Who is the father of making the case less tapered to increase capacity? Why PO Ackley, of course.
On searching I found this from https://www.shootersforum.com/wildcat-ca...thing.html
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The process of a case gripping the walls of the chamber during powder combustion is called obturation. It's one of the devils that plagued the M-16 in its early days. There is a lengthy article about this phenomenon, written by the military man whom discovered it. Can't remember his name, but he wrote a letter to the top brass about the failures of the spent cases to extract from the chambers during firefights in Vietnam. He referred to his letter as the "letter read 'round the world." Might be able to find it using that in your search string. Add "M16" to it, and your luck should improve. Very interesting reading. The failures to extract got a lot of good men killed. Sad, as well as being something that stokes the fires of rage that the rifle and round were not more thoroughly tested before being fielded. Add to that, the troops were told the rifle was "self-cleaning." Nothing could have been further from the truth, given the powder recipe they used in those days.
I think an Ackley case obturates more than a standard case because it has that small amount of extra cylindrical value. I do not know if Ackley cases are less tapered than a standard case. Maybe, to wipe out the original chamber. Might be why they stick better than standard cases. Opinions and comments welcomed...
The man's name is Richard Culver. Marine. Lots of stuff about his M16 experiences on the 'net..."
Case taper is the same on the SPC as the 5.56 but the case is shorter. Shorter cases should result in less chamber "sticktion" if that's a word.
Grendel case is shorter, so maybe less also. I would think Bill Alexander has this all worked out but I haven't read anything about it.
When I shot my Howa bolt last week, the bolt handle was difficult to lift with factory Wolf ammo which is what got me thinking.
On searching I found this from https://www.shootersforum.com/wildcat-ca...thing.html
"nvshooter's Avatar
nvshooter nvshooter is offline
Beartooth Regular
Join Date: Oct 2010
Location: Nevada
Posts: 4,884
The process of a case gripping the walls of the chamber during powder combustion is called obturation. It's one of the devils that plagued the M-16 in its early days. There is a lengthy article about this phenomenon, written by the military man whom discovered it. Can't remember his name, but he wrote a letter to the top brass about the failures of the spent cases to extract from the chambers during firefights in Vietnam. He referred to his letter as the "letter read 'round the world." Might be able to find it using that in your search string. Add "M16" to it, and your luck should improve. Very interesting reading. The failures to extract got a lot of good men killed. Sad, as well as being something that stokes the fires of rage that the rifle and round were not more thoroughly tested before being fielded. Add to that, the troops were told the rifle was "self-cleaning." Nothing could have been further from the truth, given the powder recipe they used in those days.
I think an Ackley case obturates more than a standard case because it has that small amount of extra cylindrical value. I do not know if Ackley cases are less tapered than a standard case. Maybe, to wipe out the original chamber. Might be why they stick better than standard cases. Opinions and comments welcomed...
The man's name is Richard Culver. Marine. Lots of stuff about his M16 experiences on the 'net..."
Case taper is the same on the SPC as the 5.56 but the case is shorter. Shorter cases should result in less chamber "sticktion" if that's a word.
Grendel case is shorter, so maybe less also. I would think Bill Alexander has this all worked out but I haven't read anything about it.
When I shot my Howa bolt last week, the bolt handle was difficult to lift with factory Wolf ammo which is what got me thinking.