Home Forums Hunting & Shooting Ask The Gunwriters High volume powder measuring?

For you writers, who have certainly toured more ammo factories than us mere mortals, how do the factories measure powder in volume production? Is it some modification of a drum or bar measure or ???

I'm sure they have QC, but how do they keep the level of precision?

Thanks for your insight!

The factories I've visited over the years have used some variation on a drum measure, if I recall correctly. (Some of the visits were more than 20 years ago!) In genera, they also don't use the large-granule extruded powders so many handloaders--older ones in particular--are so attached too.

Another thing the factories do that many handloaders don't is run extensive tests on velocity consistency. They also understand that the standard deviation from a 3-5 chronograph string is statistically useless--as are one or two 3-shot groups. Instead they'll often run SD's and group-tests on several dozen shots with a certain load before settling on the final powder charge for THAT lot of powder.

I bet if you pull a variety of factory loads down you will find some fine grained powder. Certainly not any 4831!

How accurate does the powder charge need to be in factory ammo? When I handload rifle ammo, I used to weigh each charge to 0.1 grain. NOw I weigh about every third charge. But I don't load that much ammo at a time.

Years ago Lake City Arsenal loaded 30-06 match ammo for the National Matches at Camp Perry with the 172 grain FMJBT bullet and IMR 4895. The powder weight varied with lot to give the nominal velocity, 2640 fps. This ammo was considered by us to be the most accurate we could get. The acceptance criterion was a 1.0 MOA group for 100 shot groups at 600 yards (indoor range!). That's a lot harder to get than 3, 5 or 10-shot groups.

I suspect the charge weight was only within 0.3 grains or so. Why? The powder only filled about 70% of the case. The elevation of the shot on the target at 600 yards varied more than 1.0 MOA depending on if the powder was in the back of the case or the front. That was more important then the exact weight, so we always loaded the chamber in the same way.

So another question is: How accurate does charge weight need to be for handloads?

I've mentioned before that to me it would depend on the purpose of the handloads and the "resolving power" of the rifle/scope/shooter combination.

I've shot many rounds of Lake City match ammo, not 30-06 but 7.62x51. This was both M118 match (not M118 special ball or the newer M118LR) and M852 match. Several lot numbers and vintages of each. I disassembled some to check out powder type and charge weights. The charges were not nearly as consistent as what a lot of handloaders assume is necessary to get the best accuracy from their deer hunting rifle. I found that the best shooting batches had the least runout. The M852 generally shot better than the M118, the M852 being loaded with Sierra Match Kings rather than 173 grain boat tail fmj bullets.

I've loaded thousands of rounds of 308 with thrown charges of IMR 4895, 4064 and 3031 and never had any trouble getting well below moa for five, ten and even twenty shot groups with rifles capable of the same.

Never in a 1000 years would I have thought of this... but when you think about it, it does make sense.

The things you learn on the 'fire' is amazing.

If you can find a copy of PRINCIPLES AND PRACTICE OF LOADING AMMUNITION copyright circa 1954, it goes into great detail on how cases are charged with powder. It also told why we went from drilling flash holes to the punched method use today. It was because it was for faster production during WW2. It's been long out of print and much is rather dull in places but educational. It even goes into measuring case expansion to determine max loads, but in a different way. My copy is rather beat up and still cost $100 on the used book market over 20 years ago.
Paul B.

If it works out for accuracy I try to load with a powder that fills the case and leaves no room for shifting. I don't know if it makes as much difference as I think it does. Now most of my loads are around 58.5 grains for a 180 grain .30-06 load. Kind of slow,but works for my purposes. The .223/5.56 load is 26.2 Varget with a 62 grain bullet, also no wiggle room.

I have a 38-55 that I shoot in the Scheutzen matches around here. In the matches that smokeless powder is allowed, my load is a 320 gr tapered bullet breech seated ahead of 16.5 gr of IMR 4227. The load shoots just a little bit over 1 MOA, but I did notice that it is very position sensitive. If I don’t make a honest effort to keep the powder towards the bottom of the case groups open up to 3-4 MOA. I eventually started using a little bit of cotton batting on top of the powder to keep the charge in place.