Keyholing 68gr 223 Remington in AR15

[MTplinker]

I loaded some .223 Remington using Hornady 10th Ed data for service rifle with Hornady 68gr BTHP on top Accurate 2230. Lake City 1 time fired brass w CCI 400 primers. COAL 2.250 inches. Shot from a 18 inch barrel with 1:8 twist Aero Precision upper chambered in .223 Wylde.

In January I worked up start load (21.8 gr of A2230) and then 23.0 gr at 50 yds. Start load didn’t cycle. 23.0 gr was cycling and grouped up about 3 inches low at 50 yds. I didn’t get to try my next ladder load. It is 23.7 gr, which is below Hornady’s 24.2 gr max.

I got to Hap Baker yesterday. It was windy yesterday (maybe 15 mph or more). Warmed up with Winchester 55gr M193; they were fine through the gun.

I tried the 23.7 gr load and my first round wasn’t on paper at 50 yards. Lost. Load cycles fine. No pressure signs. CCI 400s are a little flat but with a rounded “bagel” shoulder on the primer. I managed a couple hits with the load at 50 yds and discovered this 0.71 inch long keyhole at the 9 o’clock.

Don’t know what to think of this. I figured faster velocity would only improve the bullet’s stability. Why’d it yaw so bad? The lower charge load (23.0 gr) didn’t keyhole in Jan, but wind was calm.

The .223 Wylde barrel with 1:8 twist should love 68gr projectiles. I shoot factory Frontier 68gr BTHP match through this barrel, and they group ok at 100 yds in service rifle matches.

 

[John from MD]

Since the M193 shot well for you, I would 1) check the rifling twist on your barrel and 2) mic and weigh some bullets to see if they are what they are supposed to be.

 

[atblis]

That's pretty odd. Yeah, I'd be curious about the diameter of the bullets. Like John suggested, if you can get your hands on a micrometer, that's the right tool. A set of calipers is likely not precise enough unless they're grossly undersized.

 

[4g64loser]

Hornady quality control is a wet shart.

I exploded 81 of 100 75gr hpbt match bullets in a 9 twist 22-250ai in front of witnesses. When I called hornady "tech" they said "wrong twist, you have a 22-250, it's a 14". Wrong dipshit, I told you up front it was a 9 (what their box recommended). "Your barrel is shot out." Wrong dipshit, it has under 500rnds on it including the 100 of yours. And the rifle shoots under half inch with 55, 60, 62, 69, and 70 gr bullets (but those are all Noslers).

I sectioned a few of the hornady 75s from another box (same lot number). Looked funky. Melted the lead out and used a thimble mic to check some jackets. Significant variance in wall thickness of a single jacket.

This was only one of several times hornady "tech" has blown smoke. More recently, I have had TWO students in less than six months bring factory eldm ammo to class and, using my Labradar, it chronod over 100fps ES for five shots. One of those students is an LE sniper and the ammo came.from their LE distributor. Absolute garbage. The one.guy called me after talking to hornady and they were full of excuses again. Funny thing was we shot my handloads (with his consent) and the rifle shot under half moa with extreme spread under 20.

In short, you need to get better bullets. If you want to try some Noslers and you don't mind driving up towards fredneck/mt airy, pm me and I'll give you an handful to test.

 

[MTplinker]

Thanks, guys. I can mic them at work, but I only have calipers at home. I’ll weigh a bunch.

I’ll double check AP’s barrel, but I doubt the twist rate is wrong since I’ve shot factory 68gr loads through it with ok results.

Funny thing is I always find Hornady XTP really accurate in .357 Magnum loads. I guess it’s apples and oranges.

I load 168 gr pulled Nosler HPBT from American Reloading for my K31 and they shoot great. That might be more a testimony to the Swiss rifle’s quality, though.

 

[Russ D]

The 68 Frontier are the same bullet correct? Sounds like maybe you got a bad batch.

 

[MTplinker]

Yeah, I read somewhere Hornady makes Frontier, so I think my hand load is using the same bullets as the factory ammo. Factory shoots pretty good, which is why I thought I’d start by trying these slugs.

 

[Russ D]

Yeah, I read somewhere Hornady makes Frontier, so I think my hand load is using the same bullets as the factory ammo. Factory shoots pretty good, which is why I thought I’d start by trying these slugs.

For what it’s worth, I shoot hundreds of these bullets and I’ve never had anything close to what you are experiencing. Do you have another rifle you can test them in to help eliminate one of the variables at play? FWIW I loaded and shot 50 rounds of it last week with 5 different powders and 15 different charge ranges. Every round landed within 2 inches of one common POi and I had groups from 1.5” to .65. All holes were very what I expected. RL15 produced the smallest groups but H335 the best SD’s. I only used same lot once fired, annealed LC brass and seated to 2.260. I was using a 1/9 Rem PSS in a KRG Bravo.

 

[brianns]

Be careful with faster velocity, the stabilization comes mostly from the twist rate. You have an 18 inch barrel so you won’t get the velocity that you would out of a 20 inch or more barrel. You don’t want to push the projectiles to over stabilize or come apart in flight.

Was this just one keyhole or suspecting more since you couldn’t find some hits??

 

[MTplinker]

I pulled a cleaning patch through the barrel and measured the distance for 1 complete rotation. I repeated about five times. It’s a 1:8 twist.

 

[MTplinker]

Be careful with faster velocity, the stabilization comes mostly from the twist rate. You have an 18 inch barrel so you won’t get the velocity that you would out of a 20 inch or more barrel. You don’t want to push the projectiles to over stabilize or come apart in flight.

Was this just one keyhole or suspecting more since you couldn’t find some hits??

The photo I posted is the target on my lane. It’s a mix of Win M193 and handload. You can see 1 keyhole at 9 o’clock. It’s not a double. I didn’t see any other keyholes, and I’ve never had a load do this.

Even if my lost round was just me shooting crappy off a sandbagged rest, it doesn’t explain the keyhole.

Nobody was shooting the lane to my left, and the kid on my right was shooting .22 Win mag at 25 yds. I can’t discount that someone shot accidentally across lanes, but it’s unlikely that they keyholed my target.

 

[MTplinker]

I didn’t have time to set up the chronograph yesterday before we had to head home, so I cannot offer any velocities out of my 18 inch barrel for my load ladder.

I’ve got extra rounds of my load ladder work up. I’ll have to go up to Hap Baker again and get some velocity data. If I don’t see any keyhole maybe that’ll help determine if it was a fluke or real.

 

[Russ D]

I didn’t have time to set up the chronograph yesterday before we had to head home, so I cannot offer any velocities out of my 18 inch barrel for my load ladder.

I’ve got extra rounds of my load ladder work up. I’ll have to go up to Hap Baker again and get some velocity data. If I don’t see any keyhole maybe that’ll help determine if it was a fluke or real.

I don’t see any way that the twist in the barrel has anything to do with this issue. The 1/8 twist should shoot anything from 50 to 77 grains with no issue. How are you charging your load? Is there any chance you had a light powder charge? From the picture your groups don’t seem to be indicating consistent loads. You mentioned that you warmed up the rifle at 50 yards, how big were those groups at 55 yards? 50 yards groups out of an AR should be pretty small if the rifle is performing correctly. Are you using irons?

 

[brianns]

The photo I posted is the target on my lane. It’s a mix of Win M193 and handload. You can see 1 keyhole at 9 o’clock. It’s not a double. I didn’t see any other keyholes, and I’ve never had a load do this.

Even if my lost round was just me shooting crappy off a sandbagged rest, it doesn’t explain the keyhole.

Nobody was shooting the lane to my left, and the kid on my right was shooting .22 Win mag at 25 yds. I can’t discount that someone shot accidentally across lanes, but it’s unlikely that they keyholed my target.

Seeing how you shot factory 68s ok then might be the bad batch of projectiles or load like was suggested. I was hoping for a fluke but then you’d have a consistent group with the fluke somewhere.

 

[MTplinker]

Since the M193 shot well for you, I would 1) check the rifling twist on your barrel and 2) mic and weigh some bullets to see if they are what they are supposed to be.

John, I weighed the remaining bullets (all 67 slugs): average weight 68.1 gr with a standard deviation of 0.13 gr. Nothing weird. Mic will have to wait until another day.

 

[John from MD]

John, I weighed the remaining bullets (all 67 slugs): average weight 68.1 gr with a standard deviation of 0.13 gr. Nothing weird. Mic will have to wait until another day.

Well, that is one thing you can rule out for sure. With the weight being that close, I can't see the diameter being off enough to cause keyholing.

Aside from keyholing, your group does not look good to me at all. Are you by any chance shooting that target with iron sights? Also, has this barrel been broken in?

I have the same set up as you and it will keep everything at the most 1.5 inches at 100yards. I shoot from 55 to 68 grains and use powders such as WW745, H335, IMR 4895, CFE 223 etc., whatever I can get at the time.

 

[MTplinker]

I don’t see any way that the twist in the barrel has anything to do with this issue. The 1/8 twist should shoot anything from 50 to 77 grains with no issue. How are you charging your load? Is there any chance you had a light powder charge? From the picture your groups don’t seem to be indicating consistent loads. You mentioned that you warmed up the rifle at 50 yards, how big were those groups at 55 yards? 50 yards groups out of an AR should be pretty small if the rifle is performing correctly. Are you using irons?

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.

 

[MTplinker]

Built the gun to shoot service rifle matches and work on marksmanship, so I opted for no scope. Nothing fancy- CMMG parts. AP free float upper looked like good value for money. I know scopes are allowed, but call me weird and color me old fashioned.

The barrel is practically brand new. Maybe 150 rounds through it.

Aside from any concerns about the group (or lack thereof), why is there a crazy keyhole in the 50 yd target from yesterday?

 

[John from MD]

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.

I was concerned about you shooting a scope target with irons as you will always get a better group with a round black target using irons.

If it shoots that well, I wouldn't worry about the flyer. It is probably one of those mysteryies that happen from time to time.

 

[Park ranger]

Hornady are known for blowing up mid flight. I've smoked several. Life is way too short to shoot Hornandy or SPS seconds.