458 SOCOM Cast Bullet Help

[roharmon]

I am having no luck in finding a cast bullet to fit a Radical Firearms 458 upper. I have tried Lee 459-405, 457-405 and NOE 460-405, sized to 459 and 460 with COL of 197-202. They engage the rifling and the bold will not go all the way forward.

Would lapping the chamber help?

Thanks

[tja6435]

I think you should try sizing your bullets to .458 and making a dummy round to see if they'll chamber. I can't run .459 cast in my RRA 458 Socom upper, but it'll sure fit .458

[rockrat]

I size to .460, but I don't use boolits that heavy. More in line with the RD350gr and the RCBS 300gr. Mine is a Tromix upper

[petroid]

Do a pound cast of the chamber and compare it to saami specs. If it's in spec is up to you if you want to ream it. If it's out of spec send it back to the manufacturer

[roharmon]

Thanks, I think I will give that a try. Do you cast? If so, what mold do you use?


I think you should try sizing your bullets to .458 and making a dummy round to see if they'll chamber. I can't run .459 cast in my RRA 458 Socom upper, but it'll sure fit .458

[hicard]

Accurate molds makes at least 4 different weight molds designed for the 458 Socom. You might look them up.

[dkf]

Do a pound cast of the chamber and compare it to saami specs. If it's in spec is up to you if you want to ream it. If it's out of spec send it back to the manufacturer

There is no SAAMI specs on the .458 socom. Radical is using knockoff reamer which is not the same as the original design, but close. I wouldn't know where to look for a chamber drawing. I know who has the original drawings but I doubt he would share them if asked.(probably can't legally show them)

The .458 does not have much throat to it, at least my tromix doesn't. With a NOE 460-350RF at 2.020" COAL a .459" bullet is a tight squeeze and will touch. A bullet with a negative diameter tolerance (smaller than the bands) in front of the crimp groove will give you more room to increase the COAL.

[reed1911]

I worked with Marty (the designer of this SOCOM) there is no restrictions on the data. If you want a print of the original chamber just shoot an e-mail to PTG and they will gladly send you one. Really though, you need a print of the chamber that was cut in your rifle, and if it was a factory produced one it may not be nearly as instructive as a cast of your own chamber (due to differences in original print as well as wear on the reamer over time).

With the molds you have now I highly suspect you can use them with a little change to either your sizing of the shank or a second sizing operation to size the nose to fit your bore (i.e. size the nose to at or -.0005 of your bore size not land size).

AR's are not terribly forgiving when it comes to seating into the lands, so you have to work with it a little. These are some of the things we did during development.

[dkf]

PTG does not have the original specs on the reamer, theirs is reversed engineered. This has been beaten to death over at the .458 forum. But Radical is probably using reamers from PTG. The Radical uppers are also the ones with the most problems too. I don't doubt the dimensions for finished ammunition is shared so ammo companies and die maufacturers can make it so it works.