Building a DPMS in .257Ack?

gdcpony · December 16, 2012, 05:40 PM

A while ago I was looking at a forlorn 98 action and adding up the price to turn it into the heavy barreled varmint rifle I dream of. Boy, did it add up! I figure I will have over $1200 in it by the time I am done.

So I look over at my current project- another Mauser- in my favorite caliber of .257Roberts. I plan to re-barrel it to the Ackley version upon wearing the current tube out. Beside it sat my trusty AR15 which as a Marine I love dearly. I love both actions (Mauser and AR) and calibers (.223 and .257)! I have both a bolt and semi .223, if only I could get the same in .257.

Then it struck me: Why spend so much to pretty much duplicate a rifle I already have? Why not look into an AR in .257? I swear there were angels singing! (ok not really, but you get it). So I began researching the possibility of an AR build in .257Roberts.

In light of last week's tragic events, I decided that I might want to get the receiver sooner rather than later. So I picked up a base model DPMS LR-308 rifle. This way I can shoot it while saving and scrounging the parts I need. That list is surprisingly short. I simply need the barrel, a proper handguard, and a few little parts.

Most people and even a few gun makers (particularly those I would have to deal with) don't even know what the .257Roberts is. So the barrel will be hard to source. This is especially true since I would want it to start out in the Ackley version. Any ideas there? I would like the barrel to be a 24" heavy.

It will probably be years before I can complete this rifle, but at least I have a good start.

jackpine · December 16, 2012, 11:39 PM

I don't think it will work as your talking a 57mm case and not a 51mm. If you could get it to work you would have to fab a new magazine because the feed angles on a 7.62X51 mag would be all wrong for a 7 mauser based cartridge. You would be better off making a 25/08 or selling your 308 parts and picking up a 257 WSSM AR-15 upper as the work has been done for you already

December 16, 2012, 05:40 PM	#1
gdcpony Member Join Date: March 2, 2010 Posts: 28	Building a DPMS in .257Ack? A while ago I was looking at a forlorn 98 action and adding up the price to turn it into the heavy barreled varmint rifle I dream of. Boy, did it add up! I figure I will have over $1200 in it by the time I am done. So I look over at my current project- another Mauser- in my favorite caliber of .257Roberts. I plan to re-barrel it to the Ackley version upon wearing the current tube out. Beside it sat my trusty AR15 which as a Marine I love dearly. I love both actions (Mauser and AR) and calibers (.223 and .257)! I have both a bolt and semi .223, if only I could get the same in .257. Then it struck me: Why spend so much to pretty much duplicate a rifle I already have? Why not look into an AR in .257? I swear there were angels singing! (ok not really, but you get it). So I began researching the possibility of an AR build in .257Roberts. In light of last week's tragic events, I decided that I might want to get the receiver sooner rather than later. So I picked up a base model DPMS LR-308 rifle. This way I can shoot it while saving and scrounging the parts I need. That list is surprisingly short. I simply need the barrel, a proper handguard, and a few little parts. Most people and even a few gun makers (particularly those I would have to deal with) don't even know what the .257Roberts is. So the barrel will be hard to source. This is especially true since I would want it to start out in the Ackley version. Any ideas there? I would like the barrel to be a 24" heavy. It will probably be years before I can complete this rifle, but at least I have a good start. Last edited by gdcpony; December 16, 2012 at 06:11 PM.

December 16, 2012, 11:39 PM	#2
jackpine Senior Member Join Date: November 24, 2010 Posts: 351	I don't think it will work as your talking a 57mm case and not a 51mm. If you could get it to work you would have to fab a new magazine because the feed angles on a 7.62X51 mag would be all wrong for a 7 mauser based cartridge. You would be better off making a 25/08 or selling your 308 parts and picking up a 257 WSSM AR-15 upper as the work has been done for you already