Brownells BRN-180 Build Part 7: Prototyping

 When I started this Brownells BRN-180 build, I had grand plans for it from the very start.  And while I still want to keep some of the project top secret, I am super excited to move forward with a key component to my overall design. After having completed the custom walnut grip, it was time to move forward with the next major step; the custom wood handguard cover. 

For my BRN-180 build, I opted for the 10.5" upper as I was planning on building a pistol when I was done.  I had some general ideas of what I wanted to build, but I decided the safest way to approach the design portion of the build was to take some measurements and sketch out the dimensions.

I then took the dimensions to my computer and started the design process in CAD (I use a program called Fusion 360). 

I am by no means a pro at Fusion 360, and much like Photoshop if you start to learn how to use the program there is always more to learn.  With that being said, it is a really awesome program and I used it to design version 1 of the handguard cover.

I recently bought a 3d printer (Prusa Research i3 MK3S+) and built a custom enclosure for it and I used the CAD design to print the V1 prototype. 

V1 printed very well, and the overall fitment was awesome!

While the fitment was great, there were some modifications needed for V2.  I noticed V1 was too short to cover the forward mlock slots, and it was just too fat which made it look too imposing. 

I headed back to the computer and cut down the outer dimensions by nearly half.  I then lengthened it, and added three holes on the sides to line up with the mlock slots in the BRN-180 handguard. 

V2 printed very well, but because of the mlock slots, supports needed to be added to the print.

After cleaning off all of the printed supports, the V2 prototype looked awesome.  The only two issues I noticed was the Handguard cover was still too short to comfortably cover the forward handguard mlock slot, and I needed to decide where I wanted to add holes for mlock screws. 

I used CAD to add a few millimeters of length to V2 and added four holes for mlock screws to be mounted to the handguard. 

V3 printed perfectly. If you are interested in buying a 3d printer, I highly recommend the Prusa i3 MK3S+, it is very easy to use. 

While the changes between V1, V2 and V3 are minor, the overall refinement is significant.

I really love how the V3 prototype turned out and I can now move forward with the woodworking.  Having the V3 prototype available as a true 1:1 template for the walnut is going to be so nice.  I really love having a 3d printer; to me it is not a new hobby, but rather a useful tool which can perform a function no other tool can. And it did a fantastic job of creating a rather functional prototype which will be very useful in part 8 of this build!  Stay tuned for more!

You can find the BRN-180 upper and lower receivers at the following links;

Brownells.com/BRN180 Upper Receivers

Brownells.com/BRN180 Lower Receivers

Remember, Faith Kills Fear!