My method of finding the COAL

[waynewjw]

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.

What he said. Only exception is I drop 10 bullets and then average out (not all bullets are exactly the same. Works great. Got it all from Home Depot and Princess Auto. Been using it ever since.

 

[Viper26]

Like others have said, a rod and a couple of drill stops is my preferred method. I got a brass rod from Home Depot. Put the whole thing together for less than $25. A rubber band around the bolt handle holds the bullet against the lands with very light pressure. Measure between the stops with an inside vernier and add the thickness of one drill stop to get an accurate COAL. I also have the hornady unit but I find the rod method gives more repeatable results. After you've measured the COAL with the rod, press the cartridge down to that length and measure to the ogive. Now you've got a reference cartridge for contact with the lands.

 

[stevebc]

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

That's what I learned to do. Someone here posted pics of this long ago, I tried it, works like a charm.

 

[Digger1]

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.

Yes, and if you color the bullet with a marker you will know if it got tight in the lands and pulled out a bit when pulling back. Works great, but I just slit a case neck with a razor saw and adjust for tension.

 

[GreenBob]

There is a number of howto videos on youtube... click here check them out.

This is the method I use;

 

[GUB]

Couple of days ago a guy up at the range was getting his best groups at 80 thou back from the lands.
With a certain bullet powder combo. he was showing me his targets on how the groups were getting tighter as the OAL was getting shorter
So much for 10-15 thou from the lands??

 

[Viper26]

Here's a good vid of the rod method.
https://m.youtube.com/watch?v=GmDi7v530Og

 

[burnaby]

Buy the Hornady OAL gauge, one time cost. Then make your own as detailed below. Tap from eBay is $4US. 7.2mm bits same or use 9/32=7.1mm (easier to tap with 7.2, 7.3 is even easier).
Very accurate, measure same bullet three times, +- a thous.

Using drill press I drill a hole in piece of 2x4, put in case, clamp wood to vice. If it still slips add piece of 800x sandpaper.
After drilling attach tap to drill press, hand turn the tap which is now inline with the just drilled brass.

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.

 

[257Roberts]

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.

I also have been using this method for more that 15 years now but I use brass rods and have made my own locking collars.
It really works well.
One thing that you need to remember is to #### the rifle and put on the safety so you do not measure the firing pin protrusion from the bolt face.

I have studied the cartridge and bullet seated method and I thing you are measuring bullet seating depth from the shoulder and not the overall length.
I have also tried seating a bullet in a case that has a slight friction fit in the neck and the bullet always seems to stick in the forcing cone.

Whatever works for you is the method that you should use.

David

 

[BigUglyMan]

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?

I use an unsharpened pencil and use the eraser end to hold the bullet in the throat and I use the cap that comes with the Dewey rods to keep the bullet nose out of the threads on the cleaning rod. It's not shop-precise but it's pretty good. I do like the brass rod and collar method too. Might have to employ that method.

 

[220]

Why not just Carosafe chamber and then you have permanent measure!