What some are not understanding is some very, very basic facts.
Headspace will vary with new brass.
Standard go gauge is a -.004 crush. Brass I have checked will vary up to .008(extreme case) on an average and I have seen larger(I am not talking about Lapua or IMI).
Brass that I have checked, will vary in headspace length new out of the box. So, you pick a normal -.004 headspace and you may have cases that are just flopp'en around in the chamber. This
-.004 is often not enough "crush" fit, and is minimal at best. ON my own guns, I like a 0.010 crush fit, and I have used up to .025.
Many gunsmiths do not chamber properly for an ackley improved case. The whole idea of jamming the bullet up against the lands to keep the case up against the bolt face is a croc of crap because the firing pin drives the bullet in deeper in the case, causing varying lengths of fire formed brass. You will then uniform them when you full length size them. In the mean time while neck sizing, you will think that you may have some hot loads due to various headspace lengths of your cases with premature tight bolt closing on loaded rounds.
NO wonder some hate Ackley cases. I learned early on to send the gunsmith 5 new cases and have him set headspace for a snug fit on the new brass. He can determine quickly which as the shortest headspace, and what you want to achieve is a length where you set the headspace on your cases with just a slight snug fit closing the bolt. All you are touching when you run them through the full length sizer is touching the area right at the shoulder neck junction, and bumping back a couple of .001.
I like the higher velocity attainable and certainly the accuracy achieved from all ackley cases that I have played around with. The case grips the chamber wall to produce less bolt thrust, also. I specify to the gunsmith that I do not want a super slick chamber, and this is to aid in the case gripping the chamber wall.
I think that I have trimmed ackley cases once in my life and I used a mid pressure fire forming load on that 50 cases which lead to premature case failue within 10 rounds...it does not take much.
Headspace will vary with new brass.
Standard go gauge is a -.004 crush. Brass I have checked will vary up to .008(extreme case) on an average and I have seen larger(I am not talking about Lapua or IMI).
Brass that I have checked, will vary in headspace length new out of the box. So, you pick a normal -.004 headspace and you may have cases that are just flopp'en around in the chamber. This
-.004 is often not enough "crush" fit, and is minimal at best. ON my own guns, I like a 0.010 crush fit, and I have used up to .025.
Many gunsmiths do not chamber properly for an ackley improved case. The whole idea of jamming the bullet up against the lands to keep the case up against the bolt face is a croc of crap because the firing pin drives the bullet in deeper in the case, causing varying lengths of fire formed brass. You will then uniform them when you full length size them. In the mean time while neck sizing, you will think that you may have some hot loads due to various headspace lengths of your cases with premature tight bolt closing on loaded rounds.
NO wonder some hate Ackley cases. I learned early on to send the gunsmith 5 new cases and have him set headspace for a snug fit on the new brass. He can determine quickly which as the shortest headspace, and what you want to achieve is a length where you set the headspace on your cases with just a slight snug fit closing the bolt. All you are touching when you run them through the full length sizer is touching the area right at the shoulder neck junction, and bumping back a couple of .001.
I like the higher velocity attainable and certainly the accuracy achieved from all ackley cases that I have played around with. The case grips the chamber wall to produce less bolt thrust, also. I specify to the gunsmith that I do not want a super slick chamber, and this is to aid in the case gripping the chamber wall.
I think that I have trimmed ackley cases once in my life and I used a mid pressure fire forming load on that 50 cases which lead to premature case failue within 10 rounds...it does not take much.
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