I bought these https://www.buymymags.com/m1a-m14-308win-20rd-gi-spec-magazine-mkd-w/ becuse they were advertised as military surplus and well they are acting funny. I have loaded and fired two mags of the five mag lot with out issue, the other two I loaded and shot today failed to feed on the last two and the last 10rds of the other mag. The followers tilted and crapped out. I took one apart and there are massive burs on the broached square hole and stand off from what appears to be spot welding inside mag. To recap my rounds are nose diving forward in mag and followers tilting. The bodies are marked W, is there anyway to check if these are real military surplus?