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View Full Version : rimless 256 Winchester Magnum

22_boomer
07-12-2011, 03:56 PM
I put together an AR carbine that's built around a rimless 256 Winchester Magnum. I'm reforming .223 brass and using Lil' Gun powder. Right now I'm shooting Sierra 70gr BlitzKing bullets and would like to go lighter but there doesn't seem to be any pointy bullets lighter than 70gr in .257" diameter. The barrel on this carbine is 11.5" long with a fake 607 moderator pinned and welded to make it a legal 16". I really don't think I want to try the 60gr flat nosed bullets that are available -- I've got a feeling they wont feed well. I really wish there was a 60gr bullet similar to the Sierra 70gr BlitzKing bullet. Does anybody here know of a pointed .257" diameter bullet that is lighter than 70 grains?

This is the carbine is below. I put the scope on there to use in checking accuracy. Normally I use a carry hand with a small 4X scope.
http://i184.photobucket.com/albums/x205/22_boomer/256wincestermagcarbineupdated2.jpg
The rimless 256 winchester magnum is the cartridge on the left next to a .223 cartridge. The 256 WM in the picture has not been fire-formed yet.
http://i184.photobucket.com/albums/x205/22_boomer/256WMand223.jpg
Greywuuf
08-22-2011, 11:49 AM
Nice looking setup,, only thing I saw in a lighter bullet that was even slightly is some almost truncated cone Flat points in 60 grain. I saw them in a midway flyer the bran eludes me right now, if they feed i am sure they would be explosive in this fast stepping little carbine. Keep us posted if you find anything.
320pf
08-23-2011, 01:35 AM
Nice! I have a couple of questions. What does the fire formed case look like and what velocities are you getting with the 70 gr Sierra BK?

320pf
22_boomer
08-25-2011, 11:18 AM
Nice! I have a couple of questions. What does the fire formed case look like and what velocities are you getting with the 70 gr Sierra BK?

320pf

The fire-formed cartridge is in the picture below -- don't know if you can actually tell any difference -- maybe the sharper shoulder.
http://i184.photobucket.com/albums/x205/22_boomer/256wincestermagfireformed.jpg

With the loads I use in the fire-formed cartridges I'm getting 2300fps. that's out of my carbine's 11.5" barrel.
22_boomer
08-25-2011, 10:09 PM
Greywuuf,
You know that at some point in time I'll just have to try those 60gr Hornady flat nose bullets. I need to see if they will feed from my modified Pmag.

this is a picture of the 60gr Hornady .257" flat nosed bullet below.
http://www.grafs.com/uploads/pictures/128/hrn2510.jpg
If they feed it should also give me a bunch more in velocity.