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[-] tal@lemmy.today 33 points 5 months ago

I've never shot paper targets, but might this be at extreme range? I mean, those don't look like circular holes, so I'd assume that the bullet is tumbling for some reason.

kagis

Sounds like the term is "keyholing".

https://www.snipershide.com/shooting/threads/308-tumbling-at-almost-a-mile.194313/

Long range noob here with some questions. Basically I was under the impression that a .308 would be tumbling by the time it reached it's target when shooting out to a mile. Now the reason I believed this is because just last week I was shooting my .338 out to 1585 and having fantastic results. I decided to try out my Warner build .260 just to see if I could get some hits at this distance. I eventually did have about 3-5 hits on a 24x24" steel out of about 20 rounds. Upon inspection of the target there were clearly visible strikes that showed the bullet impacting sideways. Essentially keyhole imprints on the target

https://old.reddit.com/r/guns/comments/el6h5q/holy_keyhole_batman/

That keyholing image looks a lot like the image of the target that OP posted.

[-] DaddleDew@lemmy.world 51 points 5 months ago* (last edited 5 months ago)

It is keyholing. It happens when as you can see the bullet loses stability and tumbles in the air before hitting the paper sideways. It can be caused by many things. Insufficient rifling twist for the length of the bullet being used is one of them. The bullet hitting the ground or something else before hitting the target is another possibility.

Either way, it isn't a desirable thing and indicates that something is wrong. The fact that the PLA members are proudly posting pictures of a bunch of keyholes randomly splattered all over a target like that suggests that they think this is normal and that therefore they don't know what they're doing.

The term "keyholing" is also sometimes erroneously used to refer to when two bullet holes are touching on paper.

[-] sp3tr4l@lemmy.zip 17 points 5 months ago* (last edited 5 months ago)

Could keyholing of ... seemingly this magnitude... be the result of basically laughably bad tolerances in internal barrel width, or perhaps the barrels are made of some kind of alloy that expands significantly from heat?

I have only ever seen keyholing in western gun videos from basically burn downs... but even then after a barrel is nearing its end of life by manufacturer specs, its more common to get some kind of failure to feed, significantly decreased precision and only occasional keyholes.

Maybe another possibility is similarly poor quality alloy of some kind used in the cartridge itself?

Combination of all of these things?

I remember seeing a fairly recent video of some kind of PLA MOUT type urban course... and you could see massive keyholing on targets that were like 5 to 10 meters away.

The prevalence of it baffles me. Ive personally dealt with and seen misfires and jams of various kinds at ranges, but I've never even seen a keyhole occur in real life.

[-] shalafi@lemmy.world 13 points 5 months ago

I've seen a .22LR of mine keyhole. Once. Or twice. Ever. I honestly thought this was an AI imagine making fun of the PLA.

[-] frezik@midwest.social 5 points 5 months ago

I saw it at the range a few times. Worst was when someone had their scope set way too low, and it was causing them to hit the concrete roof. Let off three shots, wasn't even on paper, and then the next one keyholed. Hold up here, let's twist this knob and try again.

[-] Milk_Sheikh@lemm.ee 6 points 5 months ago
[-] commandar@lemmy.world 3 points 5 months ago

Fleet yaw is a different phenomenon that impacts terminal ballistic performance. It's essentially a way of describing why some projectiles tumble and fragment after impact while others will tend to remain more stable and pass straight through for longer.

The projectile AoA being described in that context is only a couple of degrees. It's enough to change how the round behaves after hitting something, but it's not the type of in-flight wild tumbling that results in keyholing on a target.

[-] Milk_Sheikh@lemm.ee 2 points 5 months ago

This is an important clarification, you’re right. The yaw angle is minimal in ballistic flight, the level of keyholeing in the photo is rather dramatic. Though the 5.8x42mm is standard with a mild steel penetrator like M855, and the round was definitely built with cost as a major factor - maybe a bad lot of ammo?

[-] FireTower@lemmy.world 5 points 5 months ago

On the heat issue prolonged fire would cause the metal to soften allowing for increased degradation of the rifling.

The easiest ways for it to happen would be either a poorly made barrel or a barrel not designed for a specific projectile. Different barrel twist rates are better for different cartridges. A heavy bullet is better in a faster twisted barrel. If you fired a very heavy bullet in a slow twisted barrel you would likely not have it reach a proper stabilization.

[-] skillissuer@discuss.tchncs.de 5 points 5 months ago

i don't know enough about chinese rifles to speak authoritatively one way or the other, but there was a claim that it's a target from QCB training where they used rubber bullets that tumble no matter what you do

[-] igg@lemmy.world 4 points 5 months ago

I think 5.45x39mm round they use tumbles a lot which causes this keyholing

[-] DaddleDew@lemmy.world 11 points 5 months ago* (last edited 5 months ago)

The standard "ball" bullet used by the Russian military, at least, in the 5.45x39mm is designed to easily tumble once it is inside the target. It is more of an effect of the bullet's construction and fine tuning of the rifling twist rate than the caliber itself. But it is still supposed to remain stable with the nose pointed forward when traveling to the target. Otherwise it becomes extremely inaccurate and loses its velocity very rapidly, which causes it to fall short.

[-] sp3tr4l@lemmy.zip 8 points 5 months ago

The QBZ family of rifles, both the older bullpup Type 95 and its variants, and the newer Type 191, fire a 5.8 x 42mm round, not the AK 74 'poison bullet'.

While I am sure the PLA has tons of 47s, and 74s still in active use, their efforts to modernize have included introduction of and seemingly wide issuance of the QBZ 95 family since roughly the early 2000s, and more recently the Type 191.

Usually when they do publicity videos or images, they like to show off the QBZ family.

[-] maynarkh@feddit.nl 5 points 5 months ago

If I learned anything of authoritarian countries claiming to be communist, they would never manufacture a whole new line of weapons without extensive testing, and if it turned out to be shit, they would totally have the self-reflection not to keep issuing it but to fix it and retry with a new variant. Totally.

[-] sp3tr4l@lemmy.zip 11 points 5 months ago

I have seen PLA videos of basically an urban combat live fire on static targets.

You get an absurd amount of keyholing at ranges that between 5 to 10 to 20 meters.

Its possible this particular image is from a longer distance static range, but the keyholing problem seems to be quite widespread, irrespective of range.

As has already been said, something is going seriously wrong with either the guns, bullets or both that are being mass produced for around a year now.

[-] remotelove@lemmy.ca 7 points 5 months ago* (last edited 5 months ago)

That is a photoshopped picture, btw.

I can't imagine that keyholing like that would be even be slightly tolerated and it's not too difficult to get stable flight unless there are serious issues with the firearms.

If a bullet is tumbling out of the barrels, those barrels are seriously fucked. They are shot out, are using bullets that are too small or there are serious defects with the bullets.

A bad twist rate or extremely poor load generally won't cause tumbling until much later. If the bullets start at slightly at supersonic and slow to subsonic quickly, that might do it.

I would like to see those videos of the keyholing you described, which is why my brain seems to have vomited all over this comment. (This has got me super curious, is all.)

this post was submitted on 30 Jun 2024
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