460 S&W = tumbling bullets?

[Jeremiah Johnson]

I just got my new S&W 460 the other day.  I haven't got any 460 brass or dies yet so all I've been shooting in it so far are 454 casull loads.  One particular load that works well as a target round for me in my FA is a 255 gr. Laser Cast bullet over 10 gr. of Tightgroup. I tried this load in my 460 and at 50 yds. the holes in the paper indicate the bullets are keyholing.  My other heavier 454 loads using a 300gr. BTB and a 300gr. GDHP shoot fine. Any ideas on what could cause this?
Thanks.

[Jerry Lester]

Sounds like a classic case of slow rifling twist combined with low velocity loads.

Bullet stabilization is a direct product of the RPMs the bullet is turning. Longer bullets have to be spun at higher RPMs than shorter bullets to properly stabilize. The RPMs will vary depending on how fast you push a bullet through a given barrel twist.

Even shorter bullets will keyhole if the velocity is too low for the rate of twist in a barrel.

[KN]

I believe Jerry Lester has it right. If your load is mild I would try stepping it up. I'm not familiar with your load so I'm just guessing here. If you can crank it up it may very well straigten out.    KN

[Redhawk1]

Jerry Lester is 100% correct.  Why in the world would you by a 460 Mag to light load it???

[Jeremiah Johnson]

Thanks for the replies.  
Like I said, I don't yet have the means to shoot 460 ammo, so for now I'm shooting what I do have.
Redhawk1, if I remember correctly you have tried some 45 Colt ammo in yours. Did you have the same problem with tumbling bullets?
Thanks again.

[Redhawk1]

Thanks for the replies.  
Like I said, I don't yet have the means to shoot 460 ammo, so for now I'm shooting what I do have.
Redhawk1, if I remember correctly you have tried some 45 Colt ammo in yours. Did you have the same problem with tumbling bullets?
Thanks again.

I did not have a problem with the 45 L/C's tumbling. I loaded them on the hot side. The reason I don't shoot them any more, the point of impact is so different from the 460, I did not want to keep having to adjust the scope for the different rounds.  I avoid Tightgroup powder though, I just don't like a case that is not full of powder. I like full house loads like what H110 gives me.  

[slave]

Just wondering what the twist rate on the FA 454 is ? I thought it was in the 1:24 range. About the same as the Smith 1:100 GTR 1:20

IF THE LOAD SHOT GOOD IN THE FA, the twist rate alone should not be enough of a difference to cause TUMBLING.

I wonder if the bullet is getting damaged do to the difference in the chamber depth.

Be carefull Jeremiah, may be a bigger issue.

[doncisler]

jeremiah,

my 460 doesn't care for light weight bullets loaded down either. i tried 180 gr golden saber in 45 colt loadings - havn't noticed keyholing, just not accurate. heavier bullets and/or heavier loading works well.
no gun can shoot all weight bullets well. the s&w 460 with the gain twist does exceptionally well with heavy bullets at good speed and light bullets at blistering velocity.

[Redhawk1]

jeremiah,

my 460 doesn't care for light weight bullets loaded down either. i tried 180 gr golden saber in 45 colt loadings - havn't noticed keyholing, just not accurate. heavier bullets and/or heavier loading works well.
no gun can shoot all weight bullets well. the s&w 460 with the gain twist does exceptionally well with heavy bullets at good speed and light bullets at blistering velocity.

Well said.  

[jro45]

I was shooting in a match with my 45 ACP shooting these home made bullets. Almost every shot keyholed. So for me it was the bullets. After I changed bullets every thing was fine. Found out it was the lead I was using.