.243 win imp vs. .243 ack imp dies

[Titletown101]

Can someone help me with this question. I purchased a new set of what I thought were .243 Ackley imp dies but what I received were the .243 win. imp. I am in the middle of my first custom build and I want to make sure I get this right. If my gunsmith uses a true .243 Ackley reamer will the .243 win imp. dies muck everything up? Would it pay to get the right dies? Does anyone have a TRUE set of redding .243 Ackley dies they can part with?
Thank you in advance
John

 

[308sako]

I think what you are describing is what happened to me with my .243 AI from Cooper. The dies were sizing the case body of the brass way too much, like .012" just behind the shoulder. Redding was able to get the dies right when I provided 5 fired cases for them to measure and ream the die to fit. I should mention it took two tries for them to get it right! Now that the dies match the chamber I have much better results.

 

[gotcha]

Not positive of this answer but a call to the MFG would confirm. Could be simply a nomenclature thing. IE: .244 rem improved vs 6mm rem. Ackley improved. The 6mm rem. AI. Is same cartridge. However Hornady manual lists a .257 Roberts Improved which is actually the RCBS version with 30* shoulder rather than the Ackley version with 40* shoulder. Confused? Check with the mfg. to insure you have the shoulder angle you need. If your dies are RCBS there's a chance they are the 30* shoulder angle unless specifically stamped AI or Ackley improved. Hope this helps. Someone with good knowledge should come along to better clarify. Anyone?

 

[Steve Blair]

Wouldn't a set of Harrel, Warner or other custom dies put this to rest and produce a better outcome?

 

[jcampbellsmith]

I had similar issues, but http://www.accurateshooter.com/cartridge-guides/243win/ sheds some light on things. I got my Ackley second hand with the attached dies which were fine for neck sizing and seating. My brass wouldn't go into the body die.

Once I had some twice fired Lapua brass, I sent it off to Hornady for a custom full length resizing die and that's worked well.

Regards JCS