RepackboxMidSouth Shooters SupplyInline FabricationTitan Reloading
WidenersLoad DataRotoMetals2Lee Precision
Reloading Everything
Page 2 of 2 FirstFirst 12
Results 21 to 33 of 33

Thread: Air trapped under bullet

  1. #21
    Boolit Master
    Join Date
    Jul 2012
    Location
    Canada, Ontario, Durham region
    Posts
    549
    Quote Originally Posted by Flashman929 View Post
    1/5 of the bullets pop back up .01 or so, and I can compress them with finger pressure against the air pressure under them. What's the solution?
    If you can bob the bullet with finger pressure you don't have the .003" of case grip. Ether the case grip has squeezed the bullet smaller or the case has lost all it elasticity and was stretch out during bullet seating. Or your measurements are off, fine measurements are tricky to get accurately.
    How to get the trapped air out? Pin through the wad colum trick. Bronze brush case interior to make air escape scratches in the brass. Powder and or wad colum adequately pre-compressed.

  2. #22
    In Remembrance

    aspangler's Avatar
    Join Date
    Mar 2013
    Location
    Tennessee
    Posts
    1,244
    I may be way off but the thought just hit me, the postal flat base boolit has less air under it that the hollow base Lee. Could it be that there is more air and therefore more air pressure under the hollow base?
    Tennessee Hunter Education Instructor

    “The Constitution is not an instrument for the government to
    restrain the people; it is an instrument for the
    people to restrain the government-lest it come to
    dominate our lives and interests"
    Patrick Henry

  3. #23
    Boolit Buddy
    Join Date
    Oct 2009
    Location
    Springfield, MO. U.S.A. Earth
    Posts
    189
    Try a 'wad' of white coffee filter paper over the primer at the bottom of the case.
    The targets of both my .45-70 and .45-90 Shiloh's say this helps.
    LG
    Hav'n you along-Is like lose'n 2 good men

  4. #24
    Vendor Sponsor

    Chill Wills's Avatar
    Join Date
    Oct 2011
    Location
    Was-Colorado, Wyoming now
    Posts
    3,149
    Quote Originally Posted by Silver Jack Hammer View Post
    CW, My boolits don't fall out or can they be pulled out by hand. I'd probably use a different method if I were loading for week long elk hunt here in the land of constant precipitation.

    Boolits that are seated by force will have distortion, I use 20:1. 20:1 is a very common alloy. What are you using to seat your boolits?
    I have read your post a few times but I am not sure I get it. If you finger seat the bullets you can most likely finger un-seat your bullets too. Or did I miss your point?

    I hope not to distort the bullets to any degree when seating them in a case that provides a little neck tension.
    Yes, 20-1 is common -Okay?
    Is your point that bullets seated into neck tension cases can not be accurate as slip-fit bullets?

    I think we are slipping off topic of trapped air. Maybe a different thread, seating bullets for making accurate ammo could be the way to go.
    Chill Wills

  5. #25
    Boolit Mold
    Join Date
    Jul 2017
    Posts
    27
    Quote Originally Posted by Chill Wills View Post
    What you are describing is slip fit bullet seating.

    Some of us like to use a little neck tension or pressure to grip the bullet. I seat them with match bullet seaters. My bullets are tight enough that not only do they not fall out, but you can not even pull them out of the case by hand.

    Flashman - you seam pretty savvy to me. So, I do not doubt you in the least. Having said that; in my experience, having 0.003" neck tension on the bullet would not only hold place against any trapped, but would resist all efforts to move the bullet in the case unless by press or tools. I like to use about 0.001+ neck tension. Once seated, air and all, it is seated.

    All, think about it. The bullet is the piston. The case is the cylinder. If you have a larger bullet than case neck, you will be compressing air every time. It does not take much neck tension to keep the bullet from popping up.

    Flashman - I think there must be something else going on that you, and or, we don't know. I am not doubting you or your measurements, you sound like you have a GOOD handle on the facts, it is just that something else is present here you have not accounted for. I say this because, bullets with three thousands neck tension don't slip back out.
    All the best - let me know what you come up with.

    -Michael Rix
    Michael, that was my thought exactly. .003 is .001 more than I use for j words and they take a fair whack to unseat with an inertia puller. It just doesn't make any sense they could have any play at that tension.

    Your last paragraph got me thinking again, perhaps it is the annealing... these cases are brand new, and were annealed just before loading. There's no doubt the tension is 3 thou, I've measured a large sample of the loaded rounds with my mic and with calipers, getting the same measurement every time. And the measurements add up, .460 bullet into a .457 neck is. 003.

    But... measuring neck tension is only indirect. You're only measuring the expansion, not the actual gripping force. E.G. hard brass will grip the bullet much harder than annealed brass, even if both measure the same loaded diameter. That's the whole purpose of annealing, to ensure consistent neck tension. Now you have me thinking that the fresh annealing just isn't providing the tension required on some of the rounds.

    I've got a .458 and .459 expansion die on the way, I'll play around with them too and see what happens, though I don't expect that would solve it. But you never know, I've been surprised before.
    Last edited by Flashman929; 08-23-2017 at 12:04 PM.

  6. #26
    Boolit Mold
    Join Date
    Jul 2017
    Posts
    27
    Quote Originally Posted by greenjoytj View Post
    If you can bob the bullet with finger pressure you don't have the .003" of case grip. Ether the case grip has squeezed the bullet smaller or the case has lost all it elasticity and was stretch out during bullet seating. Or your measurements are off, fine measurements are tricky to get accurately.
    How to get the trapped air out? Pin through the wad colum trick. Bronze brush case interior to make air escape scratches in the brass. Powder and or wad colum adequately pre-compressed.
    And I'm thinking that's it. The annealing is right on the edge of being too soft, and some cases it's just a bit too annealed.

    Will poking the wad allow the air to escape from under the bullet into the powder charge? I always thought it was to allow air under the wad to escape up. But now that you've said it, that sure makes sense, it'll allow the air under the bullet to vent into the much larger space where the charge is. D'oh.

    Cases are brushed clean after a good soak before loading again, quick spin with a brush chucked in a drill.

    I can rule out wad and powder compression, it's like a brick in there and the wad is hard against it. Depths are all consistent too.

    But poking that wad to allow the air to vent down into the rest of the case sure would increase the volume it has to go into... thanks.

  7. #27
    Boolit Mold
    Join Date
    Jul 2017
    Posts
    27
    Quote Originally Posted by Lumpy grits View Post
    Try a 'wad' of white coffee filter paper over the primer at the bottom of the case.
    The targets of both my .45-70 and .45-90 Shiloh's say this helps.
    LG
    I tried it with thin airmail paper, and got no difference. Maybe it was too thin. I'll give the filter media a try!

  8. #28
    Boolit Mold
    Join Date
    Jul 2017
    Posts
    27
    Quote Originally Posted by Silver Jack Hammer View Post
    .45-70 lead boolits should be seated by placing the boolit in the brass all the way to the wad with finger pressure. J-words can be seated with a seating die and a press. A J-word can be placed on top a case mouth and jammed down into the brass. The lead .45-70 boolit needs to be placed down into brass that is expanded enough that the boolit bottoms out on the wad with finger pressure. Otherwise the lead boolit will be distorted by forcing the brass to expand.
    Slip fitting won't work for me unfortunately, these rounds are mainly for hunting use.

    I'm not getting any bullet distortion either, pulled bullets measure exactly the same as fresh ones, .460, and there's not so much as a mark on the nose from the seating punch, nor any lead shaving.

  9. #29
    Boolit Master
    Join Date
    May 2011
    Posts
    1,564
    OK Flashman929, slip fitting would probably fix your air trapping problem but it's no solution when your trying to build hunting boolits.

    CW, I apply a slight crimp after slip fitting, just enough to fold the bell in enough to get the case to chamber. This way the base of the boolit is absolutely prestine for match shooting.

  10. #30
    Boolit Buddy
    Join Date
    Feb 2012
    Location
    Down East
    Posts
    104
    Could be the cases are annealed a bit too soft. Maybe try shooting a few rounds, then see how they are.

  11. #31
    Boolit Mold
    Join Date
    Nov 2013
    Location
    Redding, CA
    Posts
    1
    When I have this trapped air problem, I simply give the air a means to escape by using an X-Acto knife to put a light scratch along the length of the bullet before seating it. Works for me.

  12. #32
    Boolit Buddy
    Join Date
    Oct 2009
    Location
    Springfield, MO. U.S.A. Earth
    Posts
    189
    Quote Originally Posted by Shasta View Post
    When I have this trapped air problem, I simply give the air a means to escape by using an X-Acto knife to put a light scratch along the length of the bullet before seating it. Works for me.
    That cut mark may let gas pass by when you fire it. Good way to lead up a bbl.
    LG
    Hav'n you along-Is like lose'n 2 good men

  13. #33
    Boolit Master
    Bent Ramrod's Avatar
    Join Date
    Apr 2005
    Location
    Southern Arizona
    Posts
    4,284
    When mine used to do that, I just cut a piece of Styrofoam sheet or thick cardboard, put it over the cartridges and closed the lid of the Case-Gard 50- or 60-round plastic box (or put a weight on the telescoping covers of the 20-rounders) to press everything down properly. In a few hours, the air had escaped and the boolits were in the shells to the proper depth. Then there was a slight vacuum seal from the lubricant to keep the boolits in the shells, if carefully handled.

Page 2 of 2 FirstFirst 12

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check