CAA DVSR One-Piece Mount Review
Part 1 - Bench Review
MaxIcon AR Optics Guns
For a complete list of one-piece mounts available for the AR-15 platform, see AR15 One-Piece Mounts.
At the lower end of the AR-15 one-piece mount spectrum is the CAA (Command Arms) DVSR one-piece mount. Retailing for under $25, it's an affordable alternative for those who can't or don't want to spend $200 and more on a mount.
The DVSR is a 30mm (1.18") mount with inserts to adapt it for 1" scopes.
It's available from a number of places, and has a lifetime warranty.
Note that the CAA site has the centerline height listed incorrectly at 1.82", and most vendor sites use their number. This is the height from the bottom of the mount to the centerline, not from the flat top rail to the centerline, which is the traditional measurement.
This make it one of the higher one-piece mounts available, which many like with 1-4x scopes, as the front sight is less obtrusive at 1x. Note that other examples of this mount may have slightly different dimensions, as the tolerances on inexpensive mounts are sometimes a bit loose.
The mount and inserts are made of aluminum, the screws, nut, and cross-slot screw are steel, and the finish is a semi-gloss black. The finish is very good looking, but doesn't appear to be exceptionally sturdy, and wore away to bare metal around the ring screw holes after mounting scopes 4-5 times.
It tightens to the rail with a 1/2" hex nut, and is not quick or semi-quick release. The cross-slot screw attaches to a 0.25" stud with somewhat unusual 1/4-32 UNEF threads (I think). The stud shaft and nut are the same size and threads as the Leupold CQ/T's factory rail mount. The long fixed side of the rail clamp is 2" long, and the removable clamp is 1" long on older mounts, and 2" long on newer mounts. The ring screws are metric M4x10 screws with T-15 Torx heads, and it comes with a wrench for them. The mount weighs 4.9 ounces (138 grams) in 30mm configuration, and 5.4 ounces (153 grams) with the 1" inserts. The mounting hardware is a mix of metric and SAE, which isn't uncommon with Chinese gear.
Many of the pics below have been lightened to bring out details, and the finish may appear more grey than it is. The picture with the box is pretty close to the actual finish color.
Note that it's very similar to the infrequently seen KAC 32968, with a
different finish and a lightening cut under the rear ring:
Here's what you get - the mount, a T-15 Torx wrench, and a pair of 1" inserts. There's no indication on the box or the scope about where the mount is made, but most inexpensive mounts are made in China these days.
Here's the mount disassembled as far as it will go. It's got a plastic washer for the cross-slot screw nut, similar to Armalite and other mounts.
In this design, as in many mounts (like the Eotech's built-in mount), the cross-slot screw also acts as the recoil lug. A weak point of the typical version of this style design is that recoil forces push against the rounded shank of the screw, pushing up and out of the slot. This mount avoids this by cutting a 90 degree wedge out of the shank of the screw, giving a flat surface to butt against the Picatinny slot face. This is a nice touch, and the screw shank is big enough that the structural integrity isn't compromised by this.
Here's the mount fully assembled. For 30mm, the mount side of the rings is more than 1/2 of the ring circumference, which means the scope snaps into the bottom half of the rings, similar to Leupold's QRW rings. This can scuff the scope, if you worry about these things.
DMS-1 30mm Scope Mounted
Here's the popular and inexpensive Millett DMS-1 1-4x 30mm scope mounted in the DVSR. For those with budgets that don't allow $1000 scopes and $200 mounts, this is a perfect pair. The main problem with this combo is that the DMS-1 has a very long eyepiece section, and even with the forward throw of the DVSR, the eyepiece of the DMS-1 is just above the charging handle on a typical AR15. For many, this is OK, but for those who need lots of eye relief or shoot NTCH (nose to charging handle), it needs to be mounted further forward. In this case, it's the forward ring position that limits the travel, as the adjustment cluster prevents it from mounting any further forward.
The rings were a good fit, and when firmly and evenly tightened down, there was an even gap between ring halves on both sides of the rings, which is a good thing. This gives firm clamping, to the point where the scope tube could be damaged by over-tightening, but it ensures that the scope won't be moving in the rings. The threads for the ring screws are tapped directly into the aluminum, with no thread inserts.
Alignment With The Receiver
This is the DVSR and DMS-1 mounted on a varmint upper with a free-float handguard. With the recoil lug in the second slot from the end, the mount is closest to being aligned with the upper, but overhangs slightly, though not enough to interfere with anything.
To get maximum eye relief, it can be mounted with the recoil lug in the last slot. Here, it overhangs even more. This doesn't compromise the mount stability, as the removable clamp is still fully on the upper. In this case, it still doesn't interfere with the handguard.
Mounted on a CMMG M4 style upper with a fat handguard, it still clears the handguard in the last slot, but the mount is barely touching the top edge of the delta ring on the long side. This is never a good thing, but could be fixed by either filing down the mount a bit, which wouldn't affect the mounting integrity, or by filing the delta ring where it touches. If it were mounted in the second slot, as show above, this wouldn't be a problem.
Eye Relief with the DMS-1
When mounted in the last slot, the eyepiece is about 0.5" forward of the charging handle. For those who shoot NTCH, this is still too close. Using a cheek weld a little further back works well with this setup. For me, moving back 1.5" from the charging handle gave good eye relief. YMMV, as always.
As with the varmint upper, it's too far back for good eye relief shooting NTCH. I get good eye relief with the 6 position stock in position 5, which puts my nose 1.5" behind the charging handle. For those who need more eye relief, the main 2 alternatives are an extended rail with rings, or an extended one-piece mount like the LaRue SPR-E or the American Defense Recon-X, shown in the AR15 One-Piece Mounts page.
Using the 1" Inserts
To use a 1" scope, the supplied inserts go into the bottom half of the scope mount. Of the two that came with mine, one snapped in, and the other dropped in with no resistance. There was no play in either once they were in place, however, they don't have the lips commonly seen on more expensive inserts that keep them centered in the ring. These inserts were slightly different thicknesses, accounting for the difference in how they fit into the ring - one was 0.18", the other was 0.17" thick at the thickest part. This will cause a slight offset in elevation zero, and will cause a shift in zero if the inserts are switched front to back.
Limited Clamping Force With A 1" Scope
There's no insert for the top half, so the top ring half only contacts the scope at the top center of the ring. The fit in the inserts was very good for this Leupold Vari-X IIc 2-7 scope, but the relatively small contact area on the top ring will reduce the friction holding the scope in place under recoil.
When tightening a 30mm scope in, there was a gap between the mating surfaces of the ring halves on both sides, as there should be. With the 1" adapters, though, the top ring half flexed enough that the screws pulled the surfaces together, limiting the amount of clamping force available on the tube.
This photos show the gap between the top half of the ring and the scope tube. Due to this and the limited clamping force, a 1" scope isn't held as solidly as a 30mm scope. There have been reports of 1" scopes slipping during use with this mount.
To use a 1" scope, it would take finding inserts, or ring reducers, to provide even clamping force all the way around, as well as keeping the top ring halves from flexing. Good ones can cost more than the DVSR mount, and finding the right fit for the width could be tricky, as they're usually made for a specific ring design.
Here's the Leupold mounted on an upper. A traditional scope with a shorter eyepiece works well in the CAA, with plenty of eye relief. Here, the mount is in the second slot, and the eye relief is good with NTCH, even with a long eye relief scope like the Leupold. It's got room to move it forward to the last slot, as well.
Other 1" Ring Inserts
There are many 1" ring inserts available that are full circumference and avoid the problems of the CAA half-ring inserts, but many of them cost more than the mount does. One of the members over at www.ar15.com suggested some inexpensive airsoft rings that came with full circumference ring inserts, so I bought a set to try. The rings and inserts both have cloth glued to the inside to prevent scuffing, and I left it in place, partly because removing it would increase the diameter and reduce the clamping force. The inserts are aluminum, weigh 7 grams, and are 0.085" thick with the cloth, 0.077" thick without.
These came from http://www.combatoptical.com/catalog/30MM-MEDIUM-RING-WEAVER-STYLE-1-INCH-INSERT-QW30M-182.html, and originally were $8 ($12 shipped). Since then, they've increased the price to $13, which is still pretty inexpensive.
These clamped the 1" gloss Leupold scope much better than the half-ring inserts, and I was unable to move the scope at all in these. The top ring still tightens down snug against the bottom ring, with no gap, I'll have to test them at the range to know for sure, but they've got a far better grip than the included inserts.
Other ring inserts are available that are higher quality, but they cost more than the mount:
LaRue LT-136 - http://stores.homestead.com/Laruetactical/Detail.bok?no=24 - $29 ($38.25 shipped)
ARMS #37 Ring Inserts -
http://www.armsmounts.com/catalog.php?action=124&item_id=13 - $35
Steel with a phosphate finish
Part 2 - Range Test
It hasn't been to the range yet, so that will have to wait!
The CAA DVSR appears to be a sturdy, well made 30mm mount for a reasonable price. Though it hasn't been to the range for testing under fire yet, there don't appear to be any weak spots that would fail under the stress of the 5.56 round.
It clamps firmly on a 30mm scope, but is marginal on a 1" scope using the supplied adapters. Like many one-piece mounts, it won't work well for scopes with long eyepieces or very long eye relief, but for scopes that fit well, it's had good reports from those who have used it.
It's flexible enough to fill many people's needs for mounting a scope on a range gun, and inexpensive enough to give a head start on saving up for that LaRue SPR-E mount.
All original content copyright MaxIcon - 2008