I just put this all together and manually cycled it, so it seems to be ok. So get a 30 round mag, load it with 223, and try to cycle this manually. It jambs. Can’t pull the charging handle.
Took a screwdriver and lightly levered the bolt, felt it give a bit and now, can pull the charging handle and it ejected the round… Tried it again, and it jammed.
Any idea what could be the cause? Nothing stands out to me, but I’ve never owned an AR15 before, but I have shot my step-sons and so I thought this should just be a simple build.
Did you build the upper?
What caliber is engraved on the barrel?
Is everything lubricated?
Are you slowly chambering a round, or pulling back on the charging handle and letting go?
What brand of ammo, or can you post a picture of the rounds that gave you problems?
This is an MLok kit from PSA. I bought the lower from PSA as well.
Basically it surprised me because if was ready to assemble (Blem – and they don’t seem to be anywhere but finishes). And by that I mean, pull the pins on the lower, attach the upper and the stock was already part of the lower. I had thought it would have basic “open iron” sites, but it doesn’t have any, so I"m about to order for that.
As to whether I was easing into it, no, I pulled the charging handle and let go of it just like I have on my step son’s AR15.
The rounds are PMC 223, 55 grain, brass. The Barrel is marked 5.56 NATO.
I’m going to add just a bit more oil and see if that helps (but it seems oily enough – more than I would have put on it had I just cleaned it).
Thank you all for responding so quickly (btw – I think I answered all your questions).
Ok, so I opened it up and oiled it a bit more and tried again. I got 5 rounds manually cycling it and then it jammed. Cleared it, and tried again and it jammed immediately.
Also, not necessarily the same ones from the first tests.
The only markings on these rounds are surface scratches and ejector marks. They are not bent, dented or malformed, and they are bright shiny new.
I suspect that if the mag locks in, and feeds rounds that end up in the barrel, the mag isn’t the problem. Once it jambs, it doesn’t matter if the mag is in or out, you have to pry the bolt back from the chamber to get it to come free and eject the round.
Try putting your step son’s bcg in your rifle. If that works fine I’m guessing it’s an issue with the carrier. If not I’d try to change the buffer and spring. If those don’t work I’d begin questioning the gas tube. Hope some of this helps. I highly doubt it’s the ammunition, but I suppose it could be.
Are you checking every round with a headspace gauge ?
Not trying to sound threatening, but I could causes a variety of symptoms similar to what you’re describing, just by using a hand picked piece of ammo.
When the bolt doesn’t seal completely, it is a problem.
50K psi in the chamber, bolt area about 1/7 square inch = 7000 pounds pushing the bolt towards your general neck area for a split second.
Note: I have not fired this weapon, I have been manually cycling it. Until I know the basics work first.
Tried with full and partial. Still jambs.
Gauge test? .223 in a 5.56. I think there is plenty of room.
This is like building an airplane from a kit. You do all the testing you can before you launch. Because once you are in the air, you can’t just step out of it to work on something.
So with a weapon, you make sure the mechanics work first before you fire it, because, as one example, if it doesn’t eject a round, it may pick up the next and ram it, and then that round may “explode”.
Not my first time at the Rodeo. Just my first time with an AR15.
I’ve lost my hearing in my left ear because of a pistol misbehaving and I was wearing protection. I was attempting to figure out why it would not cycle reliably. I now know that that pistol is an expensive paperweight. In case you are interested, it was a Kimber 9mm Solo.
I built two identical PSA kits in 5.56 - had similar problem with one of them. I switched out parts on the two until I narrowed it to one of the charging handles. (all other parts worked flawlessly. PSA sent me another charging handle and it works fine.
Since then, I played with the faulty one and “squeezed” it a bit with some plyers and oiled the gun a lot - I was able to get it to work.
If you have easy access to another charging handle for an AR-15, try it on this gun. That might be all that’s wrong.
Given how difficult it has been to sometimes get that sucker to go back into it’s location, I will not be surprised that it is the problem. I can’t see far enough into the barrel to see if the “fins” on the sides are still in the milled in groove.
The charging handle doesn’t just push in from the furthest rear point. There are tabs on both sides that fall into slots in the upper, about an inch inward. You put the CH into those slots, which hold it into place, and allow it to slide back and forth freely.
You are correct. What confused me was, I had the impression I was going to get parts and have to assemble it. And so given I’ve a background in machining (Grove MFG – the Big mobile hydraulic cranes) I was preparing to have to buy a few tools.
I was very pleasantly surprised to get a trigger kit and the assembly parts kit, but everything was just attach, and go!!
This is why I started off slowly, and said if it doesn’t manually cycle, I gotta know why. The charging handle (see the prior posting) has had me concerned.