My method of finding the COAL

Jetjock

Jetjock

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Pretty sure I am not the first one to use this method but after having problems finding modified cartridges to use with the Hornady OAL gauge plus the prices, I watched a Youtube video on the Simpson gauge and tried the following: I closed the bolt on the rifle and then inserted a cleaning rod down from the muzzle until it came to a stop. I then marked the rod at the muzzle with a piece of tape. After taking out the bolt, I then inserted a bullet into the breech and pushed it in with a suitable sized end of a drill bit untill it stopped when it hit the lands. Then I re-inserted the cleaning rod from the muzzle untill it lodged against the bullet. (Gently). Again I marked the rod where it entered the muzzle. This measurement gives me the COAL to the lands. If I detract 15 or 20 thousands, I believe I have a good starting point to use to set my COAL.

Does this make sense or should I buy a Hornady gauge for $60 and spend $10 or so plus shipping for each modified cartridge size?
 
Congratulations for figuring things out, not many try and figure out such things now.
And I certainly don't want to one-up you, but you figured out the prime, number one method of finding the COAL of your rifle and a certain bullet.
Actually, I have posted that method a few times.
But hey, keep working things out, such as figuring out how much crosswind you actually have in front of you, instead of asking the met office what it is!
 
I tried this method too. When you're talking .015" to .020" tape and a cleaning rod doesn't scream accuracy. And then there's the idea that you're measuring to end of your bullet instead of the ogive. The hornady oal gauge is probably the best bang for your buck. I just find it a pita to order a $5 modified case online and pay $15 shipping.

I don't do this but it's probably best if you drilled a fire formed case and tapped it for the hornady oal tool and used that to measure.
 
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A simple method is oval a fired case and seat a bullet out long by hand. Chamber the "cartridge" and let the rifling push it in to the case the rest of the way. Measure COAL and subtract whatever you want to, or whatever your magazine will allow.
 
snoopycda said:
A simple method is oval a fired case and seat a bullet out long by hand. Chamber the "cartridge" and let the rifling push it in to the case the rest of the way. Measure COAL and subtract whatever you want to, or whatever your magazine will allow.
Click to expand...

That's what I usually do.
 
I use several suitably sized lengths of drill rod and a
couple drill stop collars. The rest is about the same, except you have something positive to
measure to. Drill rod is cheap, and handy to have around.
 
Hey Jetjock I use the same method but I use plastic inserts with allen screws drilled in them to lock them on a brass rod even though I have Hornady oal gauge which gives inconsistent readings and you are right about not spending the 60.00 bucks.Was wondering why you push the bullet in with a drill bit instead of using the bolt to push the half necked sized brass and bullet into the Lands.Just a Question Thanks
 
Been doing this for years. I use drill stops on the rod. Yes you are measuring to the bullet tip and they vary a small amount. However I then use the same bullet to make up a dummy round to the length I choose, eliminating that variable.
Dummy rounds are handy when you load different bullets in the same calibre for quick die adjustments.
The depth measurement on your calipers used on the seating stem can get your adjustments pretty precise too.
 
Started using this method over 40 years ago but I use a pencil to push in the bullet. Just use a little pressure from the little finger, no need to ram it in all the way. Also, I wrap 1 piece of tape on the cleaning rod about 1" longer than the loaded round will be so both marks are on the same piece of tape. Nice to see others doing it after all these years.
 
chalkriver2 said:
There was somebody on here a few years ago making modified cases for the Hornady comparator ....anyone remember his name ?
Click to expand...

I have made them. The tap is hard to find. You need a 5/16 x36 TPI tap. I found mine on ebay cheap.

Here is a link discussing making you own, just add the http to the beginning

://bulletin.accurateshooter.com/2015/04/make-your-own-modified-case-for-hornady-o-a-l-gauge/
 
I use this method as well. Ive used a dowel and marked with with a knife blade and Ive also used my dewey cleaning rod with some kind of collars with set screws on them. As for holding the bullet I always use a straw to hold my bullet (20/22cal 6mm). Works pretty good for me. I also measure 3-4 times.
 
Thanks for the kind comments and suggestions. To reply to a couple of the questions; I used a drill bit to push in the bullet because I had a set on the bench and it was easy to find one with the right size shaft, I couldn't use a the bolt to push in a dummy cartridge as I was loading for a Ruger 1 which is a single shot falling block design so has no bolt. Like the idea of using coloured tape to mark. Will use that in the future. Tried making up a dummy cartridge with a loose fitting bullet but kept getting different results. ( bullet probably too loose). Thanks for the interest guys!
 
snoopycda said:
A simple method is oval a fired case and seat a bullet out long by hand. Chamber the "cartridge" and let the rifling push it in to the case the rest of the way. Measure COAL and subtract whatever you want to, or whatever your magazine will allow.
Click to expand...

I do the same, but instead of ovaling the case, I resize it and cut a small slot in the neck with a dremel.
 
I have the tap drill [7.2mm] and the tap [5/16-36] to make my own modified cases.
If you use a case fired in your particular rifle, it makes a pretty decent setup.
The trick is holding the case while you drill/tap it without damaging the case. :)
Dave.
 
My method
Using an old once fired neck sized case, cut 3 thin slots lengthwise from the shoulder to the case mouth in the neck of the case. Put the bullet in case mouth just enough to hold it there and insert in chamber and close bolt.Now carefully remove from chamber and measure oal.I usually do this 5 times and take the average as my coal for this particular bullet.


Seems to work for me

Z
 
Why not use a Lee collet die and size case neck only enough to hold the bullet in place....chamber round, remove and measure....pretty simply. :)
 
Jetjock said:
Pretty sure I am not the first one to use this method but after having problems finding modified cartridges to use with the Hornady OAL gauge plus the prices, I watched a Youtube video on the Simpson gauge and tried the following: I closed the bolt on the rifle and then inserted a cleaning rod down from the muzzle until it came to a stop. I then marked the rod at the muzzle with a piece of tape. After taking out the bolt, I then inserted a bullet into the breech and pushed it in with a suitable sized end of a drill bit untill it stopped when it hit the lands. Then I re-inserted the cleaning rod from the muzzle untill it lodged against the bullet. (Gently). Again I marked the rod where it entered the muzzle. This measurement gives me the COAL to the lands. If I detract 15 or 20 thousands, I believe I have a good starting point to use to set my COAL.

Does this make sense or should I buy a Hornady gauge for $60 and spend $10 or so plus shipping for each modified cartridge size?
Click to expand...

^^^THIS

I have mentioned that and was chastised for it. A very good, cheap and quick way of finding the starting point for any firearm chamber.

You're good to go.
 
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