Less Than 50 BMG .510 Rifle Cartridges

[Deleted member 46119]

No Magazine mate. Just single load through the port as normal.
If you want to got real long then remove the bolt and feed it from the rear.

The point is to have a 50cal, sub BMG chambering with magazine feed.

505 Gibbs based with a COAL of 4" or less.

 

[Bravo 4]

Are there any common rifle cartridges that would allow me to push a .510 750gr Hornady A-Max to ~1800 FPS ?

I have pushed my 16.25" barreled rifle to 1700fps with the 750 Amax. It may get more but I quit there, I was shooting without the suppressor and the recoil got pretty fierce. The picture is a 750 Amax loaded right off the lands @ 4.2" (with an Amax next to it to show seating depth). They will not load in the Savage long action magazine and I have to pull the bolt to get the Amax rounds to eject. However, when loaded with pulled (and sized) M33 and API projectiles it will eject a loaded round. A flat point or round nose bullet will load into the magazine. The cartridge is a cut down .300 RUM, about .25" longer than a .50 Alaskan. With a longer barrel you may get the velocity you posted above, maybe a bit more. Might be worth looking into. The problem I have run into is that it headspaces on the case mouth and so you have to get the brass cut just right.

 

[375rifleman]

Bravo 4 your 50 is REALLY close to what I'm looking for with a little work and reloading experimentation by me I could probably get the results I`m looking for. With a different action I would probably be able to load full C.O.A.L. cartridges. I even bet if I talked with RCBS, Pacific Tool and Gauge, or Hornady I could get some custom dies made. Maybe a 338 Lapua based action would be long enough also. Thanks for your work on your 50 cal any other information would be greatly appreciated.

 

[Bravo 4]

I cut the brass down so that I can load it to subsonic velocity without a large amount of unused space in the case. I have heard of guys necking up full length 375 Ultra Mag brass, that would give you almost another .5" of case capacity to play with.

 

[375rifleman]

I don't really want to go subsonic and if I can get a 750 grain A-Max to 1700 FPS it will stay supersonic until ~1100 yards because of the high BC of the bullet.

 

[375rifleman]

Does anyone have any information on the 375 RUM necked up to .510 caliber wildcat ? Thanks in advance for any and all thoughts opinions or answers.

 

[Bravo 4]

Home

Get in touch with these guys, I think their 500 MDM is based off a full length RUM case. However, I think it's a .50 cal not a .510 cal.

Also may have been mentioned, look into the .375 Ruger case.

 

[375rifleman]

I tried to contact the people who designed the 500 MDM but since they required me to put what company I worked for as well as my address I couldn't.

 

[Bravo 4]

I have my reamer made by Pete at PT&G, and if I'm not mistaken a set of GO/NO-GO gauges built for a full length UltraMag case necked up to .510. Send me a PM if you want to borrow them.
Give Pete a call, he may have made these for others and might have some info.

As for B&M, I contacted them a few years back when they were having SSK build for them (if memory serves me right). I contacted SSK but just didn't like the attitude over the phone, and I wasn't just prodding info I was wanting them to do the barrel and suppressor.