"The fifties" .50 / 12.7mm

Excerpt from my article in the JOURNAL # 449.

You guys remember the fifties, don’t you? Ah the fifties. Not the decade of blue suede shoes, drive-in movies, automobile tail fins, or Elvis. I mean the FIFTIES, as in 50 CALIBER BENCHREST CARTRIDGES.

At the top of the list and most often encountered is the daddy of them all, the 50 BMG. As required by FCSA rules, any rifle competing in the Light Class must be chambered for the unaltered BMG case and must accept an FCSA approved chamber gauge. The one shown here has a 50 BARRETT headstamp and a 750-grain Hornady A-MAX UHC bullet.

Every wildcatter worth his salt will take any cartridge case he can get his hands on and try to improve it. The 50 BMG is no exception. The 50 BMG IMPR shown here is loaded with an 800-grain solid bore-rider bullet.

Many 50 caliber competitors consider the case volume of the original BMG cartridge to be more than adequate for 1000 yard shooting and they seek improvements in the form of less capacity and more precision rather than added velocity. The one shown here, the 50 McMURDO, is loaded with a 705-grain bore-rider bullet and is one of the more popular.

Another often seen cartridge is the 50 BAT. Using the military Cal. 50 Spotter-Tracer M48, M48A1, or M48A2 case, the round shown has had the primer pocket enlarged and a brass flash tube with a standard large rifle primer installed. The cartridge sports a GI 700 grain M2 bullet.

A 50 wildcat that is destined to grow in popularity is the 50 DTC. Designed by a shooter in France as the 510 DTC EUROP, it was intended for use in countries where military cartridges are prohibited. The United States version is aimed at side-stepping State laws banning the 50 BMG.

A discussion of 50 caliber benchrest cartridges would not be complete without mention of the largest of them all, the 50 FAT MAC. Developed by rifle maker Gale McMillan, the Fat Mac is made from a drastically altered 20mm Vulcan cannon case. Whereas the 50 BMG Improved can launch a match bullet to 3000 feet per second, the Fat Mac will propel the same bullet in excess of 3400 fps. Unfortunately this performance comes with a high price tag. Initial tests resulted in very short barrel life and serious copper fouling after only a few rounds fired. Attempts to mitigate these problems were only partially successful and the project was eventually abandoned.


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Awesome Ray! What ranges do they shoot them at?


It’s almost exclusively a 1000 yard competition. I don’t mean to diminish 50 Cal shooting in any way whatsoever but, to dispell a popular misconception, the small caliber Benchrest rifles (6mm to 30 cal) are capable of smaller groups. But, anyone shooting a 30 - 100 pound rifle off of conventional front and rear rests, and calling it fun, deserve our admiration.


I have always wondered what BAT means. Battalion Anti-Tank? Battalion Artillery Trainer?

It’s Battalion Anti-Tank, as in the British 120mm Wombat, Conbat & Mobat series.

Hello, I just need some more information about the ammo - 50 BMG IMPR, 50 FAT MAC. I would be thankful for it.

I’m afraid I cannot offer any more information on this calibre, I simply recall using these rounds during my army service.

what sort of information?

I need construction of that ammo, also parameters and where they are used.

construction? you mean other than a parent brass case or are you talking about things like web or case wall thickness .

& where they were used is up at the top - .50 cal. benchrest shooting. usually at 1000 yard ranges

The various .50 match cartridges are based on the plain .50 BMG caliber cartridge, modified in some way to achieve _____, where _____ varies between competitors. The exceptions: The FatMac is the 20mm Vulcan case, drastically cut back and necked to .50 caliber. The .50 BAT is a military cartridge for the M48 series, but still based on a cutback BMG case, 77mm instead of 99mm. There is a match variant of the .50 BAT, called the .50 FCSA but is the BAT case with sharp shoulder ala’ the Ackley improved series of cartridges. The non-exceptions: .50 Improved is simply the BMG case modified along the Ackley design, straight wall, not tapered case, sharp shoulder. Intent was to provide optimum powder loading density for a specific, surplus, 20mm powder that is no longer available. .50 DTC is 98mm long and with a different shoulder, to prevent the DTC from chambering in the BMG rifle chamber and the BMG from chambering in the DTC chamber, to definitively qualify the DTC as not being just a BMG cartridge in disguise. The .50 McMurdo is BMG cut back to 92mm and necked with a sharp shoulder, with a neck length chosen to hold a specific Bore rider .50 caliber bullet of the maker. Cutback to achieve optimum loading density for a specific .50 BMG Powder. The McMurdo is of Lynn McMurdo, now deceased, who manufactured his own solid brass bullets. There are other such “wildcats” like the McMurdo, the .50 Longson, .50 Kyser, etc. All varying case lengths, varying neck lengths, etc. All are for match/competition. Different cartridge/chambers are authorized in different competition classes. Light Gun for example has to be BMG or DTC chamber only. DTC is authorized for Light Gun as BMG is prohibited in California unless you already owned/registered a BMG rifle. You can find out more about the .50 shooting sports through the FCSA. www.fcsa.org Competitions held in various places in the USA (see the website for specifics) and several foreign countries, Canada, UK, Switzerland, New Zealand, etc. (see websites) 1000 yard competitions, fixed targets, both benchrest and prone. If you have specific questions, let me know. I’m heavily involved in that caliber/sport.

I am afraid the .50 BMG IMPR and the .50 FAT MAC are used nowhere, because they did not fullfill high expectations. If you follow developments over time, Super Duper cartridges pop up in breathtaking speed, but very few survive the test of time. For example, look at the long line of short magnum, super short magnum and short action ultra magnum cartriges originally introduced and how many of them can be still bought today.

The Fat Mac was fired at this year’s FCSA World Championships. It’s a gen 2 variety though, different than the original. There is still one shooter using the .50 improved case. All these wildcats, though, are limited use, competition only and generally only 1, maybe 2 shooters using that specific design. The exception here would be the original .50 BMG cartridge/chamber and the .50 DTC which are regularly fired in competition. The other wildcats generally have little to no active use as most of those developers are no longer alive.