.223 low velocity "keyholes"

Sapper33

Sapper33

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How low does the velocity have to be get a .223 to tumble? ball park

I've got a Savage 10FP, 1:9 twist:
52gr SMK
CCI 450
3.8gr W231

I figured I'd play with subsonic, and that's the load I use in my .38SPL. Ended up sounding like a .22

I fired a group of 5, didn't group TOO terrible (<2" @ 100), but every hole was elongated.

I tired 7.6gr of W231 as well, grouped ~1" @100, and all the holes were nice and round and crisp.

Would the misshapen holes be simply due to low velocity, was there something else out of whack?
 
Looks kinda like this? Its nothing to do with the speed its the wrong twist barrel for the type of load your trying.

This is the reverse of what your trying to do... 80 grain bullets thru a 1-12" twist barrel.

If your able to fire them at 100 and hit the paper your twist rate is just slightly off... my bullets did this at 10 feet you couldnt even hit he target backer board at 100 yards.

You could try speeding them up slightly it might help with the keyholeing.


keyhole.jpg
 
52 grn bullet may be too small for your 1 in 9 twist, try a 62 grn bullet and you may smarten that up. some rifles are less finicky about bullet weight to twist but many like to stay in a certain range.
 
msg.drew: they looked somewhere between the top and center holes on that target.

I figure the 52s I'm shooting are right on the bottom of what my barrel will shoot. I found it odd that this is the only load I've seen it happen with. All my other 52gr handloads worked nice, even cheapy 45gr Rem/Win factory stuff worked well.

I'm looking forward to stepping up my bullet weight, but I need to find a longer range to shoot at first.
 
That again is the odd part. I have been loading from 1 batch of bullets, and I didn't change my dies. The only difference between the loads with good groups and nice neat holes, and my keyholes is the amount of powder.
 
Do you have a chronograph? When I was referring to the length of the bullet I was talking about the physical length of the projectile not the COL. If you have used those same exact type bullets before and they are from the same lot then your speed is the problem why are you trying to shoot them so slow ?
 
A chronograph is on my wish list for christmas.

I thinkt he velocity would be around the 9-950fps range. No "Crack" when fired, hodgdon gives 1060fps for 3.2gr of Clays, and I've found data saying 896fps for 4gr of Blue Dot, and W231 being in between.

Oh well, the 7.6gr load worked pretty well (for cheap), I guess I know where to stop now.
 
Now that I think of it I used 3.1 Grs of titegroup with 55 FMJ in my 1-9" twist, its right around 1000 fps, and I had no problems. The 55 FMJ is much longer then a 52 BT
 
msg.drew said:
Actually his particular situation calls for longer bullets... its a 1-9" twist not a 1-12"
Click to expand...

Sorry, but WHAT?

The tighter twist of 1-9 will stabilize longer bullets and shorter bullets. The myth of 'over-stabilizing' short bullets in a tight twist is a bit of myth.
His situation is unique in that he is trying to shoot some jacketed bullets at low velocity; a tighter twist should actually help.
I don't have an answer as to why his bullets are showing elongated holes at 100. I can guess and I don't think that it has anything to do with his twist. I suspect that his velocity is so low that by the time the bullet is reaching 100 yards it is running too slow to remain stable and point on. They are starting to fall out of the air.
I shot a lot of .223 with sub-sonic loads, both jacketed and cast. But I do most of my shooting at 25-50 yards. I have loads that are stable at 25 but elongate at 50, using some long bullets and low velocities.
 
Lots of mis-information here.

Bullet stabalization depends largely on a few things: Weight uniformity (Concentric), Barrel twist and velocity.
Think of throwing a football as a simplified parallel.

The 1:9 twist is sufficient for the bullet you are throwing out of the barrel, but it is very likely the velocity isn't.
It is possible also with bulk fmj that the weight is not completely concentric. At normal velocities this would mean maybe their limit is 2+ moa, but at lower than normal velocities, they may be 'wobbling' through to the target.
 
I am pretty sure there is a program you can plug the info in and it will tell you all you need to know about the stability of the bullet and what speed you need to fire it at to make sure its stable using your spec equipment.
 
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