I am trying some heavy proj.  75grain 80grain---
And have a few questions
1-- what are your fav. loads
2--how deep do you seat your bullets---
3--what kind of brass do you prefer

thanks for any help

I usually shoot 77grn Nosler Comp's as they are cheaper than the SMK's and just as accurate.  I use the following:

-77grn. Nosler Competition
-24.3grns of Varget
-CCI BR Primers
-Winchester brass

I use the Winchester brass as it's hard, pretty cheap and fairly consistent. You can get better brass from Lapua, etc. but you'd be wasting your money when using it in a gas gun as it will eat it up. I seat my bullet .010" off the lands, which is still mag length for me.

This load has proven to be easily sub 1/2MOA in both my Mk12 SPR and SAM/R.

The best propellants are Varget, Reloader-15, and a Vitavourhi oh propellant whose designation escapes me at the moment.  They burn at about the same speed and this gives you some added choices if your barrel is finicky about what it likes.

I use the same primers and brass as Lawman734 but I was using RL-15 and 75gr Hornady's and was very impressed.  

thanks guys  . the only powder I have is h4895   Imr 4895   748
and found a load for the H4895 with 80 nosler   but is it safe with that bullet sticking that deap in the case??

I use the same primers and brass as Lawman734 but I was using RL-15

I've been considering swapping to RE15 for both my .308 and heavy .223 load since the lot to lot consistency has gone in the crapper.

and found a load for the H4895 with 80 nosler but is it safe with that bullet sticking that deap in the case??

Both H and IMR 4895 are probably running too slow to be a good performer in .223. As we all know it is an outstanding load for .308's etc, but I'd stick with some powders that are proven to work very well. You might be able to get the 80's to mag length by using a drop tube and then letting your charged cases sit on a tumbler to le the powder settle even more-but I wouldn't just load up and go. I'd much rather run it through a ballistics program like Quickload so you can get an idea of what kind of pressure your getting vs. velocity.

I load for highpower (.223) and would strongly recommend not trying to seat 80's to mag length.  They were designed for match chambered barrels with fast twist, 1-7, 1-8, even 1-6.5...
The 77's are designed for mag length and many in highpower use them for the short lines, 200-300, and use the 80's seated out near the lands for 600,  loaded at or near max...Most popular powders are Varget, RE-15, and lately VV...all are good, I use Varget, Winchester cases, Winchester primers...