Phase 3 - A.C.R. Yellow Tip Duplex .223 Question

Have read that years of production was 85-88 for the Advanced Combat Rifle (ACR) series of Duplex. The phase 3 had been fluoroscope to prove two projectiles where strait. Yellow tip has a WCC/88 head stamp.

Did they ever make a yellow tip duplex on a WCC/ 68 case?

Not miss read, looked under a 20x . Its been pulled and in the process of being sectioned. They are the projectiles from the WCC/88, copper jacket with steel cores. Maybe filled die?

Thanks for help Kevin

my yellow tipped is dated 88 and has a GM-jacket and a magnetic core. Can’t answer about the 68 case, but it seems quite far out of the time line. I have seven examples from this series & case-dates range from 85 to 89. The Duplex in our last auction was donated by Frank Hackley for the benifit of the IAA & it had a green tip, a REM-UMC commercial headstamp & was loaded by FA in 1962.
Paul Smith or Bill W.?

Hi Kevin,

The projectiles of the 5.56 duplex ACR are quite unique. They are of a simple 2-piece construction (jacket and steel core). The base of the core of the lower projectile has a distinctive step to achieve the desired dispersion (which Pete’s x-ray shows perfectly). This is unlike the canted bases of the SALVO projectiles. As to these projectiles being loaded into a '68 case, can’t see why this would have been done. As you point out, the yellow tipped round should be from 1988 and by this time we are 3 years into the project and they would not be scrounging for cases.

Please post a picture of the headstamp. A case manufactured in the 1960’s is going to look different from the modern WCC8X of the ACR program.


A bit of background info on ACR:

Here is an X-ray of all I have, however the one on the extreme right is the one in our last sale made by FA & it has provided a very nice donation to the IAA from the winning bidder.
The one with the ‘spire point’ front bullet and flat based lower bullet [third from left] has a W C C 85 headstamp, and a black tip. The ones on either side of have red tips (different colors of red). The yellow-tipped 88 is 2nd from right. The others are without tip color.

Thanks for the replies and the cool x-rays, honestly never knew there was that many. It has to be a filled die, and after looking at it even closer on the computer, more than convinced its an “88”. Have enclosed pic of head stamp here on this thread, but doing a separate post on the cutaway. Looks like I have more to look for. Kevin

Woodin Lab has the yellow-tipped ACR duplex round with W C C 8 8 and W C C 8 9 headstamps. Your cutaway looks like it is from '89 and not '68.

What exactly is a “filled die”?

Maybe terminology mix up. When the part that makes the head stamp (Bunter?) gets filled with debris and fills in a letter or number. Grease, metal shaving, dirt. That’s what it is called in coin collecting.

Found a video of a ballistic gelatin test with the Yellow tip duplex.

Thanks Kevin, now I understand.

Kevin, not to nitpick but on a headstamp the letters and figures you see are a raised portion on the bunter (the negative). Means it will be hard to “fill in” anything.
Also headstamps are usually made in one of the last head forming operations what means that the data is not applied onto a readily done surface. A headstamp is generated by case material being formed around the raised portions of the bunter until the head reaches it’s final shape. This is the reason why sometimes the raised portions (forming the data) sometimes break off due to the extreme sheer power as the case material is flowing sideways and the bunter surface is (usually) hardened (and sowith brittle). When this happens simply sections of letters or figures are not formed anymore and appear like “weakly printed” or as you say “filled in” - in fact parts of the bunter are missing then.

Of course there are also some (few) headstamps which are stencilled onto a ready and flat case head but this will also not have anything to be filled in.

Long story short, coin stamping and headstamp shaping is two different processes which do not fully compare.

To illustrate what Alex has explained, in the following thread you can see four headstamps made using the same bunter, last one in new condition and first four in broken condition.