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.45ACP case length


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OK, 150-200 rounds per match has finally worn down my resistance and I am getting into reloading, starting with .45ACP.  Basic question, how important is consistency in case length.  My load books lists the max case length as .898.  My once fired, resized brass measure out between .882 and .897.t an OK spread?

 

Doc sends. 

 

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Bottom line- the .45 Auto cartridge does not require a lot of consistency on length.  The Maximum Case Length number is important to know, but never really gets you in trouble.  Keep reading.

 

You are generally good with that range. 

 

.45 Auto cases never get longer.  The more they are fired, the shorter they get.

 

Two critical parts of case length for .45 Auto.  Too long and the round will not fit in the chamber well, and firing pin may not fall when trigger is pulled.  That is what the Max case length value is for.  Factories are good at holding their cases less then Max case length.  So, really, your cases won't ever be too long.

 

Too short a case length, and your taper crimp die will miss putting a solid taper crimp on the round.  Then, the bullet can collapse into the case during feeding and chambering.  May cause a jam, may raise pressures, may work OK.  Make sure you have a firm crimp on the bullet.  The easy test - hold a finished cartridge in your strong hand.  Put the nose against something fairly solid, like a door jamb or the edge of a sturdy loading bench. Push with that one hand hard.  If the OAL did not change when doing that, you are good (on that cartridge).  Load one of your shortest and test it. If that one is good, all your ammo should be crimped well enough.

 

Finally, get a loaded-round gauge and check ammo all drops in and falls out.  Any more, the part that will sometimes stick due to being over-diameter is just above the extractor cut, where previous high pressure loads expanded the case, but your normal sizing die does not reach low enough to resize.  Either toss the case, or get a Lee Bulge Buster kit and a Lee Factory Crimp Die.  Push the case all the way through the FCD so that it can resize the lowest part of the case wall.  It' s amazing how much "range brass" is oversize and will fail the loaded-round gauge, and even not chamber well in some 1911s.

 

I don't ever measure case length for .45 Auto.

 

Now, cartridge OAL - THAT is pretty sensitive to both the bullet shape, the interior design of the 1911 chamber, the condition of the feed ramp, etc.  Once you find the right OAL of finished round that feeds and chambers 100%, record that, and measure as you reload to make sure you are holding that OAL.  More than 10 thousandths of an inch of driving band left exposed at the mouth is usually a recipe for rounds that won't reliably chamber.

 

good luck, GJ

 

 

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  • 1 year later...
On 4/15/2021 at 9:17 AM, Garrison Joe said:

Bottom line- the .45 Auto cartridge does not require a lot of consistency on length.  The Maximum Case Length number is important to know, but never really gets you in trouble.  Keep reading.

 

You are generally good with that range. 

 

.45 Auto cases never get longer.  The more they are fired, the shorter they get.

 

Two critical parts of case length for .45 Auto.  Too long and the round will not fit in the chamber well, and firing pin may not fall when trigger is pulled.  That is what the Max case length value is for.  Factories are good at holding their cases less then Max case length.  So, really, your cases won't ever be too long.

 

Too short a case length, and your taper crimp die will miss putting a solid taper crimp on the round.  Then, the bullet can collapse into the case during feeding and chambering.  May cause a jam, may raise pressures, may work OK.  Make sure you have a firm crimp on the bullet.  The easy test - hold a finished cartridge in your strong hand.  Put the nose against something fairly solid, like a door jamb or the edge of a sturdy loading bench. Push with that one hand hard.  If the OAL did not change when doing that, you are good (on that cartridge).  Load one of your shortest and test it. If that one is good, all your ammo should be crimped well enough.

 

Finally, get a loaded-round gauge and check ammo all drops in and falls out.  Any more, the part that will sometimes stick due to being over-diameter is just above the extractor cut, where previous high pressure loads expanded the case, but your normal sizing die does not reach low enough to resize.  Either toss the case, or get a Lee Bulge Buster kit and a Lee Factory Crimp Die.  Push the case all the way through the FCD so that it can resize the lowest part of the case wall.  It' s amazing how much "range brass" is oversize and will fail the loaded-round gauge, and even not chamber well in some 1911s.

 

I don't ever measure case length for .45 Auto.

 

Now, cartridge OAL - THAT is pretty sensitive to both the bullet shape, the interior design of the 1911 chamber, the condition of the feed ramp, etc.  Once you find the right OAL of finished round that feeds and chambers 100%, record that, and measure as you reload to make sure you are holding that OAL.  More than 10 thousandths of an inch of driving band left exposed at the mouth is usually a recipe for rounds that won't reliably chamber. 

 

good luck, GJ

Tunnel Rush

 

 

As long as they're between 0.888" and 0.898" you're okay. Load them up and shoot them. You may have to adjust your crimp a bit if you have varying lengths. 0.898" is maximum case length for .45acp. Anything longer than that should be trimmed. And 0.888" is minimum case length, generally you should toss out anything shorter. A little bit shorter and they'll still work but then they aren't headspacing off of the case mouth like they should, which means the extractor is doing the headspacing and you generally don't want that.

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