Like the title says.

A brief search, and I can't seem to find anything more then early 2000's

And do / can bullets have a "patent" ?

Was the AMU some of the first to use it ?  @Sinister

I will e-mail Sierra, I just figured my Google-Fu was off for the morning...

Sorry ( and Thank You @BobinNC  ) for all those that tried to find the info.

@mcantu   Excellent info in the video, Thank You sharing.

And Thank You @TGH456E

So... and someone correct me if I am wrong.

It appears, and prior to Black Hills producing the various improved DODIC AA53 / Mk262's,  ...

HSM, Hunting Shack Munitions, made SAMMI spec'd .223 loads for the Navy and AMU using the 77gr SMK.  From what I can find, this was the mid-late '90s.

FWIW, I could find the Nosler Custom Competition 77gr  approx.  public catalog release date. Apr. 12 2003.. on a side note prior to that date only the 69gr and 80gr .224 bullets were shown in archived webpage. ( .30cal was the 155gr and 168gr )

Sierra was e-mailed a few days ago... no response at all from them.

I did remember Sinister talking about the Sierra 77gr MK  ( weird the things that a mind can retain !? )

Quote...

"Sinister
The Navy issued HSM 77s (Sierra Match Kings) to us at the 1999 and 2000, and I think 2001 Atlantic Fleet and All-Navy Championships. We definitely shot Black Hills 77s in 2002.
I bought 1,000 rounds of HSM (Orange Box) at Champion's on Commercial Row at Camp Perry at the 1999 National Matches and it shot very well, very accurate, no problems at all.
HSM 77s came in Orange Box, virgin components, 20 per individual box, 500 per long cardboard box, two cardboard boxes per case.
I shot them in a National Match M16A2, 1-8 stainless Douglas/Merchant barrel.
At the LANTFLEET and All-Navy all shooters fire at 200, 300, and 500 yards.
Got a Silver Excellence-in-Competition Medal at the 2000 All-Navy and a Bronze EIC Medal at the 2001 Atlantic Fleet. 1st Gold at the 2002 Atlantic Fleet and 3rd Gold in the 2002 All-Navy."

Yeah, I would still like to know that myself, Lol

I understand the whole angle of a mag length / "high" BC .224 bullet... and seeing how the 80gr SMK .224 couldn't be seated short enough.
BTW... for those who have never seen the 80gr Fed. load of that.. and only for long throated barrels.

@BobinNC
@TGH456E
@mcantu
@jmt1271

Maybe ... Jan. 29 1999 announcement on Sierra's archived webpage...

"Sierra unveils the new 77 grain MatchKing!! Within the last five years, the AR-15/M16A2 rifles have come to dominate the Service Rifle category of HighPower rifle competition. In response to requests for a magazine length bullet of higher Ballistic Coefficient for this type of shooting, Sierra proudly offers our latest MatchKing. Manufactured with a small meplat, an elongated boattail, but an ogive compatible with the magazine feed requirements, the 77 grain MatchKing is sure to be a hit. With a B.C. of .372, this new bullet gives you the long-range wind-bucking ability for the 300 yard line, and beyond. For even longer ranges, such as the Infantry Trophy match, this bullet is sure to make a name for itself.

This new "Specialty Bullet" will be sold in boxes of 500 bullets and will be available in June 1998. As a result of the length of the bullet, a 1x7" or 1x8" twist is required. The stock number of the .22 caliber, 77 grain HPBT is #9377. Retail price is $74.98 per box of 500 bullets.