223 OAL consistency issue

[ronas]

Reloading on a Dillon 650XL using Dillon dies and the following components:
55g FMJBT bullet
25.1g of 748
CCI small rifle pimers 450 Magnum
mixed brass; not separated by headstamp.

Sierra loading manual gives 2.260" as max OAL. Then for each bullet different overall lengths are specified. For the bullet I'm using OAL is specified at 2.240".

The finished rounds I produced, about 60 of them have OAL that ranges between 2.240" and 2.258". Most were no longer than 2.248".

Not sure what I've done that would result in variation. Any suggestions, maybe the mixed brass. I did pull the press handle down all the way for each cycle.

What are the consequences of having bullet seated more than the specified2.240"? For instance will a bullet seated .018" deeper cause excess pressure?

[jandmtv]

There will be small variances no matter what you do, but I think it has a lot to do with technique. When you pull down the handle, make sure its with the same speed and amount of force each time.

[Hans Gruber]

There will be small variances no matter what you do, but I think it has a lot to do with technique. When you pull down the handle, make sure its with the same speed and amount of force each time.

I'm going to assume that this applies to single stages as well? I was loading my target loads for tomorrow last night and was finding variations depending on how hard I was pressing and thought that odd. Shouldn't the throw of the press be the same every time?

I figured it was my cheap Lee press. For example I was loading .308's to 2.800, I'd pull down once, measure my OAL and get a 2.805. Stick it back in and pull with a good squeeze at the top and it would come out in my target variance of 2.802-2.798.

Would a better press obviate this dependency on my technique or is this something that just comes with more experience?

[r08ert209cali]

Was all the brass trimed to same length? if it is an Ar and fits in your mag you should be ok.

[Point of Impact]

You must also consider variances in the bullet itself. The most accurate way to measure is at the ogive if the bullet but it will not give you total cartridge length.. I load my 5.56 rounds to 2.20" to make sure they fit the mag. As long as the rounds fit the mag and don't exceed the printed min and max COAL, then the only effect will be slight inconsistancies in trajectory (because seating the bullet deeper or longer will affect pressure, which affects velocity amongst other things that affect trajectory and accuracy.

From my experience, I did not notice much of a difference in POI with slight variances in OAL (2.00" to 2.015" ) so I stopped worrying so much. With my bolt guns, I pay more attention uniform OAL because those are loaded to sit about .03" off the lands and having a cartridge to long can cause some issues. For my AR, I just make sure the ram speed and pressure are uniform to the best of my ability and call it a day. I Spot check the rounds and have not had a problem. I load on lee equipment...works for me. Just giving my two cents, so if you don't like it, please send it back....its a recession you know.

[ronas]

Was all the brass trimmed to same length? if it is an Ar and fits in your mag you should be ok.

Brass was not trimmed. I did check it with Dillon headspace gauge. Yes I am using an AR

As long as the rounds fit the mag and don't exceed the printed min and max COAL,

[Beelzy]

Don't use mixed headstamped cases for starters.

You mentioned Military caes in another post, mil. cases and commercial ones
in the same loading batch is not prudent.

[ronas]

You mentioned Military caes in another post, mil. cases and commercial ones
in the same loading batch is not prudent.

I am doing that, but I am loading on the lower end of the powder charge chart.

[Beelzy]

The loading isn't so much the issue as the lack of consistency you will get
from mixing them together.

[westcoastr]

when loading for the best accuracy, mixed headstamps not a great idea. for everything else it is fine if you are not pushing the limits and keep a close eye for problems as your weakest brass type is going to fail first. then you have to decide do you trash all of them or not.

COAL inconsistancies are going to come from the bullets themselves, how straight you put them in the cases, the quality of the seater die, case neck tension, your technique being the same everytime, and how much your progressive press flexes (ask me how I know). you didn't imply that you are getting compressed loads so we can ignore that.

.02" of seating depth should not cause a safety issue as long as the longer rounds are not jamming the ogive into the rifling. as far as its effect on accuracy, only test firing will tell you. of course with mixed brass you might not be able to tell which variable is more critical.

[30Cal]

The bullets are the source of your variation. The seating die pushes near the ogive, not on the tips. The position of the tips doesn't matter as long as they feed OK from your magazine.

[swerv512]

i've experienced the same issue. getting different COALs with the same brass, trimmed to the same length. i figured it out to be the consistency of the pull. i'm learning to be more "automatic"- pulling the same speed and tension everytime. When i can tell i'm having an off day- i'll seat slightly longer and work my way to target OAL with tiny adjustments.

[ChuckS1]

Had this happen to me, too. Don't go by OAL; measure from the bullet ogive. That's the only way you'll get consistent results. Measuring from the tip assumes bullets have the same length, which they don't. I'll bet if you measure the bullets, you'll see variations in the length that come close to your OAL discrepancies.

Get a bullet comparator and your problem will be solved. I use a Davidson seating depth checker, but Sinclair's looks pretty good, too. I don't recommend the "hex nut" version. It wobbles on your claipers and it'll drive you nuts. The ones with the thumbscrews work best.

[Hans Gruber]

I just started seating my workup barnes load on my .308 a few minutes ago. I took great care to manipulate the handle the same way every time with the same pressure. I'm now seating within +/- .004 on the first go now which I can easily attribute to bullet variance.

Good stuff, didn't know that the operator had such an impact.