I have a 1905 M&P that was made about 1925 that is in fair shape except for the barrel.It has a 6 inch barrel and I would like to get another barrel in order to make this revolver a shooter again. Any suggestions on where to look for a good 6 inch barrel?

Sights like Gunbroker usually have quite afew for sale.
Be aware that the ejector rod tip on your gun should be the early "mushroom" style, the next style was a barrel tip , this changed to a knurled end after WWII.

If you use a barrel that isnt cut for the mushroom tip ejector rod you will also have to change your ejector rod.
If you decide to change your ejector rod be advised the threading changed from right hand to left hand thread around 1961.

I found a new old stock 22 mrf barrel on Ebay. You might want to occasionally check the site for a suitable barrel. Some may be like new at very reasonable prices while others in hard to find or popular larger bore barrels are sometimes very pricey. I would start by doing a Google search for exactly what you want and add for sale at end, it may find something for you. You could also put a WTB add on this website in the firearms for sale section and a fellow member could help you out.

I will take a look at both of the noted sites and see what I can find.Thanks for the help.
The ejector rod on my revolver is the large tip that requires a cut in the barrel.