Beginner 9mm - Stressing about min OAL

[Grandpa45]

Hi everyone, this is my first post here and first post regarding reloading anywhere. I've been reading about this stuff for months and finally took the plunge. I bought a Load master set up for 9mm (please don't beat me up for not buying a different press) and all the other little stuff. Picked up primers, powder, and bullets the last few weeks and have a decent supply of brass from my range trips, which is now all nice and clean.

I've loaded and shot a total of about 250 rounds so far with no surprises or disappointments (knock on wood), and think I found a decent load of MG 115 FMJ with 5.4g (disk 43) of Win AutoComp. The book says 5.1 - 5.6 and I initially loaded some at 5.1. 5.2, 5.3 and 5.4. 5.4 seems to be the easiest midrange number to hit consistently with my setup. They seem to cycle nice in my M&P9c and it's as accurate as I am for punching holes in paper at the range and I don't see any signs of excessive pressure on the spent casings.

So two questions:

1) If I try to use the adjustable charge bar (which I used to load the first 50 or so at different charges for testing) I get powder all over the place with each stroke. If I use the disk it doesn't leak but my only options are the .40 or .43 disks. The .40 throws around 4.9g which is .2g below the starting point. The .43 disk gives me a pretty consistent 5.4, a few 5.3 and once in a while a 5.5. Being new at this I measure everything. So, does this sound like an ok compromise for now (the 5.3 - 5.5 range) and seem like a safe load for shooting paper?

2) This is the one I stress about the most. I've read a lot of threads about the importance and challenges of getting a consistent OAL. For my load the book calls for a minimum OAL of 1.125. For multiple reasons (being new, inconsistent case length, the press I use, probably more) I'm seeing a variance, sometimes 1.110 to 1.140. I measured every single round and reseated and crimped the ones over 1.130 and took apart the ones under 1.120. Am I being too paranoid about this? If the book says 1.125, am I still ok in that 1.110 - 1.140 range or is that too much?

Thanks for any insight on this! I'm new to this, and so far love my new hobby. I just want to stay as safe as possible. Maybe once I get a reliable system down I can crank out a couple of hundred rounds without measuring every single one.

[g.willikers]

.2 of a grain variance is not unusual.
And neither is the .03" in overall length of the loaded rounds, as long as there's sufficient room in the barrel chamber.
By the way, slightly different case length isn't the cause; the die setting and bullet seater are responsible for OAL.
As is consistent pull of the press handle.
Although different case lengths can cause taper crimp hassles.
It doesn't take much imperfection in the nose of the bullet or rim of the case to give different readings for OAL, either.

[drklude]

I've loaded over 1,000 9mm in the past couple of months, and I had the same worries you had about length and powder variations. In my experience, I have to agree that these slight variations are nothing to worry about if it is just range ammo for paper targets or plinking.

Some will say that for extreme accuracy everything needs to be exact, which is true. But as is often the case, the bullet is not the limiting factor in accuracy, most often it's the shooter.

As far as overall safety, those variations are fine. As long as you are within published load limits, and the gun feeds them and they all go bang, you are good to go.

[Brian Pfleuger]

Were it me, I'd set up my die so that the shortest OAL I got was the specified number in the manual.

It's not that you're necessarily going to blow anything up (in this particular instance) but small capacity handgun cases have relatively massive pressure increases with minor OAL decreases.

9mm SAAMI max OAL is 1.169. I would adjust my seating die so the minimum I got was 1.125. All else being equal, your max length would be 1.155.

The variance is probably due to 2 things. One being that the bullets are slightly inconsistent where the seating plug is touching them and two being your technique on the press.

You can verify #1 by removing the seating plug and zeroing your calipers on it. Then use it in the calipers to measure 10 or so bullets. Whatever variance you get there will be impossible for you to eliminate unless you drill out the seating plug so that it touches a more consistent part of the bullet, which certainly can be done. On #2, make sure you're going to full stop on up and down strokes and applying approximately equal force at the top.

[Don P]

I'm seeing a variance, sometimes 1.110 to 1.140.

And neither is the .03" in overall length of the loaded rounds, as long as there's sufficient room in the barrel chamber.

I disagree, thats a 30 thousandths difference between rounds and not .003.

Big difference there.

[jag2]

Just keep doing what you're doing and over time you'll see what matters and what doesn't. When I first started loading 9mm in the late 80s the manual said the standard for 9mm was 1.169 so that's what I did for years. Over time with more experience and more manuals I now use 1.125, but really as long as they cycle thru your gun okay that's what is important. Maybe someone that has some factory ammo can let us know what that measures.

[g.willikers]

The type of bullet also determines how much pressure differences there are with different AOLs.
The 115 fmj doesn't go into the case as much as other longer and heavier bullets, to begin with.
So small variances in AOL won't cause as much pressure changes as say a 147 swc, for example.

DonP, yes .003 and .03 are quite different.
But doesn't 1.140 - 1.110 = .03?
Even with the New Math?

[Grandpa45]

Thanks for all of the replies! I feel a lot better about what I'm doing but will make some changes based on your replies to help quality, consistency and safety.

I noticed when adjusting the bullet seating die it made a difference if all the station were loaded or not. I read somewhere, specifically for my press, maybe others, that you should adjust the dies with the press fully loaded.... so I'll do that from now on.

Brian - I'll take your advice and adjust it so 1.125 is the shortest I get, which is what the book lists as a minimum anyway. Makes perfect sense. I'll also check a few bullets and the seating plug as suggested.

A couple of people mentioned a consistent pull... I'm pretty sure I'm doing a full stroke every time. Although I'm sure there is room for improvement in my overall technique. It seems like sometimes the stroke is harder than others though (maybe thicker cases?) and I wonder if the shell plate or something is flexing somewhere and causing some slight differences in length. But I'll keep an eye on it.

Right now I'm using mixed brass, maybe I'll sort it by brand and see if that helps to keep it consistent too.

Thanks again for the replies!

[serf 'rett]

I've got to agree with Don P. A difference of 0.030", in pistol cartridges, is significant and too large in my opinion.

Maybe my two seater plugs have wonderful profiles which just happen to work well with the six profiles on the plated flat point, plated round nose, fmj hollow point and lead bullets I normally load. Maybe it's a testimony to the accuracy of loading on a single stage press. My overall cartridge length rarely varies over +/- 0.001".

Try the checks Brian suggests.

[Grandpa45]

A difference of 0.030", in pistol cartridges, is significant and too large in my opinion.

Serf, Too large as in unsafe? Or too large as in not real accurate? Or?

Those were the extreme ranges I saw. I ended up taking apart anything shorter than 1.120 and reseated stuff over 1.130, so for the stuff I actually shot, I was +/- .005.

So, what if I had the min at 1.125 like Brian suggested, would a +/- .005 (1.125 - 1.135) be reasonable? What about 1.125 - 1.145? I'm just trying to find a safe tolerance while I continue to get more experience on this press. In the mean time I don't want to spend a lot of time redoing more rounds than I have to, if they are still safe and ok for shooting at paper.

Thanks for the reply

[Brian Pfleuger]

I'd be surprised if you find that your bullets are more consistent than 0.003 or so .

0.030 variance in your finished rounds might possibly be a safety issue if you were shooting max loads. It will vary with the powder somewhat, but QuickLoad suggests that a 32,000psi load of Power Pistol (it doesn't list Win AutoComp) would increase to 36,000psi with a change from 1.169 to 1.139.

However, your targeted length is 1.125 and your shortest rounds are 1.110, so you're only 0.015 under. A max load of Power Pistol, going from 1.125 to 1.110, increases from about 35,000psi to about 36,700psi. Essentially inconsequential and that's a max load. You're 0.20 under max on yours (in theory).

[serf 'rett]

Serf, Too large as in unsafe?

Maybe, maybe not. Where did your load data come from? Winchester’s online data is: 115 GR. SPR GDHP, COL 1.125", AutoComp powder, starting at 5.1 grains, maximum 5.6 grains. Based on the online data, let us look at some possible scenarios:

1. Suppose your bullet is longer than the 115 grain Speer Gold Dot hollow point shown online. If you seat the longer bullet at the online data COL of 1.125” then you have reduced the volume available for the powder. Reducing the volume will often result in higher pressure. This could happen just due to the difference in bullet length. Now if we add in a possible -0.015” for seating error, the pressure could jump even more. I mostly guessing here; wish someone would run this on Quickload to check difference.

2. 9mm headspaces off the case mouth; however, it is possible that a particular bullet profile can come in contact with the lands in the pistol chamber before the case mouth headspaces in the chamber. For example, I load Berry’s 124 grain hollow back round nose thick plate bullets at 1.150” but must load Berry’s 124 grain hollow back flat point bullets at 1.070”. The bullet weight is the same, but the bullet profiles are quite different. My desired set back distance is around 0.010” for these particular bullets; meaning the round will headspace off the case mouth and the bullet will be a distance of approximately 0.010” from the lands. If I add a seating error of +0.015” then the bullet would be forced against the lands, which could lead to excessive pressure.

3. You may have found a good load for your pistol, and with a tad more experience, find the OAL variations reduced.

[serf 'rett]

Or too large as in not real accurate?

Not sure what the net effect would be in this area, but 0.030" change in seating depth would change the volume under the bullet. Change the volume = change the pressure.

[JefferS]

Grandpa45, I'm fairly new to reloading and just started doing some 9mm with Unique. I've been seeing some variations in OAL kind of like you mentioned that I want to go back and look into.

I'm using Lee reloading dies and I found one thread in this forum that suggested making sure the dies were free from debris, which I guess I'll try next.

I'm glad you posted. It was a topic I was going to start trying to get on soon.

[Grandpa45]

Hi JefferS, I'm glad I could ask a question that might help someone else! When I decided to get into reloading as a hobby I had no idea there would be so much to learn. I'm happy there are knowledgeable people willing to share information on forums like this for newbies like me!

I'm not sure about the debris in the dies causing my OAL inconsistency. My press and dies were new and I saw the problem from the start, but I'll take a look at them to be sure. There were a lot of good suggestions in this thread that I intend to look at closely when I have time.

Tonight I looked at .030 (the variance I was seeing) using a micrometer and I don't think it would take much to throw things off that far. In my case, I think it might be a combination of a lot of things causing a combined affect so I'm going to concentrate on fixing a little here and there until the .030 variance becomes .020 and then .010 or better.

[skizzums]

i could be totally wrong, but if your using lead cast bullets, i think the variation could come from a difference in the nose of the bullet.if one has a slight more point to the nose and one has a flatter nose, then the presses shape might not countour to that part of the bullet. if that makes any sense.......i have also always had the same variances.

[Grandpa45]

Where did your load data come from? Winchester’s online data is: 115 GR. SPR GDHP

Serf, I'm using the same data you mentioned, but not before calling the customer service number and asking. I told them I was using MG 115g FMJ and he told me to use the same data. Based on your comments though I did a little math. Maybe you guys can tell me if I'm way off here....

I found a post that mentions the length of the Speer GDHP bullets. The guy measured 5 of them and the average was .5262. For my MG bullets, I get .563 although I only measured one for now just to check my math.

So, the total length of 1.125 in the load data I was using with the Speer bullets leaves .599 of "space" in the shell right? So, if I seat my bullets so there is the same amount of space, wouldn't I want .599 + my bullet length of .563 = 1.162?

Looking at it another way the difference in bullet size .563 - .526 = .037. Does that mean I'm seating the bullet .037 deeper than the load data suggests and increasing pressure too much maybe?

I appreciate everyone's help on this, I'm still learning and trying to understand.

[Don P]

DonP, yes .003 and .03 are quite different.
But doesn't 1.140 - 1.110 = .03?

Sure is and in my old mind, old math or new math .030" is the old spark plug gap from back in the day for a quick reference for size.
Just take your caliper and open it up .030", a large difference in what the OP states for OAL. Way to much in my opinion and dangerous, but if thats good/ok in your book run with it

[Don P]

I found a post that mentions the length of the Speer GDHP bullets. The guy measured 5 of them and the average was .5262. For my MG bullets, I get .563 although I only measured one for now just to check my math.

So, the total length of 1.125 in the load data I was using with the Speer bullets leaves .599 of "space" in the shell right? So, if I seat my bullets so there is the same amount of space, wouldn't I want .599 + my bullet length of .563 = 1.162?

Looking at it another way the difference in bullet size .563 - .526 = .037. Does that mean I'm seating the bullet .037 deeper than the load data suggests and increasing pressure too much maybe?

I appreciate everyone's help on this, I'm still learning and trying to understand.

Thats why as re-loaders we use the OAL. If you seat too deep you may compress the load. Too short of a OAL could very well cause the bullet to key hole ( tumble thru the air hitting the target sideways) because its seated so deep that the bullet is too far from the start of the rifling grooves in the barrel. Round of the length you state could very well possibly not fit in the magazine or possibly not chamber correctly.
Not all bullets are created equal. What I do is keep my OAL as long as possible with regards to the round chambering correctly and the round fitting in the magazine.

Seems like you are starting to overthink things. Ease back and relax and enjoy your reloading.

[Grandpa45]

Seems like you are starting to overthink things. Ease back and relax and enjoy your reloading.

I can't help it, it's a bad habit

Seriously though, I'm confused now. You said .030 variance in OAL is too much which makes perfect sense, because shorter ones are seated deeper which means less area and more pressure. I think I understand that part, at least at a basic level.

But what I don't understand is, even if I was hitting the 1.125 OAL dead on every stroke, wouldn't I be seating my MG FMJ bullets .037 deeper than the Speer GDHP in the load data I'm using, simply because my average bullet size is .037 longer than the Speer. So isn't that as bad or worse than the OAL variance?

[Brian Pfleuger]

Originally Posted by Don P

Too short of a OAL could very well cause the bullet to key hole ( tumble thru the air hitting the target sideways) because its seated so deep that the bullet is too far from the start of the rifling grooves in the barrel.

I can't say as I've ever heard of that before. Tumbling generally comes from insufficient stability, which is a function of bullet length, barrel twist rate and velocity.

Grandpa45, your calculations on seating depth are correct and it is something you should definitely consider if you can find the information for the various bullets. As we've shown, small differences in seating depth can effect pressure dramatically in small handgun cases. You do have a terminology or concept error, in the sense that the length of the case (the 0.599 "left") is not really the "space" left. Some of that is solid brass.

You are correct that a longer bullet will be seated deeper (and therefore raise pressure) than a shorter bullet if they're seated to the same OAL.

[Grandpa45]

You are correct that a longer bullet will be seated deeper (and therefore raise pressure) than a shorter bullet if they're seated to the same OAL.

That's what I was afraid of. So, the ones I've done so far at 1.125 have all been seated about .037 too far since the load data was based on a .037 shorter bullet.

That combined with the fact some of them had an OAL a little shorter than 1.125, and that I'm using a little over the middle of the range for powder (around 5.4, range is 5.1-5.6), tells me I should either reduce the charge to maybe 5.1g and/or change my OAL to something longer that still cycles well, maybe like 1.155 which is what some of my factory ammo is.

Does that sound like a sensible plan moving forward?

Thanks again for your help, I appreciate everyone's patience with all my questions!

[Brian Pfleuger]

I would move the OAL out a bit but I wouldn't bother reducing the charge. After all, you've already shot them at 5.4 didn't report any problems. The main factor in my decision would be that, generally speaking, loading longer will increase accuracy. It's not a guarantee but it is very often true. Also for accuracy purposes, I'd want to identify the cause of the inconsistency.

[Grandpa45]

I would move the OAL out a bit but I wouldn't bother reducing the charge. After all, you've already shot them at 5.4 didn't report any problems. The main factor in my decision would be that, generally speaking, loading longer will increase accuracy. It's not a guarantee but it is very often true. Also for accuracy purposes, I'd want to identify the cause of the inconsistency.

Thanks Brian, I think I'll move it out to 1.155 or so which I already know loads through all my guns since that's what the factory ammo is. That's .030 longer than I was trying for before. That gives me .014 before I max out at 1.169. I'll load a few and test them out.

In the meantime I'll also work on why I can't get a tighter tolerance from the press. Hopefully it will get better with more practice.

[MrApathy]

if you want a consistent Min OAL I recommend a Hornady seating die which has a collet to keep the bullet straight when seating they also have availible extra a micrometer depth adjustment think rcbs has same setup with a high end die.

keep the brass sorted and load one brass manufacture at a time and OAL will stay closer to target though when you run some you may find different lots of brass mixed in and may be a little off here and there but should be more consistent running sorted brass than not.