? how can you tell if a bullet is tumbling or


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husker
March 4, 2009, 01:59 AM
? how can you tell if a bullet is tumbling or stabilizing at such high speeds and distances

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Funderb
March 4, 2009, 02:03 AM
Is that like "True or false, how long is a battle ship?" or "What is the difference between a duck?"


detail, friendo, details..

bensdad
March 4, 2009, 02:04 AM
I don't know if I understand the question. If it tumbles, there will be a hole in the target that is not round. It may look like the profile of the bullet, slightly oval, or something in between. Also, tumbling bullets won't be as accurate. I"m not sure about "stabilizing".

PT1911
March 4, 2009, 02:06 AM
check for the "keyhole" in the target... this is indicative of a tumbler..

husker
March 4, 2009, 02:07 AM
no. guys were talking about twists and stabilizing. they made it sound like they could tell if the bullet was stabilizing or not= twist vs grain of bullet.

Funderb
March 4, 2009, 02:09 AM
The only way you would know is if the holes in your perfectly vertical target shot at mostly a perpendicular angle were other than mostly perfectly round.

It is said, often, that a high twist rate is needed to stabilize a heavier, longer bullet. But this conclusion was reached by examining targets and impact marks. (not by actually seeing the round in flight)

The easiest way to see if you are achieving consistent, not necessarily perfectly stable, flight would be to shoot it well, and get a small group.

cliffy
March 4, 2009, 02:10 AM
Yes, I have seen bullets keyhole into targets. Generally means too much powder charge for the given bullet. Drop about 2 grains of that powder, and try again. Or go to a rifle, if you require that much power. cliffy

husker
March 4, 2009, 02:12 AM
i get it now. just open my eyes and look at the holes in the target. key hole = tumbling bullet, THANKS AGAIN and i thought those key holes were just 2 perfectly placed shoots like Robin hoods. so much still to learn

PT1911
March 4, 2009, 02:08 PM
in some cases you can get two bullets in close proximity to each other and resemble a keyhole affect. that is the importance of keeping a round count.

rcmodel
March 4, 2009, 02:17 PM
If the bullet is not stable and tumbles before it gets to the target, there very likely won't be a hole in the target to look at.
Because it won't even hit the target.

A slightly oval hole indicates the bullet was only marginally stable when it got there. Still not good for accuracy, but at least you got a hole at all.

rc

PT1911
March 4, 2009, 02:22 PM
it is also a good idea to take the shots at multiple ranges. if you arent hitting at your intended range, half it, and try again until you have success.. eventually, something has to give...

Spyvie
March 4, 2009, 02:43 PM
I've seen .223 make perfectly sideways profile holes in paper. You could almost judge the caliber, weight, BC, and if it's a boatail or whatever just by lookin' at the hole.

EDIT: A qiuck Google image search came up with this.
http://www.lawofficer.com/news-and-articles/articles/lom/0304/223_ammo_selection.html

http://www.lawofficer.com/Images/target_373_tcm22-140107.jpg

KBintheSLC
March 4, 2009, 03:32 PM
Spyvie... there appears to be something seriously wrong if it is spitting rounds out like that. I can't imagine it is very accurate passed 25 yards. I have never seen a rifle round hit the paper sideways. If it did, I would likely consider getting rid of that weapon/ammo/combination. Even a heavier bullet that fails to stabilize should not go head over heels.

5.56 bullets are designed to tumble after they hit the target... not during flight. If your bullet is keyholing, try a lighter bullet weight or get a barrel with a faster twist rate.

USSR
March 4, 2009, 03:47 PM
If the bullet is not stable and tumbles before it gets to the target, there very likely won't be a hole in the target to look at.
Because it won't even hit the target.

+1. I was spotting for someone shooting a rifle with a new barrel at 1,000 yard F Class a couple years ago. The 6mm barrel was supposed to be tightly twisted for the 115gr bullet. Since the shooter was experienced, had sighted the rifle in at 100 yards, knew the bullet BC and velocity and had established his come-ups thru external ballistics software, we suspected that the reason his bullets weren't reaching the target was that the twist wasn't what it was supposed to be. He later found out that was exactly the case.

Don

Spyvie
March 4, 2009, 04:04 PM
Spyvie... there appears to be something seriously wrong if it is spitting rounds out like that. I can't imagine it is very accurate passed 25 yards. I have never seen a rifle round hit the paper sideways. If it did, I would likely consider getting rid of that weapon/ammo/combination. Even a heavier bullet that fails to stabilize should not go head over heels.

I agree, but this wasn't MY rifle...

TimRB
March 4, 2009, 04:12 PM
"here appears to be something seriously wrong if it is spitting rounds out like that. I can't imagine it is very accurate passed 25 yards."

Maybe, maybe not. Sometimes bullets are stable for most of their flight but begin to tumble as their speed drops below supersonic. M14 shooters discovered that their beloved 168 Match Kings wouldn't shoot well at the longer ranges because of this.

Tim

husker
March 4, 2009, 04:22 PM
dam it looks like i started something here. i have to say that in 25 years of shooting 5.56 i have never had paper look any thing like spyvies pic. but 200 maybe 250yrds was all i had. now thats changed to 800yrds so now im going to stretch out the mohawk 600 this spring. thanks for all the tips and schooling.

alemonkey
March 4, 2009, 08:03 PM
I had a tumbling bullet problem with my 45-70 when I first started casting bullets. I had a few that weren't up to snuff, and you could hear a buzzing noise as they flew through the air.

jkingrph
March 4, 2009, 10:40 PM
I tried some rather long cast bullets in my Ruger 458 Win mag. At 25 yards they grouped nicely, while going through the target sideways.

marsche
March 4, 2009, 10:44 PM
If the hole in the target looks like the Virgin Mary and you can sell it on Ebay, the bullet is tumbling.

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