The 20-50 caliber.(pictures :)


Well-Known Member
Feb 5, 2010
It's for people who want 20mm size gun but not the paper work .It fire's a 800 grain solid @ 3600-4200 fps usually 3600 fps though .I imagine it would be more accurate than the 50 bmg it being master etc .Gun has a 50" barrel + few different muzzle brake designs

here's a picture left to right ...50 bmg/20-50/then 20x102mm or 20mm Vulcan

yeah the fatmac was made way back though i wanna say pre 80's .but that 20-50 uses the whole length case .wounder how it does at 1500 yards or so
When I read the subject line I thought it was going to be a .50BMG case necked down to hold a .204 caliber bullet. That would be overbore!
I would be a bit sceptical that the 800 gr Solid would be accurate at all at these velocities. Its been proven time and again that the VLD solids do not like to be driven faster then 3000 fps.

Most are made from brass or some other similiar alloy that will slip the lands of the rifling at velocities higher then this.

I wonder what powder they are using. H-50BMG, US869, VV 20N29 are about perfect for the 50 BMG case capacity along with WC860 and WC872. Thats as slow burning as we can get for powder. Dramatically decreasing the expansion ratio would require a MUCH slower powder to get load densities up to where they should be for good consistant velocities.

I think its more of a gimic round more then anything. Not flaming anyone in any way but I have played with big 50 cals and there is a limit to accuracy as far as velocity. A Mild steel solid may be your best bet but even then, at these velocities, I would be amazed if anything would be accurate by our standards here on LRH.
yeah the fatmac was made way back though i wanna say pre 80's .but that 20-50 uses the whole length case .wounder how it does at 1500 yards or so

1500yrds is out of the question for this round. The 20mm, 25mm and the 30mm are all used accurately from Bradley fighting vehicles, Vulcan cannons, and the new wheeled transport up to 2 miles plus with devastating effect on leveling homes and buildings. 1500yrds would be your zero. It is capable of penetrating armor tanks to 2 miles.

ill post the pcitures of the rifles 2morrow .This was made for people who want anzio's 20mm rifle but not do the 6 months of paperwork so they made a in between.But really they could have went with 14.5mm.half inch law and calibers i know but ssk got the atf to approve his .950 jdj rifle fires a 3600 grain bullet at sum 2700 fps +.actually a 20mm -14.5mm is the 14.5mmx114mm i think it's around that size .And i didnt know that about solids not liking 3000 fps+ i thought they where the best bullet construction you could get
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