Question about Overall Lenghts

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radmacks

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Questions about overall length. Which is represented as C.O.L? So if I understand correctly the pros and cons. Too long, won't feed properly, mag jams, not enough pressure could cause a squib or poor performance? Too short, too much pressure = hand grenade.

Now I may be slices hairs here. Currently pondering my 9mm loads. I'm using a 124gr RN plated CamPro. Win 231 4.45 grains or 0.43 cc. CamPro data is 1.120 Lee Modern says 1.090 and max 1.69.

So I erred on the side of caution to start and was crimping half crimp at 1.165. No feed issue. couple thousand rounds in 3 different pistols.

What i'm wondering is if seating so far out is reducing the pressure enough to drop the power/velocity/kick whatever you want to call it. I'm guessing that in order to achieve optimum safe pressure and velocity I probably should seat as close to data as possible. I'm going to try some 1.130 and see how it feels. The reason why I was seating so far out was to create a safe buffer for inconsistencies I had with my old bench. New solid bench and now I seem to be nailing my lengths bang on pun intended.
 
ideally you want to be using a custom OAL that fits your specific gun, not what the book says because they used a different one. you can either make an OAL for each gun you own for the best accuracy or if your just making a general plinking load then pick the shortest OAL so it will fit all your guns.
 
COAL is by far the most USELESS piece of informations EVER! It is dependent on numerous variables that change with each bullet type or brand.

This idea that a few ten thousandths of an inch one way will cause a grenade and a few then thousandths of an in the other direction will reduce velocity is entirely ludicrous. In the 30 years I have been reloading I have never run into issues with loaded length and I've made more than a few mistakes in my time.

What you want is the longest seated depth that will fit in your mags and feed in your gun. That is the only important factor. Ignor everything else.

OP: if you have a seated depth that works in your guns, WHY ON EARTH would you screw with it? If you are really determined to mess with it you want to go longer, not shorter. Closer to the lands will always be better. Too far back and accuracy will suffer.
 
If you have 5 cases measuring 2805 and 5 cases measuring 2810, and load those with the same bullits,powder/weight,primers, at the same COL.
Would they perform the same?
Hope this is not off topic.
 
I'm a novice reloader myself but I would start at the midpoint of the c.o.l. range myself with the thought that that length would be most likely to feed in a variety of pistols. What I would then do is start at the lowest charge weight and load a few rounds with 0.2 grain increments. Test them until the bullets are impacting where you want at the distance you want with enough pressure to cycle the slide.

The fact that you started at the high end of c.o.l. and it still cycles is something I'd just leave alone as long as the bullet us impacting where you want. If the slide is cycling and the bullet impacts where you want, that's optimum enough I would think.
 
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I haven't changed my dies for 9 mm in about 5 times with the same cases.
Using tightgroup or CFE pistol.
I don't find any diff in accuracy or kick.
I don't even measure the cases anymore.
Maybe I should???
 
I will advocate for us novice guys....... COL is very valuable to me in that, until I am at the point that I am good enough to start f'ing around with where the bullet sits in relation to the lands, it's nice to mimic factory length ammo...... I can experiment with powders & grains, as well as bullet weight and have one less thing to worry about for now......
 
Superbrad said:
I will advocate for us novice guys....... COL is very valuable to me in that, until I am at the point that I am good enough to start f'ing around with where the bullet sits in relation to the lands, it's nice to mimic factory length ammo...... I can experiment with powders & grains, as well as bullet weight and have one less thing to worry about for now......
Click to expand...

You are entirely fooling yourself if you think that the published COAL has anything to do with any ammo you may make. COAL will change with every bullet type and weight. Unless you happen to have the exact same bullet used in factory ammo then your COAL has no real relation to that of factory ammo. That the two may be the same length is meaningless because the shape of the bullet nose could be totally different.

The reason that COAL is meaningless is that it measures to the tip of the bullet. Problem is that the bullet engages the rifling at the ogive. The ogive and the bullet tip have no relation to one another. You might as well measure bullet colour for as useful that may be.

I googled "9mm 124gr" and came up with the two bullets below, which coincidentally are both made by the same manufacturer. Does anyone think that the COAL for these two bullets will be the same? They are both 9mm 124gr.

9mm-356-124gr-rn-250ct-76848.jpg
9mm-356-124gr-fp-250ct-43234.jpg




Brianma65 said:
I haven't changed my dies for 9 mm in about 5 times with the same cases.
Using tightgroup or CFE pistol.
I don't find any diff in accuracy or kick.
I don't even measure the cases anymore.
Maybe I should???
Click to expand...

Q: What does case length have to do with bullet seating depth?

Answer: NOTHING.

Bullet seating depth is 100% determined by the shape of the bullet.
 
Suputin said:
You are entirely fooling yourself if you think that the published COAL has anything to do with any ammo you may make. COAL will change with every bullet type and weight. Unless you happen to have the exact same bullet used in factory ammo then your COAL has no real relation to that of factory ammo. That the two may be the same length is meaningless because the shape of the bullet nose could be totally different.

The reason that COAL is meaningless is that it measures to the tip of the bullet. Problem is that the bullet engages the rifling at the ogive. The ogive and the bullet tip have no relation to one another. You might as well measure bullet colour for as useful that may be.

I googled "9mm 124gr" and came up with the two bullets below, which coincidentally are both made by the same manufacturer. Does anyone think that the COAL for these two bullets will be the same? They are both 9mm 124gr.

9mm-356-124gr-rn-250ct-76848.jpg
9mm-356-124gr-fp-250ct-43234.jpg






Q: What does case length have to do with bullet seating depth?

Answer: NOTHING.

Bullet seating depth is 100% determined by the shape of the bullet.
Click to expand...
Yes, I know that the seating depth is measured off the ogive.
I guess what I meant was that once you set your 9mm dies, is there any need to keep checking your overall length? With say two diff plated bullits . Would small variation of COL make that much diff in a 9mm?
And if your cases are not exactly the same length,yes you still should have the same COL. But the bullit may not be seated ,either deeper or higher in the case, And would that even matter with regards to pressure?
Anyway, I can't tell any difference., when shooting my 9
 
I've done some COAL experiments with my Cx4, making the same ammunition (case, primer, powder charge and bullet) in lengths of 1.150", 1.120" and 1.100". I've done this with CamPro, Winchester and Hornady bullets.

Keeping in mind that the results are only good for my own firearm, I've found that the shorter COAL usually gave a worse group size. I'm now sticking to 1.150" and might try extending to 1.160".
 
Suputin said:
COAL is by far the most USELESS piece of informations EVER! It is dependent on numerous variables that change with each bullet type or brand.

This idea that a few ten thousandths of an inch one way will cause a grenade and a few then thousandths of an in the other direction will reduce velocity is entirely ludicrous. In the 30 years I have been reloading I have never run into issues with loaded length and I've made more than a few mistakes in my time.

What you want is the longest seated depth that will fit in your mags and feed in your gun. That is the only important factor. Ignor everything else.

OP: if you have a seated depth that works in your guns, WHY ON EARTH would you screw with it? If you are really determined to mess with it you want to go longer, not shorter. Closer to the lands will always be better. Too far back and accuracy will suffer.
Click to expand...

^^^

Like he said. I load for 20+ different 9mms. My CZ needs the shortest OAL (has a short throat), so I load all my ammo at 1.120 since it works well in all of them. I have no idea what the book suggests for that bullet.
 
OK, still a bit confused here! Today I am in the shop loading .35Rem. Using lever evolution powder and hornandy ftx projectiles. I have the oal called for but will need to go about 20 thou shorter for to crimp to engage the cannelure. These are FL sized and trimmed to spec casings. Wondering/worrying about going any deeper as the max load will be compressed. Googled the hell out of this, but no real answer comes up. I need a little more schooling on this. And yes I am new to reloading. db
 
I've loaded Hornady .308 with a cannalure, I just ignored the canalure.
And I've loaded Hornady .223 for my semi and I seated at the canalure, ignoring the OAL.
Didn't think such a small variance would matter . I've had no issues, I always start low and check for pressure signs.
 
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donb said:
My concern there is that these are for a lever gun with a tube magazine. Everything I read indicates I need a pretty secure crimp. Without the cannelure would it hold? db
Click to expand...
I've crimped bullits without a canalure and they held fine. Not sure about a lever though.
 
donb said:
My concern there is that these are for a lever gun with a tube magazine. Everything I read indicates I need a pretty secure crimp. Without the cannelure would it hold? db
Click to expand...

Are you shooting these in a tube mag rifle? If not then your question is moot. The bullet will hold in the neck the same as any other bullet. A cannelured bullet isn't a different diameter than a non-cannelured one.
 
Suputin said:
COAL is by far the most USELESS piece of informations EVER! It is dependent on numerous variables that change with each bullet type or brand.

This idea that a few ten thousandths of an inch one way will cause a grenade and a few then thousandths of an in the other direction will reduce velocity is entirely ludicrous. In the 30 years I have been reloading I have never run into issues with loaded length and I've made more than a few mistakes in my time.

What you want is the longest seated depth that will fit in your mags and feed in your gun. That is the only important factor. Ignor everything else.

OP: if you have a seated depth that works in your guns, WHY ON EARTH would you screw with it? If you are really determined to mess with it you want to go longer, not shorter. Closer to the lands will always be better. Too far back and accuracy will suffer.
Click to expand...

Incorrect COAL, aka "cartridge over all length" can result in out of spec head spacing.....bad. Incorrect COAL, aka "case over all length" can lead to overpreassure due to impingement of the case opening past the free bore.......very bad.

Not arguing that something will go wrong ever time but it may at some time when the moons align. It's just like walking across the street texting on CGN with your head down.....you may make it and you may not make it. Why tempt fate?
 
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Suputin said:
Are you shooting these in a tube mag rifle? If not then your question is moot. The bullet will hold in the neck the same as any other bullet. A cannelured bullet isn't a different diameter than a non-cannelured one.
Click to expand...

Yes,tube magazine. On these bullets, the cannelure is about 3 thou smaller. My read on the cannelure is, that it puts some tooth on the bullet, making the crimp more effective in holding the cartridge to length. Thanks for your insight. db
 
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