OAL Consistency

[ES13Raven]

New reloader here...

I can't seem to get my OAL very consistent.

I have loaded about 600 9mm Xtreme 147gr rounds on my Dillon 550b using the Lee 4 Die set. Everything passes the chamber check on my EGW. All my dies are locked down pretty tight with Dillon rings. I'm sure I am pulling the handle all the way down & up.

My last batch of 100 rounds, I am getting OALs ranging from 1.144 to 1.158

Is that wide of a range normal for mixed headstamp?

[levellinebrad]

Lube your cases. Even though you don't need to, it helps the machine run smoother and will probably tighten up your oal. It did for me anyway

Edited August 25, 2014 by levellinebrad

[Sarge]

Lube, full shell plate, don't stop and start the machine every few rounds, etc.

Talked about a lot on here. See what a quick search pulls up

[ES13Raven]

Lube your cases. Even though you don't need to, it helps the machine run smoother and will probably tighten up your oal. It did for me anyway

I used One Shot, but maybe I didn't use enough. I sprayed for about 1/2 second into a sandwich size ziploc bag, then put in about 100 brass and rolled them around. I let them dry on a cookie sheet for about 15 minutes before I started using them.

I measured all 100 rounds and about 40 of them were above 1.150 OAL. I ran those rounds back through the seating and FCD dies and now they all measure around 1.145 OAL.

[danman00]

Just a thought, make sure you are using the correct profile on your seating die. If you're using Dillon dies, they have a flat point profile and a round nose profile depending on what bullet you're using.(In fact I think most brands of seating dies have both options - not sure though) I load mixed head stamp on my Dillon 650 and do not see any variance at all. If you're loading 147gr FP bullets with the RN profile seating dies (or vice versa) - that might be the cause.

[chuckols]

I think danman00 has put his finger on the problem

Chuck

[CZinSC]

I just started using Xtreme 147 HP RNFMJ and the profiles have been very consistant, so my feeling is either the seating stem, or the brass is your issue. Also, don't compare the first few rounds when the shellplate is not full with rounds that were produced when the shellplate was full. There will be a variance ( not sure it's as great as you're seeing, but there will be a difference ).

[ES13Raven]

Just a thought, make sure you are using the correct profile on your seating die. If you're using Dillon dies, they have a flat point profile and a round nose profile depending on what bullet you're using.(In fact I think most brands of seating dies have both options - not sure though) I load mixed head stamp on my Dillon 650 and do not see any variance at all. If you're loading 147gr FP bullets with the RN profile seating dies (or vice versa) - that might be the cause.

I think my Lee seating die only came with one seating plug, which is for a round nose profile?

[vinceislander]

Lube, full shell plate, don't stop and start the machine every few rounds, etc.

Talked about a lot on here. See what a quick search pulls up

+1 for full shell plate.

I don't mix brass with and without spent primers, that will cause OAL variations. I set aside the first and last 4-5 rounds of my loading session since they have the greatest deviation. Consistent up and down stroke speed/rhythm. I do stop and start to measure powder and OAL about every 10 for the first 100 then every 25-50 thereafter. I'm pretty happy with Xtreme 124GR RN an FP. Just did a batch of 500 last night. OAL varied 0.002" at the most. I do sort my brass and bullets. I use a 550B with Dillion 9mm dies.

Good luck.

[danman00]

Just a thought, make sure you are using the correct profile on your seating die. If you're using Dillon dies, they have a flat point profile and a round nose profile depending on what bullet you're using.(In fact I think most brands of seating dies have both options - not sure though) I load mixed head stamp on my Dillon 650 and do not see any variance at all. If you're loading 147gr FP bullets with the RN profile seating dies (or vice versa) - that might be the cause.

I think my Lee seating die only came with one seating plug, which is for a round nose profile?

Take your Lee sizing die apart. The stem (the part that actually makes contact with the bullet) is reversable with a FP side and a RN side. I just tested it on my Lee 9mm seating die. My dillons are the same way.

[ES13Raven]

Take your Lee sizing die apart. The stem (the part that actually makes contact with the bullet) is reversable with a FP side and a RN side. I just tested it on my Lee 9mm seating die. My dillons are the same way.

Yes, it was in correctly:

[noylj]

NO, you will not see any difference on target unless you are shooting extremely small groups at some very long distance and shoot a lot of groups to get good statistics.

COL never seemed to be the concern it is now until an article appeared showing the difference between a cartridge (at about 1.100") and a cartridge where the bullet had been pushed into the case (insufficient bullet/case tension) about 0.25" (to a COL of about 0.850") and the fact that the short cartridge produced about 65ksi. Based on this, folks seem to now be very concerned about a 0.01" or less variation in COL.

Measure some of your bullets and determine what the range in length is for them and realize that any meplat/ogive variations will produce COL variations. Nobody ever seems to factory in bullet variations into COL variations. I read lots of article about measuring COL from some datum on the bullet ogive, but NONE of the articles has ever mentioned running a test on the length of the bullets themselves measuring from the datum--and bullet do vary.

Measure some factory ammo and see what their COL variation is--you may be very surprised.

Any variations in the hardness of the case necks will produce COL variations.

Any variations in how you cycle the press or fill the shell plate will produce COL variations.

All of these variations, though, are small.

What would be a concern is if the COL varies in one direction over time--then you need to find out the cause.

Next, if you are worried, run them through the seating die again--unless it is the short ones you are worried about.

[ES13Raven]

What about a sizing die that is not set right?

From the Lee Website:

"There are a number of possible causes for overall length variation... A potential solution for this on progressive presses is to turn the sizing die in far enough so that the carrier is stopping on the bottom of the die. This removes clearance problems when no sizing but yet seating / crimping is occurring. Take special care not to turn the die in further than to just touch the shell plate and possibly just a tad more. About 1/4th of turn more is all you want to go, turning the sizing die in too far causes other problems."

I think I have my Lee sizer die just touching the shell plate when I locked it down, which is what the instructions said to do. But this Knowledgebase article says to up to 1/4th of a turn more?

[thermobollocks]

Have you compared the lengths of the bullets themselves?

Also, are you using consistent force on the press handle every single time?

[BeerBaron]

hard to say without looking at the press and without watching you load. but my guess is one of 2 things.

1, short stroking. some rounds may have more resistance in the sizing die and on that same stroke of the press whichever round is in the seating die is not getting pushed as deep. that's a loading thing. with practice you'll get very consistent in your strokes.

2, one die (most likely sizing on powder drop/flare) is adjusted low enough that when a certain piece of brass in that station (possibly something a bit bulged) it is what is limiting the up movement of the ram. so again, whichever case is in the seating die at that point doesn't get seated deeper. this is reinforced by the fact that you ran them back through and they seated properly to 1.145.

My suggestion is this: check all the dies one by one. then set the sizing die to be slightly lower so that it becomes the upwards 'hard stop'. with it adjusted then re-set your seating die for your desired OAL. now regardless of buldged cases etc it should always hit that hard stop.

BUT you still need a consistent stroke and still need to watch for a really bulged case that won't go all the way into the sizing die (this is stopping the press short).

there will always be some variance in OAL when reloading on a progressive. if you want benchrest type ammo you need to load them one by one.

[chuckols]

BeerBaron Great response!

[ES13Raven]

Thanks, I will try that.

[ES13Raven]

I think I figured out what my problem was - I was not belling the case enough.

I was flaring the case about .003

Dillon recommends: "at least .010" larger than a sized, unflared case mouth measures, and no larger than .020" larger."

I set my flare to about .015 and checked the OAL of about 20 rounds - all of them are within .004 of each other.

[thermobollocks]

Glad you figured it out!

And, yeah, I always try to flare enough that the bullet pokes in a good couple millimeters.