Just FYI - If anyone needs a magazine for their FN SPR or PBR rifle I just ordered and received 5 mags from:
They are selling them for $38.79 each which is about $5-$10 cheaper than I could find them anywhere else. Shipping was reasonable as well. 5 mags delivered cost me $203.55 ($40.71 each). They arrived today. All were brand new in the folding blister packs from FN.