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jim6918

9MM and COL Variations

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I have been getting ready to load my first 9mm's after doing bunches of .380 and .40 S&W.  Of course I have been researching heavily different recipes. I will be using 115 gr. FMJ's.

contemplating either TG or W231 (which I have lots of already).

 

I see, what seems to me to be, a wider range of COL than the 40's or the 380's.  From 1.100 up to 1.165, with an assortment in between.  The commercial 9mm I have used most recently, Fiocchi 115 gr., is 1.135.  The Fiocchi shoots fine in my Sig MPX and a G17, although the Fiocchi does seem a little long for the magazines.

 

The range I use is about 30 miles away, so I just can't run over with 20 or 30 to test.

 

I am a newby and don't have a chrono, so I would like to stick with good middle of the road recipes.

 

Any thoughts?

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Oal depends on two things.

How deep is the chamber

And how long are the magazines.

Load some at 1.135 since you know they fit in the mags and chamber check them.

Commonly called the plunk test

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15 minutes ago, jcc7x7 said:

Oal depends on two things.

How deep is the chamber

And how long are the magazines.

Load some at 1.135 since you know they fit in the mags and chamber check them.

Commonly called the plunk test

 

I gauge and plunk everything I've loaded so far.  The plunk test works fine for my G17.  I can have it apart blindfolded.  Well, not exactly, but you know what I mean.

 

The MPX is a horse of another color, just for a plunk test.

 

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Safety on pointed in safe direction and see if they feed and extract smoothly.

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Here's how I determine COL.  Find your firearm in that caliber that has the shortest, tightest chamber.  Set up a crimp die for a tight crimp, and first determine your maximum OAL by seating then crimping until you are just off the lands, then shorten it up enough that your normal variation will not put you in the lands(be a little forgiving, just in case).  Now you have your COL, and you can back out your crimp die and then start tightening it just until you pass the plunk test, then add a pinch more for good measure.  Load up a test cartridge and make sure it plunks in all of your firearms of that caliber.  Feed it from a magazine in all of them and make sure it seems smooth.  At that point, you have a round that should function in all of your firearms and can move on to determining a safe starting load to work up from.  Pay attention to whether or not feeding from magazines is causing bullet setback or not. If so, you may need to look at your sizing die.

Couple notes.  First, get a chrono.  There's what books say the rounds are doing and what you think they are doing, and in my experience with local reloaders who don't have them, both are usually pretty far off.  Had a local guy shoot a full season of level 1 matches as "major" because he thought they "felt major".  When he was finally chronoed, they were 150PF.  Second, expect a bit more variation on 9mm's if using mixed brass.  There seems to be more variation in 9mm brass than 40 S&W brass in my experience.

Edited by fbzero

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I just use a case with a slot cut in it. Push the bullet/case into the chamber. Deduct 0.015" or so. 

 

And get a chrono. You can "really" do this without a chrono. 

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Edited by Dirty_J

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8 hours ago, jim6918 said:

  Fiocchi 115 gr., is 1.135.  shoots fine in my Sig MPX and a G17, although the Fiocchi does seem a little long for the magazines.

 

Each brand of 115 FMJ bullets might require a different OAL - depends on the exact shape of the bullet.

 

If they're too long for your mag, you should definitely shorten them a little.

 

If you're NOT going to do The Plunk Test because it's a lot of work to take your gun apart, don't load too

many at any one COL.  When you get to the range, they may not feed.

 

Rather than waste two hours driving to the range to find out if they're too long, I'd load one that long with

no primer and no powder, and try to feed that thru your gun.   Keep shortening, a little bit at a time, until

you find an OAL that feels just right for your gun and your mag, for that one particular 115 gr FMJ.    :) 

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You establish COL using your gun and the specific bullet you are going to load while at the bench before you EVER start to reload. All the COL in a manual REALLY tells you is what COL they tested at.

For handgun rounds, longer COL means more powder before hitting max pressure, meaning more gas, meaning more velocity.

Per Ramshot (and all other reloading suppliers):
“SPECIAL NOTE ON CARTRIDGE OVERALL LENGTH (COL)
It is important to note that the SAAMI COL values are for the firearms and ammunition manufacturers industry and must
be seen as a guideline only.
The individual reloader is free to adjust this dimension to suit their particular firearm-component-weapon combination.
This parameter is determined by various dimensions such as 
1) magazine length (space), 
2) freebore-lead dimensions of
the barrel, 
3) ogive or profile of the projectile 
and 
4) position of cannelure or crimp groove.
• Always begin loading at the minimum "Start Load".
• Increase in 2% increments towards the Maximum Load.
• Watch for signs of excessive pressure.
• Never exceed the Maximum Load.”

Note: add to the above that the timing between when the magazine lips release the round and the slide pushes the round into the chamber can be COL sensitive. With 1911s, almost all feeding issues with SWC was solved simply by changing the magazine lips to release the round sooner.
So, your COL (OAL) is determined by your barrel and your gun and your magazine and the SPECIFIC bullet your are using (bullets have huge differences in geometry). 
What worked in a pressure barrel or in my gun has very little to do with what will work in your gun. Load a couple of dummy rounds (no powder and no primer) to the max. COL (OAL) and see if it fits your magazine, feeds in your gun, and chambers in your barrel.
Seat the bullet slightly deeper until you achieve all three of these goals. This is the COL (OAL) for you in your gun with that make of bullet.

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Thanks everybody for the valued opinions.  I really had no idea that there would be so many variables to reloading when I started a couple of months ago.  

 

My #1 goal is always going to be safety, not only for myself, but also my family who will be using my loads.  That's why I don't pull that handle until I am 100% sure of what I am doing.  

 

There will be no extremes coming from this house, thats why I am always looking for the middle of the road recipes that will work in my weapons.

 

 

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