I am new at this, and for years didn't see many of these, but recently picked up this Stevens rifle at an auction.  It has a heavy round barrel about 1 inch diameter, built on a 44 action, and caliber was unmarked.  After I got it home, I removed the forend and the underside of the barrel is marked H M POPE, and while I didn't know this when I bought it, I still am a little skeptical about it, as the spacing of the letters is a little uneven.  I made a cast of the chamber, and am pretty sure it is a 25-20 SS.   The face of the action is marked with a 44 and  a O, and the barrel has 3 v shaped marks near the action, so I wonder whether they are significant.  The bore had a little dust, but cleaned up very nicely and looks great, and the action is missing the extractor and mainspring, it seems, as the lever and hammer are pretty floppy as it is.  I'm wondering what to do now, as I am pretty confident that I could replace the spring and extractor, and I've got some good books and have done some reading about breech seating, etc., but if it might be a legit Pope barrel, should I not shoot it?  I appreciate the wealth of information here, and look forward to hearing what you guys think.  By the way, it had a Fecker scope,with the numbers 6836, which I am not sure if that is a model or serial number. 

Besides the HM Pope stamping be questionable it is also lacking the additional data Harry put on his barrels.

I have been pondering the idea of using a tightly patched cleaning rod or dowel with a pointer to try to measure the pitch of the twist, to see if there is a perceptible change in the pitch of the rifling from chamber to muzzle.  I may try that tonight.  The barrel is a little over 24 inches long, so I don't know if that is sufficiently long enough for me to be able to tell, but it is probably worth a try.  If anyone can suggest a better method, I'm all ears.  Thanks again!

To add to what Mike said you should also be able to see the gain. Keep in mind that Pope is not the only one who made left hand gain twist barrels so it will actually in all reality prove nothing. When looking at the name on the barrel it appears to me that someone was trying to pull a fast one as it is was very unprofessionally done and is pretty much the opposite of Pope's high standards. I might add his name was generally located on the exposed part of the barrel for all the world to see, the barrel number, dates etc. were hidden under the forearm.

J.Louis

Not a surprise Robert. Harry Pope's name is probably the most commonly forged name ever stamped on a gun! Some are obvious fakes, while some take a very astute eye to determine. Some are just too good to even know if they do everything right, including the rifling. Most never go that far.

The right hand twist Pope barrels I've seen are for cartridges associated with smokeless powder (.30-06, .30/.405, 7.5 Swiss, 7 x 57 etc), and for those by Stevens Pope for the .30-40 Krag.  I don't recall any for black powder era cartridges like the original poster's .25-20 (S.S. most likely on a 44 action) that are right hand twist.

There is one other possibility, that is that someone who had a heavy Pope barrel had it turned down to make weight. After the smith turned it down and removed all the information he stamped Pope's name on it so others would know it was a Pope. 
If it has Pope style rifling it should be sent to someone who can make an educated guess.

40 Rod