Different types of spur gear stock

[Travis Schuh]

I have found spur gear stock (which I plan on cutting up to use in a transmission) in both the Stock Drive Products and the McMaster Carr catalog.
For a given DP and tooth count, the prices are radicaly different. I was wondering what the difference between the two gear stocks are and if the cheeper one (from McMaster Carr) is strong enough for the last reduction in a transmission.

You can buy 12in of 20DP 16 tooth gear stock from McMaster Carr for $27.80 (this works out to about $2.32/in). I do not know what it means, but it is labeled as being "cold-rolled steel gear stock." The part number is 6847K21 and it is on page 1014 of the catalog.

You can buy 6in of 20DP 16 tooth gear stock from Stock Drive Products for $37.67 (this works out to about $6.28/in). There is no indication to the manufacturing process, but it is carbon steel and the gear stock comes with a shank. It can be found by going to https://sdp-si.com/eStore/ and then clicking on "gear" tab -> "pinion wire & spur gear stocks" -> "spur gear stock" or by going to this catalog page.

I am wondering if anyone knows why there is 271% difference between the two gear stocks and if there is any reason why one would be better than the other.

Thanks,
-Travis