The BL(Bootleg)-SD Handguard Adapter makes it possible to slip your own rubber SD handguard onto a full-size MP5. Combining this with the right suppressor on a tri-lug mount, this is the closest way to achieve the ultimate SD look and feel without spending thousands on a custom build.

Installation is easy:

MKE AP5, Broad River Tactical SD shroud, and YHM R9 pictured.

Bring your own suppressor.

Although designed for the YHM-R9 and tri-lug mount, you may connect any suppressor you already own with a diameter up to 43.5 mm. For some suppressors, the BL-SD extends just far forward enough to hide the mounting hardware when viewed from the side*

Omega 9K with tri-lug mount**:

Note – this is the old V1 design

YHM R9 with tri-lug mount**:

SilencerCo Hybrid 46 with tri-lug mount:

Note – this is the old V1 design

Rugged Obsidian 9 (long config) with tri-lug mount:

Note – this is the old V1 design

*I have only confirmed that this fits and reasonably hides the mounting hardware of the above suppressors pictured. If you are unsure about yours, please contact me so I can check.

**I highly recommend either the YHM R9 or the Omega 9K for a faux SD build. The diameter and visible length of these two cans are a very close aesthetic match to a real MP5-SD.

Is it Just as Good™?

Nope! Although it looks close to the real deal, the full adapter and shroud setup is functionally different from an authentic MP5-SD, which uses a ported barrel to make standard 9mm subsonic before entering a longer suppressor. On the plus side, this allows the BL-SD Handguard Adapter some unique advantages over a true MP5-SD:

• Not as messy. The real MP5-SD’s ported barrel will splatter the inside of the handguard with residue and require frequent cleaning.
• It can be easily removed and re-attached, so you’re not locked into one style. You can change up the look of your setup at any time.

That said, there are some things you will miss out on compared to the real one:

• You will want to fire subsonic ammo if you’re looking to mimic the classic MP5-SD report.
• The front sling loop will be covered by the handguard. On a real MP5-SD, the sling loop is moved up higher to make room for the handguard. You will not be able to attach your sling if you use the BL-SD Handguard Adapter.
  • One of my customers cleverly got around this by tying some paracord to their front sight tower and using that as an attachment point.

FAQ

• Can it handle the heat?

Seems to. The BL-SD is printed with a high heat carbon fiber nylon, rated to withstand temperatures of up to 194° C, which I have put through thousands of rounds without issue. I have not been told of any melting, warping, or other heat related issues from my existing customers.

My most recent stress test involved firing 200 rounds back-to-back as quickly as possible in binary mode. Immediately after this test, I measured the suppressor (a YHM R9) with an infrared thermometer and found that the tri-lug mount, roughly where carbon fiber nylon meets the suppressor, clocked in at 71° C. It seems the real serious heat happens further up where the baffles are trapping gases, less so around the mount.

Some very minor expansion of the adapter may be seen at peak heat due to the properties of material used and the nature of additive manufacturing.

I cannot safely guarantee this product will withstand any and all heat you throw at it. I also cannot recommend attaching it to non-9mm hosts (such as an HK51) since this product has not been tested for them. However, under typical conditions like the ones described in my testing above, you should not expect issues due to heat. Feel free to contact me if you want more info, I love talking about this stuff. Science!

• Where do I get the rubber handguard?

At the moment you can buy either a German handguard, a USA handguard, or the Broad River Tactical shroud. Click here for a short guide and video I put together on their differences.

• How does the MP5-SD handguard attach to the BL-SD adapter?

Your SD handguard is made from spring steel and was designed to clamp onto a cage welded onto the MP5-SD receiver. Two small protrusions on the cage fit behind the “tabs” at the top middle of the shroud. Similarly on the BL-SD, the force of the spring steel, the locking tabs, and the flanges on the front and rear, all work together to allow the handguard to sit snugly in place. The lips on top discourage the handguard from rotating in place, and also act as a barrier stopping the handguard steel from scraping up the cocking tube.

• Why doesn’t the handguard sit flush with the front in some pictures?

This is the old V1 design which pushed the shroud forward to cover the tri-lug mount. V2 uses a cap to for a cleaner look and to allow for more flexibility with different suppressors.

• Will this fit on an MP5-K or MP5-PDW?

No. This version of the BL-SD will only fit full size MP5s and their clones. I do have one for the K models which comes bundled with a custom rubber handguard, click here for details.

• I have a 3D printer! Can I print this myself?

Coming soon. I’m working on cleaning up the geometry before posting the STL. If you promise not to roast my modeling skills, send me an email and I’ll hook you up.

• Will this fit a .22 MP5?

It will not. I am told the adapter technically fits some of the .22 models, but the sling loop protrudes out too far and the shroud won’t sit flat. I would not recommend connecting this to a .22 MP5.

• Will it fit airsoft MP5s?

It will not.