Right now the 60-round PMAGs are insanely expensive on the flea, and I think it's primarily because the Peacekeeper LL3 barter has been broken by the changes BSG made to try and fix their mistake of tying BTC to real-world prices.
The Peacekeeper barter requires a gas mask air filter and 2 green batteries. Those green batteries are also currently used in the Mechanic's Tetriz barter. This makes the batteries extremely valuable; more valuable, in fact, than the PMAGs themselves. So we are in a situation where, to get this magazine from the barter trade, not only do you have to trade in 2 items which are both worth more than the mag itself, but you also forgo using those items for the Tetriz barter which gives you a flat 250-350k rubles.
BSG needs to fix this so that the 60-rounders aren't restricted to the richest players, and so that people who want to get them from the trader don't have to make a Faustian bargain to do so. The change to the Tetriz trade was only made because BTC values were so insanely high, and now that BSG has admitted trying in-game BTC to its real-world value was a stupid idea, there's no reason for the Tetriz trade to be so restrictive. Either the Tetriz trade needs to be adjusted or the PMAG trade needs to be adjusted. Preferably both would be adjusted to use different items, but changing one or the other would mitigate the problem somewhat.