Page 2 of 2 FirstFirst 12
Results 16 to 21 of 21

Thread: Neck Tension?

  1. #16
    Join Date
    Feb 2003
    Location
    Tennessee
    Posts
    4,750
    Most, if not all, include the rifle in the equation. That is, the rifle will shoot best at one neck tension but not another. I don't believe that's true as the neck expands (if it can expand) before the bullet does/moves much at all. You have to get pretty darn close to no clearance at all before the cases begin to look different...as in the black marks on the case neck.

  2. #17
    Join Date
    May 2010
    Location
    Cornville, ME
    Posts
    143
    All of the replies state forces necessary to move the bullet in a static situation. Does the case neck expand with the case upon powder ignition? If it does, doesn't that change all the pressure parameters for moving the bullet when compared with a static state? I do not have the answer. I was just wondering if the case neck expands with the rest of the case toward the chamber walls before the bullet starts forward much, thus creating a situation whereby not as much pressure is needed to release it from the case mouth as it would have been in a static state.

  3. #18
    Join Date
    Jun 2012
    Location
    West central NH
    Posts
    380
    Sounds plausible. I thought I remembered reading in Harold Vaughn's "Rifle Accuracy Facts" that the chamber expands some as well. I didn't want to leave the Bruins game to get up and get the book, but I did find a complete, searchable edition on archive.org. There are some references to "radial expansion of the chamber." Hope I haven't caused the engineering wonks out there to stay up thinking about it.

  4. #19
    Join Date
    Feb 2003
    Location
    Fresno
    Posts
    5,484
    Quote Originally Posted by Wilbur View Post
    Most, if not all, include the rifle in the equation. That is, the rifle will shoot best at one neck tension but not another. I don't believe that's true as the neck expands (if it can expand) before the bullet does/moves much at all. You have to get pretty darn close to no clearance at all before the cases begin to look different...as in the black marks on the case neck.
    None of us can be inside the chamber watching what is going on real time. This is just reporting. Many years back, I was shooting matches at the Visalia, discovering the nature of mediocrity, and I had a conversation with the late Del Bishop about neck bushing size. I was shooting a .262 neck 6PPC as were most of those who competed at that venue, including Del and his good friend Steve Kostanich. I was turning my necks to the then common thickness of .0086 or thereabouts, and using a .258 Wilson bushing. Del told me that Steve and he had discovered that 133 shot better with more neck tension, and suggested that I might want to give that a try. I did, a .257 and it seemed to me that my groups got better. In fact I am pretty sure of it. This is not science, or me telling anyone that based on my great reputation as a competition shooter what the truth is. It is me reporting some things that happened.

    The only powder that I shot in those days was 133, some time later I happened on slightly less than a pound of Israeli manufactured 2015 and I decided to do a neck tension test. I found that it did not seem to care much what the neck tension was, that is shot just as well with very light neck tension as with moderate....but I never could get any more of the stuff, and as I understand it the factory was destroyed in an explosion. I did learn one thing that made the experience worthwhile. Not all powders are the same with regard to their "preference" of neck tension. or tolerance of it variation. At least it seemed that way to me at the time, based on what little unscientific testing that I did.
    Last edited by Boyd Allen; 04-07-2018 at 10:57 PM.

  5. #20
    Join Date
    Dec 2012
    Location
    Valdosta Ga
    Posts
    85

    Neck tension

    I was shooting a 268 neck . I was using a 263 bushing with lt32 groups was mediocre. I thought it should shoot better so I I tried a 265 bushing groups tightened up quite well . I was suprized . I also found two seating depths that shoot well one at touch and one at jam.

  6. #21
    Join Date
    Feb 2003
    Location
    Jeddo, Michigan
    Posts
    3,572
    Heard around the range."There's nothing like new brass". Why is that? "You need to anneal that brass". Why is that?
    Is seating depth more about the distance to the lands or is it about the length of the neck holding the bullet? Is a coated bullet held less by the neck than an uncoated bullet? When does ignition pressure open the neck and wave goodbye to the bullet?
    I don't declare I know the answers other than to say to look at the target.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •