Gents,
Seeing as you have a 9mm barrel thread going, I've got a couple of questions maybe someone can answer. I want to build a retro looking 635 upper.
1. Were the original Colt 635's produced with a 10.5" barrel?
2. Most barrels I've found come 1-10" twist except model 1 sales which is 1-15", is there any real issue with the slower twist?
3. If someone has a close up pic of the flash hider/bayonet lug from original 635 upper I sure would love to see one.

My issue is that the barrels by Spikes and RRA look slightly longer than the original Colt barrel to me. The distance between the flash hider and bayonet lug looks longer. Model 1 sales cuts their barrel to 10.25". I like the look of the flash hider almost touching the bayonet lug. However, spending extra money to cut 1/4inch is not in the budget right now. Thanks for the help.