ADvertise hereInline FabricationStainLess Steel MediaMidSouth Shooters Supply
Titan ReloadingLee PrecisionGraf & SonsRotoMetals2

Results 1 to 19 of 19

Thread: Machinning brass tube to reduce case capacity.

  1. #1
    Boolit Master GARD72977's Avatar
    Join Date
    Aug 2008
    Location
    TUPELO MS
    Posts
    823

    Machinning brass tube to reduce case capacity.

    I have been thinking of finding some brass tube and machinning it down to fit in a 45/70 case to reduce capacity fot light loads.

    Im thinking of chamfering the inner part of the bottom slightly. Using a arbor press to press them in.

    Any thoughts on doing this?
    " If you cant do it with a 308 , you dont need to do it!

  2. #2
    Boolit Master
    Join Date
    Apr 2016
    Location
    NC
    Posts
    411
    I’d just switch to trail boss.

    If the sleeve shifts forward a bit during firing I think you’ll be done for the day. Not likely to happen on the first firing I suppose, but multiple firings and resizing might make it a little loose.

  3. #3
    Boolit Master
    Join Date
    Jan 2011
    Location
    Prineville, Oregon
    Posts
    176
    Many years ago I tried this with a 219 Improved Zipper (for which you start with a 38/55 case made from a 30/30 and put in your filler piece for which I used .223 brass). Worked well, but I concluded it was still much more work than it was worth. But the idea is quite viable.

    I'd say "go for it" -- it'd be considerably less work to do on a 45/70 case than my bottleneck case that required blowing out, annealing, making the filler piece to fit nearly perfectly, necking down in 4 stages, neck turning, annealing again...

    Yes indeed: go for it!

  4. #4
    Boolit Master
    Join Date
    Jul 2013
    Location
    The Pacific NorthWet
    Posts
    406
    If you could neck expand the case then install the tube, then size the neck back down to normal size, that might retain the heck out of the tube.

    I do remember seeing someone discussing threading the primer flash hole in a 50 BMG case and screwing a tube into that, to pass the flash from the primer to about mid-case, for more consistency of ignition? Sounded a little uh, UNIQUE to me, but maybe it works pretty well.

    Could braze the tube in place maybe, to help retain it? Be careful of what's annealed vs not and so on of course. Interesting problem!

  5. #5
    Super Moderator




    Buckshot's Avatar
    Join Date
    Mar 2005
    Location
    So. California
    Posts
    11,558
    .............I've got a couple old articles on reducing case capacity by inserting a smaller cartridge case into a larger one, but the larger was always a BN design. Having the insert move forward into the barrel quietly waiting there for the next projectile would provide too much excitement for me. So far as 'Forward Ignition goes' (via a longish flash tube), it's been done. I forget who I'd read about doing that (back in the 60's ?), but I know in the Navy the 3"/50's and the 5"/38's (the only 2 I've witnessed) had tubes extending up 3/4 of the length of the case. Don't recall if there were any holes in the circumference of the tubes, as I didn't look close enough. Just saw them as we heaved them overboard

    ................Buckshot
    Father Grand Caster watches over you my brother. Go now and pour yourself a hot one. May the Sacred Silver Stream be with you always

    Proud former Shooters.Com Cast Bullet alumnus and plank owner.

    "The Republic can survive a Barack Obama, who is, after all, merely a fool. It is less likely to survive a multitude of fools such as those who made him their president."

    Shrink the State End the Fed Balance the budget Make a profit Leave an inheritance

  6. #6
    Boolit Master GARD72977's Avatar
    Join Date
    Aug 2008
    Location
    TUPELO MS
    Posts
    823
    If i press it down the case to the same depth as the base of the bullet you would be able to tell if it moved. Im also thinking it will press on low enough to start rounding the bottom a little. This would put pressue back on it during firing.
    " If you cant do it with a 308 , you dont need to do it!

  7. #7
    Boolit Master
    Join Date
    Apr 2016
    Location
    NC
    Posts
    411
    I still don”t recommend this, but if I was determined to try it I would do a few things to try to ensure that the bushing stays in the case.

    Make the bushing long enough that the bushing bottoms out in the test case and that the seated bullet bottoms out on the bushing.

    Cut a couple shallow grooves around the bushing and then, once inserted in the test case, roll the case walls into those grooves.

    Be sure to cut the bushing to match the interior profile of the test case, I doubt that it’s a cylinder.

    Start with a new test case.

    Good luck, and post pictures.

  8. #8
    Boolit Master
    Join Date
    Dec 2016
    Posts
    168
    I tried the same concept once for a 577 Snider, but used rolled up heavy paper instead of brass. I rolled a strip tightly around a wood dowel and pushed it into the case. They stayed in the case for several firings, but got charred and you have to remove them to wash the cases. Don't know how they would work in a 45-70, but it would be easier to experiment this way than to make up a bunch of brass sleeves . You would want to look after each firing to make sure the tube didn't lodge in the barrel, didn't in my test but 45-70 might perform differently.

  9. #9
    Boolit Master GARD72977's Avatar
    Join Date
    Aug 2008
    Location
    TUPELO MS
    Posts
    823
    There is no way I can machine it to match the interior of the case with manual equipment. If its not too thisk and I anneal the tube it would take the shape of the case as it was pressed in with an arbor press. I have little concern for it being pushed out. It will be almostto thebottom of the case and pressure will expand it to the sides of the case.
    " If you cant do it with a 308 , you dont need to do it!

  10. #10
    Boolit Master
    Chill Wills's Avatar
    Join Date
    Oct 2011
    Location
    Colorado
    Posts
    1,697
    How about reducing the case capacity by using 1/2" or 3/8" wads under the bullet? CircleFly shotgun wads and other makers are a source of thick wads in rifle calibers. Maybe safer and for sure, less work.
    Just an idea....
    Beyond that, make yourself or buy one piece brass from Rocky Mtn Cartridge Co. A few bucks each, not cheap but last forever.
    Last edited by Chill Wills; 01-14-2018 at 11:33 AM.
    Chill Wills

  11. #11
    Boolit Master 15meter's Avatar
    Join Date
    Feb 2017
    Location
    SE Michigan
    Posts
    290
    Quote Originally Posted by Mr_Sheesh View Post
    If you could neck expand the case then install the tube, then size the neck back down to normal size, that might retain the heck out of the tube.

    I do remember seeing someone discussing threading the primer flash hole in a 50 BMG case and screwing a tube into that, to pass the flash from the primer to about mid-case, for more consistency of ignition? Sounded a little uh, UNIQUE to me, but maybe it works pretty well.

    Could braze the tube in place maybe, to help retain it? Be careful of what's annealed vs not and so on of course. Interesting problem!
    Seems I read that some cannon shells had an extend primer flash tube to help ignition and that some experimenters took the tube to the top of the powder column, making the powder burn from the front. I don't remember the theories for front ignition.

  12. #12
    Boolit Master Don McDowell's Avatar
    Join Date
    Jan 2008
    Location
    Hell Gap Wy
    Posts
    4,939
    Call Rocky Mountain Cartridge and order however many reduced capacity cases you want.
    http://www.rockymountaincartridge.com
    GUSA #6
    People will forget what you said...
    People will forget what you did...
    But People will NEVER forget how you made them feel

    Want to join in adult conversation about shooting the old ways without the hysterics associated with other places?http://historicshooting.com/mybb/index.php

  13. #13
    Boolit Master
    Join Date
    May 2010
    Location
    central texas
    Posts
    521
    I think the army used a cardboard tube to reduce loads to 60 grains for the carbine 45-70.
    I picked up some brass from Gaintwist barrel co that is machined to shoot a reduced load of 23 grains 4198 and a 405 bullet.

  14. #14
    Boolit Master GARD72977's Avatar
    Join Date
    Aug 2008
    Location
    TUPELO MS
    Posts
    823
    Rocky
    Mountian is a little higher than I can afford.

    I feel like you need 10 pages of fine print when you post something like this. Internet safety experts wear it out
    " If you cant do it with a 308 , you dont need to do it!

  15. #15
    Boolit Master Don McDowell's Avatar
    Join Date
    Jan 2008
    Location
    Hell Gap Wy
    Posts
    4,939
    You could also just load with 1 f and a thick wad stack. Blackpowder cartridges don't really lend themselves to "reduced" loads particularly well.
    GUSA #6
    People will forget what you said...
    People will forget what you did...
    But People will NEVER forget how you made them feel

    Want to join in adult conversation about shooting the old ways without the hysterics associated with other places?http://historicshooting.com/mybb/index.php

  16. #16
    Boolit Master

    Join Date
    Mar 2013
    Location
    Northwest Ohio
    Posts
    7,803
    h The tubing you need may be found at online metals. It can be cut to length and turned to just what you need as to the case taper between centers. I would recommend several things if you do this. Turn a close fit of tube to case taper. Either red or green locktite the tube in or a very good epoxy for the initial installation. Then use a canelure tool and roll a canelure in the case at the end of the tube to mechanically lock it into place in addition to the locktite / epoxy. The other issue you may have here is getting cases with the tubes to expand and seal the chambers like they should. A tube with .015 wall is doubling wall thickness of the case in the head body area.

    The wad stack or thick wads would be easier the use of 1/8" or 1/4" wads may accomplish the same thing and be easier to do. Another plus to the wad stacks are cases arnt modified leaving them useable for full power loads if ever desired. You could use a thin wad ( .010-.060) a wax wad (poured to thickness) and another thin wad to fill space. Wax can be melted and poured to desired thickness then wads cut from the sheet for this.

    Elmer Keith and a few others worked with primer tubes years ago. The tube was screwed into the flash hole and extended to the front of the powder charge. Benefits were lower extreme spreads and standard deviations due to more complete ignition burning of the powder charge. Some claimed lowered fouling and unburnt powder. Heat was said to stay more localized in the chamber area of the barrel. Drawbacks were the time work installing them. flash holes drilled and tapped, tubes threaded and cut to length. Installed a little long so primer pockets can be uniformed back to truly flat. a slot or means of removing if needed. Tubes either were removed to deprime or a long skinny decapping pin was needed. Cases modified in this manner were good for one basic load as the variances in powder height and bullet depth would affect them. The tube also reduced case capacity making existing data for a given cartridge in useable.

    The other issue with the modified cases is if when someone else gets a hold of them and tries standard loads in them.

  17. #17
    Boolit Man
    Join Date
    Sep 2006
    Posts
    78
    Why bother:
    Just use Alliant Unique powder and load with the std 45-70 case
    and light bullets.
    I did this for plinking with my M86 win: 45 colt bullets and about 12 gr Unique
    beltfed/arnie

  18. #18
    Boolit Master
    Join Date
    May 2016
    Location
    Denmark (a greasy little spot in Scandinavia)
    Posts
    498
    Why?

    BP will shoot just fine with a void above, in a cartridge.
    Frankford Arsenal knew this 140+ years ago
    Gallery loads you know!

    The probelm occurs in frontloaders with a short started bullet when powder has ample time to burn and accelerate up the tube.
    Not the small amout of air in a cartridge.
    If you really think this is the case then please explain why airspace between powder cernals is no problem but doube that is suddenly a disaster. And please feel free to add documentation for blown rifles and or revolvers due to airspace in the cartridges!

    If you are adamant about depleting air then why not use some foam rod insulation: https://www.google.com/search?q=foam...D4jE6QSgk7SYAg

  19. #19
    Boolit Master
    Join Date
    Aug 2009
    Location
    gardners pa.
    Posts
    2,580
    the arsenal used cardboard tubes to reduce the .45-70 for carbine loads.

    turn the tubes to a .001 press fit in a unsized case. then put the tubes in the freezer over night then drop them in and size the cases.

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