inside case necks is another one, especially with excessive wet tumbling - it's not necessarily helpful, and if you've cleaned them to be spotless squeaky clean that actually hurts far more than it helps. It results in bullet cold weld if the rounds sit for very long, and shot to shot velocity can vary a lot more than dirty or mildly lubed case necks. If you did clean them to be spotless, I recommend putting a tablespoon or two of car wax in your dry tumbler media, and then adding the brass for a while once the wax has distributed evenly. This will deposit a little bit of wax in the case necks and will at least help with more consistent seating pressures and reducing velocity variations.

A lot of people put lots of effort and time into work that doesn't help the rifle shoot better, and sometimes (like with wet tumbling) can make it shoot worse. It's easy to fall into that trap - make sure you're not putting aesthetics or just OCD efforts in front of accuracy priorities.

I resize my cases that I have shot in the same rifle as they'll go back in, to a slight resistance on bolt closing. I also add a little car wash and wax to the wet tumbler and some NuFinish to the dry. I wish I had saved my chrono records when I got the new phone, but my shot to shot variance is minimal. This may not work for everyone, but it works for me.
ETA: The second wet tumble is just soap (car wash) and water. No pins.

Finally got the Ramshot Tac! Loaded up a bunch of rounds starting at 41 grains working up to 43. There were no pressure signs at 43 grains. I must say I am impressed! Granted, this rifle (Ruger Precision gen 1) has liked most everything I have fed it. The only thing it didn't really like was a bunch of Winchester hunting rounds I had taking up space. I didn't change any scope settings from my normal load, using Varget. It seemed to like 43 grain load the best. As always, your rifle might not like the loads my rifle does and work up slowly!! I am not recommending this load in your rifle one little bit. Caution is the rule!!
The load is as follows....
Case: LC misc. years
Primer: CCI large rifle, standard
Bullet: Sierra 168 gr BTHP matchking
Powder: Ramshot Tac 43 grains
This group measures out at .447 measuring from the outside of the holes (not the grease ring) and minus the bullet diameter.

That's nice, but size matters. What was the distance to target?

100 yards

A good load, and some good shooting too.

Thank you! I’m preparing some brass for a couple more loads of it now.