C.o.a.l. - The HuntingPA.com Outdoor Community
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post #1 of 13 (permalink) Old 04-02-2018, 09:14 PM Thread Starter
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C.o.a.l.

Not sure if I'm driving myself crazy with COAL, but quick question.

So i have what i want to me my C.OA.L. and using my Lee dies i caliper measure get good. then spot check and sometimes off by .01 .001 and i tinker with the die....am i being too anal about COAL?
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post #2 of 13 (permalink) Old 04-02-2018, 10:19 PM
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The issue is with the bullets being off, not you. I set up dies from base to ogive vs bullet tip with rifle rounds as it is just as easy for me to seat to ogive vs COAL using the Hornady tool. I still get variance, but not as much as measuring to the bullet tip.
Check ot this article from Berger Bullets:
Effects of COAL and CBTO | Part 1 | Berger Bullets Blog
If I would have used COAL vs to ogive on one of my 45\70s I could have ended up in trouble as the book data length had me just jammed into the lands.
I use this to determine CBTO from Hornady:
https://www.hornady.com/reloading/pr...-comparator#!/
I also use one of these to determine jump to the lands, but always compare the measurement with a slightly snug load without powder and the bullet covered with marker ink to see when a chambered load hits the rifling.
https://www.hornady.com/reloading/pr...ified-cases#!/


"Too anal" is very hard to define when it comes to reloading IMHO, more like how much time to you want to spend chasing accuracy.
You are going to get variances when measuring to the bullet tip, measure a handful and try to come up with a happy medium seating depth and see how the end of the brass is lining up with the cannelure on the bullet.
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post #3 of 13 (permalink) Old 04-03-2018, 09:00 AM Thread Starter
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thanks very good info. How do you set up die base to ogive?
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post #4 of 13 (permalink) Old 04-03-2018, 10:21 AM
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Base to ogive is very important for accuracy. It is especially important as you increase the distance you are shooting. Winning long range shooters mostly measure and sort their bullets base to ogive length to .001. Adjust your seating die to each lot of bullets sorted. Its much easier to do with a micrometer top seating die. To sort bullets accurately I would recommend Bob Green's sorting tool. Bob is out of York, Pa.
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post #5 of 13 (permalink) Old 04-03-2018, 10:32 AM
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Really easy. The hornady comparator is just a little piece that attaches to one end of the caliper jaw with different standard inserts for different bullet diameters. Attach it and then re-zero your caliper (or do the math with the additional length the comparator adds).
Figure out how long your chamber is to the lands (rifling) and then add the distance you want the "jump to the lands" to be, let's say .100". So, chamber length + jump = cartridge base to ogive. Just start with the die out and make little adjustments measuring with the comparator each time until you get the die set.
The hornady OAL guage makes finding the lenghth of your chamber pretty simple, especially on a bolt gun. I usually also do the magic marker covered loosely seated bullet to double check myself.
Make sure that if the loaded round comes out longer than recommended COAL that they will still fit in the mag.

Again, is all of this really needed? I just stumbled onto doing my loads this way as I was trying to eliminate as many variable as possible from the process with a problem gun. I bought the tools so I might as well use them.
If you find a happy medium in the batch of bullets and then set your dies to that length where most are right on the recomended COAL, with some a tad long, some a tad short remember that your die is seating by hitting the bullet ogive generally anyways if you are seating a spire point bullet. Once I found that happy medium place I do not "tinker" with the die, but just roll with it realizing most of the variance in COAL is from deformed bullet tips, not different ogive lengths as much.

There are some WAY more experienced reloaders who visit this forum. I only do some standard calibers on a single stage press for hunting purposes. Hopefully someone else will weigh in so you are not forming your opinion solely on my advice.
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post #6 of 13 (permalink) Old 04-03-2018, 10:53 AM
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One thing to note, C.O.A.L. is cartridge overall length. This is not what you need to be concerned about for accuracy as much as the measurement from the base of the case to the front ogive of the loaded cartridge. Hornady does make a tool but the inserts are cut so shallow the are tough to be accurate with.
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post #7 of 13 (permalink) Old 04-03-2018, 11:14 AM
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Once you start understanding all the in and outs of reloading it isnt bad. Just do it right and you shouldnt have any troubles.I can be goofy about my reloading also but the loads I make for me and friends are good loads.If someone ask me to make them bullets for their rifle I tell em I need your rifle to find the right measurements with my tools.

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post #8 of 13 (permalink) Old 04-03-2018, 12:57 PM Thread Starter
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Quote:
Originally Posted by jeffppc View Post
One thing to note, C.O.A.L. is cartridge overall length. This is not what you need to be concerned about for accuracy as much as the measurement from the base of the case to the front ogive of the loaded cartridge. Hornady does make a tool but the inserts are cut so shallow the are tough to be accurate with.
What tool is that, or is that the combination of tools sdowns mentions (which I am looking at currently)?
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post #9 of 13 (permalink) Old 04-03-2018, 06:51 PM
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I believe jeffppc is referring to the hornady comparator I listed the link for as that is the only tool for the purpose Hornady sells. I bought an assortment of the inserts and not had problems with using them as far as measuring accuracy, but I have nothing to compare it to. I did notice that after measuring the same cartridge numerous times that the bullet seemed to "wear down" and the CBTO measurement would shrink by .001-.002".
Like I said, some of these folks here have a lot more experience that myself. The 2 part Berger article I linked really helped me understand and I feel more confident with my process now since using that method for the last number of years. On the flip side I worked up some .357 for a carbine and revolver this past week and didn't bother doing CBTO because I wasn't planning on getting MOA, just groups that were "good enough".
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post #10 of 13 (permalink) Old 04-03-2018, 07:05 PM Thread Starter
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sdowns, you use Hornady modified cartridge then, or did you somehow create your own from your fireformed brass?
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