questionable keyholing

[soldierbilly1]

quick question: when is keyholing not keyholing?
I shot today in an unofficial action pistol match. After the 3rd round, on our paper silhouette targets it appeared some of my bullets had keyholed. Only some. Took the barrel off and examined and saw soot, but no real leading of the barrel, but maybe a little by the chamber, but nothing to speak of.
I am thinking the paper targets were layered on one and other and the suspect keyholes were really bulging paper areas making uneven rips in paper. I was using Lyman TC 124 gr with NRA 50 lube. 9 mm Taurus 92 w 1300 rounds through gun, almost all were casts. I cleaned the barrel and it was as clean when I took it home.
any similar experiences? tell me about paper targets!
billy boy

[btroj]

If the paper doesn't lay perfectly flat you can get oval holes.

If the barrel isn't leaded then I doubt you had key holing.

If the bullets go where they are supposed to then I wouldn't worry about it.

[MtGun44]

What diam boolits? I'll bet you are shooting .355 or .356 diam and this WILL VERY COMMONLY CAUSE
instability and tipping and slight to severe "keyholing" in the 9mm. Strongly recommend you size to .358 and
solve the problem. Possible that .357 will work, too. A very large fraction of 9mms require .357 or .358 boolits
to achieve stability, accuracy and in many examples, to stop leading. Most situations with keyholing with
9mm also involve significant loss of accy and at least some leading.

Bill

[Old Caster]

If your bullets are soft, it is quite likely that your bullets are getting swaged down by the brass case being too small. Pull a bullet with an inertia puller and measure to see if it is too small.

[runfiverun]

if it was something that just popped up i'd suspect the backer, if the target isn't flat and fairly tight on the backer it will rip where the holes are.
slow rounds will also allow keyholing as they aren't stabilized properly.

[williamwaco]

All the above.

I have also had keyholes with that bullet and they appear to be random and unpredictable.

That makes me suspect that some cases randomly have thicker walls and swage the bullet down during the seating procedure.

These occur with loads assembled from range pickup brass.

I have never tested with sorted brass of known good quality.

[waksupi]

What diam boolits? I'll bet you are shooting .355 or .356 diam and this WILL VERY COMMONLY CAUSE
instability and tipping and slight to severe "keyholing" in the 9mm. Strongly recommend you size to .358 and
solve the problem. Possible that .357 will work, too. A very large fraction of 9mms require .357 or .358 boolits
to achieve stability, accuracy and in many examples, to stop leading. Most situations with keyholing with
9mm also involve significant loss of accy and at least some leading.

Bill

This is the right answer. Also applies to rifles. Heat the bore up on marginally sized boolits, and expect key holes and wandering projectiles.

[soldierbilly1]

thanks to all for all the responses.

I will use a cardboard backer with my practice targets on my next trip to the range. I will also post a paper target on the frame very loosely to see if I can reproduce the condition. I checked all my recent practice targets with this load, and there are a considerable number of them. There are no signs of any keyholes.

There was virtually no leading in my barrel, I am thinking it was the loose paper.

However, the investigation will continue! I will let you know if I get any significant findings.
thanks for the help

billy boy

ETA I size to 357 and use NRA 50/50. If this persists, I will go to 358. BTW, good point on the range brass!

[runfiverun]

my Taurus 92 [looong time gone now] wouldn't shoot well until I went to 358 diameter.
then it had a bad habit of shooting lower and more to the right as the barrel got hot.
odd I thought,, littlegirls boyfriends tairus just shoots 3' high for the first 10 shots then throws one low at random.
pretty funny to watch him sneak 3' away from a grouse and shoot clean over it's head though.

[HeavyMetal]

for thost that are interested 9mm case wall thickness is all ove the place!

One of the reasons I always suggest sorting by head stamp to load for the 9mm. I also pay attention to how hard a boolit seats in a case, those that seem to require more "grunt" than the rest are set aside and form thier own sub lot for the future.

Case length is also a huge issue with the 9mm and Ken Waters reported a .020 difference in case length in the same 50 round box of factory ammo he fired for testing new loads!

The 9mm can test your skills, LOL!

[soldierbilly1]

for thost that are interested 9mm case wall thickness is all ove the place!

One of the reasons I always suggest sorting by head stamp to load for the 9mm. I also pay attention to how hard a boolit seats in a case, those that seem to require more "grunt" than the rest are set aside and form thier own sub lot for the future.

Case length is also a huge issue with the 9mm and Ken Waters reported a .020 difference in case length in the same 50 round box of factory ammo he fired for testing new loads!

The 9mm can test your skills, LOL!

I went to the range with my loads and a cardboard backer for my paper targets. No problems whatsoever, not one keyhole. But hey, I learned a lot on this journey!

Heavy Metal: 9 mm will test my skills, hah! After using Lubrasizing for years with my nines, I tried using Lee's LLA and a TL bullet.
She worked like a Champ! (no leading whatsoever). Secret: lee mold drops at 358 - 359, no sizing, WQ, and use a heavy coat of LLA. Get those puppies wet! I used 50/50 scrap and WW's. I gotta try AC'd scrap and see if that works.
thanks for the help.
billy boy

[Old Caster]

Not only does the brass neck thickness vary a lot from brand to brand but how deep it is before the brass starts getting thicker and varying thickness where it gets thicker according to depth. If loaded deep into the case this will make the bullet tip after being loaded and cause problems. Since 9 mm is a smaller diameter case, it causes more problem than it would on something bigger like 45 ACP which is very forgiving when it comes to varying brass. 32 ACP or 32 long shows up to have the same problems when shot from accurate pistols and separating brass by manufacture and length is mandatory.