DD-
Both my wife and I shoot an AR Service Rifle in HP competition. For our Long Range matches, (Our range goes to 1000), my wife shoots a boltgun in .223. I have watched the Service Teams, Army and Marine, shoot their service rifles for a number of years in LR matches. I guess I have a decent amount of experience shootng the .223 at 600 and beyond.
You didn't specify which 80 you are shooting, but I assume you are shooting a Sierra 80. 2230 probably is not an ideal powder for LR with a .223 and heavy bullets. I would suggest either VV 540, 550 or RL 15.
Your muzzle velocity of 2750 probably will not be supersonic at 1000. When the AMU was shooting the SMK80 at 1000, they were looking for a slightly higher MV to be sure they were supersonic. The AMU also found that their 1/7 twist barrels stabilized 80's better at 1000 than either 1/8 or 1/7.7. The AMU has now switched to 1/6.5 twist barrels and shoot JLK90's at LR, as the Sierra 80 just wasn't optimal at LR.
If your current barrel shoots well, you might try the Hornady 75 AMAX at LR. You can drive it faster than the 80SMK, with the same level of accuracy, and their BC's are virtually identical.
You also might want to experiment with shooting either the Berger 80 or the JLK 80 and see if your rifle is accurate with either or both. Both of these bullets have a significantly better BC than the 80SMK.
If and when you decide to rebarrel, I would suggest you contact John Holliger at White Oak Precision for a PacNor 6.5 twist barrel with his proprietary chamber. John was/is the pioneer with the 6.5 twist barrels and 90's. He has done 7 or 8 6.5 PacNors for me and all have been hummers. The advantage of the 6.5 twist barrel is obvious, it alows you to shoot the 90 JLK at LR. It also delivers superb accuracy with any available bullet for the .223. I have used the Hornady and Sierra 52, driven as fast as I can and have not had any blowups in .223, with superb accuracy. (My 6.5 twist 22 BR prone rifle is another matter!)