Sig Sauer SBX vs SB15 Arm Brace Dimensions

Sig Sauer SBX vs SB15 Arm Brace Dimensions

We will probably hear ten different reasons why a second version came out, and thankfully everything you read from the internet is true. I will entertain a couple of them for you guys. One speculation was that due to it’s stock like appearance they wanted to move to a model that was more “brace” like to further avoid any “Stock” debates. Another speculation is that the SBX is just a pure upgrade to the SB15, thinner and lighter.
I want to review the apparent dimensional changes and design tweaks they incorporated.


Weight comparison.
SBX weighs 9.7oz
SB15 weighs 11.9oz




Here you can see how the SB15 gets some of its additional structure support from its polygonal shape compared to the SBX which has squared off shape.
The SBX incorporated a larger velcro strap for additional stability. I have yet to tell the difference between the two in stability, so the larger improved strap may, or may not be to thank for it.
Side by side, the SBX has a shorter height.

The SB15 has a thicker structure for sure, the SBX was slimmed down and also fluting, this is definitely one of the places they shaved off some of the weight.

Calipers on the fluting

Caliper on the thicker part of the brace

Side by side refernce


Now the SB15 and SBx have the same dimensions for mounting to the buffer tube. But where they differ most drastically is the length of each brace. The new SBX brace is shorter and the back end is closed off now.


Now because the back end is closed off on the SBX, that will limit how far down the buffer tube you can mount it. I have the SBX mounted as far forward as it can go and you can see the gap that is left in front of the SBX on the KaK Super Sig Tube.



I am unsure how I feel about the new SBX. I say this in a positive way! If I don’t hate it means they did not sacrifice anything in this new version, if I don’t love it means you don’t need to run out to replace your current SB15. This is just an article about dimensions, I just wanted to share my initial impressions on it. I will be doing a follow up article on its application and usage.