This magazine extension for the BMR will add 7 rounds to the 5 round magazine without the need for a different spring! Colors may be substituted if desired color unavailable.
Used it last weekend at a match took some sanding to get it to fit correctly (expected that being 3d printed) tough to get in12rds. Will do some more sanding and trimming before I shoot another match. Absolutely recommend it if you have the 5rd magazine.
I got the product no instructions. So I found a YouTube video and watched it. The block didn't fit so I sanded it down. As I put the extension together there was a time lip still from the block the video said I might have to tap this one so I did and broke the lips on it. That attach to the 5 round mag. I super glued it and put black tape on it. The mag does feed good though. But everything was a tight fit. So be careful and slow with it. When putting together.