Using Dillon 550B, loading 9mm, moly coated lead bullets.

How much variation is normal in OAL?

Just depends. Same headstamp brass or random? What type of dies? I’d say .007+/-

quote:

Originally posted by sigarmsVin:
Just depends. Same headstamp brass or random? What type of dies? I’d say .007+/-

Random brass, Dillon dies. You say +/- .007, so that would be end-to-end of .014 on the spread. That's just about what I'm seeing, a difference of .013 from shortest to longest.

Being new to this, and not really knowing what to expect, I was thinking that a spread of .013 on a 9mm round was kind of a large spread, but now that I look at it, this is just a hair over 1%, so I guess it's fine.

LC brass, all the same bullet...I'm getting about +/- .005".

Mixed brass, pulled bullets of the same weight...I'm getting about +/- .01" (oal will be 2.24" to 2.26"...with most being about 2.25" oal)

quote:

Originally posted by Dae Zee:
LC brass, all the same bullet...I'm getting about +/- .005".

Mixed brass, pulled bullets of the same weight...I'm getting about +/- .01" (oal will be 2.24" to 2.26"...with most being about 2.25" oal)

2.25" -- That's probably not 9mm.

 
You will get some minor variation on a progressive press depending on how you hand position the bullet before seating. For 9mm, I strive for an average of 1.150" OAL. It's under the maximum, and feeds well in every 9mm I've owned. And with WSF as the powder, there is never an issue with a compressed charge, even with 147gr bullets. I see variations of +/- .005", but most are right near the mark.
 

You should have ±0.005 Max with most being with in a 0.005" total spread. Since your bullet seating plug does not contact the tip of the bullet measuring down the ogive would give you a better reading of variation. If your getting more you mat be doing something that is exerting a lot of load on the base causing some flex. Most of us do case prep steps (sizing/trimming) prior to setting the charge and bullet. This way we don't have extreme force of the sizing impacting our finish bullet. This is for rifle brass only.

I do not yet load 9x19, but did have this happen when loading .32 acp with mixed brass and cast bullets my OAL seems to wander a bit with a range of about .018. I did not observe this OAL variation when loading the Berry 71gr. TMJ but I have only loaded 48 of those so far.

I am going to do another batch of .32acp and I will be segregating brass next time when using the cast bullet.

In .45 acp I try use the same head stamp in my load batches. I also have 4 seperate seating dies each set to desired OAL with my most commonly loaded bullets. I also crimp and seat in two seperate stages. My last batch of 100 200gr. SWC bullets had a vaiance of .003, with OAL between 1.241. - 1.244.

 
For the life of me I cannot see how mixed brass enters into the OAL equation. The OAL is determined by the distance between the seating die and the shell plate, is it not? Or am I missing something (which is not unusual)?
 

I see the same thing in my 9mm loading. Not that it realy makes for inaccurate ammo but it bugged me.
I cut down the variation some by having a few cases that have spent primers inserted upside down* . I use these as "station fillers" when real ammo is being set up or finished up.
*All* stations have a case in them at All times.

I also have the shell plate tighter than what some internet sites say is "normal". Mine takes a more deliberate push to move it, that removed a lot of slop.

*- ETA obviously the decapping/sizing station has it's case w/o a primer in place.

There can be slight differences in brass thickness(head) with varying brass. More so with rifle bullets, tips can vary just a bit.

Whatever slight variation one has, a little shouldn't matter. That would mean, matter to where pressure or feeding became any kind of issue. I say it wouldn't matter because the loads aren't(shouldn't be) at the ragged edge with pressure or max COL.

I found it in the Dillon manual (who woulda thought to look there?). Variation up to .016 is not abnormal. I was fretting about .013

A discussion dear to my heart..Ive been reloading quite a long time. I was anal about rifle caliber reloading and with a single stage press, OAL can be controlled much better. Using a progressive press with pistol calibers, using range brass and coated bullets, the variations pop right up. As sourdough44 stated, and I agree, rim thickness is a big variable. Try loading a single round on a progressive press followed by a few rounds with a full cycle and you will see a BIG variance in many cartridges. Now , with premium jacked bullets and the best fitting seating die you can find, then these variables lessen a bit. But with all the handgun loads I shoot ( 10,000 rds per year easily) in many calibers, I can live with the + or - .005. Of course I'm not using any compressed powder loads.

quote:

For the life of me I cannot see how mixed brass enters into the OAL equation. The OAL is determined by the distance between the seating die and the shell plate, is it not? Or am I missing something (which is not unusual)?

Brass thickness will impact OAL as the bullet nose will deform a bit on seating. Why 0.005" +/- is totally acceptable. Individual nose shapes can vary that much within the same box of bullets. Then you have the deformation of the bullet nose.

quote:

Originally posted by henryaz:
 
For the life of me I cannot see how mixed brass enters into the OAL equation. The OAL is determined by the distance between the seating die and the shell plate, is it not? Or am I missing something (which is not unusual)?
 

My head is starting hurt from trying to figure out what mixed brass could possible have to do with Col! I agree with your answer. Every thing you do in reloading has variables built into it. I find that if I am careful I can keep the col around .002 to .005 and mixed brass does not inter into the equation, How can it? The shell sets on the shell plate and doesn't move, the seating stem regardless of where it contacts the bullet will seat the bullet where you set it to. Your technique is the only thing that I can see that would make a difference on the external measurements. What is happening inside the case can't be measured or seen. Just too much variance from bullet to bullet.

I started this thread because when I saw a .013" spread on 9mm, my gut feeling, no knowledge, just jumping to a conclusion, was that this was a pretty big variation.

Sanity returned when I

1. pulled out my calculator and realized that this was only about 1.1% of the OAL, and
   
   
2. I actually pulled out the manual that came with the Dillon 550B and saw that they said that .016 was not an abnormal variation.

So, it certainly appears that I was worrying needlessly.

I'm not hand loading for bullseye accuracy. I'm just trying to control ammunition cost for quantity range practice. My goal is to be able to stay within an 8" circle at distances between 5 yards and 20 yards, while trying to get my speed up, so 1/2" one way or the other on the target won'e make a significant difference, for my purposes.

quote:

Originally posted by V-Tail:
I started this thread because when I saw a .013" spread on 9mm, my gut feeling, no knowledge, just jumping to a conclusion, was that this was a pretty big variation.

Sanity returned when I

1. pulled out my calculator and realized that this was only about 1.1% of the OAL, and
   
   
2. I actually pulled out the manual that came with the Dillon 550B and saw that they said that .016 was not an abnormal variation.

So, it certainly appears that I was worrying needlessly.

I'm not hand loading for bullseye accuracy. I'm just trying to control ammunition cost for quantity range practice. My goal is to be able to stay within an 8" circle at distances between 5 yards and 20 yards, while trying to get my speed up, so 1/2" one way or the other on the target won'e make a significant difference, for my purposes.

I understand completely with what you were trying to say. My favorite target is a paper plate because they are quit inexpensive and a black marker will last a year if my wife or kids don't ever find it. What accuracy means to one person can be different to the next person.

quote:

Originally posted by chansen92:
My favorite target is a paper plate because they are quit inexpensive ... What accuracy means to one person can be different to the next person.

I have something even less expensive than paper plates.

The gun club has outdoor ranges. We have to supply our own target stands, backers, targets, etc. My target stands cost me maybe five or six bucks to make. Some PVC pipe, couple of 90 degree elbows, couple of large, maybe 10-inch heavy nails, two furring strips, and that's a stand.

For backers, I just cut 18" x 30" (more or less, accuracy is not required) panels from cartons on incoming shipments. We bottle the cleaning products that we sell with our carpet cleaner machine rentals, so I have a lot of cartons incoming, containing bottles from the plastic manufacturer. I have a LARGE supply of target backers.

For targets, a small package of colored dots, maybe 1/2" diameter, from the office supply store, will last a long, long time. Just stick a few dots on a backer for an aiming point.

If you want to play games, use different color dots, and have an accomplice yell as you shoot, "red red blue red green" etc. You shoot at the dots of the named color.

I had read this earlier before I started and I’m glad I did. I was 1.135-1.142 and I was going for 1.138

Powder coated bullets will have more variation than plated, jacketed and lead. I've seen thickness of the coatings vary .002 - .005. The Hi-tech stuff a bit less variance. The steel and paper don't care...