close

Privacy guaranteed - Your email is not shared with anyone.

Question about using small pistol magnum primers in a .40

Discussion in 'Reloading' started by imknadian, Apr 4, 2010.


Tags:
  1. imknadian

    imknadian
    Expand Collapse

    Joined:
    Jun 7, 2007
    39
    0
    I bought some primers at Scheels yesterday for my .40 cal. When I got home, I realized they were small pistol magnum primers instead of the regular small pistol primers that I usually use.

    Is it possible to load safely using the small pistol magnum primers? Are there any issues? Currently I am using 4.8grains of tightgroup and getting around 1050fps with 180grs using the regular primers.
     

    Wanna kill these ads? We can help!
  2. wavetrain75

    wavetrain75
    Expand Collapse
    Useless Member

    Joined:
    Jan 31, 2008
    3,409
    1
    I was told by the guy behind the gun counter (and we all know they're never wrong) to dial back your load by 1/10 grain when using magnum primers, and to stay at least 2/10 or 3/10 grain below maximum charge.
     

  3. ron59

    ron59
    Expand Collapse
    Bustin Caps

    Joined:
    Jan 3, 2009
    6,927
    20
    Location:
    Smyrna, GA
    I run sp magnum primers with my 9mm loads... no problem. It only makes a difference of a few fps (8, 10 maybe?) across the chrono.
     
  4. DEADLYACCURATE

    DEADLYACCURATE
    Expand Collapse
    Senior Member

    Joined:
    Oct 24, 2009
    3,139
    0
    I don't know if it is recommended, but I used em during the primer shortage.
     
  5. Jayman

    Jayman
    Expand Collapse
    Big Dummy

    Joined:
    Nov 3, 2002
    393
    0
    Location:
    Chantilly, VA
    The load you are using is .1 higher than the max load Hodgdon lists on their webpage. If you're going to switch to magnum primers, I'd back that load off a bit, as you're already out in un-charted territory. Do you really need 1000+ fps from this load?
     
  6. IndyGunFreak

    IndyGunFreak
    Expand Collapse
    KO Windows

    Joined:
    Jan 26, 2001
    25,686
    977
    Location:
    Indiana
    :agree:

    Obviously, it depends on what bullet you're using, OAL, etc.. but if you're loading a 180gr FMJ, they are over what Lyman says already.

    The 40, is one of those rounds that I just don't play around with. It's already high pressure enough. *Most* of the data I've read where people tested the difference between standard and magnum SP... it was around 30-60fps... Plus you did it w/ Titegroup? Man, I'd probably be sitting w/ the bullet puller for a while if it were me.
     
  7. kimberguy2004

    kimberguy2004
    Expand Collapse

    Joined:
    Jan 14, 2007
    927
    26
    Location:
    Austin, Tx
    I use them on .40 & 9MM with no problems, but my loads are not even near the top of the scale. I load for a power factor and when the chronograph says I'm there, I stop. I see no need to impress anyone at the range with how much punishment me or the gun can take. If I'm really feeling masochistic, I have a FA .454 and a couple of .44s I can play with.
     
  8. dudel

    dudel
    Expand Collapse

    Joined:
    Dec 10, 2008
    4,589
    162
    Location:
    Texas Hill Country
    +1 Changing components, running near maximum. If you're not working with a chrono under those conditions, you're just asking for troubles. (yes, plural)
     
  9. sonick808

    sonick808
    Expand Collapse

    Joined:
    Dec 29, 2009
    101
    0
    Location:
    Chandler, AZ, US
    it's of negligible consequence. Unless you're running max loads already, just use your regular recipe. If you can't stand it psychologically, knock off a tenth of a grain, but it won't matter.

    The funny thing about loading pistol is that you're usually using a powder thrower instead of a trickler and a scale; there's not a powder thrower in existence that doesn't have a margin of error of at least .5 grain each way. Backing off ".1" is pointless unless you're using a trickler and a scale for each charge.

    Keep an eye on your recipe, i re-read and saw someone said you were above the lyman max load; that's where things like magnum primers start to matter. The chronograph doesn't really tell you much about the max psi in your gun. you've got set back, oal, charge compression, the 180 grain pills that shouldn't really be used in .40SW anyway, and other variables. Might want to back off and find a middle of the road recipe. Use the chrono less as a meter of load safety and established data more.
     
    #9 sonick808, Apr 5, 2010
    Last edited: Apr 5, 2010
  10. ron59

    ron59
    Expand Collapse
    Bustin Caps

    Joined:
    Jan 3, 2009
    6,927
    20
    Location:
    Smyrna, GA
    !!!????!!!!????

    Sorry, but I'm gonna have to dispute this. My 550B in no way has this wide of a margin of error. In fact, whenever I start for a session I check it, and may have to adjust it .05grain (that's half of .1gr), but that's about it.
    It does NOT vary during a session, and I only check it every few hundred rounds... and usually don't even need to touch it.

    I don't know what crappy reloader you're using, but .5gr each way would be a powder thrower in the garbage can for me.
     
  11. LoadedTech

    LoadedTech
    Expand Collapse

    Joined:
    Mar 19, 2009
    1,058
    0
    Location:
    virginia beach
    I agree with Ron59. My Lee powder disc is so consistent that I check when I change powders or CC hole, then it balls on accurate every dump. I have only been reloading for 6-8 months now and have ONLY used Magnum primers (the only thing I could find) and don't run to max loads with any powders, they have been fine. I have read the same thing Indygunfreak said 30-60 fps, which I like to make up for my shorter barrel 27. I will continue to use them because they are $20/1k cheaper and usable.
     
    #11 LoadedTech, Apr 5, 2010
    Last edited: Apr 5, 2010
  12. jing1117

    jing1117
    Expand Collapse

    Joined:
    Oct 10, 2008
    268
    0
    Location:
    Roseville, CA

    Sorry, but in my experience the dillon 550, hornady lnl, lee pro 1000 disk system throw very consistent loads - especially when I use powders such as Win WST, WSF, 231 - even with flake type powders I have never gotten a .5 variance. they are all within the .1 variance if that. If something is not right I check everything. The .5 variance can be a lot to some powders - especially running near max loads.

    Going back to the topic - Yes I have used small pistol magnum primers in loading .40. I just started from the bottom of the loading data and worked it up.
     
    #12 jing1117, Apr 5, 2010
    Last edited: Apr 6, 2010
  13. Hoser

    Hoser
    Expand Collapse
    Ninja

    Joined:
    May 22, 2002
    2,339
    34
    So what your saying is that if I want to throw 4.0 gns of N320 I could expect anywhere from 3.5-4.5 gns?

    If that is what your powder measure throws you need a new powder measure.

    I have measures made by Dillon, RCBS and Harrel. None are anywhere near as bad as yours. Maybe .1-.15 either side of what I am looking for.
     
  14. Hoser

    Hoser
    Expand Collapse
    Ninja

    Joined:
    May 22, 2002
    2,339
    34
    No issues at all. Back off your load a bit and chrono your ammo.

    Heck I use small rifle primers.
     
  15. professor gun

    professor gun
    Expand Collapse

    Joined:
    Dec 18, 2007
    212
    0
    I use an RCBS powder measure that varies about 0.1 grain charge to charge with pistol powders I use.

    I have read that mag primers burn hotter and may increase pressure a bit so the advice above on decreasing from max is very good I think.

    My experience with the .40 is that it is not as tolerant of changes as other calibers (.45 ACP).
     
  16. sonick808

    sonick808
    Expand Collapse

    Joined:
    Dec 29, 2009
    101
    0
    Location:
    Chandler, AZ, US
    i've tried throwing mostly flake via rcbs, hornady and lee throwers; weighing the charge with a diamond scale calibrated on US standards weights.

    I suspect some of the above accurate charges may in fact be indictments (or increments) of inaccurate scales but if you ARE getting +_ .1gn, don't EVER get rid of that thrower.

    funny thing: lee was the most accurate. ha
     
    #16 sonick808, Apr 6, 2010
    Last edited: Apr 6, 2010
  17. arkdweller22

    arkdweller22
    Expand Collapse
    Cuhootnified

    Joined:
    Dec 26, 2008
    3,880
    5,713
    With regard to velocity, pressure, etc.: Typically it makes very little difference if you're using Magnum primers as opposed to standard.

    Like others, I have used Magnum primers during the ammo shortage and did not need to change my recipes.
    I did note, however, that Magnum primers (at least the Winchesters I was using) are a bit harder than standard. Thereby causing occasional failures to fire due to light primer strikes, especially with mouse guns.
     
  18. TexasFats

    TexasFats
    Expand Collapse
    NRA, TSRA, SAF

    Joined:
    Sep 14, 2006
    1,002
    1
    Location:
    Austin, TX
    The priming composition in magnum primers is hotter and throws more "fire" into the powder. A lot of it depends on what powder you are using. Ball powders may need magnum primers just to fire reliably. Flake powders may burn too fast with them. Back off and work up slowly.