SSN Vet
Member
I got a smoking deal a few years ago on an FN made M16 contract overrun upper (without M4 feedramp cuts) and when I finally got around to completing my build, the barrel I wanted did have the M4 feed cuts.
Not ideal, but not a total bust. All in all, it has mostly functioned and fed well.
I'm now experimenting with loading 70+ gr. bullets and am seating them at the max COAL, and have had a few feed hang ups.
Any body ever filed the M4 cuts in an non-M4 upper?
If so, did violating the anodized finish cause erosion or peening from the impact and friction associated with feeding?
I have the tools and the steady hands to do this, but I've read some warnings about issues with the AL being to soft.
Not ideal, but not a total bust. All in all, it has mostly functioned and fed well.
I'm now experimenting with loading 70+ gr. bullets and am seating them at the max COAL, and have had a few feed hang ups.
Any body ever filed the M4 cuts in an non-M4 upper?
If so, did violating the anodized finish cause erosion or peening from the impact and friction associated with feeding?
I have the tools and the steady hands to do this, but I've read some warnings about issues with the AL being to soft.
