9mm Production load tolerances

Most powder measures at their BEST will only do +/- 0.10 grains. With some spherical powders it might be a little better and with some flake powders it can easily be +/- 0.20 grains. That's fine. It won't blow up a gun or produce stuck bullets. Load 'em up, blast away, and don't worry about it.

A .1grn difference in a charge of 5.6grn is only 2% variance, .01grn is .2% I probably can't shoot that difference.

In my loads, I hope for a .1grn variance either way... 6.4 to 6.6grn Unique, for example, in my target weight of 6.5grn... that with a 'poorly metering' flake powder. As long as you aren't right up against maximum with a powder that is known to be peaky (think TiteGroup...) you should be OK.

My LADPM throws +/- 0.2gr with flake and +/- 0.1gr with ball powders. I don't shoot competitively and mostly shoot offhand; I don't notice the difference with that variance.

71GTO said:

. I am using the Lee Auto Drum on a Lee CTP and shooting for 5.6gr. I weigh every 10'th round.

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On hand gun ammo I do a 10 dump average. I weight each charge (10) then average the 10. I adj the powder dispenser to give me my target load for the 10 drop average. This will set you in the mean of the average.

Here is my observation and thought.

When I first started loading this time I started with the 9mm, 115 and 124gr plated bullets with HP-38 powder and I was using a Lee Auto Disk measure. With the HP-83 powder it could reliably hold +.0 to -.1 on any given cavity. Only that wasn't the weight I wanted as a target so I had to trickle. I did this from the starting charge up to within .2gr of max and in all honesty I could not tell a difference between the start load and one .3gr heavier. Late I observed the same results after I got an Auto Drum. So if you are loading from the middle a variance of +/- .1gr isn't going to even be noticeable.

I get +/- .1Gr with my Lee Auto Disk and Hodgdon Universal. I don't worry about that since I am not loading to max anyway. My load for 9mm is Berry's salted 115Gr bullets over 4.2Gr of Universal. Hodgdon calls for 4.0Gr start and 4.5Gr max for 115Gr FMJ and the .46cc on the Lee Auto Disk throws 4.2Gr. A lot of times I get + 0/-.1 but the most I've seen is +/- .1Gr.

One thing that I have noticed with the Lee Auto Disk and the Lee Turret Press is that the more consistent I am with how I pull the lever the more consistent the powder charge is. IF I get into too big of a hurry I can get light powder drops.

71GTO said:

After working up and finding an accurate and safe load for a 9mm pistol, what do you consider an acceptable tolerance for your production loads?

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It depends on what I find during load testing and what the load is used for. When I’m trying to insure the load meets a specific minimum PF, I’ll shoot for a PF slightly higher that takes into account the accumulated SD data. Different powders may have a bit higher SD with mixed brass HS so they have a bit different tolerance. I load with a LNL progressive and try to keep individual powders throws within +/- .1 gr.
COL is checked as well, since that affects velocity and/or accuracy and groups. If I see +/- .004” I’ll start looking for why such a larger deviation exists.
I also check neck tension and either use the scientific method of putting in the firearm and letting it chamber, or unscientific method of slamming it on a piece of wood on the reloading table. Either way if it’s greater than .002” I start looking for answers.
You didn’t ask but these checks are done more frequently during the startup of a production run, and depending on how consistent the numbers are, may be less frequent as the session wears on. I agree with other comments that consistency on my part plays a big role in this. Good luck!

For example only: The best load found for a given 9mm pistol is 5.6gr. of BE-86. I am using the Lee Auto Drum on a Lee CTP and shooting for 5.6gr. I weigh every 10'th round.

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• You make it sound like you're weighing the whole, completed cartridge. Due to variations in the brass and bullets, that doesn't work.

• As to powder measure adjustment.... Always put the first 10 "drops" back into the hopper. This allows the powder time to settle to a consistent density. Then, set the powder measure by averaging 10 "drops". If you want to meter out 5.6gr per, then the weight of the next 10 drops should be very, very close to 56.0gr. Some drops might be 5.55gr and some 5.65, but the average drop will be the closest to 5.6gr you can get.

In this way you don't need to stop in the middle of production, because IMHO, stopping in the middle of a run simply invites a host of other errors to enter.
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What I consider acceptable varies with the powder and amount of charge. I've been loading 9 mm with Titegroup and since it's a low charge weight powder tolerances have to be tighter. I don't load max so I have a +/- of 0.1 grain with that powder. I've found that 4.2 gr gives me an average of 1117 fps with my 115 FMJ's which is right where I want to be so I will accept loads between 4.1 and 4.3 as close enough. Listed max is 4.8, so plenty of safety margin.

I load my .45 ACP rounds with CFE and am satisfied with 6.0 grains with 230 RNP's which chrono slow at 725 fps average but always cycle properly. Since that's the suggested starting load I don't want to go lower but have lots of room up top, so I feel anything from 6.0 to 6.3 is good. Nothing below 6.0 is acceptable so I dial for a 6.1 target charge.

Since the rifle rounds are much heavier charges percentage wise there is more tolerance. I use H335 with my 55 grain .223 rounds and haven't seen much difference in velocity going between the starting load of 23.0 up to 23.8, so realistically anywhere in that range would work. I setup for the upper end of that range since it's still well below the max.

I always weigh and dump till I get 10 in a row that are in the range I consider good, then weigh every 10th round after that. I do all my reloading on a single stage so I have eyes on every round and would see if there was a significant problem with the charge drop.

When I'm working up a load I weigh every charge and when I find "the load" I'll relax my standards. Even though I know that I can't see a .2 or even .3 grain difference for my semi-auto handgun ammo, my head tells me +/- .1 grain is good enough. One way to "help" is to develop a measuring routine that is as close as possible to exactly the same every time (same motion on the powder measure handle or if on a press the same motion and speed on the press handle, same amount of powder in hopper, etc.). I have a Lee PPM that will hold .1 grain variation of W231 when I do my part and my CH is just a hair larger in it's variations...

71GTO, I am loading on a progressive press and use both a Lee Auto Disk and an Auto Drum measure. With the powders I am using I find both of these measures very consistent and because they are volume measures I find they are either right on or just under weight. Rarely do I find one that is over unless something had happened and then I can usually hear or feel a clunk. In which case I always stop and weigh check.

Even as reliable and consistent I find these measure to be I still weigh check probably way more often than is needed. Just a force of habit from when I was weigh checking every charge because I was using dippers.

At one time I even measured the lengths on a number of different factory loading's and found that I was being as consistent with mine than they were and at times even more so. I do not sweat a variation of .005 as the way the seating stem fits to the bullet is not always perfect. But then neither are the shapes of the bullets always absolutely perfectly the same. I once had a box of 9mm plated Xtreme and I couldn't get them consistent at all. Changed to a different bullet and everything was much better.

Lastly, out of complete boredom one cold snowy night I weigh checked a couple different boxes of 9mm and 380 plated bullets and even with those the weight spread was about .9gr between high and low on the 100gr and 115gr bullets that I was testing.

So over-all I feel if I can stay within +/- .1gr of powder and .005 length with the average pistol loading then I'm doing my part to do the best I can.

71GTO said:

The best load found for a given 9mm pistol is 5.6gr. of BE-86. I am using the Lee Auto Drum on a Lee CTP and shooting for 5.6gr.
Thank you all

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I load 9MM using BE-86 and RMR 124 Gr. Multi Purpose JHP's I load 5.4 grains and found that to be best for me.
I went from Lee to Hornady after my Auto Drum broke and I have had one heck of a time making the adjustment to the progressive. After about a year of tinkering with the LnL I finally got it dialed in to where I am only getting .10 max variation. Most weigh in at +/- .05 if not 5.40
I have done dozens of work up ladders and I cannot feel or notice any difference in slight variations of up to .20 at that load.
.10 is in my opinion only an acceptable variation.

Depends on the load.
Most of my measures will hold + or - .1gr with most powders so I am happy with that in 9mm.

Best I could get with Unique was + or - .2 so I just loaded for it.
But I sure wouldn't want to load MAX loads in a 9mm with a .2gr swing....

Dudedog said:

But I sure wouldn't want to load MAX loads in a 9mm with a .2gr swing....

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Some cartridges are more tolerant of loading variations... I've not found 9mm to be one of those. The right powder is key... loading a powder that you don't have to run right at the max certainly helps, as does a better metering powder. Unique and .45ACP go together like macaroni and cheese, but there is a lot of forgiveness there, not so much in 9mm, for example.

I used several different powders mosty for IPSC. As to your question about powder charge tolerances .... it doesnt matter. If my charge is 4.3 grains and during the loading process it climbs up to 4.4 grains ... i dont do any adjustments and just keep loading. If it drops down to 4.2 grains it is still above the factor of 125 so dont care. Load 1500 rounds on a xl650 and you check powder only every time you refill primers.

If loading for bulls eye competition i may load 400 rounds without stopping. But i will store them per 50 rounds in a box making sure these 50 rounds were produced in a row. Therefor they are very likely to have consistent powder charges, crimp, seating depth ... you name it.