Unknown .50

Need help with the ID of this round for my collection.

Can’t find it in Fuchs. So…

On originally T Z 87 headstamped brass, with a shallow vertical ‘cut’ through the “T” and the ”45” & “8” appearing to be hand stamped.

Dims are;
.800“ / 20.33 mm rim
.797” / 20.25 mm head
.785” / 19.95 mm shoulder
.552” / 14.03 mm neck
3.314” / 84.17 mm case length
.510” / 12.95 mm bullet
5.278” /134.06 mm OAL

If you also know of a place this has been referenced, I should also like that too.

Thanks in advance for any help.



The match looking bullet, the turned neck, the sharp shoulder, all point to somebody’s wildcat. The name? Who knows? Maybe Keith P. has seen this one before.

The .50 McMurdo, seen below, is very similar. Yours could even be a 50 McMurdo Short. I think he had several versions.

Good Luck. Tracking the wildcats, especially the exotic ones like the Big Fifties, is no easy task.


Perhaps the .50 Longson, it’s a bit short for a .50 McMurdo and a bit long for the .50 FCSA. Regardless it’s one of the FCSA Wildcats for competition.

TZ 87 is the original .50 BMG headstamp, before the case was cut back and necked. The Slice mark thru the T is the index point, the case is positioned (rotated) in the chamber so that mark is always in the same position, for each cartridge. The other numbers are indicators to the original loader, could be his own lot, powder charge, or something used to keep track of the number of reloadings, etc…

Thanks Ray & Keith

Interesting the indexing mark. How common was that?

Do either of you have case lengths for some of these FCSA wildcats?

My .50 FCSA (from Skip Talbot when he shot his, then world record, 4.034" group) has a 2.959" / 75.17 mm CL

Be nice to see in print.

indexing rounds is a common match procedure, all calibers, not just .50

I don’t know of any work on the wildcats, the .50 is such a small competition world compared to the NRA matches, F class, etc. There have been some writeups in Very High Power Magazine over the years about some of the variants.

Most FCSA stuff is done with the BMG. The wildcats that I recall were:

.50 DTC (current)
.50 FCSA (Skip Talbot, no longer shot, .50 BAT Improved)
.50 McMurdo (shot only by Lynn M and Scott Nye)
.50 Longson (only shot by Bruce Longson)
.50 Kyser (don’t think it was ever used in competition, more like prototype)
.50 BMG Improved (Full length BMG, blown out case like the Ackley, only shot by Eric Williams, no longer shot)

There was one additional wildcat, but I don’t recall the designation. It’s not an active competitive caliber either.

Differences were varying case lengths, driving varying case volumes, but also varying case necks, differences driven by which projectile was being loaded. (smooth bullets like Hornady AMAX requiring different case neck retention than, say, a driving band equipped bullet)


Being wildcats, there is no standard case length. The shooter may have had his reamer ground to meet his own particular requirement.

As I said, there was more than one McMurdo. The one I have has a case length of 3.635".

The 50 DTC (510 DTC EUROP) is 3.800". I think some of the originals were 3.810".


Many thanks gentlemen

Keith do you have case lengths of any that you mentioned? Other than Eric’s & Skips, and the two Ray mentioned.
That would be a shorter version McMurdo, the Kyser, and the Longson, which you thought as a possible.

Perhaps even with ‘shooter variation’ case lengths I can put a name to this.

Really ought to subscribe the VHP

.50 FCSA 76mm
Longson 83mm
Kyser 84mm
McMurdo 92mm
DTC 96mm
BMG Improved 99mm

GREAT many thanks Keith, I’m going to call it probably a Kyser, for now.

PS catalogs posted yesterday (6-9) priority mail.


There is no guarantee that your cartridge was/is being used in FCSA competition or that the designer/owner is an FCSA member. The large majority of 50 caliber actions and rifles sold by McMillan and other makers do not go to shooters competing in BR matches but to guys who wish to remain anonymous and who may use them for nothing more exotic than shooting rocks or tin cans.

Adding a name to a wildcat cartridge without provenance is never a good idea.



About indexing markings on the headstamp. What is the purpose? Isn’t a cartridge body a more or less uniform circular entity? And if there were irregularities in wall thickness during production, it would be undetectable from the outside? Do indexing markings appear in semi-auto competition style also, because it is probably very difficult to load a magazine with all markings pointing the same way?


You are correct that case wall differences are not normally detectable from the outside, but shooters have devised very accurate tools and methods to locate them from the inside. Cases that are found to be lopsided or banana shaped are usually set aside for practice or other use, or trashed if they are bad enough. Using known high quality cases to start with helps.

Indexing may or may not make any difference whatsoever. Advantages of indexing may be more psychological than real. Most shooters do not do it. Some types of competition do not lend themselves to indexing.

It may be hard for non-competition shooters to comprehend, but the difference between winning and first loser is often measured in thousandths of an inch. Sometimes, even less. So, competition shooters are very anal when it comes to little details that normal people would not find important. Most will admit that there are probably only 4 or 5 things that are really important, and yet they will do 10 or 11 because no one is really sure what the 4 or 5 are, and so they hedge their bets. Indexing may be one of the 4 or 5 - or it may be number 11.


There are also the 510 Allen magnum and the 50 Allen magnum.

The 510 AM is an improved version of the basic 50 BMG and the 50 AM has a shorter case, quite similar to Pete’s sample bur probably with a larger shoulder diameter and a sharper shoulder