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.50 Browning Machine Gun Calibre Ammunition Re-Loading data and dimensions

Disclaimer... This page is a collecting point for fragmentary information that comes to light during my wanderings through my old notes. As a result it may be incomplete or even contain some incorrect information. It would be unwise to rely on this page of information until this warning notice is removed.

Also known as 12.7 x 99 mm, 0.50 BMG, 'fifty Browning' or just 'half inch MG.

This page is not about machine gun applications, but this calibre is ideal for long range sniper applications. The data presented is mainly for the standard form of the round, rather than the Saboted Light Armour Penetrator (SLAP) round or it's saboted variants, but there are a few details further down the page.

The .50 Browning Machine Gun cartridge (.50 BMG) was developed at the end of WWI (1918). Browning also developed the fully-automatic heavy machine gun that was adopted in 1923.

More recent developments, have expanded the use of .50 BMG to a sniper-rifle with high velocity that allows for effective use over thousands of yards. The military adoption of .50 BMG sniper riles followed it's use in long range competition shooting. In order to aid stability and reduce recoil a muzzle brake is often incorporated.

Date... Originator...
Bullet Dia... 0.510" or 0.511"Main Usage... Machine guns or long range rifles for sniping or specific material damage
Die Set...
full length re sizing Set... RCB56702 .50 BMG... 1 1\2"-12 thread
Neck Sizer Die... RCB56704 .50 BMG...1 1\2"-12 thread
Intended barrel length... ??
Primer... Boxer, BMG type, 3 point crimpMax overall length... 5.450"
Trim Case... RCBS Trimming Die... RCB56706
.50 BMG... 1 1\2"-12 thread
Lyman 50 BMG accutrimmer #7862130
Max Case length...
Crimp... Bullet Seating...
Shell holders... RCBS... Lyman... Pacific/Hornady... Bonanza...

Extra large deburring tool... Lyman #7810206

.50 BMG cartridge Dimensions in inches and mm

Water capacity 289 gr.

Wt. Grains
lb/Sq in
ft lbs
Jacketed720 Gr281012630??
Jacketed647 Gr298012756??

Notes (shift to SLAP page)

Saboted Light Armour Penetrator (SLAP) round consists of a sub-calibre 0.30" (7.62 mm) Tungsten penetrator projectile carried within a 0.50" (12.7 mm) sabot, which falls away soon after the round exits the muzzle. Thereby, the penetrator gains a higher velocity (3,985 ft/s as opposed to 2,900 ft/s) producing a flatter trajectory and greater penetration of armour.

I have seen some information on the net that indicates that the SLAP round was devised by American Military personnel during the 1980s... However, I was involved in discussions (in UK) about this technique during the late 1960s, but the idea of doing it is many years older than that.

 Written... 12 May 2003, New Domain... 19 November 2003, Upgraded... 18 January 2007, Additions... 01 February 2007, Code Altered... 17 May 2008,
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