OAL inconsistant

[Sarge]

Maybe, if loaded hot enough. Yes. But I was staying more in line with trying to stay in minimum PF range. If you are loading to 125 PF and come up a little short by a .01 or so not bad but shorter and shorter gets much worse even in mousefart territory.(hence your reference to exponential increases) But yes you are right especially if you are near the top of the charts and come up too short.

In a round about way we are both right?

Edited March 9, 2010 by Sarge

[GForceLizard]

Using a Hornady LNL AP loading 9mm FMJ I've learned to accept a +/- .003 variance. When I loaded 115gr FMJ to 1.155 I get 1.158 down to 1.152 I can't get it to be more consistent than that.

[BradGannaway]

Maybe, if loaded hot enough. Yes. But I was staying more in line with trying to stay in minimum PF range. If you are loading to 125 PF and come up a little short by a .01 or so not bad but shorter and shorter gets much worse even in mousefart territory.(hence your reference to exponential increases) But yes you are right especially if you are near the top of the charts and come up too short.

In a round about way we are both right?

Oh hell yes you're right!!

It's just that I have tested some major power factor 9mm loads and have been reading about that pressure spike, and it scares the poop out of me!!

I don't think that .01 or .02 variances will make a difference. In fact, I'm not sure i could keep within those tolerances on my 550 or Turret press unless I had match bullets, match brass, and took my time. But who wants to do that? I like running 300 rounds an hour!!

[Baer45]

OK guys..I dreaded taking the time to measure bullets with the stem so I loaded 45's on my dedicated 1050 for that caliber until I could get my mind clear on the 9mm problem. I broke down the machine and cleaned it thoroughly and then load Hornandy 115 gr RN that I could expect to have good tolerences and used new brass. They loaded fine without a hitch so I switched back to the Ranier with used cases and although there were differences of .002 up or down; nothing like I had before...so was it the cleaning? my mental state from pulling the handle on those little bullets? or something else? at this point I do not care and just look forward to loading up a few hundred 147's tomorrow!Thank you for all of your input and getting me through a tough spot. I know now to measure the bullets and stems along with all the other good suggestions here and made notes in my book....C

[StephensOutdoors]

Group the bullets by the measured length, with groups each .005" different; ie: .500-.505", .505-.510", etc. For this to show anything, you MUST measure in conjunction with a bullet seating stem. Once the bullets are divided into groups based on length, then weigh the bullets in each group. I suggest doing 20-25 bullets to start, up to 100. Please post your findings.

I just spent the last 2 nights chasing various OAL's loading 147 gr Berry's on my Dillon 650, so I was glad to find this post. I was trying to achieve a 1.142" OAL on my loads and they where varying between 1.146" and 1.136". My 115 gr load OAL's are all within 2/1000th's of each other so this was frustrating to say the least. I took the bullet seating stem out of seating die and sampled 50 bullets from the box. All but 4 of the bullets measured between 1.469" - 1.471" (stem and bullet together). I cleaned my Dillon dies, took apart the shell plate and cleaned that. I did find an excess of brass or plating build up in the seating die ... the OAL consistency got better, but still varied between 1.144" & 1.138". Next step was to increase the flare or "bell" on the powder die station ... in the process of that I noticed that I had the collar clamp for the powder funnel tight on one side and slightly loose on the other side. I adjusted the collar clamp so that it was barely "snug" on both sides and proceeded loading. I brought my OAL down between 1.143" & 1.139", but still had the occasional oddball OAL. All the information on this thread was a big help and I'm glad I brought my tolerances in tighter. The only thing I can come up with at this point is this point is that the bullet profile on the plated Berry bullet varies enough to make it inconsistant.

[DougCarden]

Guys, I hate to say it, but as long as you get a repeatable OAL that falls within a close number, like the 139-142 range, that is the best you are going to do. Using one headstamp brass and jacketed hollowpoints is about the only way I know loading 9mm to get dead nuts on OAL. I notice when loading Steel ammo, I will use mixed brass, speer, FC, and win. I set the OAL to be really close to what I want, and most of the times one if not two makes will be almost the number I want, and the other will be a little shorter. When I start loading the batch, I check and see what the different makes mike out to. Most of the times the different makes come out to the same number through out the whole batch.

If you are Uber Anal, and want to sort by headstamp, by all means go for it. I do it for my 50yd accuracy ammo. For most stuff we do inside of 35yds, having a small variation on the OAL is just the way it is. Most FMJ ogives are not the same, and for plated it is much worse. If it is really a problem, buy a Redding seater die, and send them the bullets you want a stem made for. They can grind one down for that ogive. That is about as close as you will get to repeatability. Just remember with plated bullets you need to bell the case much more than you would for jacketed or lead.

In the area of things you need to obsess over or worry about, this ranks right up there with checking the crimp for .378 or is it .3785....and is that a problem.......

Hope this makes some sense......

DougC