Correct Smith Corona.

[1563621]

Picked this up at an auction. Barrel gauges just over 0 both ends. Looks like a six groove also. Eyes are not too good. I am sure not a 2 groove. Picked up the TE gauge somewhere, marked machine gun also. http://imgur.com/a/WkUPS

[1563621]

680 plus the ride.

[CPC]

Looks like a nice rifle, thanks for sharing. The bolt parts are not correct for your rifle. The bolt sleeve does not appear to be SC as well as the striker/firing pin rod from my quick glance of your rifle on imgur. I am no expert but like everyone I have an opinion and I believe your rifle may be a little early for a square lugged SC bolt. Hopefully some of the gurus with experience will chime in. You can take a paper clip, etc. and just count the bumps around the muzzle and that should indicate how many lands or grooves the barrel has.

[1563621]

Another SC 2-44 barrel with pinned stock. Thanks for the paper clip trick.http://imgur.com/a/Iuu5r

[Cosine26]

An easier way is to take a bullet,point in first, insert it into the muzzle and give it a tap. Then extract the bullet an you will find the number of grooves easily. Use a bullet only, not a cartridge!
FWIW

[Rick the Librarian]

I just focus on the grooves at the muzzle - start with the 12 o'clock position and go clockwise - works every time.