I've been loading up 9mm recently and the one thing I haven't quite figured out is what the desired OAL should be. The reloading books (I have Lee and Lyman handy) both state a minimum OAL, and the Lee manual states a max for 9mm (1.169, if memory serves), but I didn't find guidance on whether I should be trying to load to the minimum or just keep it between the min and max.

For example (be warned, do not use this data, it is from memory) when loading a Hornady XTP 115gr I believe the OAL was listed in the Lee manual as 1.125" when using Win 231 powder (4.7 to 5.1 gr). I've loaded 4.9gr, as that is what I can do with the Lee Auto Disk reliably (weighed about 20 out of 100 charges, all came in at 4.9gr) and have loaded the rounds to 1.130" (technically ranged between 1.1295 to 1.1305, I measured every 2nd round). Should I be trying to load closer to 1.125, as that might generate slightly higher pressure and increase velocity some, or is having a .005 margin of error between the minimum OAL and your actual OAL (and a .039 margin below max) acceptable?

For what it is worth, the rounds chamber and shoot wonderfully. Far better than almost any factory ammo I have tried.

Use the data published by the bullet manufacture.

Hornady 9th for Hornady bullets, Spear 14th for Spear bullets, etc.

I have the Hornady book on order already. I am still curious as to whether you load to the exact minimum OAL or a value between min and max.

Forget what the Manual lists for OAL.  Find the Longest OAL that Fits-Feeds-Fires in YOUR pistol.  Once you find an OAL that works with your choice of bullet in YOUR pistol, then start low and work up.

 To find this OAL use dummy rounds with no primer/powder.

I try to seat as close to the longest listed OAL. Usually I'm just a bit under max.

Fit and function are my main concerns. Accuracy is 2nd, which I achieve by adjusting the powder charge.

I've done both with seating as long as possible for my barrels and the also working off the listed OAL from either the bullet or powder manufacturer. First work on OAL that will feed and fire in your gun then work on adjustments for accuracy.

You're going to get a couple of different answers . . . er, you already got a few lol . . . so here's another:

Whether the load range comes from the powder or the bullet manufacturer, for pistol I load to that recipe's minimum OAL. That OAL is the one that generated the data (eg. velocity, pressure, and sometimes accuracy) shown in the recipe. I've never had such a cartridge fail to feed smoothly in my firearms.

FYI, for 115gr 9mm Hornady data shows an OAL of 1.100" for FMJRN and 1.075 for XTP. XTP's with 4.6gr of HP38/Win231 and taper "crimped" lightly by a Lee FCD die out of a CZ75B run at 1129 fps.

So what do you do when there is NO data available for a specific bullet?  There are lots of bullets and bullet moulds that have no published data.  What OAL do you use for these?  

Since you mentioned bullet molds I am assuming your now referring to cast. Pick up Lymnan's Cast Bullet book to help with those. Otherwise average out data from several sources for the bullet weight and work up a load.

The OAL published in the loading manual or load data for the bullet you are using is a good starting place.  It will generally work.  If you don't have the OAL for a specific bullet, look for published data on bullets of similar construction.  For the 115gr FMJ about 1.1" OAL is pretty standard.  

As per previous post, bottom line is you have to make sure your reloaded cartridges will chamber reliably.   So load a few and drop them in the barrel and ensure the base of the cartridge seats flush with the top of chamber.  The best way to test them, load a few live rounds and test fire them.  This may not be practical for you.  So then as stated previously, load some dummy rounds and cycle them by hand from the magazine and see if they chamber without hanging up.

Noting that the OP asked quite a different question . . . I'd look for data on comparable bullets, ask questions of others, make dummies and test for physical fit and feed, and work up loads very carefully.

I find a bullet with a similar weight,  and try to find OAL dimensions for anything that might be close.  Hollow points and flat points will vary of course,  but for FMJ's,  you can get pretty close based on bullet geometry.  

If nothing else is remotely close in bullet OAL vs weight,  I'll see what longer and shorter bullets want for a length,  with a lean towards the data for a longer bullet.  

Most of my loads end up pretty near 1.140" with 147gr bullets,  give or take .010".  When my roomie had me run some 115's that I picked up for him,  he wanted a length of 1.075" on them,  which seemed about right for an HP at that weight/length.

Perhaps I should rephrase the question to get to my core concern...

There is some variability in OAL when loading with my Lee Classic Turret press and all Lee dies (including the FCD). While the average variation in my finished rounds overall length is +/- .0005", the largest variance I have observed was .006 (target OAL of 1.130, book states 1.125, actual of 1.124) which caused me some concern as it was .001 less than the Lee book states for minimum OAL. I checked my Lyman book, and it states 1.09 (if memory serves, I'm not in front of it right now) for 4.9gr of Win 231 and a Hornady XTP 115gr, so I figured I was good to go for that round - but it caused me some concern as my understanding is that as OAL decreases, pressure increases, and the stated minimum OAL is listed for pressure control purposes, whereas the max OAL is listed for chambering purposes.

Am I correct in interpreting the responses here as follows:

1. Shorter OAL = more pressure and possibly more velocity (all other things being equal)
2. Too short OAL can cause feeding issues
3. Longer OAL = less pressure and possibly less velocity (all other things being equal)
4. Longer OAL = possibly better accuracy
5. Longer OAL = possible chambering issues
6. Some people load to max OAL, some load to a specific OAL (possibly what Lee refers to as minimum, but other books simply provide as a OAL for a given load).

"When loading any pistol cartridge, the golden rule is: not too long, not too short. Generally speaking, the length of the loaded round should be as long as possible to enhance feeding reliability, but not so long that it jams in the magazine or in the chamber. And the bullet should not be seated so deep that it hampers reliable feeding or pushes pressure too high."

from: http://38super.net/Pages/Bullet%20Design%20and%20Feeding%20Reliability.html

IMO, you're nit-picking on .001" deviation.  This is within acceptable tolerances, and more can likely be seen using a progressive with or without a fully loaded shell plate (meaning round at a time processing w/otherwise empty shell plate, or loading all stations).
Also, realize that with most mfgr load data, there is very likely still some margin of safety.  This one can likely be debated, as powder formulation changes can happen over time, but many earlier books have a wider load range with a higher max for the same powders and projectiles.  This is not in any way condoning loading about max published load data, but an observation that many make.

In your list above, a too long OAL can also result in feeding issues, depending on your mag.
Typical factory FMJ runs around 1.15", and JHP around 1.10".  We can assume for the most part the difference is down to bullet ogive shape, and allowing for the rounds to feed in the widest range of firearms safely, which means at least somewhat on the short side.  

Otherwise, your list is correct, if slightly questionable for pistol rounds (thus the 'possibility' mentioned, right? ;) )  
I and I'm sure many others had some of the same questions, and were concerned about being very careful on each and every step, but since then, I've seen no indication that longer OALs are impacting accuracy in my own shooting, nor have I found anyone stating this as the case for pistol rounds.  You can also go and chrono some of your rounds - use the same (low to lower mid range load that you know will cycle your gun), and load up some FMJ with an OAL of e.g. 1.15", 1.14", 1.13", 1.12" (assuming 1.15" will chamber and feed ok in your gun...most likely but not definite).  Hand weigh and trickle if you'd like, but keep the powder charge constant.  Set up chrono and shoot the 'weakest' load first for safety check, which would be the longer rounds.  Note chrono measurements on 5-10 rounds.  Load second mag with next shorter round available, repeat.  

The point?  You're concerning yourself over .0005"-.001" variances, when .01" OAL variances not at max load with a correct powder will in most cases have relatively small changes in velocity (assuming pressure tracks to some extent to velocity).  Maybe someone will come up with some super unique powder not at max load or above to prove otherwise, that it was in fact that .001" OAL deviation leading to a kaboom, but I'll say my initial thought wouldn't be to believe it.

Note that for checking YOUR specific gun's OAL, someone mentioned it already - use an already fired shell (it's already expanded slightly from firing), push a new projectile of whatever type you're loading into the mouth slightly (may need to try a few fired cases), remove barrel from pistol, then push into chamber until it's seated.  Remove slowly, use calipers to measure, redo a few times to show consistent measuring, and consider this your absolute max OAL for your gun.  Subtract .01"-.02" from this and consider it to be your max COAL to load to.
Great pictures here starting at post #4: CZ Forum OAL pictures

FWIW, I load my 124gr JHP 9mm at 1.085".  I do gage/chamber check a sampling of them, and measure OAL on the same sample.  Most are pretty close to 1.085", but if I see one come up at 1.081" for example, I'd grab a few more, do a slight die adjustment, but shoot it just the same.

Hope some of this helps.  

Just in case nobody told you recently...


I appreciate the time you spend here helping us ALL out with your experience and wisdom...

Thanks a bunch for what you do Dryflash.

I usually end up around 1.125 more or less (shooting mainly JHP or TC cast boolits). I started loading long and reduced the OAL when I experienced failure to feed malfunctions. JHP and TC bullets at 1.125 and fmj at 1.145 (apprx). I have not seen any accuracy changes based on OAL

I measure a factory bullet that cycles well with my pistol and duplicate that taking into consideration what my Lyman or hornady book says.  Basically if it fits my case gauge, cycles well and is somewhere between min and max and matches a factory round pretty closely..    I'm good to go

"While the average variation in my finished rounds overall length is +/- .0005", the largest variance I have observed was .006 (target OAL of 1.130, book states 1.125, actual of 1.124) which caused me some concern"

Unless it wont feed, you have little reason to worry.  The variation not great enough for handgun loading & shooting.


Am I correct in interpreting the responses here as follows:

1. Shorter OAL = more pressure and possibly more velocity (all other things being equal)   - Yes but in the range of 1000s not significant.
2. Too short OAL can cause feeding issues  - Yes
3. Longer OAL = less pressure and possibly less velocity (all other things being equal) - Yes but in the  range of 1000s not significant.
4. Longer OAL = possibly better accuracy  - Maybe (I guess you can ransom rest some loads and find out.)  But for most handgun shooting not really a major consideration.
5. Longer OAL = possible chambering issues  - Yes
6. Some people load to max OAL, some load to a specific OAL (possibly what Lee refers to as minimum, but other books simply provide as a OAL for a given load). - Generally safe to use the OAL that is specified for the bullet in the manual or by the mfg data.    The more data the more references you have for different bullet types.  Experienced shooters load to the length and use he crimp that functions and shoots the best in their gun i.e. chambers reliably, accurate, burns the powder, and not excessive pressure.  The main issue with OAL is loading cartridges that function and shoot reliably.

Yes in your interpretation with the highlighted part the first rule of thumb.