Determining Precision COALs

JakeC

Well-Known Member
Joined
Oct 10, 2020
Messages
164
Location
North Utah
Edit 1: Turns out Erik's video came out longer ago than I thought so I definitely had his method in mind when planning, even though I'd sort of got there already knowing I was moving away form the lands as they were burning forward.

edit 2: I didn't say how I found the lands. Cleaning rod method. People tell you to google stuff like this and where does that take you? A forum posting that's 16 years old on a hard to read website, so why be a bad friend? I put 6 inches of scotch tape over my carbon cleaning rod at roughly barrel length and I have a cleaning jag I put on. I filed the jag flat on the tip for this purpose. I gently grit my teeth as I send it all down the muzzle to the bolt face. I mark the end of the muzzle as square as I can with a razor blade flush to the crown. Just rock the razor on the tape, don't cut your carbon fibers. Pull the rod out and see if you got a clear marking. Then I drop the bullet into the barrel with the gun pointed down and gently tamp it into the lands with the rod or something else. Gentle tamping as in about the same pressure you'd poke your snoring bride with to get her to move. Not the pressure she uses on you, don't be an animal. You'll get the bullet stuck. Just a light tap to square it up and get it lightly stuck, not push it into the lands. Then mark the tape in the same way. Maybe do this a couple times just to be a good boy. Also, do all the bullets you have on hand at the same time. I find if I go back two days later in a different mood I can fall down a rabbit hole of different measurements just because the light was different when I was lining up the utility blade. You'll be surprised how identical your measurements are, though. When you're done pull your your calipers and measure the distance between the fine markings on the tape. That's the hardest part for me, lining up the two jaws on two lines on the slippery rod. Once you get the same number a couple times, that measurement is your max COAL.
 

lobo56

Well-Known Member
LRH Team Member
Joined
Mar 6, 2010
Messages
144
Location
Heart of Texas
Edit 1: Turns out Erik's video came out longer ago than I thought so I definitely had his method in mind when planning, even though I'd sort of got there already knowing I was moving away form the lands as they were burning forward.

edit 2: I didn't say how I found the lands. Cleaning rod method. People tell you to google stuff like this and where does that take you? A forum posting that's 16 years old on a hard to read website, so why be a bad friend? I put 6 inches of scotch tape over my carbon cleaning rod at roughly barrel length and I have a cleaning jag I put on. I filed the jag flat on the tip for this purpose. I gently grit my teeth as I send it all down the muzzle to the bolt face. I mark the end of the muzzle as square as I can with a razor blade flush to the crown. Just rock the razor on the tape, don't cut your carbon fibers. Pull the rod out and see if you got a clear marking. Then I drop the bullet into the barrel with the gun pointed down and gently tamp it into the lands with the rod or something else. Gentle tamping as in about the same pressure you'd poke your snoring bride with to get her to move. Not the pressure she uses on you, don't be an animal. You'll get the bullet stuck. Just a light tap to square it up and get it lightly stuck, not push it into the lands. Then mark the tape in the same way. Maybe do this a couple times just to be a good boy. Also, do all the bullets you have on hand at the same time. I find if I go back two days later in a different mood I can fall down a rabbit hole of different measurements just because the light was different when I was lining up the utility blade. You'll be surprised how identical your measurements are, though. When you're done pull your your calipers and measure the distance between the fine markings on the tape. That's the hardest part for me, lining up the two jaws on two lines on the slippery rod. Once you get the same number a couple times, that measurement is your max COAL.
I bought some 1/8 inch brass rod with slip collars to basically do the same thing on all my guns.
 
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