9mm COAL too short for safety?

This is a discussion on 9mm COAL too short for safety? within the Reloading forums, part of the Defensive Ammunition & Ballistics category; Hey guys, I loaded 100 9mm the other day. Here's my recipe: 124gr FMJ Round Nose (jacketed, not plated) 6.0gr Accurate No. 5 Federal Small ...

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Thread: 9mm COAL too short for safety?

  1. #1
    Member Array pacman's Avatar
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    9mm COAL too short for safety?

    Hey guys, I loaded 100 9mm the other day. Here's my recipe:

    124gr FMJ Round Nose (jacketed, not plated)
    6.0gr Accurate No. 5
    Federal Small Pistol Primers (No. 100)

    I have the Speer Reloading Manual #14. (Manual says min charge 5.7, max 6.4)

    In this manual it tells me to load hollow points and flat nosed bullets to 1.120", and round nosed to 1.135". For some reason or another I set my die to load them about 1.122" (I must have misread the round nose length).

    It looks as if the COAL's are ranging from 1.121" - 1.126".

    My question is, "Should I pull all 100 of these and reload them or does anyone think these would still be safe?

    According to Hogdon data a Sierra FMJ rn bullet can be loaded to 1.090" and Accurate states 1.010". I have noticed that according to the Speer manual the max charges are higher than all of the other data I have seen so I am reluctant to shorten the COAL any more than the manual states.

    What is your opinion?

    **Edit**
    Sending these bullets downrange with a M&P Shield that seems to eat anything I put in it.

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    I consider the quoted "COL" for a cartridge to be theh most inconsistant specification for all reloading specs. Every bullet and powder maker has their own dimension. And is that the minimum? The maximum?

    Personally, with a mid-range load .01" off from the quoted spec--I'd shoot them. But that's me, and if everyone did what I do there'd be a lot of us in trouble.
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    Quote Originally Posted by OldVet View Post
    I consider the quoted "COL" for a cartridge to be theh most inconsistant specification for all reloading specs. Every bullet and powder maker has their own dimension. And is that the minimum? The maximum?

    Personally, with a mid-range load .01" off from the quoted spec--I'd shoot them. But that's me, and if everyone did what I do there'd be a lot of us in trouble.
    Thank you for your input.

    Regarding the min/max coal, the manual only states "COAL tested". It doesn't say whether it is minimum or max.

    After further reading through the Speer manual it specifically states:

    "It is important not to load compact cartridges like the 9mm Luger shorter than we show"

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    I load mine to 1.15 OAL. When it is shorter it raises the pressure of the cartridge for a given load.
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    Re: 9mm COAL too short for safety?

    I load mine to 1.13 and have had no problems. Make sure those rounds extract in your gun ok. I've loaded ten rounds to 1.09 before and those had problems extracting from my old M&P.
    If you're going to carry one weapon, might as well carry two, because as the saying goes, "Two is one, and one is none."

    "Liberals can decline or whine, but I will still carry and conceal mine." - Cold Warrior. Excellent quote good sir!

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    Member Array pacman's Avatar
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    I shot 25 of them today without issue. Cases and primers look good. They shoot nice too! I was only concerned being that the length was shorter than what the Speer manual was stating for a given load. Thanks guys.
    aus71383 likes this.

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    Senior Member Array FLSlim's Avatar
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    Glad they worked for you. In the low to mid range of powder loads, especially with slower burning powders, I don't get too worried about slight differences in OAL from that published. In your boat, I would have consulted a couple of other manuals or online powder mfg data to get a better feel for the safety of the powder charge/OAL combo with which you were dealing.
    Chose a weapon that goes bang EVERY time!

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    Its My opinion that the COAL length is a max. loading too short won't raise pressure till you start crushing the powder. So the little difference in your loaded length will only matter if your gun wont feed them well. I would just shoot them. DR

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    dangerranger -

    Your opinion seems counterintuitive to me. Less volume in the case + same amount of powder = higher pressure. Powder is low explosive - it turns to gas almost instantaneously when it's in the open. In a contained space it's even faster.

    The overall length of the cartridge is listed in the data because it relates directly to the volume available in the brass for the powder to turn into gas safely. Making a cartridge longer than will fit in a magazine or feed in your gun isn't the reason for the measurement - those measurements come from the cartridge data itself. Individual load data is specific for a reason. If you load your rounds shorter, they will go faster. This isn't good! It means the chamber pressure is higher than it should be.

    pacman -

    I missed this thread last time around. I agree with OldVet on this one, and I'm glad they worked out for you.

    In the future - try making a dummy round. It's a great time saver. Take a sized and deprimed piece of brass, and seat a bullet in it (with crimp) to the correct OAL for that bullet. Then when you go to adjust your seat/crimp die, you can use the "dummy" in the die to get things close, and to compare to the rounds coming out. Are you using a progressive press?

    Austin

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    Ex Member Array hartlathers's Avatar
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    I'm handloading for a CZ 75 and a CZ 100 9mm using 125 LRN cast bullet. CZs are finicky and tend to like a shorter OAL. I'm using 4.8 grains of 3N37 with an OAL of 1.115. These cartridges cycle and fire with no problems.

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    Distinguished Member Array dangerranger's Avatar
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    Quote Originally Posted by aus71383 View Post
    dangerranger -

    Your opinion seems counterintuitive to me. Less volume in the case + same amount of powder = higher pressure. Powder is low explosive - it turns to gas almost instantaneously when it's in the open. In a contained space it's even faster.

    The overall length of the cartridge is listed in the data because it relates directly to the volume available in the brass for the powder to turn into gas safely. Making a cartridge longer than will fit in a magazine or feed in your gun isn't the reason for the measurement - those measurements come from the cartridge data itself. Individual load data is specific for a reason. If you load your rounds shorter, they will go faster. This isn't good! It means the chamber pressure is higher than it should be.

    Austin
    This opinion is from loading both BP and smokeless rifle rounds. The loads that achieve the least velocity deviation are the loads that fill the case without crushing the granules. [of course with proper powder that safely allows this fill].
    I have also made light revolver loads by seating a round ball over a min load of powder. those that I seated at the case mouth suffered from poor accuracy and wild changes in velocity. But by setting the ball back to the level of the powder group sizes were cut in half. not target grade but certainly minuet of raccoon!

    Actually I think you are wrong about confined burn rate of powders. Not compressed but confined should give a more even burn rate. Also if ballistic engineers were using OAL to regulate the air space inside a loaded cartridge they would express it in volume used instead of over all length. But that's just my opinion. DR
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    VIP Member Array aus71383's Avatar
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    Quote Originally Posted by dangerranger View Post
    Actually I think you are wrong about confined burn rate of powders. Not compressed but confined should give a more even burn rate. Also if ballistic engineers were using OAL to regulate the air space inside a loaded cartridge they would express it in volume used instead of over all length. But that's just my opinion. DR
    I could easily be wrong. My expertise isn't with small arms powders and reloading - it's just a hobby for me.

    It makes sense that a well filled case will be the most accurate with regards to velocity deviation. With pistol/plinking ammo the deviation doesn't matter as much, and it's more about cheap powders/loads. So then you end up using a low volume powder that burns fast because it's cheaper in the long run.

    I don't have any experience reloading black powder - yet! - but I do know a thing or two about making low explosives detonate. The faster the powder, the tighter/stronger the container, and the less air space, the better.

    Austin

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