Keyholing 68gr 223 Remington in AR15

[Russ D]

I think John was asking, “Are you sure the manufacturer built a 1:8 twist?” Yep. They did.

Changed via Hornady LNL powder measure with the rifle powder drum. Weighed each charge on Lyman digital scale. A2230 seemed to meter well: it was pretty fine. I doubt I could have a light load because it wouldn’t have cycled the gun. (See my OP re: start load didn’t cycle).

That target had a mix of me and my not-as-skilled son shooting Win. M193. You’re right, there’s no obvious group.

Iron sights. Midwest Industries combat fixed front sight and UTG A2 style fixed rear mounted on the Pic. rail.

If your concern is that the AR is somehow fundamentally flawed, you’re off base. Here’s a picture of my Dec. match target at 100 yds: prone slow, rapid, and off hand. It zippered 8 rounds into a strip about the width of a ruler during slow prone. If I do my part the gun does it’s.

Other than bad projectiles, the only other thing I can think of is bad powder. Has it been stored correctly, or is it old?

 

[MTplinker]

Yea, I didn’t appreciate how much less contrast there was orange vs a simple black bullseye.

The main question I had is, had anyone seen a situation where moving up the ladder caused keyholing.

The 23.7 gr of A2230 is max in the Western Powders Manual 8th Ed, and it’s below max in Hornady’s 10th Ed. It’s not like I was trying to drive the slug really Uber fast.

 

[MTplinker]

Other than bad projectiles, the only other thing I can think of is bad powder. Has it been stored correctly, or is it old?

Yep, it’s ok. I got it in October 2022. Stored in the house- climate controlled to normal house temps. Lot label says “1072822 2017” whatever that means.

 

[TheOriginalMexicanBob]

While I've no experience with Frontier ammunition I've heard a lot of negative experiences people have had with it...primarily with .223. Hornady's quality control on this line must be for shyte.

 

[topguntin]

Who made the barrel?

 

[MTplinker]

Who made the barrel?

I have read that Aero Precision uses Ballistic Advantage barrels. It’s demonstrated good performance as far as I’m concerned. See Dec 2022 match target at 100 yards.

 

[4g64loser]

While I've no experience with Frontier ammunition I've heard a lot of negative experiences people have had with it...primarily with .223. Hornady's quality control on this line must be for shyte.

Their QC is LTWS.

Their so called 68 match ammo is EXTREMELY lot variant. A coworker had some that was acceptable out of his primary carbine. In the 2moa range at 100 (he uses a 1-10 Vudu). He bought more (different lot number when I got into the details) and it shot a 10moa group, twice in a row. And when chronographed the ES was twice that of the previous lot, with a notably higher AVG. I'd have to call him to get exact numbers as I didn't save the string data. For comparison, PMC 55gr ball shoots 3-4moa from the rig. Consistently.

 

[smokey]

Nobody asked yet, soooooo.... what muzzle device? Also, was anyone shooting next to you? With the variation a tumbling bullet induces, it wouldn't be out of the realm of possibility of the person next to you had a f'd rifle/load combo that it could end up on your target. Was the keyholing repeated while you shot? I'd expect more oblong holes elsewhere instead of just one random sideways impact in a group of circles.

 

[MTplinker]

Nobody asked yet, soooooo.... what muzzle device? Also, was anyone shooting next to you? With the variation a tumbling bullet induces, it wouldn't be out of the realm of possibility of the person next to you had a f'd rifle/load combo that it could end up on your target. Was the keyholing repeated while you shot? I'd expect more oblong holes elsewhere instead of just one random sideways impact in a group of circles.

Good question- I figured somebody might ask about muzzle device or crown. It’s a plain Jane Aero Precision upper w A2 flash hider. Did not find anything odd at the muzzle during cleaning.

One keyhole only on paper. Range went cold before I could put more rounds down range, so no telling if the remaining ones in my load work up are good or bad. My first round in the 23.7 gr work up wasn’t on the paper, so who knows if keyholed or not.

I posted above that there was nobody on my left and a kid on my right shooting .22 Win mag from a bolt gun w a scope.

Time will tell when I get to the range again. I still have rounds from the ladder.

 

[MTplinker]

I know all of MDS, has been eagerly awaiting the answer to this mystery.

What caused the keyhole? ricochet. No problems with 68 gr Hornady slugs outta my barrel.

At Hap Baker there’s not a lot of vertical clearance between the 25 yard berm and the center of the targets at 50 yards. This time I saw the puff when the round hit top of the near berm and skipped off to continue downrange to my 50 yard target. During my sighters, I found I had to hold 3 inches over at 50 yards to put the Frontier 68gr factory in the middle of the bull or I’d strike the 25 yd berm.

Dialed up the A2 rear elevation for POA = POI and mounted my targets higher next time!

Now you can all begin mocking my marksmanship since I hit the berm off a sandbagged rest. Sigh.

But I did find some potential loads for service rifle matches.

 

[lazarus]

I know all of MDS, has been eagerly awaiting the answer to this mystery.

What caused the keyhole? ricochet. No problems with 68 gr Hornady slugs outta my barrel.

At Hap Baker there’s not a lot of vertical clearance between the 25 yard berm and the center of the targets at 50 yards. This time I saw the puff when the round hit top of the near berm and skipped off to continue downrange to my 50 yard target. During my sighters, I found I had to hold 3 inches over at 50 yards to put the Frontier 68gr factory in the middle of the bull or I’d strike the 25 yd berm.

Dialed up the A2 rear elevation for POA = POI and mounted my targets higher next time!

Now you can all begin mocking my marksmanship since I hit the berm off a sandbagged rest. Sigh.

But I did find some potential loads for service rifle matches.

At least you didn't hit your truck shooting off the hood...

Too many people have done that.

 

[erwos]

Ricochet kinda makes sense, although I'm surprised it didn't hit you on the way back with that sort of trajectory.

My experience with true keyholing issues is that it's not hard to replicate them consistently. My dad had a PSA upper that would keyhole like crazy with a certain lot of 55gr Wolf ammo, but seemed alright out of my AR. I built a new upper for him with "quality" parts (or at least tolerably good ones), and it resolved all of that immediately. I'm sure the ammo is still garbage, but sometimes better barrels can make the best out of a bad situation.

 

[MTplinker]

Maybe it just runs in the family. My uncle shot the far side of his truck bed while using the truck as a rest.

I did notice some helpful folks had whittled down channels about as wide as your fist into the top of the 25 yard berm. The berms look like dried muddy dirt piles, so doubt that any rounds are going to come back at me.

 

[MTplinker]

The upside to impromptu body work on your truck is that the second round should go clean through, unimpeded. The downside is the game might not stick around to get shot.