Well unless you plan to single load the 88-90’s........
I shoot 77 mk262 clone loads out of all of my 223’s in 1-7 and 1-8 and all are hammers if I am in my wind game.
And at no point in my chat did I mention 1-9. but frontier had a 75gr OTM that was built for 1-9. I believe it was called the T2 shot very well out of the only 1-9 I had and was AR mag length.
You don't need to single load the 88s or 90s, but you would need to modify the AI AccurateMags to do it.
I run the 223 with a Defiance clone of the SA Rem 700 from modified AccurateMags that feed rounds of up to 2.650 OAL. The barrel was chambered with a reamer I ordered from Manson with .190 free bore, but in retrospect it probably should have been a tad longer.
Loaded rounds with 88 ELDMs jam the lands at 2.640 OAL and the base of the bearing surface is forward of the donut, so that's not an issue.
I feed from a 10 round mag with no problems whatsoever and I have no trouble safely hitting 2900 FPS using Varget with the 88s. With fire formed brass I can sneak up to 2950 but I don't recommend that for guys who dont understand how temperatures can affect pressures.
I get a solid 1/2 MOA accuracy with 88 ELDM so far, but when time permits, I do plan the play with jump a bit more to see if I can improve on that. I also have to test some 90 grain Bergers, while they dont have the BC of the 88s, they are likely more accurate at 100 yards.
I'd be real curious to hear about what guys might be doing to get better than 1/2 MOA accuracy with Hornady 88 ELDMs or 90 grain ATips. What secret sauce might lead to sub 1/4 MOA accuracy with those high BC bullets.
As for Gerrys Post about the 223 struggling at longer distances, I would agree for F Class with 1/2 MOA V bull, that's a tall order, but still plenty accurate for PRS or other more general shooting. The problem with the 223 for long range F Class is getting really low velocity spreads to maintain the widest center horizontal part of the V Bull. Accuracy is generally on par with any other cartridge... After all the cartridge only dictates your speed, not accuracy. Accuracy comes from the chamber and barrel, so its not something that can be blamed on the case used to hold powder. At 300 to 600 yards in F Class the properly outfitted 223 is just as competitive as any other cartridge, but velocity spreads can cost you past that, if you do shoot past that.
As for PRS, there is a class dedicated for the 223 which limits bullet weight and speed, so running the loads I describe here simply requires that you'd run as an open class shooter. Some guys feel that 223 uses too small of a bullet to spot impacts at longer ranges, but I don't buy that argument. Long range targets these days are usually fitted with flashers that indicate hits, so it's not an issue. The light recoil of a 223 for PRS is an obvious advantage. When you "objectively" evaluate the ballistics of the 223 with heavy bullets compared to the ever popular small 6mms used for PRS, there's not a hair breadth difference between them.
As for a 223 Creedmore, well that is a recipe for disaster in my opinion. Way too hot for a 223. Barrel life will surely be sacrificed. Anything more than about 33 grains of powder should never be used with .224 projectiles.
This is the modification required for AccurateMags for long 223s
Not shown in the video is that the front wall can be thinned out as well.