MudRunner2005
Well-Known Member
Re: Most accurate, smoothest cycling, short, deer cartridge
Do a google search for Kenny Jarrett.
Do a google search for Kenny Jarrett.
Need pros advice for short heavy deer and target rifle build
- Thread starter rangerdanger
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J E Custom
Well-Known Member
Re: Most accurate, smoothest cycling, short, deer cartridge
The 7/08x40o Is not one of the cartridges that Ackley actually tested and designed, so some call it a 7/08x40 because that was the wildcat designation when it was first created by the bench rest shooters. But you can call it an Ackley because it meets all of the designs of the Ackley's and is head spaced the same way with -.003 less than the 7/09 head space gauge for accurate fire forming.
Lots of the original 7/08x40s were different lengths than the now standard SAMME length 7/08.
All of the dies are now the standard 7/08 length but there are still some 7/08 x 40 and 7/08 x 30o that some shooters prefer. Everything with a 40o shoulder is not an Ackley, but some like to call them an Ackley and that's fine as long as the barrel ID is correct for the cartridge and prevents the use of the wrong ammo.
I build and chamber all of MY rifles and if I want something different, I design the reamer drawing
to accommodate what I want the chamber to be and make or buy custom dies for it. The 7/08x40
(7/08 Ackley) can be chambered with available chamber reamers and standard dies can be used.
Standard 7/08 brass can also be used as well as 3/08 brass to fire form for the 7/08 x 40.
The advantage to any cartridge/wildcat with a 40o shoulder is better powder efficiency and brass life
The 30o shoulders are preferred for Simi Autos to aid in rapid feeding.
Shoulder angles have always been controversial but PO Ackley liked the advantages of the 40o shoulder at the time because of the available powders. Now we have so many more powder burn rates the real potential of the 40o shoulder can be achieved.
So when you see a barrel ID that says xxx Ackley, It should be a SAMME chamber IF it is not a SAMME chamber it should be marked xxx 40o so the owner knows that it is/can be, different.
J E CUSTOM
The 7/08x40o Is not one of the cartridges that Ackley actually tested and designed, so some call it a 7/08x40 because that was the wildcat designation when it was first created by the bench rest shooters. But you can call it an Ackley because it meets all of the designs of the Ackley's and is head spaced the same way with -.003 less than the 7/09 head space gauge for accurate fire forming.
Lots of the original 7/08x40s were different lengths than the now standard SAMME length 7/08.
All of the dies are now the standard 7/08 length but there are still some 7/08 x 40 and 7/08 x 30o that some shooters prefer. Everything with a 40o shoulder is not an Ackley, but some like to call them an Ackley and that's fine as long as the barrel ID is correct for the cartridge and prevents the use of the wrong ammo.
I build and chamber all of MY rifles and if I want something different, I design the reamer drawing
to accommodate what I want the chamber to be and make or buy custom dies for it. The 7/08x40
(7/08 Ackley) can be chambered with available chamber reamers and standard dies can be used.
Standard 7/08 brass can also be used as well as 3/08 brass to fire form for the 7/08 x 40.
The advantage to any cartridge/wildcat with a 40o shoulder is better powder efficiency and brass life
The 30o shoulders are preferred for Simi Autos to aid in rapid feeding.
Shoulder angles have always been controversial but PO Ackley liked the advantages of the 40o shoulder at the time because of the available powders. Now we have so many more powder burn rates the real potential of the 40o shoulder can be achieved.
So when you see a barrel ID that says xxx Ackley, It should be a SAMME chamber IF it is not a SAMME chamber it should be marked xxx 40o so the owner knows that it is/can be, different.
J E CUSTOM
J E Custom
Well-Known Member
I wanted to add this to my last post.
A good example of the importance of identifying the correct cartridge on the barrel ID, is the "NEW" 280 AI. It is the new SAMME specification and now all reamer manufactures are required to build there reamers to the new SAMME dimensions. so any future 280 that are the original dimension (.014 to .015 Longer) should be marked 280x40o to id them as not a SAMME standard chamber and if it is the SAMME spec. it should be marked 280 AI.
J E CUSTOM
A good example of the importance of identifying the correct cartridge on the barrel ID, is the "NEW" 280 AI. It is the new SAMME specification and now all reamer manufactures are required to build there reamers to the new SAMME dimensions. so any future 280 that are the original dimension (.014 to .015 Longer) should be marked 280x40o to id them as not a SAMME standard chamber and if it is the SAMME spec. it should be marked 280 AI.
J E CUSTOM
