making an accurate cartridge..

[mniesen89]

what makes the round accurate? Is it the OAL length of the round or is it the brass length? Or maybe something I dont know?

[steve4102]

what makes the round accurate?

A whole bunch of stuff. Bullet design, bullet weight, powder, brass, headspace, runout, OAL etc., etc. What makes a round accurate is when all of these things come together and the bullet exits the barrel at he optimal point in the harmonic wave of the barrel. Think of barrel harmonics as a wave. The high and low points in the wave will produce the best accuracy. Maybe this will help explain it better.
http://www.browning.com/faq/detail.asp?ID=108

[mniesen89]

I understand the components of it all, but my concern is,does the brass all have to be precisely the same length or is .02 off a big deal?

[mrawesome22]

A whole bunch of stuff.

Ditto. Many books have been written on the subject. Read one. I don't have time to write one here.

[mrawesome22]

is .02 off a big deal?

A huge deal if your goal is ultimate accuracy. Uniformity is the goal for accurate loads.

I'm also assuming you mean .020". Hopefully not .020' or yards, or miles.

[mniesen89]

obviously awesome....so there is a separate manual just for accuracy?

[mrawesome22]

but my concern is,does the brass all have to be precisely the same length or is .02 off a big deal?

Let me put it this way. For benchrest accuracy, .020" is a big deal. But just one of many things that could be a big deal. Runout could be a big deal. Neck tension, case volume, flash hole size, case weight, OAL, case fill, ect. These are all important.

Anyway, case prep is everything when it comes to ultimate accuracy. So yes, .020" is a very big deal.

[steve4102]

or is .02 off a big deal?

Considering that Max brass length is only .01 less than Trim to Length, I would say the having brass .02 off is a big deal. You either have some vary short brass or some very long brass. If your brass is to long (over Max length) then you need to trim it before you load it.

[mniesen89]

not in my lyman 48th edition its not steve

[steve4102]

not in my lyman 48th edition its not steve

What cartridge are you loading for? I have several manuals including the Lyman 48th. I would like to find out if we are comparing apples to apples here.

[mniesen89]

that would be the 30-06 springfield.

[Scorch]

lyman 48th editionI would recommend taking time to read all that stuff in the front of the manual. It deals with case prep (exactly what you are asking here), powder selection, bullet selection, actual reloading operations (sizing, priming, charging, bullet seating), and sources of variation. Once you have read it all, most of your questions will be answered.

[steve4102]

that would be the 30-06 springfield.

OK, According to Lyman 48 the 30-06 has a MAX brass length of 2.494 and a Trim to Length of 2.484. That is a difference of .01 and your brass is off by as much as .02. Where in the Lyman 48 are you getting your measurements? These measurements above are found on page 220.

What are the measurements of your brass and what are you using to measure it? Brass that is over 2.494 can cause problems such as difficulty chambering and extremely high pressure. Not good for accuracy and safety.

[amamnn]

We'll assume you've already covered the two more important accuray issues: the shooter and the rifle. Here are some places to start learning about loading for accuracy.

http://www.gunnersden.com/index.htm.rifle-reloading-accuracy.html

http://www.6mmbr.com/index.html

http://www.benchrest.com/

http://www.sinclairintl.com/

http://www.precisionshooting.com/