bullet recommendation. 20" .223, hbar match, 1:7 twist

77gr Sierra Match King?

Anything longer makes it a single shot, which may or may not bother you.

-J.

Bullet: Sierra MatchKings 80 gr. Charge of CFE223 dependent on your rifle.

I recently started shooting CMP/NRA high power. My rifle is a RockRiver NM with 20" Wilson stainless barrel with a 1/8" twist and mil spec muzzle brake. It has a Wylde chamber/throat.
My 200-300yd load is the Hornady 75gr bthp match over 23.8gr of H4895 @2.25"oal.
For 600yds, I'm using the Sierra 80gr matchking over 22.5gr H4895 at 2.555" (touching lands). CCI primers, ofb match prepped LC-10,11,12 brass.
Benched at 100yds, how accurate can you hold/shoot? My receiver is an A4, so I can mount a scope (allowed next year, 4.5x maximum). With a 4-16x scope I get 5/8" groups with the 75's, 1/2" with 80's. (100yds, 5shots, or however many you want to put through the hole!)
I use the Hornady's because I got 2,000 blems for ~.12 each. Will continue to use them as they are normally ~.19 each. Sierras run close to .30 each. However, I got 500 80's on sale at $92. Should have got both boxes Midway had at that price, but I didn't know if the rifle would like them....
I also plan to try both the Midway "dogtown" and Midsouth "varmint nightmare" 55gr hp's for the 200-300yd lines. I'm "cheap". With the 55's, I like 27.0gr of BLC2. I've never seen a .223 that didn't shoot it well.

Added: I tried Rl15, and IMR4064. Accuracy was/is good but H4895 is ~100fps faster. Means a tad bit less wind drift... Have recently acquired some Varget to try... But have lots of H4895.

I get good groups with 69 gr Nosler bullets.

The lightest bullet I can run well are 60 gr Vmax out of my Daniel Defense. The 68 gr Hornady BTHP are very good. Haven't figured out the 77 SMK's yet.

77gr Sierra Match Kings shoot absolutely lights out in my Krieger 7.7 twist, best part is they do that loaded to magazine length. The 80gr SMKs also shoot very well, but must be loaded too long for the magazine and single loaded to shoot well for me. I'm not good enough yet to really tell a difference between the 77 and the 80 at the 600yd line.

The Hornady 75gr match HPBT also seem to shoot about as well based on what testing I have done, which isn't a lot given how happy I've been with the 77s. A couple other shooters I know favor the Bergers, I bought some 82s but haven't loaded any up yet.

75gr HPBT or 77gr SMK over IMR8208 has given me very good results in 18" WOA and Douglas barrels. I've also had good results with H4895 and Varget. I tried CFE but couldn't get it to shoot well. YMMV.