last day to use NJ nics permit

Is 15 days enough time to buy, wait for shipping , wait for nics, and then pick up? Barely. So i bought a gun from grab a gun on sat (9/8). I received an email verifying the sale but they didnt process and ship it until the following thursday (9/13). They took 4 business days to process it (with 2 day shipping) as the only mailing option. It went out fedx 2 day shipping on thursday. it didnt get to my local ffl store until monday (9/18). my local FFL store is closed on monday, so it was re-delivered on tuesday (9/19). the store texted me that day, but i couldnt get there due to my work schedule. i figured my permit would expire and applied for more permits. However, I was able to get to the store early on thursday (9/21) due to a small gap in my schedule. The nics check was submitted on thursday (9/21). I received a text today, saturday  (9/23) that nics was approved and picked it up today. The last day my permit was usable , with extension, was next monday (9/25). But, based on the store's hours, (closed mondays) my last day to use the nics permit was really today! I was extremely lucky that the Nics approval only took 3 days. I have never let my nics permits and approval time get so tight. I am very lucky that it worked out but I need to make better use of my permit calendar for my next batch of permits. I guess I cant blame grab a gun as their website does say 3-5 days for processing, and sometimes longer. Its a shame that NJ makes the gun buying process so difficult. My suggestion is give enough time for shipping and nics approvals.