how 'off' is too off?

[mbpautz762]

I just got started reloading 10mm and have run into problems. I've been trying to load all my rounds to the standard 1.260" OAL, but my bullet seater die is seating to very inconsistent depths. the last 20 rounds I reloaded ran anywhere from 1.250" - 1.267". Even after setting the depth perfectly for one round, the next round might load to a much different depth. How important is the actual OAL after all? I'm more worried about pressure right now than actual accuracy, since I'm just getting started. also, what on earth can I do to make things more consistent??

thanks for you help and your time!

[mrawesome22]

It can't be the dies fault. Either the press is flexing (aluminum press) or your bullets have varying ogives or tips.

[Al Norris]

... Or the brass is not all the same length.

[croc4]

I have not found a fix for it, I use the lee loadmaster btw, not sure if that makes any difference as I have not tried any other progressive that I could compare against.

[armoredman]

Happens. Bet if you measure, not all your bullets are exactly the same length, either. Don't sweat it too much.

[rwilson452]

I have a Loadmaster. I suspect the bullets you using don't have a consistant ogive. there is one thing, you could be short strokeing without noticing it. When loading on your loadmaster be sure you really going all the way on the lever. Proper usage involves going slower when the shell plate is moving and then slam it home. The reason you don't want to go fast when the shell plate is rotating is you can go fast enough to throw powder out of the case The loadmaster can take the forces needed to work large bottle necked cartridges your 10mm is a light weight by those standards.

As long as the chamber and shoot don't sweat the small stuff.

[kestak]

Greetings,

You got me curious. I checked with my 357 mag soft points and 45ACP FMJ.

For both of them, I have a variation of less than 0.015. I am using mixed cases and a Dillon 550B. ALl my 45ACP feed like a charm into my XD45.

I am new to reloading, but I was told in previous questions I asked you do not have to worry too much about the lenght of revolver cartridge as long as they are not extruding the barrel and are within the min and max specifications. For the automatics, it is another story, you need to be more precise.

Thank you

[mbpautz762]

you're right....it probably has something to do with my set-up. I'm a college student, so I don't have a work bench. I have to use a lee turret press mounted to a folding tv dinner tray that I found at walmart for 8 bucks. there is a lot of flex in the downstroke, so I'm sure that's causing the problem. but it's good to know that it's not a serious issue that's going to blow up my gun or anything.

[Don H]

... Or the brass is not all the same length.

Hmmm. I'm having a little trouble envisioning case length variation being a factor in this instance. Al, would you expand on your comment a bit?

It seems to me that OAL is a function of the relationship between the shellholder and the seating stem. I recall an experiment years ago that involved 9mm cases purposely trimmed 1/10" short; they loaded to the same OAL as normal cases. More recently, I remember a .380 case that got mixed in with 9mm cases; it went through the loading process on a progressive press and came out loaded to the same OAL as the 9mm.

[Tom Matiska]

Seating plug matched to the type of bullet?

My RCBS 44 mag dies came with one plug, but my Lyman came with plugs for both semi wadcutters and round nose. Most manufactures offer various plugs on their sites.

The FAQ section of Mr Lee's site has some words on the length issue. (select dies then seating depth variation) The FAQ section of Lee/RCBS/Lyman... etc... are all good reads


http://www.leeprecision.com/cgi/faq/index.cgi

[Al Norris]

Don, when I first started reloading (.44, natch), I was using 240gr XTP's and OT's 240gr RNFP's and mixed brass. I was getting a fairly consistent COL with the XTP's, but... The crimp wasn't always in the same place.

With the RNFP's, the crimp wandered and the COL was off by .005 to .015.

Not a real problem with my Vaquero, but I was kinda ticked, as I first thought it was me... A friend suggested that I trim all my brass to the same length. This solved (most of) the problem with all the jacketed bullets I use (Hornady, Sierra and Speer). But the problem remained with the lead bullets. Oregon Trail, Ranier and Meister were what I was using, by the time I had most of the problem was solved.

What remained was a variation of .005 to .009 in COL. This was finally solved by measuring each and every lead bullet and sorting them. This is something I no longer do, BTW - a .004 variation is simply not enough to worry about, in the firearms I use.

What I learned from this (futile?) exercise was that if the ogive varied, then the COL would vary... But even more-so, if the length of the brass itself varied. Eliminate the easiest problem first - all my brass is trimmed to the same length. This reduces the remaining problem of differing ogives to be almost negligible.

Note: I now use my "original" mixed brass for plinking only. Of the brass that I have by manufacturer (Win; Star; Magtech and TopBrass in .44 and .357), TopBrass seems to be the most consistent in overall quality. YMMV.

[44 AMP]

Check the seater die, for cleanliness. Crud (dirt, bullet lube, etc) can build up on the saeting stem, and change the OAL slightly from time to time.

Also, mentioned was a turret press. Check that the turret part does not flex too much during loading. There has to be some "give" otherwise it won't revolve, but too much may be the cause of varying OAL.

Could also be your bullets vary in length as well. That happens sometimes.

[30Cal]

It's the bullets, not the press, dies or whatever. It doesn't matter. Find a setting that gives you good accuracy and reliability. That's what matters, not what the calipers say.

Ty