[AR guy]

I have some questions on the sizes for my .223 rounds im trying to make. Im using the speer load book #14. In it it gives me my measurements for my cases.
max case lenght is 1.760"
trim to lenght 1.750"
max cart. oal 2.260"

now i dont have a automatic trimmer, so im trimming by my hand tool. Am i getting the case sizes between the trim lenght and the max case lenght or does every shell have to be 1.750"

and when i go to set my bullet depth im having difficulty getting it set to exact 2.260" im getting it to 2.599" 2.261". can it be the one thousandths over or under the coal? I know im asking alot of questions lately but I just wanna get it right. dont want nothing to happen when i go shoot. and at the same time im learning my sons learning too so just want to be safe you know.

 

[X Ring]

Nothing in heaven or on earth is perfect especially if it was made by man. Ideally all cases should be trimmed to 1.750 but as long as they are between that and 1.760 it will be OK. I try to keep COL within +/- .005

 

[Twicepop]

If you are putting a roll crimp on them .010" will make a difference, .003" is about max for a consistant roll crimp. If you're not, then the slight difference shouldn't be a problem.

those who beat their guns into plowshares, will plow for those who didn't

 

[LDBennett]

AR guy:

While I am not suggesting at this point in your reloading experience you deviate from the reloading manuals, you will find with experience that changing the COL is a variable you can use in trying to find the best accuracy. Consistent COL is the best way, but only within several thousandths. But....

What is important in the search of accuracy is consistency. Measuring the COL from bullet point to the end of the case is not an accurate way to get consistent results. What is important is how far the ogive (curved part of the bullet nose) is from the start of the rifling in the barrel. To accurately measure that you need to use a bullet comparator:

http://www.midwayusa.com/product/365474/ptg-bullet-comparator-17-20-22-27-30-33-calibers

It slides onto the bullet nose and is sized to the rifle bore. You then measure the length of the case with the comparator installed and make all rounds match that measurement within a couple of thousandths. To calibrate this process, seat one bullet on a case to the manual COL then install the comparator, measure it, and that becomes your reference number you try to make all others match within a couple thousandth. I think you will find it easy to do.

The manufacturing process for bullets is such that the OAL of the bullet itself is not all that controlled but it is well controlled if you use the comparator on the bullet. Any excess material in the bullet ends up in excess length in the nose making COL measurement seem erratic when the comparator measurement may show very high consistency.

LDBennett

 

[AR guy]

Ok thanks that definitely explains a lot. And I'm gunna go check out that bullet comparator. :thumbsup:

 

[Guest]

A thousandth here and there isn't going to kill you or cause you to blow up a gun.

 

[JLA]

In the AR the 1.260 is magazine length. you can run shorter and not get into trouble, but if youre trying to seat at 1.260 id suggent adjusting your die to seat a touch deeper. 1.255" should keep your +/- .001" well under 1.260" so they wotn bind in the magazine

 

[LDBennett]

AR guy:

JLA is absolutely right. The cartridges have to fit in the magazine IF you intend to feed the gun with the magazine. The cartridge overall length in reloading manuals usually considers that but to be sure you should at least check you magazines to be sure.

LDBennett