hunting Elk with a 500gr arrows 3 bladed BH shooting it out of my 51#WIDOW

Should work great for anything you are likely to hunt.  

Sounds like a dead elk to me!!!  

That will put meat on the ground.  Get close and aim straight. If you put it in the boiler room at close range broadside you should get a complete pass thru.  

Having said that, I prefer to shoot a bit more arrow weight for large game animals like elk.  I am hunting elk with a 55 lb longbow with 584 grain arrows.

this arrow fly so good at that weight .I can put a 125 feildpoint  no feathers and shoot that arrow straight out to 35yds even keep a good group(paperplate)

What kind of shaft and at what length you shooting? Sounds like it dialed in!

Arrow placement is the key !!!!!!

 can't wait to see the pics. good luck!

That is the same set up that I have. Should work fine.  

What brand/model 3 blade Bhead?

I prefer a heavier arrow for a large animal like elk.  But if your placement is good, should be a short trail.

How 'bout a 3 blade Woodman Elite 250gr head out of a 55# longbow? My arrow weight was 600 gr though, and I got great penetration with the arrow sticking in the offside shoulder at 27 yards...Personally I like arrows a bit on the heavy side but that's just me    

I'd go heavier on the arrow, Good Luck ...