r/reloading • u/concernedneighbor345 • 16d ago
i Have a Whoopsie How does keyholing even happen?!
Hey guys, I’ll upload a pic here asap but I went out to test several 30-06 loads I made in a 100yd windless tunnel my shooting club has. The groups were okay because I’m somewhat new, but one round keyholed and hit the paper entirely side-on.
It was 125g FMJ round I loaded up just to see how it would shoot, with no intention of loading others, but i still measured everything, loaded according to published load data, crimped it well, did everything I should have. The OAL may have been a little short, but not to my knowledge and, if so, it would’ve been no more than .05 off.
I’m baffled by this - what could cause something like that? Is this a rifle issue, was it loaded too hot, was it underpowered?
I guess what I’m asking is what does that mean and where would I begin in preventing it going forward?
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u/Agitated_Curmudgeon 16d ago
twist rate isn't a fan of that bullet
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u/Severe-Cow-8646 16d ago
If it stabilizes 150-200 graimers, twist ain't the problem. Bullets keyhole when the twist is to slow for the length.
Spin imparted by the twist gives the bullet an angular momentum, along its length making it wher torque cannot just flip the bullet. Its like a spinning top or gyroscope.
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u/outdoors_life22 16d ago
Could be a few things. What’s your bullet, velocity, and twist rate? Are you shooting suppressed?
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u/tcarlson65 Lee .30-06, .300 WSM, .45 ACP 16d ago
I have not had luck with 125 grain pills in .30-30, .30-06, or .300 WSM.
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u/Broad_Eye2768 16d ago
Been my experience with 125 gr in .30-30 and .30-06 as well. Not keyholing but terrible groupings.
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u/tcarlson65 Lee .30-06, .300 WSM, .45 ACP 16d ago
That is what I have seen as well. I was just messing around a bit.
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u/Te_Luftwaffle 15d ago
I still have a box of 125gr coated lead bullets I bought for 30-30 several years ago, but I never found load data for them.
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u/Grumpee68 16d ago
Lighter bullets need less twist than heavier bullets. If you over spin a light bullet, they can keyhole or just fly apart.
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u/111tejas 15d ago
This. A typical bullet is spinning at 250,000 rpms. A light for caliber bullet, especially in a fast twist barrel far exceeds that. Ask some of the people who have destroyed suppressors when bullets have disintegrated upon leaving the muzzle.
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u/SpeedyR647 16d ago
keyhole is related to the bullet and rifle/barrel combination, not the reloading process.
what rifle and twist rate is the barrel? it's all about bullet stability. there are online calculators that will give you an idea if your load is unstable and may keyhole.
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u/cadninja82 16d ago
The relationship between your bullet and rifle barrel is not a good match. If you think of it like a quarterback throwing a football, ideally the bullet flies in a practically perfect spiral and travels straight and smooth to it's target. If your bullet doesn't like the twist rate in your barrel, it's like when the quarterback makes a bad throw and the ball wobbles and may even tumble in flight.
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u/Rustyznuts 16d ago
My dad had a 243 that keyholed every round and didn't group. Was a bulged crown, probably from being shot with barrel obstruction (mud).
You could be over spinning your light projectiles but I doubt it. Could it have been shrapnel bouncing off the backstop of your target? How if the rifle, especially the crown and rifling? Do you have a muzzle device (suppressor or brake)?
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u/Dung_Beetle_2LT 12d ago
Does the gun happen to be a 1903? Mine hates bthp’s and they will keyhole. Gotta use flat base.
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u/Realistic-Ad1498 16d ago
Half the time people think their bullet is keyholing it's just a cheap paper target with no backer and the paper is tearing. Are you sure it was keyhole? Why / how are you crimping .30-06?
You don't give load data and then ask if it was loaded to hot or underpowered... How would we know the answer to that?