I've got an Armalite DEF10 on the way.  I would like a scope and mounts that will work and not break the bank.
I've got magpul flip up rear and front sights, and I'd like a scope mount that will go over them so I can leave them on
the gun.  I saw a reference in a thread to a Vortex Crossfire 11 is something like this what I'm looking for? I have no intention
of shooting past 200 yards.  Thanks

Since your max range is 200 or less, you shouldn't have to spend a great deal of money to obtain decent optics and mount.  Consequently there are a ton of good options.  You shouldn't need anything bigger than a 2-7 or 3-9.  Some would even suggest something like a 1X prism red dot along the lines of a Vortex Spitfire with a DRT reticle for no more than 200 yards.  There's a lot of preference and variables here.

On a mount I'd suggest something along the lines of a one-piece cantilever design like a Burris PEPR.  With an AR you need a slightly more specialized mount than what most bolt rifles use.  Still, even here there are preferences and variables all over the place.  These slightly more robust mounts like a Burris PEPR and such are probably a better match for the harsher recoiling of a bigger caliber AR.

I have one Armalite .308 AR10 with a 20" barrel that I have a 5-20 Burris scope attached on a PEPR mount and a 16" model with a Burris 2-7 on a PEPR mount.  I found the Burris 2-7 E1 scope on sale for about $135 last year and the mount was on sale for $75.  I could see myself also going with a 1X prism red dot on the 16" carbine since I have the longer 20" AR, but if the 16" was my only AR10 I'd probably stay with the 2-7 scope for a wider use.

Again, there are lots of options, preferences, and variables, and yours could change once you really start to use the rifle for whatever uses become your priority.

Take a look at SWFA's scopes. They are the best scopes for the money. Lots of 30mm tubes for $300-350 that are better than most $1000+ scopes. Aero Precision makes some nice mounts.

https://swfa.com/optics/browse/riflescopes.html?brand=2744&p=2

http://www.avantlink.com/click.php?tt=cl&pw=55963&ctc=iwsr1cjblh00zk8a02gtd&mi=13601&url=http%3A%2F%2Fwww.aeroprecisionusa.com%2F

SWFA scopes are not better than $1000+ scopes, never have been, never will be. The OP's rifle has a 16" barrel, I'd look at an Aimpoint Pro red dot and call it day. It will serve very well inside 200 yards.

Leupold's 1.5-5 Fire Dot or VX-3 scopes would be my next pick.

I need some magnification, I'll be 60 this summer and I need visual aid

Do the cantilever type mounts leave clearance to keep a magpul flip sight folded down on the rifle?

https://rover.ebay.com/rover/1/711-53200-19255-0/1?type=3&campId=5337559805&toolId=10001&customId=iwtmy1ke6v00zk8a00004&mpre=http%3A%2F%2Fwww.ebay.com%2Fitm%2FHammers-One-Piece-Offset-30mm-Scope-Mount-w-1inch-inserts-Picatinny-QD-Cam-Lock-%2F381605014084%3Fhash%3Ditem58d96e6a44:m:mNBFyyybO9FMPkMDhWanRUw

I have this mount, but it's cheaper on Amazon ($52).

It's actually the best inexpensive mount I've purchased, and I use it on my AR-10 for hunting. It holds zero pretty well in detached mode (not perfectly, but POA returns to within 1.5" at 100 yards after removing the mount/scope, and clamping it back on the rifle).
It's perfectly stable/solid when you leave it clamped to your rifle.

I took mine apart after receiving it, cleaned it up, painted it, and then lubed/greased the appropriate fittings.

Read the reviews on Amazon.

G.

If BUIS are a necessity, you MIGHT save yourself hassle and get the Magpul MBUS pros.

Yes, they are a bit pricey, but they don't require you to even think about what to do with the scope if something goes wrong with it, or you just don't need it. No special scope mounts, no driver set to remove the scope/mounts if it fails, etc.

The Def 10 I have came with a gas block rail and an A-2 type mid length handguard.  If you aren't going to use a railed handguard then check to make sure you have the correct height front sight.  I don't know how well a non metallic front sight will hold up on a gas block. Maybe someone else has experience with that.

I need the scope eye piece backed up so far it makes a rear BUIS unusable. I find that the eye relief on most scopes requires that it be almost even with the rear of the receiver. This makes using the BUIS an option only after removing the scope and mount.

The scope mounts that extend further forward seem to work with any scope, the ones that aren't cantilevered at least a little sometimes can't be used at all. AR10 upper receivers are longer than AR-15's and sometimes allows standard rings or mounts to work with some scopes. Unless you have a true 1x scope and an adjustable stock you won't be able to use the BUIS without removing the scope anyway. The magnification will screw up your sight picture makit it impossible to see the front sight.

I'm certainly not an optics snob, my optics come from wal Mart. I was looking for a good AR mount recently that was sturdy and didn't look rediculios like anything UTG makes, or cost a fortune. First of all, larue mounts actually aren't that expensive, but I wanted a little cheaper. I found the Weaver SPR thumb nut mount. It looks good, mounts with 2 thumb nuts just like a usgi m4 carry handle. I'm told it returns to zero pretty good. I haven't used mine yet, but I plan on indexing the nuts with a dot of white paint. You can remove the mount with your hands or a flat head screw driver in the field (who doesn't have a pocket knife/leatherman tool on them at all times?) It only cost $50. I think it's the best cheap mount, from there I'd just buy a larue.

AR-10s don't necessarily need a cantilevered mount, because of how long the upper receiver is.

Normal, extra high rings can be used. I have a high regard for TPS rings, and I think paired with a Vortex Strike Eagle would work well for what you're trying to do.

Zia, I agree that one can usually mount a scope on most big caliber AR's with separate rings due to receiver length.  However, do you think there's any improvement in mounting integrity with a one-piece/cantilever mount?  I realize one can get a one-piece mount that isn't cantilever.  

Yeah, I've read quite a bit about the pros and cons stated by others in regards to one and two piece mounts, but most of it seems more opinion based than structural evidence.  Any source out there that has somehow qualified a potential strength benefit with the one piece units?  I also realize that all brands/models of one or two piece mounts aren't created equal.  A one piece mount just appears structurally more sound, but that's definitely unqualified on my part...LOL!

As to my using a one piece cantilever mount on my AR10's vs. an inline one piece, I'll admit that it's because I can use the cantilever units on my AR15's and AR10's interchangeably.

I bought this at a gun show today, and kind of like the Nikon 3x9 pro staff for the price. If this mount does not work on the Armalite when it gets here I'm sure I can use this on a 5.56 gun.  It's a Rock River 1" mount. Is the Nikon pro staff ok? Attached File

Nikon has different levels of Prostaff, but all of them are decent scopes...again, your 200 yard requirement is well within the Prostaff's capability.  On that mount, do you know what brand/model it is?  The quality level can make a difference down to up to a certain level.  As far as fitment, even though the large receiver AR's don't necessarily need a cantilever mount, it should work just fine with the 3-9 Nikon.