AR15 One-Piece Mounts
MaxIcon AR Optics Guns
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
One of the simpler and sturdier methods of mounting magnified optics to an AR15 is with a one-piece mount.
Here's the Big List of AR15 one-piece mounts. I'm always interested in reviews and experiences, good and bad, and in any mounts I may have missed or corrections to the info below. You can email me at maxiweb1@maxicon.com
Notes:
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
American Defense RECON Scope Mount
Recon mount with 1" rings.
http://www.bravocompanyusa.com/American-Defense-RECON-Scope-Mount-1-inch-rings-p/ad%20recon%201in.htm
Recon mount with 30mm rings. $180 new -
http://www.bravocompanyusa.com/American-Defense-RECON-Scope-Mount-30mm-rings-p/ad%20recon%2030.htm
The Recon mounts are $180 new. They extend the scope forward approximately 2 inches.
Recon X extended mount with 1" rings -
http://www.bravocompanyusa.com/American-Defense-RECON-X-Extended-Scope-1-in-rings-p/ad%20recon%20x%201.htm
Recon X extended mount with 30mm rings -
http://www.bravocompanyusa.com/American-Defense-RECON-X-Extended-Scope-30mm-rings-p/ad%20recon%20x%2030.htm
ADM Recon mounts are aluminum, and have quick-release lever locks that adjust for wear or out of spec rails.
The Recon X mounts are $190 new. They extend the scope forward approximately 3 inches.
Recon S straight mount with 1" rings -
http://www.bravocompanyusa.com/American-Defense-RECON-S-Scope-Mount-1-inch-rings-p/ad%20recon%20s%201in.htm
Recon S straight mount with 30mm rings -
http://www.bravocompanyusa.com/American-Defense-RECON-S-Scope-Mount-30mm-rings-p/ad%20recon%20s%2030.htm
The Recon S mounts are $160 new. They mount the rings directly above the receiver.
Thanks to Bravo Company for these pics!
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
Armalite
1" mount -
http://www.armalite.com/ItemForm.aspx?item=EX0027
30mm mount -
http://www.armalite.com/ItemForm.aspx?item=EX0022
The Armalite is $89 new, $50-75 used (the new price was briefly reduced to $69, but has returned to the old price now).
Centerline height - 1.25" for 1" and 30mm
Weight - 211 grams, 7.4 oz (1"); 194 grams, 6.8 oz (30 mm)
Body -
Aluminum
Ring Screws - 1/8" allen head, 6-32 x 1/2 threads
Clamp Attachment - 10-32 x 5/8 pressed studs, high-profile knurled thumbscrews
with plastic washers
Recoil lug - Integral Picatinny lug
The Armalite is one of the lower of the one-piece mounts, and is one of the best made for under $100. This makes it difficult to clear most rear BUIS', depending on the scope, but is better for those who want to be closer to the bore axis. It has a single recoil lug. There are 4 screws for each ring.
It's got good forward offset, though not enough for scopes with long eyepieces (like many illuminated scopes), like the Mueller in the picture below. With low-profile handguards, it can be mounted with the recoil lug in the last slot, which leaves the front thumbscrew hanging out over the handguard. This gives a little extra eye relief and is still very stable, though it still may not be far enough forward for some scopes.
If Armalite would make this mount available in a 1.5" centerline version, they'd have the sub-$100 mount market locked up.
The factory finish on my 30mm is purplish anodizing. My 1" mount was RealTree camo, and I sprayed it black with barbeque paint, which looks better than the factory anodizing to me.
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
B-Square 15150 Flat Top Mount - 1"
http://secure.armorholdings.com/b-square/colt_military.html
$60-70 new, $20-40 used - frequently available on ebay, unlike most AR15 one-piece mounts
Centerline height - 1.7"
Weight - 178 grams, 6.3 oz
Body -
Aluminum
Ring Screws - 1/8" allen head with 8-32 threads
Clamp Attachment - Knurled low-profile thumbscrews with coin slots and 8-32 x
3/8 threads
Recoil lug - Roll pin
This is a fascinating mount. B-square isn't usually associated with high-precision name brand rifles, but a version of this mount shipped for a while on the high-end Colt Accurized Rifle, model CR6724, and you often find take-offs on the used market. The Colt version of the mount has the Colt logo on one side, and commands a slight price premium. Interestingly, it's often seen mounted backwards on the rifle, possibly because of the A2 stock, which didn't require the same amount of extended eye relief as shorter stocks.
It's got semi quick release thumbscrews with coin slots, and instead of a traditional recoil lug or cross-slot screw, it's got a roll pin that sticks down into the slot. It also has see-through cutouts, in the tradition of many B-Square mounts and rings. The B-Square can provide a good bit of forward eye relief, depending on the handguard, and has a single screw per side for the rings. The rings are 3/4" wide.
If it's installed with the cutout above the delta ring, it covers all the slots to the rear, so there's no room for a BUIS. On an upper with M4 handguards, it can be installed further forward, with the cutout over the handguards. This gives more eye relief, but barely uncovers one slot, so there's still no room for a BUIS.
With a varmint-style FF handguard, it can be mounted as far forward as the roll pin position will allow, though it starts to get unstable once the front thumbscrew is ahead of the rail. With the front thumbscrew at the front edge of the rail, there's plenty of room for a BUIS, and lots of forward eye relief as well.
The lack of BUIS space could be fixed by cutting off the mount behind the roll pin or by extending the front cutout further back to allow more forward mounting without hitting the handguard.
On my mount, there are machining marks on the base where the rings are squared up to the body and on the flat surfaces facing front and back. The base has a glossy black finish, while the ring tops have a duller matte finish.
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
Command Arms DVSR Dual Scope Ring Rail Mount - 30mm with 1" inserts
http://www.commandarms.com/product.asp?pID=175&cID=22
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=578080&t=11082005
http://www.bigrivertactical.com/catalog/item/2510573/5528077.htm
http://www.calssportingarmory.com/ProductDetails.asp?ProductCode=CAADVSR
The DVSR is $23 new.
Centerline height - 1.58" (30mm); 1.67" (with included 1" inserts)
Weight - 138 grams, 4.9 oz (30mm); 153 grams, 5.4 oz (with 1" inserts)
Body -
Aluminum
Ring Screws - Torx T-15 heads, M4x10 metric threads
Clamp Screws - 1/4" pressed stud with 1/4-32 UNEF threads (I think), 1/2" nut
Recoil lug - Cross-slot screw shaft with 90 degree wedge cut out
See a full review of the DVSR here, with lots of pictures, including the
Millett DMS-1:
CAA DVSR
One-Piece Mount Review.
The DVSR is a surprisingly good mount for the price when used with 30mm scopes. It holds up well, provides decent forward offset and plenty of height to clear a BUIS, and has been reliable for most people. It's a fairly close copy of the seldom seen KAC 32968. With the included 1" half-circle adapters, it doesn't clamp most 1" scopes well enough to keep them secure under recoil, but with full circle 1" adapters, it works much better.
While the forward offset is good, it's often not enough with long eyepiece illuminated scopes, like the popular and inexpensive DMS-1.
Vendor site -
http://www.aimsurplus.com/acatalog/Command_Arms_Dual_Scope_Ring_Rail_Mount.html
Manufacturer's site -
http://www.commandarms.com/product.asp?pID=175&cID=22
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
GG&G Accucam QD Scope Mount
Accucam QD
30mm Mount (GGG-1198) -
http://www.gggaz.com/index.php?id=149
AC-30
30mm Extended Mount (GGG-1238) -
http://www.gggaz.com/index.php?id=166
AC-34 34mm Mount (GGG-1264) -
http://www.gggaz.com/index.php?id=225
The Accucam QD is $200 new. The AC-30 extended and AC-34 34mm versions are $210 new.
Centerline height - 1.40" (Accucam QD)
Weight - 6 oz (AC-34)
Body -
6061 aluminum alloy, T6 temper
Ring screws - socket head cap screws
Clamp assembly - 4140 steel
Clamp attachment - QD cam lever
The GG&G Accucam is one of the better made QD mounts, and is preferred by some over the LaRue. The QD mount is also made in a lower 1.06"centerline height version for traditional rifles.
The base is aluminum and the locking mechanism is steel. It has a 1.400 centerline for the AR version, and 1.060" for the bolt gun version. Repeatability has been tested by the manufacturer at 0.5 MOA. The QD lever is adjustable for worn or out of spec rails.
For the QD, the center to center distance between the rings is 4.4". For the AC-30 and AC-34, the overall length of the mount is 5", the base is 4", and the distance between the inner ring edges is 3.75".
Accucam QD 30mm
Accucam AC-30 Extended 30mm
Accucam AC-34 Extended 34mm
Burris FFII Tactical 3-9x40 scope in a GG&G mount
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
JP Rifles One-Piece
1" mount -
http://www.jprifles.com/buy.php?item=JPFTSM-1
30mm mount -
http://www.jprifles.com/buy.php?item=JPFTSM-30
The JP mount is $150 new. It's one of the best made and sturdiest of the non-QR one-piece mounts.
Centerline height: 1.5"
Leupold VX-III 4.5-14 scope mounted in a JP mount - note more forward offset is
available in both rings
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
Knight's Armament (KAC)
http://www.knightarmco.com/mod_weapons_2.htm
25284 (black) 34mm, 1.4" high - $270 new
24755 (FDE) 34mm, 1.4" high - $270 new
24755 M110/SASS (FDE) 30mm - $213 new
32968 - 30mm, 1.57" high - Price unknown.
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
LaRue Tactical
SPR/M4 LT-104 -
1", 30mm, 34mm -
http://stores.homestead.com/Laruetactical/Detail.bok?no=30
SPR-E LT-139
Extended Eye Relief -
http://stores.homestead.com/Laruetactical/Detail.bok?no=40
SPR/M4 LT-135
1.93" extra high -
http://stores.homestead.com/Laruetactical/Detail.bok?no=67
SPR-S LT-158 -
Slightly lowered version, 10 MOA elevation -
http://stores.homestead.com/Laruetactical/Detail.bok?no=42
The LT-104 and LT-158 are $195 new, $150-180 used.
The LT-135 and LT-139 are $215 new, $160-190 used.
Centerline Heights:
LT-104, LT-139 - 1.5” (30mm), 1.41" (1")
LT-135 - 1.93” (30mm), 1.84" (1")
LT-158 - 1.44” (30mm), 1.35" (1") - 10 MOA elevation
(The 1" mounts are 0.09" lower than the 30mm mounts)
Clamp Attachment - 2 QR levers with oiling holes, one with a lever lock
Recoil Lug - 2 Integral Picatinny lugs
Considered one of the best quick-release mounts, the LaRue is pretty close to a perfect mount for the AR. It has a good reputation for return to zero when remounted in the same position, is well made, has an assortment of heights and forward offsets in multiple versions, and the company provides good customer support.
LaRue mounts leave enough room behind the rail for mounting a BUIS, and have 2 integral recoil lugs. The QR levers are adjustable for worn or out of spec rails, requiring a wrench for adjustment.
For traditional scopes, the LT-104 SPR mount provides good eye relief for most people. For scopes with long eyepieces, like most illuminated scopes, the LT-139 SPR-E extended mount provides more flexibility. The SPR-E works well with the popular and inexpensive DMS-1 scope, but costs nearly as much as the scope does.
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
Leatherwood Hi-Lux 3DSMT Mount - 1" or 30mm
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=617607&t=11082005
http://www.opticsplanet.net/leatherwood-3d-all-steel-tactical-mount-w-cam-and-calibration-ring.html
The Leatherwood Hi-Lux 3D is $360-$370 new.
Body -
Steel
Weight - over 2.5 lbs
This curious and fascinating mount gives up to 120 MOA of vertical adjustment. It's a 30mm mount with 1" full circumference ring adapters that are flanged to keep the adapters from shifting in the 30mm clamps.
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
Mamba Products Long Range Mounts
25 MOA, One inch rings, 0.875" centerline -
http://www.midsouthshooterssupply.com/item.asp?sku=000331WAR2508
25 MOA, One inch rings, 1.00" centerline -
http://www.midsouthshooterssupply.com/item.asp?sku=000331WAR2510
25 MOA, One inch rings, 1.30" centerline -
http://www.midsouthshooterssupply.com/item.asp?sku=000331WAR2513
40 MOA, 30mm rings, 1.30" centerline -
http://www.midsouthshooterssupply.com/item.asp?sku=0003330WAR4013
The Mamba 1" mounts are $150 new, and the 30mm mount is $200 new.
The Mamba Long Range one-piece mounts provide additional MOA elevation for long-range shooters. They have no additional eye relief compared to standard rings. They use Torx-Plus screws, and include a wrench and spare screws.
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
Model 1 Sales - 1" or 30mm
http://www.model1sales.com/item-detail.cfm?ID=SMR001Y&storeid=1&image=mountring.gif&CFID=15996856&CFTOKEN=50254977
The M1S mount is $65 new, and $40-50 used.
Centerline height - 1.75" (1" mount)
Body - aluminum
The M1S mount is one of the higher one-pieces. As a result, it will clear a folding rear BUIS better than shorter mounts, and 1x scopes will have less of the front sight in the field of view. However, it may need to be mounted so that it will overhang the handguard in order to leave enough slots open for a BUIS.
3.3-10x44mm Nikon Monarch UCC in a M1S mount
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
Nightforce Uni-mount - 30mm
http://www.nightforceoptics.com/RINGS__BASES___MOUNTS/rings__bases___mounts.html
Standard Height -
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=342977
Extra High -
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=540085
The Uni-mount is $260 new.
Centerline height - 1.125" and 1.4" versions (also available with 20 MOA of elevation)
The available info on it isn't clear (the Midway links list it as both aluminum and steel), but it appears the standard version is steel, while the Ultralight has a 7075 T6 aluminum body and titanium alloy crossbolt, nut, and jaw. The Nightforce gives a good bit of extension, while leaving plenty of open slots for a BUIS, as seen in the picture below.
The Nightforce with a Nightforce 2.5-10x24 NSX mounted. There's room to move the scope even further forward in the rings for those who need lots of eye relief.
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
ProMag One-Piece - 1" and 30mm
http://www.promagindustries.com/accessories.asp
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=371698&t=11082005
The Promag mount is $35-55 new.
Centerline Height - 1.68" (1" - measured), 1.45" (reported)
Weight - 277 grams, 9.8 oz
Body -
Aluminum
Clamp Attachment - Flat thumbscrews on separate threaded stock
Recoil lug - Square stock shank of the front cross-slot screw
The Wilson, ProMag, and RRA mounts all appear similar to each other.
The Promag is an inexpensive mount that gets mixed reviews on vendor sites, usually for stripped threads or screws. It's a tall mount, with lots of room for clearing a BUIS, and several slots open behind it that will fit most BUIS. It provides little additional forward offset compared to rings. Due to the ring width and spacing, it can have less offset than just rings, as seen in the picture below, where the rear ring limits the scope's forward offset.
The rings have a layer of tape in them to help protect the scope from scratches and to give a little extra pressure. The ring halves don't fully meet when a scope is in place, which is good because it allows enough pressure to hold the scope firmly and keep it from shifting under recoil. You can crimp a scope tube by over-tightening them, but this is common with most scope rings. There's some color mismatch between the mount body and the top ring halves. The rings are 1.16" wide, which gives plenty of clamping area, but can limit how much some scopes can be adjusted in the mount. The ring screws are allen head.
The recoil lug is the square shank of the front cross-slot screw, which limits how far forward the mount can be placed, and is 0.155", which is a size range for use with both Picatinny and Weaver slots. The rear shank is ground down flush with the base, removing about half the metal, even though it lines up with a Picatinny spaced slot. Both screws are separate from the base - they're pinned at the non-screw end and glued into place. The rail clamp is spring-loaded to ease in removal and install. Rail attachment is by flat headed steel thumbscrews. Once the screws are tight, there's no option to re-adjust the screw angle as with some QR lever rings.
The mount packaging was marked "May be assembled from domestic and imported components".
Nikon Primos Monarch in a PM067 mount - note the scope barely fits due to ring
spacing
Many thanks to anonymous for the great pics and data!
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
RRA mount - 1"
http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=326
The RRA is $48 new.
Centerline Height - 1.7"
Body -
Aluminum
Clamp attachment - thumbscrews with coin slots
The Wilson, ProMag, and RRA mounts all appear similar to each other.
The RRA is a tall mount, with lots of room for clearing a BUIS, and several slots open behind it that will fit most BUIS. It provides little additional forward offset compared to rings.
Redfield scope in an RRA mount
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
Talbot (actually a 2 piece - one-piece ring pair and mount base adapter
for different rifles)
http://www.talbot.us/scope_mounts.php?osCsid=3ded5efc5ef2dd81d5790e99f442bece
The Picatinny base is $312 new, and the optics adapters are between $125 and $188 new, for a total cost of $437 to $500(!).
The Picatinny base is available in 0, 10, and 20 MOA elevation versions, in both high and low mounts. The optics adapters are available in 1", 30mm, 34mm, 35mm, and 40mm, and are also available in a reverse version for mounting the optic further back.
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
US Optics (USO) Posa-Slide and Lock - 30mm
http://www.usoptics.com/acc.php?typeID=Mounts
$170-250 new, $150-180 bundled with a USO scope.
Centerline Height - 1.2"
Body - aluminum - available in custom colors
Most frequently seen bundled with their SN-4 scope, but also available separately. The rings only have screws on one side. The Posa-Slide system has a spring loaded recoil lug and thumb/coin screw for quick detach.
Posa-Slide and Lock Mk I - 2 rear screws, 1 front screw - $250 new
http://www.usoptics.com/accD.php?recordID=PSL-100
Posa Lock MkII - 3 rear screws, 2 front screws - $250 new
http://www.usoptics.com/accD.php?recordID=PSL-200
Posa Slide and Lock MkII Quick Detach - 3 rear screws, 2 front screws - $170
new
http://www.usoptics.com/accD.php?recordID=PSL-220
Posa Slide and Lock MkII T. S. version - extended length - 2 front screws, 2
rear screws - $250 new
http://www.usoptics.com/accD.php?recordID=PSL-240
The non-screw side of the ring mount system
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
Wilson Combat
30mm mount -
http://www.wilsoncombat.com/r_lo_mount_scope_mount.asp
1" mount -
http://www.wilsoncombat.com/r_lo_mount_scope_mount1.asp
The Wilson Combat is $80 new.
Centerline Height - 1.65" (it's not clear if this is for both mounts or just
one)
Machined from bar stock
The Wilson, ProMag, and RRA mounts all appear similar to each other.
The Wilson is a tall mount, with lots of room for clearing a BUIS, and several slots open behind it that will fit most BUIS. It provides little additional forward offset compared to rings.
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
After all those choices, what do you do if nothing works out the way you need it to? There's another option with maximum flexibility, both for price and configuration - an extended, or scout, rail with rings.
Super Sniper 16x in Burris XTR low rings on an RRA extended mount
An extended rail and rings can fill the same need as a one-piece mount. On the plus side, it's very flexible in both height and eye relief, there's a wide price range for the parts, and you can upgrade one part while keeping the other. On the minus side, there are more connections to loosen or shift, but with the right tradeoffs, they can be as stable as a traditional one-piece mount.
The goal for height is the same as with a one-piece mount - you want the centerline somewhere around the 1.4" iron sight centerline height, but some people like a little more or less, and sometimes extra height is needed to clear a tall BUIS. For the total height, you'd add the rail height to the ring centerline height. Most extended rails are about 0.5", but there are lots of variations, just like with all AR optics.
One of the benefits of this approach is that you have a much wider selection of rings available, as many traditional rings are available in the 1" centerline range, while the 1.4-1.5" rings needed for mounting directly to the flat top are often only available in more expensive brands.
With this setup, you can change your scope height with new rings, or change the forward offset with a different rail, without having to change everything at once. You can even go with a QR mount using something like the LaRue LT-101 rail, though this will have you approaching the cost of the LaRue SPR mount by the time you add good rings.
Millett DMS-1 mounted on a GG&G scout rail and rings - additional forward offset
is available by moving the rear ring forward.
Extended rails are available from YHM, ARMS, RRA, GG&G, Millett, LaRue, and others. When choosing an extended rail, here are some of the things to look for, depending on your needs:
ADM Armalite B-Square CAA GG&G JP Rifles KAC LaRue Leatherwood Mamba Model 1 Sales Nightforce Promag RRA Talbot USO Wilson Extended Rail and Rings Rings Only
Another option that some people use is to mount rings directly on the flat top rail, as you would with a traditional rifle. There are a few potential problems with this, but it works out well for some uses.
Leupold PR 3-9x40 scope in Leupold Mk4 high rings - these could be a little
taller
The biggest drawback is that rings don't provide much forward offset, so scopes with long eyepieces or lots of eye relief can be too far back for some people, especially if they shoot nose to charging handle (NTCH). With a long stock or a cheekweld far back on the stock, this can work out fine. In the picture above, the scope is as far forward as it can go, and is limited by the front ring position. This would work for some setups, but not for NTCH. Likewise, many illuminated scopes have very long eyepieces, and would be even further back.
The other problem is that you need very high rings to get the scope centerline around the 1.4" iron sight centerline. Most traditional scope rings aren't nearly tall enough - they need to be designed to work with the AR platform, and are often called ultra high or something similar. Many of the AR specific rings are expensive, and most affordable rings don't go high enough, though there are some exceptions.
Rings high enough for use on an AR include Leupold Mark 4, Burris XTR, Badger, Millett Tactical, IOR, Warne Maxima and Tactical, and ARMS.
A note on ring heights and sizes
Like so much else in the optics world, there aren't many standards regarding ring heights and sizes, and many companies don't give enough information to make the right decision before you have the rings in hand.
Heights are different between different brands and models - Burris' XTR high is different from Warne's high, and Leupold's QRW high are different from Leupold's Mark 4 high.
In addition, some vendors spec the height to the centerline (like Leupold), while others spec their ring height to the bottom of the ring (like Burris). To get the centerline height for these rings, you have to add 1/2 of the scope tube diameter to the spec height - 0.5" for 1" rings, or 0.59" for 30mm rings.
As an example, the popular Burris XTR extra high rings are spec'ed at 1" high for both 1" and 30mm. Burris specs to the bottom of the ring, so the 1" version would have a centerline of 1.5", while the 30mm version would have a centerline of 1.59". Leupold's Mark 4 super high rings are spec'ed at 1.40" high for 1" and 30mm. Since Leupold specs to the centerline, both rings have a 1.4" centerline.
The important thing is to find out what the specs are for the rings you're interested in, and whether they spec the ring bottom or centerline. This can save a lot of frustration and wasted money.
Thanks to kwrangln, Blacktail-8541, army_eod, nvhunter, Bravo Company, Glock24, fatbarrel, and many others for some of the great pics and info on this page. If I haven't given you credit for a photo or data, let me know and I'll fix it!
