I know Glock, Springfield Armory XD, and some 1911's are single action, but what else are?

I like the constant light trigger pull.  Good brands only please.

Glock is double action, but the pull is very light for DA.  In addition, you can get a 3.5 lb connector and lighten even more.

XD might also be double action.  I'm not sure.  I don't have one.

As for your question, I don't think I know of more.

If you're just looking for constant trigger pull and no DA/SA transition, then you might be into things like the sig DAK and H&K LEM.  Good luck getting either of those under $550 though.  Sorry, I guess I'm not much help.

BHPs (SA ones)

personally, there is only ONE SA auto, and thats a 1911 w/ a nice trigger

Quoted: The CZ75 and family are mostly DA / SA but can be carried cocked and locked ansd used strictly SA if desired. Careful shopping can find NIB CZs for $400 and under...one of the best deals in handguns today.

there is also a cz75 single action version.  linky.  in my area i have seen it for $450 but you can find them for less at gun shows or if you just shop around.

I just bought a 98% condition used Springfield Loaded .45 for $500.00. Hope that gives you another choice. Alot of people never use their guns enough to break them in, much less wear them out.

In this price range I think Glock is the only manufacturer worth discussing. I would buy a G19 and be done with it.

Quoted: In this price range I think Glock is the only manufacturer worth discussing. I would buy a G19 and be done with it.

a cz75 while heavier is infinitely more comfortable than any glock.  they are probably the most underrated pistols by shooters in this country.  you will not be unhappy with it.  

To be technically correct, Glock is neither single nor double action.  Read up on the details of the "safe action" to see what I'm talking about. The striker is partially cocked when a round is chambered/when the slide is racked, the striker is fully cocked and released by pulling the trigger.  With that said, it's somewhat similar in usage to a two-stage single-action trigger.  Anyways, I'm surprised nobody mentioned the Auto-Ordnance (Kahr) 1911.  I know it's a POS, but it's below $550.  In all seriousness, you may be able to find some Taurus pistols for what you're looking for.  What about those Rock Island Arsenal (Philippine-made) 1911's ?  I'm sure there's some less-expensive Hi-Power clones out there, too.  Oh yeah, AK and AR pistols are single-action, too, and I'm sure you could find some for the price you're asking If it were me, though, based on your parameters, I'd pick the Glock.  

Quoted: Quoted: In this price range I think Glock is the only manufacturer worth discussing. I would buy a G19 and be done with it. a cz75 while heavier is infinitely more comfortable than any glock.  they are probably the most underrated pistols by shooters in this country.  you will not be unhappy with it.

Yep, it is, but the person who started the thread only wants SA pistols.  CZ75 is DA/SA, and I'd seriously consider it or a pistol similar to it if it were me looking for a pistol.  

EAA Witness
HK USP (used)
FN FNP9 or P40 (aka Browning Pro 9) in some variants
High Power and clones (FM, Argentine, FEG, Charles Daly, etc)