My editors keep telling that articles have to have a point. Apparently I don’t listen too well as this article doesn’t have one. Well, if it does, I don’t yet know what it is, so we’ll all find out together by the end.
The other day, I was at my desk clawing my way out of endless distractions from my writing. Between fits of topic inspiration, I was sorting obscene amounts of .223 Remington and 5.56mm brass by head stamp. When I say obscene, I’m talking multiple five-gallon buckets. I wasn’t sorting everything, I was just throwing Lake City brass into one bucket and all other types into another. My logic was simple. I knew I had a ton of Lake City in my stash from a couple years of range pickups, so I figured it made sense to have a supply of “same head stamp” brass available when I wanted to make accurate and consistent loads. From my experience, the Lake City stuff is good, meaning pretty consistent and strong. I planned on using the mixed head stamp brass to load practice and plinking ammo.
As I tossed my 40 millionth case into one of the buckets, I started to wonder if this was sorting thing was really worth it. When fired from an AR-15, which isn’t the most accurate rifle anyway, at least compared to bolt gun standards, would it really matter? Was I completely wasting my time? I decided to find out.
Just to be clear, I know that using identical cartridge cases is a big deal for bench rest shooters and anyone else concerned with improving groups by tenths or even hundredths of inches. You’ll get no argument from me that meticulous sorting by size, weight, concentricity and global community membership is essential for maximum obtainable accuracy. My informal experiment simply intended to figure out whether brass sorting was worth the trouble for training, plinking, hunting and other less accuracy-critical uses. Before anyone gets all worked up about the hunting use for less accurate ammo, I’m just saying that it doesn’t really matter if this stuff shoots groups that are a half-inch larger. In most scenarios, it just doesn’t really matter if a given ammo groups into one or two inches at 100 yards – that’s good enough to hit the important parts.
My plan was to load two batches of ammo with one batch made from new vintage, once-fired Lake City brass. The other batch would use identical primers, powder, and bullets and random brands of once-fired .223 Remington brass. And when I say random, I picked it up from my range without regard to what type it was. Of course, I inspected everything to make sure all the brass involved was in good shape and safe to reload.
While I didn’t use premium components, I did pay careful attention to my process for both batches. I tumbled all of it, trimmed every case to spec, and ran them all through a Dillon primer pocket swaging tool. I used CCI 400 Small Rifle Primers for everything and weighed each individual charge using an RCBS Chargemaster powder dispenser and scale. If you’re curious, I used a charge of 24.7 grains of Ramshot TAC powder, which is kind of in the middle of Ramshot’s published load data for .223 Remington with a 55-grain full metal jacket projectile. For bullets, I stuck with the Average Joe plan and used bulk blemished bullets from Midway USA. To be clear, these bullets are fine from a consistency standpoint. I weighed and measured random ones and they checked out. They were just sold at a discount for cosmetic reasons.
After packing up the two fraternal twin batches, I set off for the range along with an FN-15 DMR Designated Marksman Rifle. This 18-inch barrel gun has proven itself accurate in various testing, so I decided to use it for this little experiment. To get a great sight picture at 100 yards, I mounted a Hawke Optics Tactical IR 10x fixed-power scope. It’s a monster that can double as an impact weapon in a pinch and I’ve always gotten good results from it. As I fired everything from the same rifle, I made sure to alternate groups so both loads would be fired through the rifle in the same “all heated up” condition. Five shots with Lake City brass reloads followed by five shots of mixed brass reloads. Repeat until finished.
So what happened?
Mixed Brass Results
Doing a quick scan of the 50 round batch, I counted about a dozen different headstamps including brass like Winchester, Federal, Remington-Peters, Prvi Partizan, GECO, DAO, PMC, and even Poongsan Metal Manufacturing Company (Korea). Heck, there were even a couple of older vintage Lake City cases in there because, why not? I don’t think I could have ended up with a more random assortment of range pickups had I hand picked them.
Anyway, I fired five different 5-shot groups and measured each, center to center.
Group 1: 1.29”
Group 2: 1.80”
Group 3: 1.29”
Group 4: .89”
Group 5: 1.21”
Average 5-shot group size: 1.296 inches
Lake City Brass Results
Remember, everything else in this batch was identical, except I painstakingly sorted spent cartridge cases to pick new vintage Lake City once-fired cartridge cases only. Again, I fired five different 5-shot groups and measured the diameter, center to center.
Group 1: 2.34”
Group 2: 1.81”
Group 3: 2.13”
Group 4: 1.34”
Group 5: 2.15”
Average 5-shot group size: 1.954 inches
I have no earthly idea why the mixed brass reloads grouped better than the Lake City brass reloads. I doubt that the mixed ones are, in fact, more accurate. I’m guessing that due to the small sample size, there just wasn’t enough data to show minute differences. The takeaway seems to be that choice of brass doesn’t matter a whole lot in this specific usage case.
Clearly five 5-shot groups of each type isn’t enough to make a life-changing statistical conclusion. Like I said, I was curious, and I figured if there were a huge impact associated with using mixed brass, I would see some difference in the group sizes.
I used “regular” 55-grain full metal jacket bullets on purpose, as my experiment was to find out whether I should go to all the trouble to sort brass for “normal” uses like plinking, training, and competition. Based on this quick and dirty test, yours truly isn’t going to be sorting brass anymore for my everyday reloads!
While I was surprised that the mixed brass grouped better, I was not really surprised that the two loads performed similarly. Consider that the AR-15 is a semi-automatic system and not designed for ridiculous accuracy as you might find in a bolt-action bench rest rifle. The platform probably isn’t “precise enough” to show a difference in performance from relatively small variances in cartridge cases. Heck, the outside dimensions are identical, especially since all the cases were resized. The only possible differences were brass thickness and, therefore, internal volume and maybe a difference in neck tension related to the specific brass used to manufacture each brand.
Just to be clear, I deliberately used a mid-range load recipe and not a maximum pressure load. I did this because brass is different. Some brass is thicker so internal volume can vary a little. I wasn’t keen on pushing the limits of pressure AND introducing cartridges with slightly different internal capacities. I would recommend that if you decide to pursue a “what the heck” mixed brass approach that you stay below maximum published loads as well.
I’ll go out on a limb and guess that if I were to take this to the next level and use all premium components except the brass, I might start to see some difference in group sizes. For example, I would probably use IMR 8208 XBR powder paired with Sierra 77-grain Tipped MatchKing bullets and bench rest primers. That might be interesting, especially with more rounds fired of each type. If you’re interested in such a study, say so in the comments and maybe I can convince the Editorships in charge here to let me go play in the reloading cave again. Because science.