Bullet ID help

[volshooter]

I took apart the range back stop and of course I collected many spent bullets. I came across several that were perfectly mushroomed. Look like .30 caliber and have a "T" on the end of them.
I have spent 2 hours on the net trying to find a projectile with such markings, I'm not smart enough to ask the right questions. I am asking for your knowledge to identify this projectile. It was fired recently.
Dadgum perfect expansion.

 

[Pat-inCO]

Picture?

 

[JFB]

http://forum.afte.org/?topic=6883.0

 

[gramps]

Great info JFB. Thanks.
gramps

 

[volshooter]

I'll try to post some pictures. The range owner hunts all over the world. I know there are some .500 Nitro rounds in there somewhere, love to find some of them.