Lee PrecisionRotoMetals2Titan ReloadingADvertise here
RepackboxInline FabricationWideners

Page 1 of 2 12 LastLast
Results 1 to 20 of 26

Thread: 10mm to .40 s&w

  1. #1
    Boolit Master
    Join Date
    May 2013
    Location
    MUSKOGEE
    Posts
    1,301

    10mm to .40 s&w

    does anyone cut down 10mm to .40 S&W length?

    if so any notable things to consider? (other than 10mm large primer and .40S&W small primer)

  2. #2
    Boolit Master
    Join Date
    Apr 2010
    Posts
    1,099
    I can't imagine anybody doing this. 40S&W brass is all over the range. 10mm is not, and is expensive.

  3. #3
    Boolit Buddy
    Join Date
    Aug 2014
    Location
    Central Ohio
    Posts
    159
    PM me. I’ll give you two for one. 2 40 cases for one 10mm.

    I don’t even own the 10mm yet.

  4. #4
    Boolit Buddy
    Join Date
    Oct 2017
    Location
    New Jersey
    Posts
    404
    I agree not worth the time and 10mm is in high demand now so I would just trade and save your time. I can offer you the same deal 2 x 40 for 1 x 10mm as well and you wont have to bother cutting anything down.

  5. #5
    Boolit Grand Master Outpost75's Avatar
    Join Date
    May 2013
    Location
    over the hill, out in the woods and far away
    Posts
    7,733
    Also if you cut down 10mm to .40 S&W, you also need to mouth ream them. Labor intensive.
    The ENEMY is listening.
    HE wants to know what YOU know.
    Keep it to yourself.

  6. #6
    Boolit Master maxreloader's Avatar
    Join Date
    Jan 2015
    Location
    Southern March 15th, 1820
    Posts
    558
    ^^^ What DanishM1Garand said... except I have 3 10mm's and can never have enough brass to feed them.
    Looking for Ideal molds 419181 (44 Evans Long) and 375167 (38-72)
    "Joined Dates" are deceiving if you factor-in "lurk" dates.

  7. #7
    Boolit Master
    Join Date
    May 2013
    Location
    MUSKOGEE
    Posts
    1,301
    i'm not looking to trade...doesn't anyone actually read and comprehend each word in a sentence?

    the question was purely that...a question.

  8. #8
    Boolit Buddy
    Join Date
    May 2016
    Posts
    186
    Im sure someone does. There are a lot of people out there loading. One of them is probably in a situation where 40 s&w brass is hard/impossible to get and 10mm is easy, maybe its illegal to own a 10mm auto firearm and illegal to own 40 s&w brass.
    I dont know any of these people so cant attest to any issues they have ran into.
    Praise the Lord and pass the ammunition.

  9. #9
    Boolit Bub 1006's Avatar
    Join Date
    Apr 2013
    Posts
    41
    Consideration: the brass may get too thick in the case wall as you trim down the length to 40. This would cause a problem. The case mouth might swell to a diameter too large for the gunís chamber.

    I am a 40S&W fan. Load it hot or light.

  10. #10
    Boolit Grand Master

    Join Date
    Mar 2013
    Location
    Northwest Ohio
    Posts
    11,267
    Okay the 40 S&W and 10 mm are very close other than length. cutting down 10 mm to 40 S&W was the how the original testing was probably done. Things I would look at are internal case tapers the 10 mm may have a heavier taper in it and need reamed to make bullet seating room with out bulges. 10 mm is large primer and 40 data is for small pistol so loads should be dropped and worked up but not a big deal. Last that should be checked is the case head thickness heights so capacity may be lower or different

  11. #11
    Boolit Buddy
    Join Date
    Oct 2017
    Location
    New Jersey
    Posts
    404
    Quote Originally Posted by mozeppa View Post
    i'm not looking to trade...doesn't anyone actually read and comprehend each word in a sentence?

    the question was purely that...a question.
    I'm pretty sure that we did understand the question and I believe we all answered. Can it be done? Yes. Is it worth the time , effort and frustration, probably not.

    As many pointed out besides cutting those down you might have to deal with brass being too thick now so thats another step plus when its all said and done you'll end up with 40S&W brass but with large primers because 10mm uses LP and not SP primers so you'll have to develop your loads from nothing as there will be no published data for 40S&W brass with LPP.

    As I get older I realize that its easier when you dont try to reinvent the wheel but if its something that you are dying to try and have time to play with then more power to you. I wont stop you. I'm actually curious how that works out.

  12. #12
    Boolit Master KYCaster's Avatar
    Join Date
    Mar 2005
    Location
    Rineyville
    Posts
    2,185
    It's called the "Centimeter".
    Those crazy old IPSC guys did it way back when (that's where S&W got the idea for their .40).

    Like others have said, necks have to be reamed and the thick brass also reduces case volume, add the LP primer and high working pressure and powder selection becomes critical.

    Not really relevant to your question, but another complication at the time was the trend toward heavy-for-caliber bullets to reduce felt recoil. Those guys were launching 200 and 220 grain bullets at 900 and 820 fps to make the old 180PF. There were very few available powders at the time suitable for the task (the situation hasn't improved substantially), and there were no SAMI specs or reloading data available to guide those intrepid pioneers in their quest for the ultimate IPSC cartridge.

    Interesting times.

    Hope this helps...
    Jerry
    Buzzard's luck!! Can't kill nothin', nothin'll die!!

  13. #13
    Boolit Buddy
    Join Date
    Jul 2005
    Location
    Northwest Indiana
    Posts
    247
    I'd think yes, similar maybe to making 9mm Makarov from 9mm Luger. Constantly amazed at the judgement introduced in responses. It's a case forming forum, making sense isn't one of the criteria. Bravo to the original poster for asking. Take it a step further, make 40 from 10 then make 45 jacketed bullets from that new case. (Geeez but jacketed bullets are available everywhere!). And as I think about it, why cast? Cracking up here on a cold Indiana morning......

  14. #14
    Boolit Master
    Join Date
    May 2013
    Location
    MUSKOGEE
    Posts
    1,301
    for those who say "ream the case mouths"
    ....my 180 grain boolits are nearly as different from my 150 grain boolits in length as the .40 S&W is from the 10mm.

    so what i'm saying is that the 150 grain boolit would sit no deeper into a cut down 10mm case than a 180 grain boolit does in a "non cut down" 10mm case.

    so in reality ....there would be virtually the same volume under the base of the boolit ....so again, why would reaming be necessary?

  15. #15
    Boolit Grand Master

    Join Date
    Oct 2009
    Location
    England,Ar
    Posts
    5,800
    Quote Originally Posted by marek313 View Post
    I'm pretty sure that we did understand the question and I believe we all answered. Can it be done? Yes. Is it worth the time , effort and frustration, probably not.

    As many pointed out besides cutting those down you might have to deal with brass being too thick now so thats another step plus when its all said and done you'll end up with 40S&W brass but with large primers because 10mm uses LP and not SP primers so you'll have to develop your loads from nothing as there will be no published data for 40S&W brass with LPP.

    As I get older I realize that its easier when you dont try to reinvent the wheel but if its something that you are dying to try and have time to play with then more power to you. I wont stop you. I'm actually curious how that works out.
    I think this pretty well covers it.

    It sounds like no one does it. It looks like a lot of work to make a case thats readily available. I see 2 potential problems with this. The case walls possibly being too thick and working up a load with large primers.

    But it will be interesting to see your results

  16. #16
    Boolit Buddy
    Join Date
    Mar 2014
    Posts
    267
    why??

  17. #17
    Boolit Master


    Join Date
    Oct 2009
    Location
    Northern Michigan
    Posts
    3,970
    Must be a good reason...just not apparent.
    Don Verna

    NRA Endowment Member

  18. #18
    Boolit Grand Master
    Join Date
    Nov 2010
    Location
    Casa Grande, AZ
    Posts
    5,483
    I'm still sitting on 40 or 50 lbs of 40 cal brass that I don't reload anymore that will get re-purposed into bullet casings.
    Last edited by 6bg6ga; 01-20-2020 at 10:40 AM.

  19. #19
    Boolit Grand Master


    richhodg66's Avatar
    Join Date
    Nov 2009
    Location
    Kansas
    Posts
    5,407
    I RSO'd a local pistol range yesterday. I could have walked away from there with a five gallon bucket of .40 S%W brass, I think it's even more common than 9mm brass now. I really should get a .40 if for no other reason.

    I have a 10mm I occasionally shoot, one of the few auto pistols that I really, really like. Wish I could pick up 10mm brass like that.

  20. #20
    Boolit Grand Master


    jonp's Avatar
    Join Date
    Feb 2013
    Location
    Planet Reality
    Posts
    6,163
    Frankly I don't see much problem using LPP in one as I've read numerous posts elsewhere of people using SRP in them with good results. Just lower the starting load and have at it.

    How many on here have experimented with rifle primers in pistols or magnum primers in place of standard? I know I have.
    I am become death. The destroyer of worlds

    We all do our duty when there is not cost to it, honor comes easier then. Sooner or later there comes a day in every man's life when it is not so easy, a day when he must choose and live with it for the rest of his days.

    The further society drifts from the truth, the more it will hate those that speak it
    George Orwell

    "I prefer dangerous freedom over peaceful slavery."
    - Thomas Jefferson, letter to James Madison, January 30, 1787

Page 1 of 2 12 LastLast

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