Same problem, different part AR .308

[gun'sRgood]

First! Thanks to all you kind folks who have been so very helpful in teaching me so much about gas systems. Awesome! Here's the new issue: I put the new .308 on an old .308 and it functions just great. I tried to replace the buffer weight and then the buffer spring, then both. No change. The new .308 will not strip off rounds and put them fully into battery. The mags "feel" a fair amount looser in the new .308. Can I shim the mag well? Or? I hope your not too tired of me. I can't tell you how much I feel I've learned from you folks! Awesome guys! Thanks.

 

[Armorer 101]

In this learning process did someone say, the 308 ARs ain’t mil spec or standard? Some lowers take one mag, some lowers take another. Once you get full function in one, it is best to stick to that make and that model.