Bobro Users: Is this Normal?

**FourT6and2** · 11-29-14, 08:40

Being a QD type mount, is it normal for the mount to take chunks of the rail out every time you attach and/or remove it? This isn't merely a "mark" in the finish of the rail. It is all the way down to the bare metal. Over time, will this eat more and more of the rail away? Hard to see in the photo, but the length of the damage goes to about half-way down the height of the lugs. And can naked aluminum rust? The reason it's doing this is the mount's recoil lug has a rather large "bump" in it (by design) that indexes against the rail's lug. It's supposed to compress I guess. But in doing so, it's gauging up the rail. I know "it's a gun," a tool, and not something that's going to remain pristine. But this is actual damage. It's not cosmetic.

**C4IGrant** · 11-29-14, 09:21

Who made that receiver?

C4

**HeavyDuty** · 11-29-14, 10:51

I have three Bobros, and they don't do that.

**SpeedRacer** · 11-29-14, 11:02

Originally Posted by C4IGrant

Who made that receiver?

C4

This.

To answer the questions, no that shouldn't happen, and no aluminum does not rust.

**titanse05** · 11-29-14, 11:09

Out of spec reciever issue here I suspect. Tuning in for manufacturer of the upper.

I have three Bobro mounts and all leave no marks on either of my AR upper recievers (Rainier Arms and BCM).

Sent from my Samsung Galaxy S4

**556Cliff** · 11-29-14, 11:12

This doesn't happen with my Bobro ACOG mount.

**Amicus** · 11-29-14, 11:16

1. One of my Bobros has left a circular mark on the horizontal surface of the slot. Not a concern so I don't think about it.

2. Aluminum oxides, but does not rust. This is a surface condition only and should not be something to worry about. Aluminum oxide is quite hard (harder than pure aluminum) and forms rapidly after exposure to oxygen.

3. Having been down this road with other mounts more than once, I am going to guess what will happen: the mount maker will blame the rail for being out of spec, the rail maker will blame the mount for being defective. You can't fault them for that, it's just each maker will not want to instantly take the blame for the situation. This may lead each to ask you to send them the whole assembly for examination.

4. First thing is to check the Bobro against another piece of rail from a good manufacturer (preferably aluminum). If you can (or can not) replicate the mark on another in spec rail section, then you may have the answer.

**FourT6and2** · 11-29-14, 17:57

The rifle is a Noveske, Gen III upper.

I checked the mount on a separate piece of Noveske Keymod and it didn't cause any damage or marks. The piece of keymod rail I have has a different coating. The rifle is anodized and cerakoted according to the specs listed on Noveske's website. And the keymod I tried the mount on is much darker and slightly textured.

I contacted Bobro, but they didn't really say much in response, just that "The index is designed to contact the rail, and it shoves itself forward in the slot. There is contact." Reading between the lines, I think they're saying to forget about it. But this isn't cosmetic. It's actually digging into the metal of the rail. and since the rail and receiver are one piece, it could be a problem if I continue to use this mount. I specifically bought a Bobro mount to avoid the issue of Larue mounts digging into the side of the rail, only to find that the Bobro is digging into the top of the rail. Lose lose for me.

So I guess I need to contact Noveske now. But I don't know what they're going to do. Other than me asking for a refinish or a new upper receiver, which I doubt will happen. I just bought this rifle about 3 weeks ago. ugh.