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Posted: 10/1/2010 3:14:17 PM EDT
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DISCLAIMER: this pictorial review and comparison is my personal observation, not of Battle Arms Development.
I have four 4x32 ACOGs, (TA01NSN, TA31F, TA31DOC, and TA31ECOS), all of them have the excellent LaRue ACOG mount. Having heard so much great reviews on the Bobro mount, I had to get one from our friends at Loess Hills Tactical to try one out. The Bobro mount is auto compensating, and so does not come (or need) any tools, since it's not adjustable or needs to be adjusted. Before I got this mount, I thought the locking mechanism stuck out quite a bit. After comparing it with the LaRue mount, the protrusion is very similar, with Bobro's 0.10 or so thicker (not counting the protrusion of the cam on the LaRue lever.) 
Top view 
Bottom view 
Other than the locking mechanism, the biggest difference has to do with where the mount sits on the receiver. With the LaRue mount, it can be mounted almost right next to the BUIS, whereas the Bobro's (whether with the locking lever on the left, or right), leaves a rail space between itself and the BUIS. 
Notice the ACOG is fully seated and enclosed in the LaRue mount, whereas a tiny portion of the ACOG's bottom overhangs the Bobro's mount. I don't think this has any ill effect, and it does serve to bring the ACOG further toward the rear. For a short eye relief optic such as the 4x32 ACOG, I like the scope to be as close to my eye as possible, though with the carbine retractable stock, this isn't much an issue. On rifles with fixed stocks, every bit helps. With the Bobro's mounted one rail space forward, I wondered if the slightly rear cantilevered aspect would offset or negate the mount being one rail space forward... Yes, not by much. LaRue's mount still places the ocular lens closer to the eye than the Bobro's. 
The height of the mount is similar, the channel where the ACOG sits on is identical on both. LaRue's mount that interfaces with the ACOG'd bottom is taller, whereas the Bobro's is shallow. I'm not sure if this makes any difference, it seems LaRue's offers more resistance to the ACOG canting if it's knocked very hard, but I'm just guessing. 
Regarding the locking mechanism, this is all personal opinion: Bobro's is easier to unlock and remove, being it has a single lever, the thumb pushes down on the lever's security lock while the index finger swings it open. LaRue's has two levers, the rear lever has a security lock, one pulls the lever rearward then swings it open. The auto compensating, no-adjustment-required aspect is appealing to me. I rarely have had to adjust my LaRue mounts (and I have several, on top of my ACOG mounts). I keep a wrench in my pack in case I need to, so far I've only lent it to others to adjust theirs, having never needed it for myself yet while in the desert or at the range. When it comes to non-adjustable vs. adjustable comparison, it is not solely a comparison of solely LaRue against Bobro, but every other adjustable mount against Bobro. ADM's can be adjusted without a tool, as many others like GG&G, Surefire, KAC, Wilcox, etc. What if there is no adjustment necessary as with a Bobro mount (not the old ARMS that can be hit or miss, while being non-adjustable)? 
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<Start thread hijack - sorry, BallisticTip - Z> NOTE TO ANYONE POSTING IN THIS THREAD: Do not make this thread personal and keep all replies within the realm of a TECHNICAL discussion. I will not tolerate this thread going off-topic. <End thread hijack - sorry, BallisticTip - Z> Good info. |
Excellent review Duffy! 
I too recently received a Bobro ACOG mount to try out, although mine happened to come from Primary Arms. I am running a pair of TA11-series ACOGs, which typically get mounted further forward on the rail due to the difference in ER: 
As is the case with your 4x32's, the LT mount places the optic about 1/8" further rearward for a given rail slot. Here are a few closer shots of the respective mounts: 
With the body forgings of the 3.5x35's the Bobro is slightly more "centered up" longitudonally, which is the converse of the 4x32 forgings. It is interesting to see that the underneath of your LT mount exhibits the same "burnish" marks as all of mine do. I haven't run the Bobro long enough to see whether or not it will do the same. One aspect that you sort of alluded to, but didn't explicitly elaborate on, is that the lever of the Bobro can be reversed for "left" or "right" operation by simply removing the two Torx screws and flipping it around. I don't consider this as a particularly big deal as the LT-100's seem to now be available with either "left" or "right" levers. I hope that you don't mind my augmenting your thread with some additional pics of a slightly different application. 
ETA: You will probably notice that I am also running a BAD ASS safety selector on the 5.56; I haven't gotten around to installing the second one on the 6.8 yet. I am really liking that product that y'all have come up with. |
Thanks John, I actually did not know the lever's orientation could be reversed, as usually I didn't read the manual  The manual doesn't say anything about this anyway, so thanks for augmenting my comparison, I knew I left a few things unsaid since I'm not fully familiar with this mount yet.
Another thing I noticed but didn't go into was the perception that the Bobro's lever is further out than LaRue's, the levers on the LaRue are more tucked in. The space left between the Bobro lever and the receiver COULD potentially catch on gear, I can only speculate on this as I haven't tried shooting the rifle with full armor and gear on yet. This is just speculation, I have nothing to back up anything  If that indeed proves to be the case, then I wonder if reversing the lever's orientation would help?
Re: the marks on the bottom of the LaRue mount, the mount is fairly new, but I do remove and remount the ACOG on the MRP more often than other ACOGs on my other rifles, I think a wipe with some light oil they might go away. I remember seeing these marks on other (non-LaRue) mounts too. |
Roger, you are correct that the Bobro "manual" doesn't make any mention about reversing the lever; it is something that I simply observed during my typical dissection process.
I am not sure why they don't advertise this as a "feature"? I have not tried running the mount with the lever on the ejection port side, but I seriously doubt that there would be any interference. As you have mentioned, the lever only protudes ~0.125" further outward than the LT when engaged by my caliper. As far as the LT "burnish" marks, I have 7-8 mounts of their mounts, and they all have them; they do not wipe off. As I have posted before, IMHO they are simply cosmetic in nature, and do not adversely affect repeatability, or anything else of substantive nature in my experience. |
Dang, does Andrew know you did this with the mount? 
If the manual doesn't mention it, (well it doesn't mention anything against it either), I wonder if this really is a feature designed into it, or just a happy, but unintended consequence? With some design and manufacturing background under our belt now, in the case of our modular selector (both semi and select fire), most of these happy but unintended consequences were decidedly in our favor, some of them were unforeseen, some of the effects we knew about but turned out even better than we expected
If the lever does catch on gear, I think I'll simply swap the lever from the left to the right side, my track record for taking things apart then putting them back in isn't perfect 
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I'd sure like to think that I am qualified to operate a Torx driver and a dial caliper, as well as re-applying liquid thread locker and counting to twelve.....it certainly isn't rocket surgery. There has only been one manufacturer who explicitly advised against my disassembling their products, but I took those apart as well anyway; would you like to also see those pics. 
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I wonder if this really is a feature designed into it, or just a happy, but unintended consequence?
Its a design feature. This feature allows the mount base to be rotated to have the lever on either side as well as have the lever mechanism facing either forward or rearward.
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| Great review Duffy! This topic appears to be popping up more and more on this forum as well as others! I think more and more people are giving the Bobro mounts a good look and checking their options with a Bobro vs Larue or several other QD mounting options from other manufacturers. I think your review answers several questions that others may have had and also a very detailed, including great photos, comparison between the two big dogs! I'm sure there were several people who had no idea about reversing the QD lever. As mentioned in several previous threads...both LaRue and Bobro QD mounts are solid, made extremely well, and function even better. You really can't go wrong with either!! It's just nice for us to actually have a few high quality options to choose from when considering a QD mount for your optic. |
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Roger, you are correct that the Bobro "manual" doesn't make any mention about reversing the lever; it is something that I simply observed during my typical dissection process.
http://i16.photobucket.com/albums/b42/murderman_/resize_IMG_0403.jpg http://i16.photobucket.com/albums/b42/murderman_/resize_IMG_0406.jpg I am not sure why they don't advertise this as a "feature"? I have not tried running the mount with the lever on the ejection port side, but I seriously doubt that there would be any interference. As you have mentioned, the lever only protudes ~0.125" further outward than the LT when engaged by my caliper. As far as the LT "burnish" marks, I have 7-8 mounts of their mounts, and they all have them; they do not wipe off. As I have posted before, IMHO they are simply cosmetic in nature, and do not adversely affect repeatability, or anything else of substantive nature in my experience. those look like extractor springs... that would be an interesting design feature using standard extractor springs to provide the auto-tension... that way if the springs do loosen up over time, extractor springs are easily found in any armorers supply... hmmm... anyway we can get a side by side comparison of an extractor spring and the bobro tension springs |
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It would appear as though I can also succesfully operate a 3/8" closed end wrench: 
I am surely damned to hell for all eternity for having done this. murderman, yes dammit, you will surely go to hell for that ... ... serendipity does rule again, as you damn sure perfectly displayed what K.I.S.S.** mount engineering looks like. Succinctly well put ... once again, a picture is worth a thousand words. Someone's knockin' at your door ... 
ETA - Are you and SC comin' to the " LaRue Field Day " October 16th ? ** K.I.S.S. = Keep It Simple Stupid
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Quoted:
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Roger, you are correct that the Bobro "manual" doesn't make any mention about reversing the lever; it is something that I simply observed during my typical dissection process.
http://i16.photobucket.com/albums/b42/murderman_/resize_IMG_0403.jpg http://i16.photobucket.com/albums/b42/murderman_/resize_IMG_0406.jpg I am not sure why they don't advertise this as a "feature"? I have not tried running the mount with the lever on the ejection port side, but I seriously doubt that there would be any interference. As you have mentioned, the lever only protudes ~0.125" further outward than the LT when engaged by my caliper. As far as the LT "burnish" marks, I have 7-8 mounts of their mounts, and they all have them; they do not wipe off. As I have posted before, IMHO they are simply cosmetic in nature, and do not adversely affect repeatability, or anything else of substantive nature in my experience. those look like extractor springs... that would be an interesting design feature using standard extractor springs to provide the auto-tension... that way if the springs do loosen up over time, extractor springs are easily found in any armorers supply... hmmm... anyway we can get a side by side comparison of an extractor spring and the bobro tension springs The two smaller springs actually cause the "shoe" [my term, not necessarily Bobro's] to retract when the lever is released, thus facilitating easier removal / re-installation of the mount to the rail. They are not at all like extractor springs, maybe you meant ejector springs? The four larger springs are the ones that produce the preload of the "shoe" against the rail when the lever is engaged. Quoted:
murderman, yes dammit, you will surely go to hell for that ... ... serendipity does rule again, as you damn sure perfectly displayed what K.I.S.S. mount engineering looks like. Someone's knockin' at your door ...
ETA - Are you and SC comin' to the " LaRue Field Day " October 16th ? Good morning Mark, how are you doing these days? Hopefully, this doesn't breach Zhukov's warning.... I suspect SC will be attending the LT Field Day; I'll ask him later today when he comes by to drop off some parts. If I end up going, it will only be as a spectator, since I recently had spinal surgery, and am not supposed to do any shooting for a couple of months. Hope to see you there.
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Couple more pics to illustrate the position of the lever in relation to the receiver. As mentioned earlier, LaRue's levers are more tucked in.
Below is a comparison of the channels of these two mounts. LaRue's channel walls are taller, and fully enclose the ACOG's bottom forging. 
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Couple more pics to illustrate the position of the lever in relation to the receiver. As mentioned earlier, LaRue's levers are more tucked in. <SNIP> http://i75.photobucket.com/albums/i314/Duffypoo/leverprotrusion2.jpg <SNIP> Now this top down view is a good one. Want to hear if any gear snags are relevant with the Bobro  Haven't run with one.
P.S. Maybe the "reversing" may be a good thing. |
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The angles on these two pics aren't the same, the lever on the Bobro does stick out more than LaRue's. The easy way to address this, if indeed this proves to be an issue, is to simply swap sides, so the lever is on the ejection port side.
I'm curious to hear if others' experience on this, as I haven't run it with my armor and gear on yet. 
This picture shows the position of the levers
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Great photos. I have not had any issues with the Bobro lever snagging gear, but most of my optics use LT mounts.
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Murderman, I am referring to the four screws. They look like extractor springs. Not the two smaller ones Those springs are much bigger and have much more gusto than extractor springs. |
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Great photos. I have not had any issues with the Bobro lever snagging gear, but most of my optics use LT mounts. Quoted:
Murderman, I am referring to the four screws. They look like extractor springs. Not the two smaller ones Those springs are much bigger and have much more gusto than extractor springs. 87GN is correct...extractor spring on left, Bobro preload spring on right: 
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I'm curious to hear if others' experience on this, as I haven't run it with my armor and gear on yet. ...
Here's one from the archive... http://www.ar15.com/archive/topic.html?b=3&f=18&t=461931 ...with a couple reviews including mine from back in the T&E days. And no, till this day, I haven't ever had an issue with snagging.
As for the lever sticking out a bit further, it was part of the design criteria. The lever had to be able to be actuated with heavy gloves on. Design Criteria:
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Excellent review Duffy!
I too recently received a Bobro ACOG mount to try out, although mine happened to come from Primary Arms. Remind me not to loan you a Nightforce to try out.
We trade this Acog between several test weapons and loan it to local customers to try out. Gets taken on and off way more that it would in normal use and it always locks up tight. Marshall 
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Thanks for all the valuable input!
While I was mounting/removing the TA31ECOS (with the Bobro mount) and the TA31DOC (with a LaRue mount) on a brand new upper to take more pictures, one of the Bobro's features became clear to me. The TA31DOC was adjusted for one of my old rifles, I needed to loosen the LaRue mount going from the old rifle to the new upper, whereas the Bobro went from one to another, then back, without me having to do anything. When I put the TA31DOC back to where it normally sits, I needed to tighten the levers. My ACOGs rarely change their homes. If I were to toss my ACOG to another user, the mount is ready to go (even if the ACOG may need to be rezeroed) |
| I would have to agree with Jason...I've not run into my Bobro snagging on any of my vests and some of my my vests are a bit on the heavy side with gear. It does look like it would snag but, again, no issues here. If I had I wouldn't use it! Great pictures Duffy! This has been the most productive comparison thread between Bobro and LaRue mounts. The pictures really show some of the minute differences that you would never see without the side by side pictures. Excellent job!!! |
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This picture illustrates a point.
When I got a Bobro to T&E a while back, what you see in this picture drove me nuts. The fact that the mount does not end flush with the raised portion of the rails on the upper. You can see that the end of the mount is about half way back on the raised portion of the rail. It's the same in the front. On an Aimpoint Cantilever mount that means that the front edge of the mount will either overhang the front of the upper, or sit back from it. No big deal, just a cosmetic thing. My LaRue mounts all lined up and made my cosmetic side happy. Why didn't the Bobro mounts line up? Well, I was told, that the mounts are made to the picatinny spec. And that dimension is what the specs called for. I was told that being to spec was more important in this case then the appearance of the mount. In the case of the ACOG, if there was that added length on the mount, then I suspect that the optic base would not overhang the rear of the mount like that. I'm sure it makes no difference in how solid the mount holds, or how the optic functions. But this picture really re-emphasizes it. |
Lancelot, if I understand your post correctly, have a closer look at my pics of 3.5x35's which are typically mounted on the front of the receiver rail, and you will see that the exact opposite is true. The wierd thing is that my LT-104's are "flush" with the front of the receiver like the Bobro ACOG mount, but my LT-100's are not. 
I think most agree that form follows function, but it is always nice when things can be concurrently aesthetically most pleasing. I am not suggesting than either mount is particularly better; quite the contrary, they are both great....just different.
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| this is an excellent thread, and it's nice to see it staying on track. my only observation is, from the very first pic, that the Bobro appears to have less "meat" to it where it interfaces with the receiver rail (on the bottom), specifically on the side opposite from the locking lever. is this based on the camera angle, or is it actually thinner? |
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One other aspect of these respective mounts that has not yet been hyper-analyzed in this thread is the recoil lug. Duffy's third pic in his OP illustrates the differences quite well.
The LT lug is integral to the mount, but it s not "full width", presumably to facilitate machining of the dovetails. Full width is inconsequential to nearly all applications, but I happen have an "oddball" bolt gun in the form of a Browning A-bolt, and the only off-the-shelf rails that I have found for it have a channel cut longitudonally through them, thus I choose not to use LT mounts on that host due to minimal recoil lug engagement. Maybe, I will swap out the Bobro for the LT-100 on my custom D-740 low mount so that I can use it on the bolt gun, since that would also provide better lever access, but I will probably just have a custom rail made....or both. The Bobro lug is a separate component attached by a pair of relatively small Phillips-head countersunk machine screws. It incorporates a "cantilever spring" [again, my term, not Bobro's] to preload the mount forward, such that it doesn't shift due to optic inertia during recoil. As JTrusty has quoted, "The unit must always repeat the forward shift (recoil forces direction of influence) not only to maximize zero repeatability, but to take this step of installation out of the users initial mounting sequence." Since there has been some commentary on potentially "reversing" the Bobro lever presumably associated with moving it to the ejection port side of the weapon, the recoil lug would also need to be "reversed" to maintain the functionality intended by the manufacturer. Are we having fun yet?
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The LaRue mount's channel is deeper. The Bobro mount's channel is approximately the same depth as ARMS ACOG mounts
http://i75.photobucket.com/albums/i314/Duffypoo/ta31.jpg The Bobro channel is also approximately the same depth as the Trijicon factory TA-51 mount. As the optic indexes both vertically and laterally on the angled portion of the interface, one might argue that the additional material of the LT mount is superfluous, as there really isn't any contact of consequence on the elevated surface. |
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the recoil lug would also need to be "reversed" to maintain the functionality intended by the manufacturer.
Not necessarily. The point of the index lug is to keep the forward / rearward shift the same after the optic has been zeroed. The preload on the driver supplies more than enough force to keep the mount and optic in place under sustained fire, even with only a single lever. I have tested and run my mounts with the index lug removed and they retain their location on the rail. That said, if you reversed the lever mechanism and then zeroed the optic, the shift would be ( ever so slightly ) rearward. Each and every time you remove and reinstalled the unit, the shift would remain the same and zero wouldn't be affected. The Bobro channel is also approximately the same depth as the Trijicon factory TA-51 mount.
And there is good reason for that. Trijicon supplied the necessary dimensions to Andrew and requested that it be built to those dimensions.
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Good discussion here. I'm a huge LT fan, but I certainly appreciate any company that makes top notch products (as the Bobro seems to be). I surprised, though, that no one has addressed return to zero. I've seen a ton of write up on LT return to zero, but none on the Bobro. Just curious if anyone has done any testing on the Bobro mount to test return to zero. |
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I have both Larue and Bobro mounts. I haven't had any issues with the Bobro mounts, but there certainly are more parts to clog / break with the Bobro, unlike the Larue gear, which is the definition of simplicity.
For mounts that stay put I prefer Larue. For mounts that move around a lot, I prefer the Bobro because of the self adjusting mechanism. |
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I think one becomes smarter just by reading some of the posts in this thread
John, the LaRue mount has vertical walls that appear to make contact with the ACOG's mounting interface, so on top of the two 45 degree surfaces and the bottom, it also has two short 90 degree walls. While not entirely necessary, do you think these 90 degree walls help it withstand lateral impact better than without? |
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This really is a great thread. I am a huge Larue fan on all my optic mounts. My optics stay put on their specific
weapon and they don't move. The optics come off for the cleaning, and or any work on the weapon, but they go right back on, in the same spot......no adjustment needed. That being said, I would love to try a BOBRO mount on my flash lights. I have a couple really nice lights that I move around between several weapons. I currently use LT-707 mounts for my lights, but there seems to be a slight adjustment needed when moving the lights to a couple of my guns. I think a BOBRO light mount would be perfect for this use.....or anything that moves from gun to gun on a regular basis.......like my bipods too, come to think of it.
How about a light mount, and a bipod mount from the BOBRO folks????
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...snip John, the LaRue mount has vertical walls that appear to make contact with the ACOG's mounting interface, so on top of the two 45 degree surfaces and the bottom, it also has two short 90 degree walls. While not entirely necessary, do you think these 90 degree walls help it withstand lateral impact better than without? In a single word, nope. Neither the vertical nor the bottom surfaces have significant contact force, elsewise, the angled surfaces couldn't do their job. Think about how screw threads work. |
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We (Battle Arms Dev) should hire you to do some analysis for us
Thanks, I do enjoy reading posts Murderman, Jason and others have contributed to this thread, it's easily one of the most technical data rich threads for a while. As to other mounts, I have no idea what Andrew Bobro is up to, but we sure would like to see more mounts (flashlight, bipod, etc) if they're not already out or on the drawing board. |
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...but there certainly are more parts to clog / break with the Bobro
True, there are indeed more parts. However, not any more parts than are necessary in order to achieve the goals as stated. And for the record, you can clog them up all you want and they will continue to function just fine ( as pointed out in my linked review above ).
How about a light mount, and a bipod mount from the BOBRO folks????
No light mount in the works that I am aware of, but the GENIII Bipod is phenomenal and comes equipped with the same BLAC interface. Makes sharing a bipod between weapons ridiculously easy.
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How about a light mount, and a bipod mount from the BOBRO folks????
No light mount in the works that I am aware of, but the GENIII Bipod is phenomenal and comes equipped with the same BLAC interface. Makes sharing a bipod between weapons ridiculously easy. How about some sort of bipod mount for those of use who already own 3 Harris bipods??? 
A light mount would be very beneficial for moving lights from weapon to weapon.
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| As for new products in the works...There is a new mount for the Aimpoint T1 that will look a little different than the currently available Bobro mounts, considerable smaller to better match the size of the T1. Also a spacer compatible with Aimpoint products so the user could convert the Bobro mount from an absolute to lower 1/3 co-witness! |
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