BCR-15 Lower Receiver

The Brass Creek Rifle BCR-15 is designed to be 3D printed and assembled using fewer detents making it much stronger than many other printable designs out there. Strength does come at a cost of more filament being required. The left-handed version can be found here: https://cults3d.com/en/3d-model/various/bcr-15-lower-receiver-lefty

This model also includes a built in anti-pin walking solution. The pins must be installed from the left side of the receiver. The pin holes on the right side are too small to allow the pins to walk to the right but large enough to allow you to insert a tiny punch for disassembly.

The left side of the receiver has slots to allow the pin covers to be installed preventing the trigger and hammer pins from walking to the left.

To prevent the roll pin for the bolt catch from sliding out of position, there is also a block that slides just forward of the pin's position holding it in place.

All three anti-walk pieces are designed to fit snugly into the receiver.

The hex nuts can be pressed into the optional nut caps to allow for tool-less breakdown.

This model takes the following standard parts.

Trigger
Trigger Spring
Hammer
Hammer Spring
A2 Style Grip (also supports grips with duck tails)
Buffer Retainer Pin
Buffer Retainer Spring
Safety Selector
Bolt Catch Spring
Bolt Catch Plunger
Disconnector
Disconnector Spring
Bolt Catch Roll Pin
Magazine Release Button
Magazine Catch
Selector Spring
Safety Selector Detent

Additional materials required:
(1) 1/4-20 x 1 bolt for the grip screw
(2) 1/4-20 x 2 bolt for takedown and pivot pin positions
(2) 1/4-20 Hex Nuts for takedown and pivot pin positions

It is suggested to print this lower receiver in polycarbonate. I have printed this in Priline Carbon Fiber Reinforced Polycarbonate. I have also printed in ABS during the development of this lower receiver and have had a lot of luck with ABS. I've also performed several magazine dumps in both the ABS and polycarbonate. Print with 100% infill. Supports are required.