..for all I care the upper could be bolted to the lower for how infrequently I open mine. There IS a detent on the front pin, its a full circle groove with a spring clip around it. Mine is tougher to push out than any AR pins Ive pushed. If I were to be taking it apart all the time id appreciate the fact that the pin is captured so you can pull the pin far enough to remove the upper but the pin stays in the lower unless you deliberately remove the clip from the pin, which itsnt required for take down. Less parts on the bench or in the grass.
The point isnt taking the gun down, thats not the problem. The problem is the upper receiver popping open when its run hard and dirty. All thats holding the gun together is spring pressure, which can be affected by dirt and rough useage. Not to mention the takedown tab which can be snagged on things and cause it to self-disassemble, causing the entire contents of the gun to slide out and onto the ground.
As for the front pin not coming out, My little spring clip got loose and fell off. Now the front pin didnt fall out, but it did bother me that they would use such a stupid little clip instead of drilling another hole and installing a detent like the AR15 has.
Its a culmination of the little things that bothered me, many of them easily fixable. I was very patient with it as well, and I really tried to like it. Heres what happened to me.
I unboxed it, gave it a quick cleaning and oiling. Took it out to zero it and break it in with 200 rounds of brass cased 5.56. I got 3 rounds down range before i had a malfunction, caused by the extractor deciding to fly out the ejection port with the spent brass. Couldnt find it, called Robarms, they fedex'd me a new one and I was up and running within a week.
Then I couldn't figure out why I was getting 6" groups at 100 yards with my Eotech. I blamed it on my bad eyes and the wind of the day. It was running just fine, but shot placement was erratic at best.
Tried all different kinds of ammo, 55gr,62gr, 45grJHP's, 69gr, etc. I tried an aimpoint t1 and a bushnell 3.5-16x50 instead of the eotech, I was still getting erratic shot placement. So I called up Robarms again and after speaking with Mr Robinson I had the barrel sent off for replacement mid July. I recieved a new barrel by early November. He promised me a 1/7 but instead I recieved a 1/9. No big deal. And so I took it shooting again, it shot 1.5"-2" 10 shot groups at 100 yards, much better than before. So I took it out and shot it a bunch. Then the ejector and other small bits started coming loose. The shell deflector and the bolt release for instance. Loctited those.
With a bipod and glass, its still a 10+ pound rifle with okay accuracy. So I sold it and bought a rem700 in .223, which better suited the purpose I bought it for, longer range shots on coyotes and other small game.
So in total, I bought it in March '10 and sold it in December '10. In 10 Months I managed to get 500 rounds down the pipe with 1 month of that actually having a completely working gun. Sort of. And they say 1911's are bad for maintenance. When I sold it, it was running perfectly, but I'd had enough of it.
Once Robarms improves their design and quality control, which i doubt they will, I may reconsider. I did like the ergonomics and it shot very smoothly.