Another 5 rounds of 7.62 is a lot of weight not to mention 10. A rifle I bought came with a 25 and I never use it. In addition, I really don't like the idea of that much weight hanging on my op rod spring guide etc. The extra weight at that extended moment sure makes the balance different. If putting 20 rounds downrange isn't enough to at least buy me the time to change mags, well I'm probably screwed anyway. Just my .02 GI1
I am not trying to get off track too much, and really can't advise the OP on a source for 30 rd. mags,....but, I would take the quote above one further, and say that if the ten round mag that comes with the rifles from Springfield, were not enough to give me enough breathing room to displace, evac, or hit a reload.......well, then you are correct Sir, you are in big trouble anyway, and are probably not gonna make it......My philosophy is the rule of thumb......Stick your thumb up at arms length, try to cover the threat with it, if you can't, you are too close and need to get some rounds downrange to keep their heads down while you displace....or as my ole Nam buddy Tommy Holliman would say....
" We need to be findin us some yonder" DI5