C.O.A.L.

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Bucksnort1

New member
If a reloading manual specifies a COAL, for a revolver cartridge, of lets say, 1.610" and this information appears in the gray area where maximum charge data is located and there is no COAL outside the gray area for other charges, do I assume the 1.610" is the same for all other charges?
 
Yes, I've never seen any load data that had different lengths for different powder charges in the same table.
 
Revolver bullets are seated to the crimp groove, regardless of "book" OAL. If the cylinder is longer than the ammo, yer good to go...
 
Higgite, it's not my manual. I'll get the name from my reloading friend but I think the answer is below in my response to Allen J.

Allen J,

I agree. Let me tell you what started this. While at a friend and fellow reloader's house, a couple of days ago, he showed me a reloading manual, of which I don't know the company, as mentioned above, but will get tomorrow, with the data columns (the gray highlighted columns) for the maximum charge amount, pressures, etc. The COAL is shown in this gray area so he assumes the COAL is only for the max charge. I disagree with him.

He's somewhat new to reloading and is a former sailor and we know how they can be. Oops, did I say sailor? I hope you know I'm just kidding about sailors.
 
COAL

POGY:
Gotcha on the [sailor] bit; Navy brat myself. You spoke the true word on that. :D
You can always go a few thousandths longer on the OAL [IF] your Cylinder(revolver) or chamber (semi-auto) will take the longer length. It's going to a shorter OAL that you need to be very careful.

WILL.
 
do I assume the 1.610" is the same for all other charges?
Click to expand...

As long as it is used for charges within the min and max load data for that powder or powders listed in the load data chart.

This is basic reloading 101. the COAL is determined by the bullet you are using, shape, weight and length and not by the powder charge within the published min and max loads.

A 308 bullet is 308 no matter if it is 150 grains or 165 grains, what makes it different is that the 165 grain bullet is longer to accommodate the extra lead needed to increase the weight. The space between the base of the bullet to the primer will determine the pressure and the amount of powder that can be used.

So the COAL for the 150 grain bullet will be less than the COAL for a 165 grain bullet, not on how much powder is in the case. The rule of thumb is that as the weight of the bullet goes up the amount of powder used goes down and as the weight of the bullet goes down, the amount of powder used goes up. What you are trying to do is maintain a specific pressure within the case and keep the VOID area (space between the tail of the bullet and primer) the same no matter what bullet size (expressed in weight) that you use.

You will note that in your manuals as the weight of the bullet changes so does the COAL. The exception to this is for guns that use removable magazines such as the AR-15 or AR-10 where COAL max is limited by the COAL of the mag.

So yes it would be safe to use 1.610 for a lesser charge than max. And in some cases a smaller COAL would be acceptable depending on TOTAL pressure generated by a specific load so that it would stay within the pressure limit to that revolver and caliber.

Hope this helps.
Jim
 
The problem with OAL is that unless you are using the exact same bullet, as the written spec, your mileage may vary. This is especially true with cast bullets. Unless your 158gr SWC came from the very same mold as the 158gr SWC in the book, your OAL will more likely be different than the same.

The good news is that the seating depth for most 158gr SWC is pretty standard if you simply seat to the cannelure they put in there to make it simple for you, and IGNORE OAL for revolver cartridges.
 
Will-J,

Being an Army brat and retired Air Force, I have a special place in my heart for brats and veterans.

Regarding your comment about COAL, I agree with you about going a bit longer if the chamber will handle it and I agree with your statement about going shorter. And speaking of going shorter, but this brings up a question I posted on the firing line about head space in semi-auto hand guns. I received one interesting response, which I will tell you about in a minute. Here is what prompted me to post the thread.

I was shooting a 1911 (not my gun and not my loads) in 45 ACP. I fired several rounds. One of the rounds went bang but did not cycle the slide. The gun owner picked up the spent case and found it to be a 45 GAP. This case is considerably shorter than that the 45 ACP. If head space is determined by the mouth of the semi-auto case, why was there not a problem with the length of the GAP case.

The one interesting response I received, which makes a little sense is, head space is also set by the extractor holding the case against the face of the bolt. I can understand where a semi-auto case is too long would present problems with chambering.

I love big oil.
 
Revolvers:
While any finished cartridge may have the bullet seated to the crimp groove in for any given bullet, the MAX pressure charge was determined
using the OAL as listed in the loading manual for the specified bullet shown.

If shooting a different (but similar-design & weight) bullet requires a longer OAL
to fit the crimp groove, you are OK pressure-wise..

If on the other hand the bullet/crimp groove requires a shorter OAL
than the manual, then you need to reduce the max load listed.**




**
Just how much reduced is a whole`nother topic. :rolleyes:
 
Poggybait,

If you look in Hornady's manual, you find that for each caliber they have a picture of every bullet they make in each weight, and the COL tested is listed next to the picture. Sierra does the same thing.

Since you mention a maximum COL of 1.610", I assume you are loading .44 Magnum. Here there can be two COL's. This is because the .44 Special, Elmer Keith's parent cartridge for .44 Magnum, has almost the same in maximum COL (1.615") but a shorter case, so you find some 0.429" and 0.430" bullets that have two crimp grooves. The upper is for the longer .44 Magnum cases, and the one nearer the bullet base is for .44 Special cases. If you use the lower crimp groove with a .44 Magnum case, you wind up with a COL as long a 1.740". If you then measure the length of your .44 Mag cylinder (open it, drop a case in and measure from the case head to the front of the cylinder), and find it is 1.740" or longer, you can then use the longer COL, giving you more room for powder for higher performance. But you then have to adjust your charge weight upward to compensate for the greater powder space.
 
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COAL

UNCLENICK:
You and everyone else have made some good points; However, please explain to those out there the difference between [COAL] and [SEATING DEPTH]
I would try to explain that the simple weight of a bullet (in and of itself) does not necessarily determine a cartridge's OAL. The length of bullets in a given caliber/weight will vary due to shape [Amax vs Round nose, etc.] Same weight but different COAL. HOWEVER; the [Seating Depth] of the bullet-(that part which is in the case) should...I repeat...SHOULD be the same so as not to raise pressure. This is more an issue with pistol cartridges than with rifle cartridges due to the limiting factors of magazine length and bullet profile, and a few others I have not encountered yet as I have been reloading only 40 years and I don't think anyone can find all the problems in only that length of time.

Explain all that to 'em U. NICK. I'd try to, but my tongue gets in the way of my eye teeth and I can't see a word I'm sayin'

WILL.
 
Same weight but different COAL. HOWEVER; the [Seating Depth] of the bullet-(that part which is in the case) should...I repeat...SHOULD be the same so as not to raise pressure.
Click to expand...

If the same seating depth for bullets of the same weight is critical, then someone needs to explain that to Hornady and Speer because they don't abide by it in their reloading manuals. None of the different profile bullets of the same weight have the same seating depth when seated to the OALs specified in their respective manuals. For instance, Hornady lists 3 different bullets in 9mm, 124 grain. All use the same min/max charge table, but none have the same seating depth when bullet length is subtracted from OAL. The same is true for Speer.
 
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mikld,

I will do just what you suggest.

Mehavey,

For revolver cartridges, I have always seated and crimped to the cannelure and it's a rare situation where I load more then the minimum charge. Sometimes, I will load somewhere between min and max. You can say I load for mostly plinking/target shooting and not for driving tacks at one thousand yards.

My question about your description is this. You say if I crimp in a cannelure that requires a shorter OAL, I need to reduce MAXIMUM charges but, what if my OAL is shorter for charges less than maximum say, minimum charge. Currently, I'm faced with this scenario with 44 magnum. I have 245 grain, plated, semi-wad cutter bullets with cannelure. I'm crimping in the cannelure (with minimum charge) but my OAL is shorter than suggested in my manual. Is this safe?

I've been loading for almost twenty years and, as I said for revolver, I always seat to and crimp in the cannelure. It sounds like I've been doing it correctly.
 
Unless your are grossly shortening the OAL from that listed for that design bullet
in the manual, a min charge cartridge is highly unlikely to be a problem.
 
Mehavey,

I don't think I'm grossly shortening bullets. Later this morning, I will measure my finished product and send to you.
 
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