How's your COL?

[nf1e]

CBTO " cartridge base to ogive " measurement is probably the most effective and useful when setting up ones dies to produce home grown ammo. A few simple tools make the chore a breeze and take most of the guess work and questions out of the equation. Because of the difference in dimensions of bullets it becomes almost a necessity for precision ammo. The published COL has it's place when used as a minimum only measurement. Getting more technical in loading only enhances the effectiveness of producing the best of the best. Understanding what you are doing makes it a whole lot more fun and way safer that just " getting it close enough" to function. Whatta Hobby!


CBTO 7.jpgCBTO 3.jpgCBTO 4.jpgCBTO 5.jpgCBTO 6.jpg

[fguffey]

How's your COL?

Again I received a phone call from a man that built 4 magnificent rifles, he made the chamber reamer, started with barrel blanks and did all of the woodwork. I thought the rifles were beautiful, problem, one of the rifles shot patters like a shotgun; he asked me why? I told him I did not know because it is always easier on me if I do not get involved.

He started out in West Texas with the help of a gun smith, he finished the rifles in the Dallas/Garland area, the way he explained it he tried to get help from ever gun smith between here and there without results. The last one used a bore scope, after that he went to the Internet, and then called me with the results. Again, I did not know what was wrong with the rifle and I had no interest in determining what someone did to the rifle that would cause it to be different.

My friend went through all of the advice from the Internet and built a contraption, after building the contraptions he wanted to bring all of it over for me to show him how the contraption worked; I insisted I was not interested, he brings the rifle, dies and ammo. He made the dies with a lot of help from the West Texas smith, a friend of Ackley, I do not believe Ackley ever mentioned him, but he did spend a lot of time with him when he, Ackley was visiting his brother.

My friend wanted to know where I would start when determining what the problem was, I wanted to see the reamer, he broke it, I wanted to see one of the other rifles, he did not bring one etc. etc.

So, I was left with tools I made for determining the maximum overall length of ammo. He was not happy because I used his formed cases, he did not have a 7MM seating die when he built the rifles, so I broke up a set of Lyman Dies and gave him the seater.

To shorten the story: I loaded 60 rounds of ammo for his rifle and then headed for the range. Before I shot a round, I determined the length of the chamber. I pushed the bullet out of the case neck before the bullet contacted the beginning of the rifling. The bullet traveled .250" after leaving the neck of the case before it contacted the rifling.

I have a Boffer machinegun barrel that is chambered to 308/7.62 NATO heavy barrel that would be considered a little loose in the neck by Internet reloaders.

F. Guffey

[lyman]

bought the do dads and measured this and that, mostly to keep an eye on wear,

shooting Service Rifle and not any PRS stuff, I don't or did not need Bench Rest type ammo,
so after a few conversations with some of the mentors and fellow shooters, when I was active, I stopped checking it that close (still use(d) a Forster Co Ax and CH4 benchrest seater, and a Redding powder measure, just did not go that extra mile like I was shooting PRS)


now a buddy, that still shoots Long Range, measures every little detail and makes sure it is all consistent, all the time,

[JimF]

For years, my method of determining OAL was to simply seat the bullet SLIGHTLY in the mouth, then CAREFULLY chamber the round, letting the lead determine the depth.
Then placing the cartridge back in the press and lowering the seating stem ?til it contacted the bullet nose.
Then putting about one-half turn MORE rotation on the stem to keep the bullet from jamming in the lead.
EASY PEASY!!

[Major Tom]

For years, my method of determining OAL was to simply seat the bullet SLIGHTLY in the mouth, then CAREFULLY chamber the round, letting the lead determine the depth.
Then placing the cartridge back in the press and lowering the seating stem ?til it contacted the bullet nose.
Then putting about one-half turn MORE rotation on the stem to keep the bullet from jamming in the lead.
EASY PEASY!!

Yes, that's the way I do it! Simple and fast!

[fguffey]

Then putting about one-half turn MORE rotation on the stem to keep the bullet from jamming in the lead

Again, I want all the bullet hold I can get, I have no clue what methods all of the tensioners use. I do not want a loose bullet in the case neck get stuck in the barrel. And then there are all of the tools that are not necessary.

F. Guffey