Magazine seating issue.

[nfa1934]

I'm having a problem with my two new builds. Loaded magazines won't seat (taking out two rounds doesn't help, they won't seat with even one round loaded). Had no problems previously with either upper on a Bushmaster lower. I doubt two Spike's lowers are out of spec, but the upper/lower fit is tight. Considering filing down the mag catch a little (lower parts are Wilson except for the trigger, wondering if they might require a little fitting, a couple of the pins were a beast to drive into place). Magazine manufacturer doesn't make any difference. Same problem with Magpuls, Bushmaster, C-Products, AR Stoner, And D&H. Any thoughts before I break out a file?

[NAPOTS]

I'm having a problem with my two new builds. Loaded magazines won't seat (taking out two rounds doesn't help, they won't seat with even one round loaded). Had no problems previously with either upper on a Bushmaster lower. I doubt two Spike's lowers are out of spec, but the upper/lower fit is tight. Considering filing down the mag catch a little ( lower parts are Wilson except for the trigger, wondering if they might require a little fitting, a couple of the pins were a beast to drive into place). Magazine manufacturer doesn't make any difference. Same problem with Magpuls, Bushmaster, C-Products, AR Stoner, And D&H. Any thoughts before I break out a file?

have you tried seating the mag in just the lower without the upper attached?

[nfa1934]

have you tried seating the mag in just the lower without the upper attached?

Yes, seats with no problem without the upper.

[abpt1]

did you try it with out the bolt in ?

[Helen Keller]

Measure the mags depth with the upper on and the upper off, mark it with a fine sharpie or something.

take out the mag catch and see exactly how close it's fitting. It just might need a teeny bit amount of filing.

[NAPOTS]

will they seat with the upper on with the bolt locked back?

[nfa1934]

Seats with the bolt locked back (assuming it will also seat with the bolt removed)

Marked the depth of the magazine. Slight difference.

Tried the magazine catch from the Bushmaster lower in the Spike's. Same problem. Looks like the issue is the lower, not the mag catch.

Time to file the mag catch a little to compensate for a tighter upper?

Edit: OK, I'm officially in the freakin' twilight zone. I got out my Bushmaster SBR that I used these two uppers on previously. I tried both uppers on it since they worked before. Now I can't seat a magazine in the Bushmaster either. Got out the old Bushmaster 20" upper to try. Loaded magazines won't seat with any combination of upper/lower. I get really frustrated and walk away for a while.

I return a little while later. Now loaded magazines seat in any upper/lower combination with just a smack on the bottom of the magazine. Nothing changed! WTF!? Do I have AR15 gremlins in my house messing with me?

[Helen Keller]

pffft....


stop being a pussy and smack it.

[nfa1934]

[Helen Keller]

I said the exact same thing to a guy at the range last week who couldnt get his rounds to feed after he put the mag in.

"Dont be a pussy, smack it like you want to break it. "

[Solidus-snake]

I always have to slap my mags with my Spikes lower build. Very tight fit with my Stag 16" upper.

[Schuetzenman]

No do NOT file the mag catch. It positions the mag so the rounds can be picked up. Mags might sit too low if you file for a feather touch seating. As has ALREADY been suggested, smack the bottom of the mag to seat it. That or get use to having the bolt locked back for loading. I've got 4 AR rifles; Colt HBAR, match rifle built off of DPMS receivrs, Rock River built up as a Dedicated .22 LR normally and a Stag Arms lower built up as a Middy. I have to smack all the mags to get them to seat ... UNLESS the bolt is already locked back.

If you were firing in the "Zombie Apocalypse" Reloading would come when the bolt locks back and you know that your current magazine is empty.

[nfa1934]

I'm used to driving a mag home with some force. This was different. Beating it against the floor wasn't seating the mag. The really confusing thing is that after walking away for a while and then returning later (without changing anything other than playing musical uppers with three lowers and then moving them back to the original receiver), the mags seat with just a slightly sharper smack than I'm used to.

[Solidus-snake]

Freaky man..

[NAPOTS]

I've got a few mags that won't seat when full with the bolt in battery but with it locked back they seat fine and function wihtout issue.

[Schuetzenman]

I'm used to driving a mag home with some force. This was different. Beating it against the floor wasn't seating the mag. The really confusing thing is that after walking away for a while and then returning later (without changing anything other than playing musical uppers with three lowers and then moving them back to the original receiver), the mags seat with just a slightly sharper smack than I'm used to.

Any particular type of mag, GI or PMag as examples?

[nfa1934]

Any particular type of mag, GI or PMag as examples?

All the mags listed in the first post. PMags are still the most difficult to seat.