bullets keyhole, 223 wylde ar

[Josh555]

Hello everyone , longtime lurker.

I was at the range today and left completely stumped.

25yd indoor range
aero m4e1 receiver set
faxon match series heavy fluted 223 wylde 1-8 twist.
Precision Armament EFAB

I was doing some load development with the hornday 68gr bthp-m #2278, LC '20 brass, and GM205MAR primers.
Everything was good with A2230 and A2460.
When I got to TAC and W748 I was getting horrible groups and finally noticed some keyholes.

This barrel probably has ~500 rounds through it, exclusively handloads, 36gr all the way up to 77gr and no issues.

I had recently done some load development with these same bullets in a 24" 9 twist ar + varget with great results.

I see no evidence of bullet strikes on the muzzle device and no contact on the magnetospeed V3 + MK Machining chassis mount that I regularly use.

The only thing I can think of is the lands in the barrel "stripping" the jacket thus not imparting sufficient spin.

Thanks for the time,
-Josh

 

[357Max]

Hello everyone , longtime lurker.

I was at the range today and left completely stumped.

25yd indoor range
aero m4e1 receiver set
faxon match series heavy fluted 223 wylde 1-8 twist.
Precision Armament EFAB

I was doing some load development with the hornday 68gr bthp-m #2278, LC '20 brass, and GM205MAR primers.
Everything was good with A2230 and A2460.
When I got to TAC and W748 I was getting horrible groups and finally noticed some keyholes.

This barrel probably has ~500 rounds through it, exclusively handloads, 36gr all the way up to 77gr and no issues.

I had recently done some load development with these same bullets in a 24" 9 twist ar + varget with great results.

I see no evidence of bullet strikes on the muzzle device and no contact on the magnetospeed V3 + MK Machining chassis mount that I regularly use.

The only thing I can think of is the lands in the barrel "stripping" the jacket thus not imparting sufficient spin.

Thanks for the time,
-Josh

Don't worry they'll go to sleep in another 50yards.


Jokes aside.

What was velocity difference between Keyhole loads and the others?

Were you using the same mags for all loads?

 

[357Max]

Did you do anything different with neck tension or annealing between these loads?

 

[RegionRat]

Just food for thought...

I have been at public ranges, indoor and outdoor, where many of the holes in my target were from other folks bouncing and skipping rounds into mine.

Is there any chance these were not your shots?

 

[GBMaryland]

Just food for thought...

I have been at public ranges, indoor and outdoor, where many of the holes in my target were from other folks bouncing and skipping rounds into mine.

Is there any chance these were not your shots?

That’s what I was thinking.

given that the groups are generally decent, I’d have to assume those were someone else’s shots.

 

[357Max]

That’s what I was thinking.

given that the groups are generally decent, I’d have to assume those were someone else’s shots.

I was thinking the same, but top row are all 4 shot groups and top right keyhole is 4th.
Bottom left groups are missing shots,,,,,,,,,keyhole to right could be one of the shots missing from left.

 

[RegionRat]

At 25 yards, it would be pretty hard to explain a "normal" situation where the general groups are tight, and an unstable bullet goes off by several MOA so quickly without leaving some evidence of a strike.

Maybe the OP should scope the barrel? Check to make sure everything is still tight?

In abnormal situations I have seen some very strange things... If the bullets are the wrong ones, then stranger things can happen.

A good way to find out for sure is if the OP shoots somewhere by themselves where it is impossible to catch stray rounds from some other shooter, and then watch every shot.

 

[Josh555]

Thanks for the responses.

@357Max
At the time, I did not thing to take note of the specific shot that was a keyhole. I didn't even know it was happening until the 2nd one, the first one was the high-right one.

All loaded to mag length, using 20 rd pmag.

I am not Annealing (yet) and brass is on its first reload.
Using the redding FL type S die, set up for .004 shoulder bump, .003 neck tension.

@RegionRat I completely understand where you are coming from. This happened a lot at an outdoor range I used to go to, especially since targets could be set up a 25,50,75, and 100 yd distances.

For this current issue, I doubt it is the case. there was one other group 2 lanes down, I could see their hits on the bullet trap. There are times though, I do see new shooters doing some interesting things..

 

[Josh555]

At 25 yards, it would be pretty hard to explain a "normal" situation where the general groups are tight, and an unstable bullet goes off my several MOA so quickly without leaving some evidence of a strike.

Maybe the OP should scope the barrel? Check to make sure everything is still tight?

In abnormal situations I have seen some very strange things... If the bullets are the wrong ones, then stranger things can happen.

A good way to find out for sure is if the OP shoots somewhere by themselves where it is impossible to catch stray rounds from some other shooter, and then watch every shot.

I used a borescope the check for anything that looked "off" and best I can tell the twist is 1-8.

I had a light graze on the magnetospeed once. I have since taken a bit more time to set it up. The MK Machine mount makes set up much more reliable.

I suppose the most immediate thing to try is removing the muzzle device. Used the borescope to examine the inside of that as well.

 

[RegionRat]

I used a borescope the check for anything that looked "off" and best I can tell the twist is 1-8.

I had a light graze on the magnetospeed once. I have since taken a bit more time to set it up. The MK Machine mount makes set up much more reliable.

I suppose the most immediate thing to try is removing the muzzle device. Used the borescope to examine the inside of that as well.

A graze on the MS is not trivial. I would still recommend you follow through and check everything twice.

 

[Josh555]

Today is a new day, checking things over again..

I was just thinking, perhaps the diameter of the lands to large? I scoped a different faxon 5R barrel that I just retired and the lands look "taller".

Maybe this will be a conversation with Faxon customer support, I feel like it has been hit or miss with their barrels lately.

 

[BuildingConceptsllc]

Today is a new day, checking things over again..

I was just thinking, perhaps the diameter of the lands to large? I scoped a different faxon 5R barrel that I just retired and the lands look "taller".

Maybe this will be a conversation with Faxon customer support, I feel like it has been hit or miss with their barrels lately.

I've never had one but thats kind of the consensus it seems from others I've seen comment on here. Sometimes their barrels are ok and sometimes horrible. I generally kind of stick with what I know works on barrels and stay with proven manufacturers. Ie for AR: Bartlien , Kreiger, ect.

 

[Josh555]

I was looking back through some other loads I was working on with this barrel. 50gr hornady v-max + h335 looked promising.

I would hate to trash this barrel already. I suppose I could see if faxon wants to warranty replace it.

Now this thread is changing direction...

Should I keep it and just shoot what works or stop trusting it?

 

[RegionRat]

Are you familiar with the concept of "slugging" the barrel with a piece of soft lead to examine the diameters?

If you see the keyhole again, and don't find a common cause for it, then I would pursue your theory with an examination of the barrel diameters.

It would be unusual to see this much normal behavior and only occasional keyholes, but stranger things have happened.

Usually, if a bullet is too small for a barrel, and it can go that wonky inside of 25 yards, the majority of the shots will be bad not just one here and there.

 

[Johnnybar]

Mic that batch of bullets.

 

[sgtsmmiii]

Mic that batch of bullets.

This. I bought a set of "cosmetic" blems from a well known distributor and noticed several seated with noticeably more pressure. Mic'd them and found their diameters were all over the place. Was planning on shooting them through a can - so - pulled all of the ones already loaded, measured ALL of them, and pitched the out of spec ones.

Good thought Johnnybar.

 

[supercorndogs]

I would be checking the 77g bullets if it shoots like that.

I had bullet go inexplicably go sideways through a target once. I still don't know why. It was right beside the rest of the group. 10 rounds you could have drawn a 1.5moa circle around, with one sideways through the target. I lost the target when I moved last. I wonder if I will find it someday.