Inconsistent OAL


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JBrady555
May 4, 2014, 08:15 PM
Hello I've been reloading on a dillon 550 for a few months now and the dillon bullet seat die was pretty consistent but lacked a adjustment stem. I change bullets so much that it was a pain to reset all the time. I went to a lee seat die which has the stem and makes changing easy for me but the bullet creeps longer the more I load. I can gain .005 over 15-20 rounds. I marked the stem and it doesn't seem to be backing up, not sure what's happening. Anyone have this problem before. What is a better seat die with stem that I can upgrade to? Thanks. Oh by the way, the caliber is 9mm and I see inconsistency with all kinds of bullets.

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Conservidave
May 4, 2014, 08:28 PM
In my opinion it has to be the bullet thats not consistent. I have been loading Berrys 115g RN and OAL's have been all over the place. I've seen it range from 1.118 up to 1.130 from the same box. It's been frustrating to say the least with having to mic a bunch of finished rounds. Im using Hornady dies which seen to be excellent quality so i just live with it.

JBrady555
May 4, 2014, 08:32 PM
Thanks man

bds
May 4, 2014, 08:36 PM
With progressive reloading, tilting of the shell plate can affect OAL of the finished rounds.

FWIW, if I want greater consistency from my reloads, I resize my cases separately so when I am reloading in progressive mode, I am only applying minimal pressure from flaring case neck and seating bullet/taper crimping.

YMMV

JBrady555
May 4, 2014, 09:03 PM
With progressive reloading, tilting of the shell plate can affect OAL of the finished rounds.

FWIW, if I want greater consistency from my reloads, I resize my cases separately so when I am reloading in progressive mode, I am only applying minimal pressure from flaring case neck and seating bullet/taper crimping.

YMMV

Great idea. I'll try this tomorrow

ImjinScout85
May 4, 2014, 09:12 PM
That's also what I do on my LnL, I do all my reloading in steps. I will de-prime and resize about a 1000 casing's, then I will set up the press for priming only and put all the primed cases in a zip lock bag for when I'm ready to load. This always just seems to work best for me and that way when I can concentrate more when I'm actually charging the cases. But with that being said I only use Berry's bullets and do notice some OAL changes during reloading but it has not been by more than .005

Magnum Shooter
May 4, 2014, 09:12 PM
Do you get anything more than .005? Because +/- .005 doesn't hurt anything.

Wreck-n-Crew
May 4, 2014, 09:24 PM
It is not unusual to have a .005" variance. Generally your stroke can change it that much either way. Not to mention (as already stated) .005" is usually not enough to cause issues. I would concentrate on an even repetitive stroke at the same speed and same pressure on your arm/lever if it bothers you that much.

tcoz
May 5, 2014, 04:01 PM
I've also found that taking a couple of extra seconds to set the unseated bullet straight on the case gives me much more consistent OAL

chiltech500
May 5, 2014, 04:35 PM
I have the same problem with my 550 and have been measuring completed rounds because I'm doing ballistic and accuracy testing. I have measured Missouri bullets IDP# 1 200gr LSWC and found a .005 size difference in them also.

I find the OAL is shorter on the 1st and last couple of bullets because of tilting of the shell plate with less than 4 bullets. I had thought about stroke affecting OAL but wasn't sure.

Level10
May 5, 2014, 05:05 PM
Because of the torsion on the shell plate it is best as others have stated to process brass/rounds in "steps". Also on any brand of progressive it is best to position the Swage and seating die OPPOSITE ( or equal distances left/right of the ram) of each other to help "balance" so to speak the torsion/rocking motion. Sometimes this is hard to do when a PTX adapter is used.

Schwing
May 5, 2014, 05:14 PM
This is kind of a different track but do you use lead bullets with some kind of tumble lube?

I found, that with my lee dies, every bullet leaves just a little bit of lube behind in the die. As the lube built up on the die, it was not uncommon to see what you are experiencing. Then I would tear down the die and clean it and my OAL would be back to where I started.

If this is the case, you either can try cleaning the die periodically or switching to a none tumble lube bullet. This is one of the big reasons I switched to powder coating instead of 45/45/10 or alox lube.

chiltech500
May 6, 2014, 08:49 AM
I have found with poorly manufactured bullets that lube is left in the seating die but even worse, in the crimping die. Fortunately with the Dillon both pop out easily for cleaning. On my Dillon 550 the crimping die actually picks up more lube than the seating die.

I have had a manufacturer with so much excess lube that I had to clean out these stations every 6-7 bullets. The warning signs of excess lube are lube left around the bullet on the completed round. I have not had those issues with MBC SWC in B.E.#1 or IDP#1. However the MBC 185 gr "button" (for 45acp) had excess lube and required cleaning. I will say I have only bought 1 batch of those and many batches of the SWC's with no issues at all.

Oldgoat03
May 6, 2014, 08:16 PM
I reload on a Dillon SDB, 550 and a Lee Classic 4 hole turret. With all presses (and several die brands) I have experienced minor fluctuation in OAL. As mentioned in prior replies you can attribute the variation to, inconsistent stroke, shell plate flex when rounds not present in all stations and in my experiecne the biggest culprit is - the use of mixed brass.

It has been mentioned in many threads that all brass is not equal. 9mm brass like FC, PMC and Blazer typically have thinner walls than other brass such as Winchester and S&B. Resized thin wall brass doesn't grip the bullet as tightly as thicker wall brass. Thin wall brass allow the bullet to seat deeper resulting in shorter OAL using the same the same seating die setting. I am a bit OCD so I sort/load cases by head stamp to minimize variation.

NOTE * In the thin wall brass I actually have experienced bullet set back when I push the nose against my bench by hand. Since discovering this setback I now run all thin cases through a Lee U ("undersize") die to ensure proper neck tension. The "U-die" ompetely eliminates setback and achieves much more consistent OAL as well.

My suggestion is to sort your brass by head stamp, adjust seating depth and then see if your OAL variation doesn't improve. Test for setback. You may not need a Udie but the bench test will tell you.

Hope this helps
OG03

JBrady555
May 6, 2014, 09:29 PM
Yea I do use mixed brass, could be the problem. Thanks for the suggestion.

Wreck-n-Crew
May 7, 2014, 08:48 PM
the biggest culprit is - the use of mixed brass. What does mixed brass have to do with OAL? Measuring from the case bottom to bullet point and I'm confused as to how a casing will change OAL. I mean I am open to the possibility of them causing it but I have loaded all PMC and all Winchester separately and still had the same inconstancy with each batch of 9mm and 45acp.

I know Ogive can cause it. Seating dies don't work off of the point of a bullet rather the Ogive. That makes it more likely if the Ogive has a little inconsistency. But a good bullet and the same stroke usually keeps me withing.0025' either way on both the single stage and the progressive. seemed the same way on my friends 550 we used regularly.

Mr. Farknocker
May 7, 2014, 10:09 PM
Brady,

The OAL or COL (Cartridge Overall Length) measurement is usually only important for determining whether the ammunition will feed properly when inserted into a magazine. Otherwise it has little relevance in reloading (at least in my own mind). Unless the OAL for your handloads are running so close to the recommended COL for your given application, I can't see that a .0005 variation would present a problem as cartridges are usually loaded well under the max COL. When I first started hand loading, I used to pay great attention to the COL until finally it dawned on me that the max COL is merely a measurement given to ensure that your round will fit in the rifle's magazine and feed properly. I now keep my hand loads for semi-auto firearms in line with the recommended max COL or under but disregard them for my bolt action rifle. The rifle I load for shoots best when the bullet is .002" off the lands. Seating the bullet .002" off the lands, however, requires that the COL exceed the recommended max COL so the round must be loaded by hand.

It's also important to note that there is usually a greater variation in bullet lengths when measured from the base to the tip of the bullet then when the measurement is taken off of the bullet's ogive. That's why your measurements of COL tend to vary even when using the same bullet from the same box and loaded with the same press set up. The variation is even greater when rifle bullets are used due to manufacturing tolerances (or lack thereof). If you want consistency, measure the length of the round using the bullet ogive rather than the bullet tip.

Check this thread out for more information on measuring COL:

http://www.thehighroad.org/showthread.php?t=728980

Good luck

chiltech500
May 8, 2014, 08:29 AM
Thanks Mr Farnocker, I read your post and the associated link and have come to be more settled about my .005 OAL spread - though my bullets are LSWC and my press uses a flat nosed seating die I have come to believe my stroke has been affecting the OAL.

Potatohead
May 8, 2014, 09:21 AM
I now run all thin cases through a Lee U ("undersize") die to ensure proper neck tension.

Never heard of that one. Im interested though because ive had lots of trouble with my 380 dies. Lee replaced sizer body (I think that's what the fella said, its been awhile) but I still get bad neck tension with some brass.

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