https://en.m.wikipedia.org/wiki/Colt_9mm_SMG

Does anyone know the correct height FSB for a colt 635?
I'm building a clone with an A1 style upper,  and want to have the correct FSB height. I have both F height and A2 height FSBs I can use but don't want to go to the trouble of pining it if it's the wrong height,  and I really hate the sight picture of a front sight that is screwed in deeper or higher than it should be.  My instinct says F height because it's a carbine,  but it's also 9mm so I don't know if A2 would be better.  Also, I think these were designed for a 50m zero. Can anyone confirm?

Thanks

Carry handle uppers get standard non F marked FSB.
Flat tops get the F marked FSB.
Someone else will chime in to confirm or you can do some research.

Well I ordered an A2 FSB from JSE surplus. You're probably right,  that is an A2 height.  I did finally find one other thread that said the same thing.  And with 9mm especially,  a taller front sight is just going to lower the point of impact without burying that post into the FSB.   I know it's probably crazy but I can tell that the F height FSB looks too tall.

Are you using a heavy barrel with the .750" sight base journal?  I'm asking because I believe all 635s had light weight barrels with .625" journals.  The A2 sight will not fit a light barrel.  Also, if using a fixed carry handle (or detachable), you'll need THIS rear aperture.  One side is for a 50 meter setting.

Thanks for the link!

Yes it's a .750 journal.  JSE had an A2 height FSB with .750 journal. Basically what they use on service rifle barrels. I had one but it had the bottom sling mount area ground off and no bayo lug.

It's not a good clone, just an approximation using the parts I had.  Having the correct rear sight should make it that much more useful.  Thanks again!

For posterity,  I pinned the A2 FSB yesterday and zeroed it(at 20yds for now). It zeroed nicely without having to bury the front sight into the base.  This turned out to be a good zero as I was able to easily hit a steel silhouette out to 100yds without holding over.  Strelok shows a 5in drop for 9mm at that distance from my zero.  

So an A2 height FSB is in fact the right answer for an 11" 9mm.  Glad I didn't use the F height FSB.
Thanks everyone.