keyholing problem using light loads?

[paulnyc]

I am using light loads of various powders, Viht 140, H380 and Varget all using Sierra 55gr Blitzkings. Bullets seem to be tumbling a little, not real keyholing but the holes are a little oval shaped - groups at 100 yards are horrible.

I had some Nosler 50 grain spitzers with N135 powder and these shot perfectly -

Is it the powder? The bullet? Any help or suggestions would be greatly appreciated!

Thanks!!

 

[Lt. Arclight]

Re: keyholing problem using light loads?

Why are you using light loads? Are they lighter than published minimums?

Is the load that is accurate a light load?

 

[paulnyc]

Re: keyholing problem using light loads?

using loads from the manual - not lighter that published.

Could I be too close to the lands? Not far away enough from the lands - I am just loading to COL in the book.

 

[Greg Langelius *]

Re: keyholing problem using light loads?

I think you answered your own question. Try stepping thw loads up to more conventional charges and velocities.

The bullet's stability requires a certain minimum RPM, and this in turn is dependent on a corresponding minimum velocity.

Go too slow, and stability could suffer. I suspect that's at the basis of your problem.

Velocities are also dependent on barrel length. The shorter the barrel, often the lower the velocities. Combine shorter barrels with lower charges, and velocities could end up being inadequate to generate reasonable stability.

Greg

 

[Clark]

Re: keyholing problem using light loads?

I have had keyholing with a 303 Brit with .318" groove diameter and .311" bullets.

I have had keyholing with a 6mmBR 1 in 14" twist and 75 gr Vmax.

My brother has had keyholing with 55 gr bullets in a .223 with 1 in 16" twist [normally a 22LR twist rate]. His rifle shoots 33 gr and 50 gr just fine.

 

[paulnyc]

Re: keyholing problem using light loads?

I called Sierra (very helpful) it turns out that the 55 gr Blitzking 1455C cant stabilize in a remington VTR with 1:14 twist - so I am out a bunch of money for the 500 bullets I bought. Maybe an excuse to buy another rifle!!

 

[jbaldwin]

Re: keyholing problem using light loads?

I was going to ask what twist you were shooting but that has been established now. Good luck.

 

[oldgrayone]

Re: keyholing problem using light loads?

If they are slightly keyholing with a light load I would bet they would come out of it if you pushed them faster. Give it a try and see if you can get the use out of the bullets.

 

[Hummer]

Re: keyholing problem using light loads?

You could rebarrel to 9 twist and save that barrel for a 22-250 rechamber (another rifle) which would most likely stabilze it once you kick it on up.