Seating Die Conundrum

[Saluki91]

I'm working up a .223 load for a bullet that is new to me (55gr HPBT - no cannelure), and am experiencing something I have not seen before with my Dillon seating die.

The target OAL is 2.244". After setting up my seating die for this length, the next three rounds came out quite short - 2.239.5", 2.240", and 2.242.5". I attached a photo of these three rounds

Assuming my brain was in flatulence mode, I started over... backed off the seating stem, and re-set the die to 2.244". After triple checking the test round, I ran another round through the press, and came up short again - 2.242"!

The bullets don't show any signs of being forced into the case, and it certainly doesn't feel like anything unusual is happening. They have not been crimped.

So what gives? Is there a problem with the process or a problem with the operator?

These short rounds are loaded with the minimum recommended charge of VV N530... is it safe to throw them in my stash of plinking rounds, or should I break them down in an effort to save some of the components?

As always - THANKS!

 

[IMtheNRA]

That's just normal variation in ogive location and bullet tip uniformity. If you're using a progressive press, you are also seeing the results of shell plate flex.

 

[Soonerpesek]

I really wouldn't consider ".004 to be quite short, but that's my opinion.
I would agree with NRA, and consider that spread to be acceptable...

 

[Hooda Thunkit]

This comes up occasionally. I usually advise finding a box of factory rounds and spending some time with a caliper.

That should ease your mind.

 

[AJC1]

Each system has its range for allowance. The wilson die and arbor press has the least and progressive presses are on the other end of the spectrum. For progressive I would not be terribly concerned.

 

[runner3264]

As a loader of .223/5.56, the variation you have is very normal. I usually see .005 deviation among COL.

 

[film495]

I've played this game with seating depth. The bullet shape varies a hair and changes the length measurement of the finished cartridge. There will be some standar deviation, give or take a few thousandths, either way from the average bullet. Trick I'm starting to notice is doing 3 or 4 before really locking the die down to try to find the middle of the variation for what I'm aiming for. Annoying to set the die and then have them all short or long, and set up again, only to find they are all off the other way.

 

[Walkalong]

OAL is almost meaningless here, check base to ogive. There are plenty of ways to do that.

These are Sinclair and SS, but Hornady makes the same thing in aluminum a little cheaper.

You can check base to shoulder position with one style insert, and base to ogive with the other.

.22, .6MM, & .30 inserts cal for base to ogive, and a 30 degree insert for base to ogive on 30 degree shoulders.

 

[cfullgraf]

I find when I am setting up oal on the seating die, if I make a few adjustments “walking” the bullet to my desired oal, when I seat the next bullet to the final setting the oal will differ.

So, I seat a bullet and measure. Then I make an adjustment and seat another bullet and measure the second cartridge.

I do this until I get the correct oal. I then run all the test cartridges through the seating die to get them close to the desired oal.

Micrometer seating stems make this process quick as it is easy to make an adjustment that gets you spot on with two or three cartridges.

As said, there is some variability bullet to bullet. Measuring off the ogive has less varability.

Also, you will get different results on a progressive press between having one cartridge in the shell plate at the seating die versus having the shell plate fully populated and performing all the tasks at the same time.

 

[ArchAngelCD]

Like the others said, I would not worry at all about a difference of .004". Do you realize how small 4/1000 really is? Being careful is very god but worry about real problems not tiny variations. You are doing well, enjoy shooting your ammo... Also, take the advice from Walkalong if your still worried.

 

[lordpaxman]

I also see differences in COL of a few thousandths.

I'm working up a .223 load for a bullet that is new to me (55gr HPBT - no cannelure), and am experiencing something I have not seen before with my Dillon seating die.

I’m really curious, what was your previous experience???

 

[edwardware]

Did you just attach a photo intended to show 0.0045" of seating variation? lol

It sounds to me like you're measuring the bullet's seated position from the tip, not the ogive. Never, ever, bother to do that, unless your checking COAL for magazine feeding.

Bullets tips vary 0.010" all the time even in premium HP bullets, which is why we (almost) never measure them. Reference the ogive, the same way your seating die does, and you'll be measuring useful data.

BTW, that your batch of bullets shows a mere 0.0045" tip-to-ogive variation is remarkable, and lower than expected.

 

[Rule3]

2.239.5"

2.242.5"

Now that is getting down to the nitty gritty!

 

[Saluki91]

I also see differences in COL of a few thousandths.

I’m really curious, what was your previous experience???

First - Thanks to one and all for their input and reassurances. I appreciate it very much!

In answer to your question, my experience with this press (XL750) and dies (Forster & Dillon for .223) must be unique <knocks on wood>. My pistol and rifle ammo comes out with very little variance in OAL. .004" seemed significant enough to ask questions.

It sounds like I was heading down a rabbit hole, and you guys pulled me out before I got lost.

Thanks again!

 

[Saluki91]

Did you just attach a photo intended to show 0.0045" of seating variation? lol

It sounds to me like you're measuring the bullet's seated position from the tip, not the ogive. Never, ever, bother to do that, unless your checking COAL for magazine feeding.

Bullets tips vary 0.010" all the time even in premium HP bullets, which is why we (almost) never measure them. Reference the ogive, the same way your seating die does, and you'll be measuring useful data.

BTW, that your batch of bullets shows a mere 0.0045" tip-to-ogive variation is remarkable, and lower than expected.

You are correct - I was measuring tip to base. I have ordered a comparator.

I attached the photo because many responses to questions I see posted here often include the phrase "A photo would be helpful." It wasn't in this case. ; - )

 

[Rule3]

You are correct - I was measuring tip to base. I have ordered a comparator.

I attached the photo because many responses to questions I see posted here often include the phrase "A photo would be helpful." It wasn't in this case. ; - )

For comparison.
Common copy paper is .004" thick
Is it all worth that amount? What are you using to measure 2.242.5"?

https://www.jampaper.com/paper-weight-chart.asp

 

[GeoDudeFlorida]

I attached the photo because many responses to questions I see posted here often include the phrase "A photo would be helpful." It wasn't in this case. ; - )

Sure it was. Figured it out right away. I could see from the photo the bullets were seated correctly and with very little variation and that the cases looked they were done right so, it must be how you were measuring, not the seating process. Pictures always help!