9mm coal

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  • cotman68

    Active Member
    Feb 21, 2010
    796
    Stewartstown, Pa
    Making my 1st batch of berry’s 124 gr flat point.
    Manual says coal is 1.06 for this Bullet with 3.6 grains of Titegroup. Got my die set to 1.06 but sometimes the round will measure 1.055-1.06 with calipers. My question is this normal ? Are their acceptable tolerances. They are passing the case gauge checker.


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    platekiller

    Ultimate Member
    Jun 7, 2011
    1,780
    Martinsburg, WV
    COL is normally min. I set mine slightly over and make sure they fit in the mag. Should be fine. I don’t worry too much since all my pistols are rated for +p so they will be fine


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    cotman68

    Active Member
    Feb 21, 2010
    796
    Stewartstown, Pa
    Hand all the short ones over to me, and I’ll shoot them for you.


    Lol. Kinda what I thought but I’m a newbie. I’m using RCBS carbide dies and seat and crimp at the same time and wasn’t sure if that was causing the difference


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    John from MD

    American Patriot
    MDS Supporter
    May 12, 2005
    22,729
    Socialist State of Maryland
    Making my 1st batch of berry’s 124 gr flat point.
    Manual says coal is 1.06 for this Bullet with 3.6 grains of Titegroup. Got my die set to 1.06 but sometimes the round will measure 1.055-1.06 with calipers. My question is this normal ? Are their acceptable tolerances. They are passing the case gauge checker.


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    Unless you make your bullet seating stem specifically for that bullet, you will get a lot of variance. Even with the mated seating stem you will still get a little. It only really matters 1 if you are shooting long range rifle or postal matches or 2 if you load to the max and are shooting on hot days.
     

    cotman68

    Active Member
    Feb 21, 2010
    796
    Stewartstown, Pa
    Ok. This is just a range round loaded to the minimum powder charge. I’ll test these out Friday before I make too many up


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    Magnumite

    Ultimate Member
    Dec 17, 2007
    6,561
    Harford County, Maryland
    What others stated is true. My experience has been case work hardening, length, consistent bullet diameter, consistency in press operation, etc. all affect the C.O.L.. extreme spread of about .005” (target +/- .002”) works okay. If these are practice, action/steel shooting, or general target ammo that COL spread will work.

    When I build real match quality ammo all bullets get measured and weighed, sorted appropriately then the round is built. So consistency is th
     
    Last edited:

    GuitarmanNick

    Ultimate Member
    Jan 9, 2017
    2,221
    Laurel
    When using quality projectiles, the COAL will usually be very consistent. Lower quality projectiles will have more variance between them and can often result in slightly different lengths.

    I would not use the minimum charge in a semi-auto pistol unless it has been specifically tuned to use a light charge. In my experience, this can result in cycling problems. I generally start about .2 gr above the minimum and work up from there until the performance of the load is similar to factory ammunition. That way, my training/practice rounds will actually prepare me should the need arise to use a pistol for self defense.

    In the current environment, quality projectiles are in short supply like many other items related to our hobby. Ammunition manufactures get most of the good stuff before the public. Much of what is available, has been rushed through production and is likely to vary more than in the past.
     

    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    Also case. Are you using all the same head stamp? If I am using all the same, I typically see about a .005” spread. If I use mixed headstamp it’s more like .010” spread. Which is still fine to me for range Ammo with a lot of stuff. I just don’t load anywhere remotely near max.

    Typically I start at about mid charge when working up a lot unless my stuff is really far off the recommendation. Example, my Vz70 with Berry’s had to be loaded really short because of the meplat. So I started at the minimum for that and worked up.

    I absolutely find better ES and SD as well as grouping when COAL variance is kept to a minimum. But even with a .010” spread I’ve seen SDs in the 10-12fps range in 9mm for 5-10 shot groups and good accuracy.

    Rifles in my limited experience are a bit more susceptible to accuracy and velocity consistency issues with COAL variances. Could of course be you are usually shooting both at longer ranges and the velocity is a lot higher. So what is a 10fps at 100fps is more like a 30fps at 3000...
     

    cotman68

    Active Member
    Feb 21, 2010
    796
    Stewartstown, Pa
    Also case. Are you using all the same head stamp? If I am using all the same, I typically see about a .005” spread. If I use mixed headstamp it’s more like .010” spread. Which is still fine to me for range Ammo with a lot of stuff. I just don’t load anywhere remotely near max.

    Typically I start at about mid charge when working up a lot unless my stuff is really far off the recommendation. Example, my Vz70 with Berry’s had to be loaded really short because of the meplat. So I started at the minimum for that and worked up.

    I absolutely find better ES and SD as well as grouping when COAL variance is kept to a minimum. But even with a .010” spread I’ve seen SDs in the 10-12fps range in 9mm for 5-10 shot groups and good accuracy.

    Rifles in my limited experience are a bit more susceptible to accuracy and velocity consistency issues with COAL variances. Could of course be you are usually shooting both at longer ranges and the velocity is a lot higher. So what is a 10fps at 100fps is more like a 30fps at 3000...


    Mixed head stamps. Got a 500 round bag from Everglades in the summer. Went to range yesterday and shot 1 round at a time to make sure slide locked back. Don’t have a chronograph yet , but grouping was better than win white box. 1.06 was max coal and 1.053 was shortest. Took all four of 9mm handguns also. Really wish I would’ve started reloading years ago , but better late than never


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    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    Mixed head stamps. Got a 500 round bag from Everglades in the summer. Went to range yesterday and shot 1 round at a time to make sure slide locked back. Don’t have a chronograph yet , but grouping was better than win white box. 1.06 was max coal and 1.053 was shortest. Took all four of 9mm handguns also. Really wish I would’ve started reloading years ago , but better late than never


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    I’d call that totally expected. Yeah, my little experience I’ve built up the last few months reloading, at a guess bulk range ammo is loaded with powder metered with a ladle by a blind drunk octogenarian in the factory or something. So far I’ve yet to turn out something that isn’t at least slightly more accurate than factor range ammo. And I am not doing my utmost to control everything.

    Generally mixed brass, ballpark COAL, etc. I am using a Lyman powder dropper and at least from what I can see it’s keeping every charge within .1gr. Once I get it dialed in on a session weighing the occasional charge I’ve yet to see it deviate over the several hundred rounds I’ve loaded (1k now maybe?)

    Now, I am not claiming my stuff is match accurate, haven’t been working on that yet. Well, not much yet.

    Biggest spread I’ve seen is mixed head stamp cases with 147gr XTP bullets. .013” spread from longest to shortest. Most was within what I wanted for the COAL by about .003”, but federal was coming in .013” shorter. Blazer was .010” shorter. Only PPU m885 brass was about .002” longer than my desired and dialed in COAL (press had been set with UMC brass). Win, Speer and Geco brass were all within that -.003 to spot on COAL (well and UMC/Rem).

    Didn’t weigh it, but curious if the federal 9mm brass is a lot thinner or something.

    Anyway, I DID segregate out the federal brass (only one blazer round, which I shot on its own over the chrono and didn’t bother to keep its data). Turns out best group was like 7FPS SD and I think 18fps ES and it liked it hot. Run in CFE pistol up to near max and that is where it liked it, .2gr under max (didn’t load at max).

    The federal being .013” shorter was 30fps faster...which seems like that is cranking on a lot of extra pressure from the shorter COAL.
     

    noylj

    Active Member
    Jun 3, 2012
    144
    Measure bullets--they vary (besides length variation, even the shape varies as they don't all come from the same die or mold)
    Measure factory ammo--they vary
    Measure COL pulling handle hard vs slow--they vary.
    All a manual tells you is their test COL. You find the COL best for you--then you work up the load from the start load.
     

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