Hey guys. I'm new to the ARs, but I just bought an M&P 15 OR MOE. The gun is gorgeous and shoots awesome when it shoots.

I gave it a good look over and made sure to clean the barrel and oil any needed parts before taking it out.

It has the chrome lined barrel and heard I could just fire it out of the box, but since i was in no hurry i was running a snake in the barrel between each of my first 5 rounds, then every 5 rounds until 50.

Basically after my first 20 rounds, the trigger just stuck like the safety was on. It wouldn't budge. I would put the safety on and off and nothing. Finally I pulled the pin and flip the upper off. Nothing looked wrong, but what do I know, this is my first AR. After pulling the trigger a bunch and just kind of messing with it, it finally released the hammer. I put some oil on around there in case it was just dry and catching.

I was able to fire another 5 rounds before this happened again, and it seemed to keep happening every 5-15 rounds after i'd fix it. I finally put it up after 80 rounds.

I'm not sure what is going on, if this is a common problem or perhaps a random issue. Is there something I can easily check/fix to cure this as it is quite annoying and I really don't want to have to send the gun in since I just got it.

Thanks in advance.

Check down in the trigger mechanism for an anvil from a blown primer wedged in one of the springs. This has happened to me a few times using green tip in my issue M4. There are several other possibilities but this came to mind from reading your post. If nothing obvious can be found you may need to call S&W.

Read my post regarding my "VTAC" trigger problem.

Just received back from S&W via FedEx 4 hour ago. Quick turnaround time...6 days out of my hands. They replaced entire trigger works.

Went to my local outdoor range during lunch and shot 60 rounds with no problem. Trigger touch seems better. Will shoot more on Sunday.

Ask for Pat @ S&W Customer Service...she'll take care of you. Have serial # of rifle.

While sending back to S&W is an option - the firing mechanism of an AR is relatively simple to take apart and inspect.

I too have seen AR's go belly up from a primer coming out of the case. What ammo were you using?

It's just two pins to push out to remove all of your trigger parts - but be careful, there are springs involved.

Look here for pics of putting a AR lower together...

Assemble your own LOWER, UPPER, FREE FLOAT, TRIGGER, GAS BLOCK - Step by step instructions! - AR15.COM

I'd pop out the trigger and give it a good cleaning & lube first.

If you bought it from a real gun shop, they should also be able to do this, and most wouldn't charge for it. (if you bought it from them and just didn't have it shipped in to them, that is)

Good luck,
Bob S.

p.s. Where are you located, someone might be able to help you.

Thanks for all the responses. I am located in Columbia, MO.

I was looking in to the lower unit tonight and everything still looks good. I didn't disassemble as I didn't have anything with me to help punch out the pins and didn't really have much time, but here is what I was able to find.

All the springs looked good, none looked broke from what I could see. I started to put the hammer down to catch in the sear and pull the trigger multiple times in a row. Finally I was able to reproduce the problem and when I look down in the lower I can see that the disconnector has caught the hammer. After pressing the trigger and jiggling it a few times I was able to get it to let go and release the hammer. I tried for another 5 mins or so of putting the hammer down and firing and was not able to recreate the catch.

I did a test of pushing down the hammer, pulling the trigger and holding the trigger, and making sure the disconnector caught, and then released the trigger to make sure the disconnector releases and it resets. Everything worked good. I could not recreate.

It's just weird how it is acting up only at times.

Should I take the time to remove the assembly and inspect? Or should I call S&W or does this help anyone to diagnose?

Thanks

I would blow out, de-grease, and lightly lubricate the trigger mechanism, then take it to the range again. You may have had some sticky factory grease down in there, or a burr which has been worked out. Try firing it again, and if it keeps happening then call S&W and see what they say. The AR trigger is very simple, and while I wouldn't completely disassemble it at this point, it may be a simple issue which you can revolve yourself or have already resolved.

As easy as it is to remove and clean the trigger (and parts), I would personally do that first before shipping it off. Would rather spend 10 minutes doing that then being without the rifle for some unknown period of time.

__________________
Stu

As others have suggested, I would fix it myself (having to ship your rifle and be home to receive it is a hassle).

The fire control group is very easy to remove and reinstall. Consider just doing the work yourself. In fact, I'd just get a DPMS lower parts kit, and install the trigger parts (three springs, disconnector, trigger, and hammer). That way, you're replacing possibly defective parts. You can find video how-to's on YouTube.

Since you'll have new springs to play with, you should probably also consider modifying them as described on the "15-minute trigger job" web page. (15 Minute Practical Trigger Job for the AR-15). The pull will lighten considerably just by modifying the hammer and trigger springs. I've done it a few times, and it really helps.

The only tool you'll need is a 1/8-inch drift punch (and a hammer of course) to tap the pins out. Remember, they're held in position by springs and they'll just pop out if you're not prepared. You can get a whole set of appropriate drift punches (ESSENTIAL tools for any AR15 owner) from Home Depot for $13.

The side benefit of doing it yourself is that you become that much more intimately involved with your rifle, and that's always a good thing.

I went to the range today to see if the problem had been fixed randomly.

Shot about 5 rounds and it locked up again. Then again after another 2 or 3. It shot fine for about the next 15 rounds but then something else happened that hadn't happen before. It started locking up on every shot, but this time, as long as I would switch the safety on, I would feel the disconnect reset and let the hammer go, then switch back to fire and it would fire. It did this for about 12 straight rounds then it stopped and was fine for the next 30 rounds I shot. I was done at that point so not sure if somehow it is fixed. But that is by far the longest shots in a row I have been able to fire.

So not sure, but I will take every ones advice and just take the trigger apart, inspect, and re-assemble. If this continues I'll probably just send it in since its getting cold here and I'll be deer hunting and not using the gun for a while. I'd rather have the S&W parts then DPMS. I may do the 15 minute trigger job tho in the future, thanks for that link.

As for buying the parts and doing it myself, I do plan on taking the gun apart and putting it back together many times to get to know it better but I'd rather the gun work perfect before I do that way I will know if I do break/cause something wrong in the process.

Thanks every one for all the help/replies. I'll keep you guys posted on any new findings.

Hmm, could be something lodged under the disconnector which is preventing it from releasing normally. Could be a bad spring. Either way disassembling the trigger mechanism should reveal the problem. I assembled a lower this weekend using parts from Barnes Precision and am extremely happy with the quality. Flawless fit and function and a great trigger pull. Their lower parts kit is only $54 on their website.

Parts kit for Lower Receiver

S&W vs. DPMS parts doesn't really matter, they all get their parts from a handful of suppliers. However, I emailed the owner of BPM before buying and he said they use only top quality mil spec parts.

Good luck.