Guest,
It is not a round barrel is like a shaped liked a stop sign
That is called an octagon barrel and many old Winchester rifles had barrels of that shape. There are small differnces on the rifles from one model to another so it isn't real simple for some one not familiar with them to tell them apart. You might read these posts and see if they help you out some. But photos will be the best way to figure it out without playing 50 questions.
http://www.gunvaluesboard.com/why-i-need-photos-
254864.html#25490
http://www.gunvaluesboard.com/give-me-what-i-need-
294224.html
I look forward to helping you on this mystery rifle.
Thanks
2bit