Bullet hits sideways

noslerpartition

Handloader
May 26, 2018
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Saturday a friend tested ammo I loaded for him.
308 win, 124 gr brass bullets.

Test loads were checked for pressure.
3700 bar, 950 m/s. OAL to CIP max, I did not have the rifle to check length to the rifling.

Surprise - the key-holed.

His barrel is short, around 18 inches. But there should be enough speed to stabilize those light bullets.

He uses a silencer, so that was my first thought, but other bullets fly true.

Bullet diameter is correct.

Any ideas what might cause that?

Will try them in another rifle, as soon as the stands are open again and he will without silencer.


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After 2000 rounds unlikely, but not impossible.


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Copper fouling. Might have him do a deep cleaning with a good copper solvent.

JD338
 
Had a fresh cleaning before (copper solvent), including some foulers before testing.


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1:11 as far as I know
It is the 3rd from left.
The guidance rings are very narrow. Maybe the barrel is a little wide and it jumps the twist?
Bullets like TTSX with a wider bearing surface work well.
Left 185 gr Mega, 140 Los HT, 124 ok, 168 Nosler CC, 180 NP and - well. Another bullet...
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31324da6a88e29801d64af9170d04e81.jpg
 
I wouldn’t think any 124 grain bullet would come loose in an 11 twist. Is it possible the Bullet hit some debris or something on the way to the target.
 
SJB358":1kpb6eae said:
I wouldn’t think any 124 grain bullet would come loose in an 11 twist. Is it possible the Bullet hit some debris or something on the way to the target.
Several hit sideways on an open shooting range.
If it is not the silencer, maybe we have to slug the barrel?

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Yeah, I’d say it’s something as an undersized bullet or oversize bore somehow.
 
Bullet has 7,82 mm. So exactly on target.
Guess it is the barrel.
It did not like the other shiny brass bullet with the small bands either

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if other bullets don't key hole and only the brass ones, then the brass ones are undersized.
 
Well - the bullets seem ok. I guess it is more likely the barrel and the guidance bands might jump the rifling

I will try the bullets with some other 308's/30-06.

As said - that rifle made some problems with other bullets with slim guidance bands. Or whatever they are called in English.



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noslerpartition":3om5rdl5 said:
Saturday a friend tested ammo I loaded for him.
308 win, 124 gr brass bullets.

Test loads were checked for pressure.
3700 bar, 950 m/s. OAL to CIP max, I did not have the rifle to check length to the rifling.

Surprise - the key-holed.

His barrel is short, around 18 inches. But there should be enough speed to stabilize those light bullets.

He uses a silencer, so that was my first thought, but other bullets fly true.

Bullet diameter is correct.

Any ideas what might cause that?

Will try them in another rifle, as soon as the stands are open again and he will without silencer.


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That's why I said other bullets but the ones you said keyhole.
 
Capture one of the bullets by shooting it into water jugs and then inspect it. You might find that the rifling is not engraving on the narrow bands. The bands may be chipping off or just smearing without imparting a spin.
 
When a rifle tells me that it simply doesn't like a particular bullet... I just move on. Go to another bullet.

The goal is to use a bullet that shoots well. If that rifle shoots other bullets well, use them, and don't waste effort on a bullet that doesn't work.

Guy
 
Guy Miner":2g6hg5t8 said:
When a rifle tells me that it simply doesn't like a particular bullet... I just move on. Go to another bullet.

The goal is to use a bullet that shoots well. If that rifle shoots other bullets well, use them, and don't waste effort on a bullet that doesn't work.

Guy

it's more than a rifle not liking a particular bullet.
 
I'd bet those bullets are undersized. Brass is harder than gilding metal and may be purposely undersized to prevent pressure spikes.

Try to mic them and compare them to a standard bullet that doesn't keyhole.
 
At least the diameter of the bands is not.
But since they are quite slim, they might jump the rifling if the barrel has issues.
I will try the bullets with other 308 rifles.
That one rifle seems to have issues..



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May be that 1:11 twist rate is too short for that light and speed bullet.
In addition the rifling edges have to work on the slim bands instead a solid bullet body.
I've check with the Don Miller Twist Rule where the minimum ratio suggested is 1.4
Supposing 1 in 11 with your speed and weight, it calculates 1.41 but supposing solid bullet body.
So may be the bullet flight is already near to be not stable, then it could lose some due the slim bands.
Could it be reasonable like that?

Sent with 82.7 gn of N560
 
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