I finally had an opportunity to get the newest build out to the range to break-in the new barrel and shoot some groups with hand loads. This is a bit of a combination post as I’ll be discussing both the gun and the loads. In the last post, I wrote about Justine, my new 5.56 AR platform rife. With the new barrel installed and everything bolted back up, it was time to hit the range.
Still being somewhat new to barrel break-in procedures, I followed the advice on Faxon Firearms’ website. The procedure was thankfully simple.
1. Shoot one round. Clean bore. Repeat two more times.
2. Shoot 5 rounds. Clean bore.
3. Shoot 10 rounds. Clean bore.
Barrel is broken in.
So that’s what I did. I kept the rate of fire down so the barrel wouldn’t heat up during break in, and used M-Pro 7 cleaning products to clean and remove copper fouling. It was fascinating to see the groups tighten up.
The first shot sailed right over the sighter steel. The second one also missed completely. Figuring my scope was way off since I had completely re-fitted it since my last sight in, I bore-sighted the gun after the second shot/clean process. Sure enough, it was many clicks off. The target you see here is the next 16 shots that followed.
Shot #1 was surprisingly close to zero, only 3” left and 1 3/4” down. Bore-sighting works, kids. Group 2 was the five-shot group after the step one. That group measures 1.911”. That wouldn’t be terrible, but I’m fascinated to see groups tighten as a barrel breaks in. After a cleaning, I shot Group 3. That one measures .785”. A bit of an improvement. Group 4 would have been better had I not pulled one shot. If I remove my mistake, the group is .651” I will take that any day. And, based on the fact that there are two holes with two bullets each in them, I’m pretty sure the gun shoots better than I do at the moment.
By the way, this was all shot with Freedom Munitions .223 Rem loaded with 69 grain Sierra Match King bullets. I have got to get me some of those! Everything you read anywhere suggests (or flat out tells you) that SMKs shoot extremely well. They are simply expensive. Freedom gets $0.56 a round for them. Even hand loading will come in close to $0.35/round. But those groups…
Being the frugal guy I am, I decided to see if I could get SMK-like (or SMK-lite) performance with a much less expensive projectile. So I tried out Hornady’s Match 68 grain Boat Tail Hollow Point (BTHP). I’ve seen it tested on Johnny’s Reloading Bench, and read quite a few reviews. The consensus is that it shoots well in some guns over some powder, but not in others. I went with Hodgen Varget as that seems to be everyone’s go-to accuracy powder. I followed published load recipes from the Hornady manual. With one exception.
One of the big downsides of shooting an AR-platform rifle is you are limited (to some extent) on the length of cartridge you can load. The magazine is only so big, and you can only load your bullets out so far. In fact, 2.250” is pretty much maximum overall cartridge length. However, in Justine (and most other ARs) that means there is a pretty long jump between the bullet sitting in the chamber, and the time it engages the rifling on the barrel. We’re going down the rabbit hole a little bit, so if this is of no interest to you, check out now.
One way to measure cartridges is to measure overall length; cartridge base to tip of bullet. However, due to manufacturing anomalies, the tip length (and thus bullet length, and thus overall length) can vary somewhat. And, the tip of the bullet never engages the rifling anyway, so we don’t care so much about that. Until we try to put the round in to a magazine, anyway.
Another way to measure is from cartridge base to ogive. That’s the point where the bullet profile changes. If I check my chamber with a Hornady OAL gauge, I find my CBO (cartridge base to ogive) length is 1.978” with the 68 grain BTHP. However, the normal max length of a .223 service rifle round is 1.859” with that bullet (that gets me to 2.250 OAL). That gives me a 0.119” jump. Many people suggest best accuracy is achieved with a jump somewhere around 0.020” give or take a hundredth. I’m a lot over that.
Being the sort who likes to experiment, I decided to load some rounds out a little longer, knowing that I’d have to feed them in one at a time. These “long” rounds came in at 2.306” OAL, and 1.909” CBO. That still gives me a 0.069 jump, but it’s about half what the magazine length loads are. So what were the results? I loaded up the same ladder of charges with both lengths; from 23-25 grains in .5 grain increments. Velocities didn’t vary much; though oddly, on the lower end of the charge scale, the longer cartridges were a bit slower. On the higher end, they were a bit faster. But the swing is ±35 fps, so nothing to get excited about.
However, accuracy. This is where it gets interesting. Here is the best target from the standard, magazine length loading. The best 3 rounds came in at just over an inch, with a 2.735” overall.
But here is the “long” version of that load. The best 3 came in significantly less at .390” and the overall took a full inch off the group. So maybe there is something here. But not so fast.
A couple of other factors may be in play. First, I’ve already shown that the groups were tightening up as the barrel was breaking in. I didn’t think about this until I got home, but I shot all the regular loads, then all the long loads. So it’s possible that 25 more rounds of break in happened and the long loads were more accurate due to the barrel being happier.
Second, I’m still fairly new to precision rifle shooting. And because I’m an idiot and forgot my targets at home, I had to buy these round targets. I’m used to shooting at grids, which I find a lot easier to line up on than circles. It’s very possible that it took me 4-5 targets to get my technique down.
So while I think loading long is something I’m going to continue to explore, I’m not giving up on magazine length. I think what I’ll do is order up some more supplies and load up another set. This time, I’m going to do finer steps of powder, working around the most accurate charge weights for each length. Then, I’ll alternate magazine length and long for each load to make it more fair. And I’ll bring the right targets. There are so many variables, it’s hard to decide which ones to change (and figure out which ones I can control). But that’s what makes it fun.
After all the science-y stuff, I decided to load up a magazine and just have fun. There were a bunch of guys shooting at 300 and 500 yard steel, so I stuck to 200 yards. Back to the Freedom SMKs, I dialed up .4 mils of elevation and about .6 mils of wind and put 10 shots into a single splatter mark on a piece of steel. Yeah, she can shoot!
Stay tuned. There will be more to come!