Went to the range with my new dpms ar 15. Used 55 g remington
Fmj. First 15 or so were fine. Always extracted no problem but sometimes when it was stripping a new round, the bolt wouldn't lock forward. It happened like 15 times or so. When I pulled the trigger it would click and wouldn't fire. So I would drop the mag then the bolt would close. I would insert mag extract round then release. It would run about 10 shots then fail to lock forward with a round. Is this normal break in for a dpms or is something up. I plan on buying magpul mags for it since I font care for the mags it came with. I will say I never cleaned it before shooting it like the manual says and I didn't clean the barrel after every shot like the manual says. I ran about 150 rounds through it. Was getting frustrated with it. Do I need to bare through it and hope for the best????

yes try the magpuls. What led you to buy a DPMS?

Impulse buy. I was in cabelas and happen to have a.large sum of gift cards with me. I handled it and liked it so I took it home. Wish I would have done some homework as I am green when it comres to the black guns. I guess everyone has to start somewhere.

Clean it and LUBE it like the manual says. I have a DPMS lower with a hodge podge of mixed company parts and an Armalite upper. It shoots great and I've never had an issue. Do like the owners manual says. Brownells has magazines for $10 and they work great. Try another magazine after cleaning and lubing the rifle. kwg

It was probably shipped with oil in the bore and chamber area, shooting with oil in the chamber results in carbon buildup and can cause a cartridge to stick before the bolt locks up. Thus clean before you shoot...

Could also be a defective mag catch or bad mag. Strip it down, clean it then lube the thing but keep the chamber dry.

That was the first thing I did when I got home was clean it. The book says to clean it for 3 strait days after firing . Guess better safe than sorry. Also it says to lightly oil the chamber but your method makes since to me as to not oil it. Thank you guys for the input. Hoefully I can get back out and really have some fun with it. On the plus side I really like the bushnell trophy red dot site I put on it and it gave me pretty nice groups for its first time out.

Good luck with it

Have a new mag handy to try.

Then as others note, clean but even more important is lube the upper correctly so its got speed going forward and isn't cycling "dry"

No oil in the chamber is a better thing.

Clean RE the carbon fouling for sure.

Beyond that, there are some guns that get out that have to be tweaked. If you want 100% reliable out of the box you gotta pay for it. But with most of all the cheaper ones being around 95% good, I don't sweat it much.

Usually fairly easy to diagnose.

AR's run much better wet than dry. I think once you clean and lube, you will be fine.

That clean for three days after firing isn't necessary. That goes way back to the days of corrosive primers. It's amazing how some things just won't die.

Is this a failure to feed or failure to extract. I am a Marksmanship instructor for the US Army and an Armor. I may be able to help. Go back out and shoot it again. When the insodent occurs take pics before clearing the malfuntion. Let me know if I can help....