What is a Type 5 barrel?

This question got my curiosity going for my T/C Contender barrels, I looked on the web and found this. 

T/C Contender Barrels

Type

Description

T-1 Octagon

One line address, flat base, set screw, short site. 6 caliber's T/C Arms Rochester N.H. Caliber (There are variations also) 1967

Pre Type 2

Not Type 1 has the N.H. BUT the caliber is located at the muzzle end

T-2 Octagon,

2-line address, flat base, set screw, significant identification is a period after the N.H. This type has the largest caliber selection and dates 1967-1972

T-3 Octagon

2-line address, flat base, set screw, now the period is only after the H. NOT THE N 1973-1975 (bull barrels also found is this vintage)

T-4 Octagon

2-line address, flat base, set screw is replaced with a roll pin to hold in locking lug. (bull barrels and 14" found in this vintage)

T-5 Octagon or Bull

The significant change is the flat base that now has a step on it, if you check any of you 14" barrels it will have this step.

Now with in each of the above there are variations that mainly address sites. Sights are another classification in their own right.

For those of you shooters out there T-1 - T-4 typically have the solid locking lug, which generally require changing to use on the newer frames, easy open started at serial # 195,000.

T-6 thru T-9 are current variation that describe hunter barrels, stainless, 16", 21" scope models and so on..

Unofficially I have deemed the T-9 indicating the newest rear site as used on the Encore and post-fire Contenders. Once we clearly sort through the 6 thru 8s this may change again. One thing for sure as a collector of TC's, just when you think you have it figured out.... something else jumps up and changes everything