Berger COAL and jam/jump

[Brambles]

Question for you guys, I'm switching a couple rifles to Bergers.

I use my hornady COAL gauge and bullet comparator to get the distance to the lands.

So for example with the above tools on my 338 edge with 300 OTM tac's I get 4.110" coal. No obvious land marks on the bullet

Now I seat a bullet long and bump it back till I can close the bolt with ease...I get a coal of 4.145. There are some good land marks on the bullet, upon extraction I get no bullets pulling out or powder spilling or coal lengthening. It by no means does it feel like I'm forcing it into the lands..

Simple math suggests the second method is resulting in a .035" Jam...

Never jammed a bullet before and although it's a hunting rifle, even at the .035" jam, I see no dangers of separating a bullet and case in the chamber.

Does this all sound right or am I missing something?

 

[Brambles]

I loaded some up at

4.080.....030 jump

4.100......010 jump

4.110...at lands

4.125.... .015 jam

Going to gland shoot some groups tomorrow at long range and see if any one out performs the other...

 

[DUSTY NOGGIN]

heres a good article

Getting the Best Precision and Accuracy from VLD Bullets in Your Rifle | Berger Bullets Blog

 

[Gene]

That's a good article - read it twice. Note "Other groups of shooters were discouraged by our recommendation to touch the rifling. Some of these shooters knew that at some point during a target competition they will be asked to remove a live round. With the bullet jammed in the rifling there was a good chance the bullet will stick in the barrel which could result in an action full of powder. This is hard on a shooter during a match. "

The Hornady guage or comparator just gets you close. You should be measuring from ogive to base of loaded round.

The only way to know you are kissing the lands is to see very faint land marks on the bullet, then back out .005" at a time until those marks disappear. Write that length down. You can jam or jump em from there.

 

[FEENIX]

That's a good article - read it twice. Note "Other groups of shooters were discouraged by our recommendation to touch the rifling. Some of these shooters knew that at some point during a target competition they will be asked to remove a live round. With the bullet jammed in the rifling there was a good chance the bullet will stick in the barrel which could result in an action full of powder. This is hard on a shooter during a match. "

The Hornady guage or comparator just gets you close. You should be measuring from ogive to base of loaded round.

The only way to know you are kissing the lands is to see very faint land marks on the bullet, then back out .005" at a time until those marks disappear. Write that length down. You can jam or jump em from there.

+1! Another great article >>> Berger Article on COAL and Cartridge Base-to-Ogive PART 2 « Daily Bulletin

 

[Corey Schwanz]

Lots of good links and info already posted. If it is a hunting rifle, I would shy away from actually jamming them, especially .035" into the rifling (that's a long way into the rifling). I know a lot of people jam them for competition guns but I've always stayed away from jamming personally. Just too much of a chance to stick a bullet and cause a big mess. You may be able to eject the round now, but it only takes one.

 

[PGJPJ]

Bergers are currently kicking my butt, so don't ask me. I did the recommended macro seating testing, (0.01, 0.05, 0.09, 0.13) and closer seemed better. Then I tried 0.005, 0.010, 0.015, and 0.020. I still haven't found where my barrel likes it.

My next two are just kissing the lands, and a 0.005 jam. Since mine is a hunting rifle, I really don't want to jam. But I want to see if ANYTHING will work. If not, I'll change to a different bullet.

This is my first experience with a secant ogive bullet, and it has not been easy.

 

[Corey Schwanz]

Bergers are currently kicking my butt, so don't ask me. I did the recommended macro seating testing, (0.01, 0.05, 0.09, 0.13) and closer seemed better. Then I tried 0.005, 0.010, 0.015, and 0.020. I still haven't found where my barrel likes it.

My next two are just kissing the lands, and a 0.005 jam. Since mine is a hunting rifle, I really don't want to jam. But I want to see if ANYTHING will work. If not, I'll change to a different bullet.

This is my first experience with a secant ogive bullet, and it has not been easy.

The seating depth test is only part of the equation. Find which depth is showing more promise than others, then you need to play with powder charges to fine tune it and find the velocity node where you'll have the tightest group. Playing with seating depth alone wont give you the best group possible (unless the velocity node happens to be at the starting charge you are using for depth testing).