The MAGNUM Small Pistol Primer Experiment .40SW

Discussion in 'The Ammo Can' started by mousegun380, Apr 5, 2009.

  1. mousegun380

    mousegun380 XDTalk 100 Member

    Joined:
    Jul 21, 2008
    Messages:
    368
    Likes Received:
    1
    Trophy Points:
    0
    Ratings:
    +1 / 0
    Hello guys,

    As primers are becoming nearly impossible to find, I decided to do a set of test runs with magnum small pistol primers in .40SW. Often, you will be able to find magnum primers, just not the standard and that is why I decided to do this test. It seems like there are so few loads which call for magnum small pistol primers that they are much more available. So, in dry times, you can use this info to decide if magnum primers are a viable option for you.

    Disclaimer - This is just for the sake of argument. If you try this, work up from a low starting load with known components. I am not responsible if you kaboom yourself. -MG380

    Chrono Data: (averages are from 10 shot strings)

    Mixed Headstamp
    155 Grain Precision Coated .40SW
    5.7 Grains Unique
    Winchester STANDARD Small Pistol Primers
    AVG: 737.2 FPS

    Mixed Headstamp
    155 Grain Precision Coated .40SW
    5.9 Grains Unique
    Winchester STANDARD Small Pistol Primers
    AVG: 829.42 FPS

    Mixed Headstamp
    155 Grain Precision Coated .40SW
    5.0 Grains Unique
    Federal MAGNUM Small Pistol Primers
    AVG: 875.9 FPS

    Mixed Headstamp
    155 Grain Precision Coated .40SW
    5.2 Grains Unique
    Federal MAGNUM Small Pistol Primers
    AVG: 922.65 FPS

    Mixed Headstamp
    155 Grain Precision Coated .40SW
    5.4 Grains Unique
    Federal MAGNUM Small Pistol Primers
    AVG: 969.98 FPS

    Mixed Headstamp
    155 Grain Precision Coated .40SW
    5.6 Grains Unique
    Federal MAGNUM Small Pistol Primers
    AVG: 1002.03 FPS

    Mixed Headstamp
    155 Grain Precision Coated .40SW
    5.9 Grains Unique
    Federal MAGNUM Small Pistol Primers
    AVG: 1066.8 FPS

    So by the data I accumulated, one can seem to expect an average of 237.38 FPS increase when all other variables (within reason) are the same. Same bullet, powder charge, OAL, barrel length...just the primer was different. In fact, if I wanted to be in the same neighborhood as my usual plinking round (the 155 precision on top of 5.9gr Unique) I would have to use around 4.8-5.0gr of Unique to achieve approximately the same velocity when substituting magnum primers for standard.

    Don't forget also that primers vary by brand somewhat so this experiment would have been better with all Winchester or all Federal primers. If you try this, I would start from the ground up like I did.

    With regards to powders, you may also have widely varying differences in results with super fast burning brands. I would not use them with magnum primers.

    In conclusion, I think that using magnum primers in .40SW is a viable option in times of absolute necessity. The brass was fine too and did not exhibit bulging or deformed primer pockets. I would not seek any higher velocity though. The 1066 achieved at 5.9 gr Unique is more than I usually load to anyway.

    -Mousegun380
     
  2. Texas-Gun-Man

    Texas-Gun-Man XDTalk 1K Member

    Joined:
    Nov 1, 2007
    Messages:
    1,102
    Likes Received:
    11
    Trophy Points:
    0
    Location:
    Grainger Lake Area
    Ratings:
    +11 / 0
    Sounds like you figured up some very viable loads good work.:D
     
  3. fredj338

    fredj338 XDTalk 10K Member

    Joined:
    Jan 13, 2007
    Messages:
    10,293
    Likes Received:
    6
    Trophy Points:
    38
    Location:
    kommiefornia
    Ratings:
    +6 / 0
    THanks for sharing the data. Using mag primers has always been acceptable but, as you have found out, it does raise pressures & requires reworking oyur loads. W/O a chrono, this is very diff. So best to drop powder charges at least 5% when switching to mag primers. THis will vary of course w/ faster or slower primers. For faster powders than Unique, I would want to drop 10%. For slower powders, 5% will work fine.
     
  4. dsr30

    dsr30 XDTalk 500 Member Founding Member

    Joined:
    Dec 20, 2006
    Messages:
    902
    Likes Received:
    8
    Trophy Points:
    0
    Location:
    Roanoke, VA
    Ratings:
    +8 / 0
    Interesting info, thanks.

    Kind of a side thought, but what about the Standard/Magnum combo large pistol primers, are they a hybrid.?
     
  5. mousegun380

    mousegun380 XDTalk 100 Member

    Joined:
    Jul 21, 2008
    Messages:
    368
    Likes Received:
    1
    Trophy Points:
    0
    Ratings:
    +1 / 0
    That is a good question! I don't know...
     
  6. fredj338

    fredj338 XDTalk 10K Member

    Joined:
    Jan 13, 2007
    Messages:
    10,293
    Likes Received:
    6
    Trophy Points:
    38
    Location:
    kommiefornia
    Ratings:
    +6 / 0
    WW started this back a while ago. They tend to run between most std. & magnum primers so work for both. You still should rework your load if switching to those primers, especially shooting uberfast powders like CLays, BE, etc.
     
  7. dsr30

    dsr30 XDTalk 500 Member Founding Member

    Joined:
    Dec 20, 2006
    Messages:
    902
    Likes Received:
    8
    Trophy Points:
    0
    Location:
    Roanoke, VA
    Ratings:
    +8 / 0
    The primers are Winchester. I use them with W231, 4.6grs under a 230gr LRN & the same load for a 200gr LSWC.
     
  8. imonfire

    imonfire XDTalk 100 Member

    Joined:
    Jan 4, 2009
    Messages:
    245
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Eastern NM
    Ratings:
    +0 / 0
    Good job. I also worked up loads for mine using exactly the same bullets you used. I used Magtech mag primers because thats all I could get lately. I started out with 5 grs. of Universal and worked my way up to 6 grains. I dont have a crono so velocity is an unknown but the brass at 5.8 grains would still fit in the case gauge after firing so I know the pressure wasnt excessive.
     
  9. mousegun380

    mousegun380 XDTalk 100 Member

    Joined:
    Jul 21, 2008
    Messages:
    368
    Likes Received:
    1
    Trophy Points:
    0
    Ratings:
    +1 / 0
    On an unrelated note, how do you like the Universal? I like Unique a lot and I considered Universal as a sub if I could not get Unique.
     
  10. ThumperIII

    ThumperIII XDTalk 1K Member Founding Member

    Joined:
    Jul 27, 2008
    Messages:
    1,622
    Likes Received:
    3
    Trophy Points:
    0
    Location:
    Maryland
    Ratings:
    +3 / 0
    Thanks for the MAG primer evaluation. I had picked up 5000 SM pistol MAG primers a few days ago when no STD primers were available. I knew they would work, but with no chrono I would have many rounds to fire to get safe, quality loads. Your info gives me a good researched foundation for what to expect when building my loads (heavier bullet). Sorry, but I won't be able to provide any MAG primer load information for quite a while. Still waiting for my 40sw dies and powder order to be filled.
     
  11. mousegun380

    mousegun380 XDTalk 100 Member

    Joined:
    Jul 21, 2008
    Messages:
    368
    Likes Received:
    1
    Trophy Points:
    0
    Ratings:
    +1 / 0
    No problem Thumper! Glad I could contribute!
     
  12. imonfire

    imonfire XDTalk 100 Member

    Joined:
    Jan 4, 2009
    Messages:
    245
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Eastern NM
    Ratings:
    +0 / 0
    I like it but I dont have anything to compare it to. I have reloaded rifle and shotgun for years, only lately have I started on pistol. I chose the universal because I had it for shotgun already in a fairly large quantity. It seems to be clean and measures okay but not perfect. I have some WW 231 I was going to work up loads on too.
     
  13. ichy_trigger

    ichy_trigger XDTalk 10K Member

    Joined:
    Jan 24, 2004
    Messages:
    10,954
    Likes Received:
    27
    Trophy Points:
    0
    Location:
    Dayton, Ohio
    Ratings:
    +27 / 0

    I like universal alot for .40 and find that I get very consistent results from it.
     
  14. LittleDave

    LittleDave XDTalk 500 Member

    Joined:
    Jan 20, 2009
    Messages:
    925
    Likes Received:
    1
    Trophy Points:
    0
    Location:
    Dayton, Ohio
    Ratings:
    +1 / 0
    I don't know, but I think that's 20% difference with the magnum primers. I wouldn't think the the extra charge in the primer would account for that. I would imagine the magnum is also helping detonate the slower powder more effectively.

    I'd guess to test this theory I'd do the comparison with fast burning powder and see if the difference with the magnum primers is less dramatic.
     
  15. fredj338

    fredj338 XDTalk 10K Member

    Joined:
    Jan 13, 2007
    Messages:
    10,293
    Likes Received:
    6
    Trophy Points:
    38
    Location:
    kommiefornia
    Ratings:
    +6 / 0
    You'll likely see a greater vel/pressure increase as the powder get faster. It will also change w/ diff. cartridges. Faster powders peak pressure sooner, so any extra increase spikes the presure sooner.
     

Share This Page

Search tags for this page
40 s&w federal primers
,
are magnum small pistol primers for .40s&w
,
can federal #200 primers be used in 40 s&w
,
can i use small pistol magnum in 40 sw
,
can i use small pistol magnum primers for .40 cal
,
can you use magnum primers in 40 s&w
,
large magnum pistol primer loads
,
magnum pistol primer in 40s&w
,

magnum primers in 40 s&w

,
magnum small pistol primer for .40
,
need .40 loads that use magnum primers
,
pistol primers used for40s&w
,
small magnum primers in 40sw
,
small pistol magnum primers 40 s&w
,
small pistol magnum primers for 40s&w
,
small pistol magnum primers in 40 s&w
,
smallest load for .40 with unique
,
using magnum primer in .40 s&w
,
using small magnum pistol primers in .40s&w loads?
,
using wspm primers for 9mm