AR Bolt sticking,

So i hav e a new never fired AR, It was functioning fine when i put it together, Now i tried to cycle it with some plastic rounds (snap caps?) and the bolt is sticking failing to pull back and eject the round, Any ideas ?

AR Bolt sticking,

So i hav e a new never fired AR, It was functioning fine when i put it together, Now i tried to cycle it with some plastic rounds (snap caps?) and the bolt is sticking failing to pull back and eject the round, Any ideas ?

Did you disassemble it for cleaning?  Did you disassemble the BCG?

If you let the bolt close on its own at full speed, it might have cracked or expanded the rear of the snap cap.  I use dummy rounds made from real ammo brass myself to prevent such problems.

If you can't get it to extract, use a wooden dowel or cleaning rod with the muzzle pointed up and butt on the floor/table.  Pull the charging handle while tapping on the dowel/rod inserted into the barrel.  Easier with 2 people.

+1 on making and using dummy rounds instead of snap caps.  I had some red clear plastic snap caps that were damaged from bcg cycling after a while.  This way you can also check if neck tension is good after initial cycling.

I did use a magpie dummy round and have it get stuck in a hot barrel. Ended up losing the round because I treated it like a hot situation and tried real hard to eject it, load another magazine, and continue to fire. I didn't see where it wen't and couldn't find it. I am assuming temperature played some part in my gun failing to work properly on the dummy round. Is that a possibility for you?

My bolt jammed after firing a round. The bolt was disassembled and cleaned before and I did not put the firing pin in properly before inserting the cotter pin.  The pin backed out and jammed itself in the receiver. Check to make sure you reassembled your bcg properly.

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AR Bolt sticking,

So i hav e a new never fired AR, It was functioning fine when i put it together, Now i tried to cycle it with some plastic rounds (snap caps?) and the bolt is sticking failing to pull back and eject the round, Any ideas ?

Is this a factory built gun or a custom/user built gun? 

When you mentioned it "functioning fine", I assume you mean basic function checks where you cycle the bolt, dry fire, check trigger reset, safety function, etc.  Then when you tried to test the cycling of the action/bolt with a dummy round, it bound up after chambering the dummy round?  If you haven't used that same dummy round before, it might be off just enough to cause the binding (like mentioned before).  I've seen where a primer was ever so slightly too high and that bound up the bolt really bad.  Reportedly, it was a reload and I believe they chambered the round and it misfired (didn't fire).  Then when they tried to diagnose, the bolt was STUCK!!!  I didn't work on the gun myself, but they needed a hammer and a block to pound the bolt back out. 

If that dummy round was previously used in another gun just fine and assuming it's not damaged, I can only assume that something is up with the headspace. 

I managed to get the snapcap out but had to put a lot of pressure on the charging handle, I then cycled the bolt with an empty magazine well and it functioned fine, I then loaded another magazine with more snap caps, first couple cycled 3rd didient, Again applied force and cleared it. next round stuck again,

Drooped the mag cleared it again, Loaded a new mag with live ammo, cycled the bolt and first 4-5 cycled normally and then it got stuck again, Applied pressure to clear, repeated and it seems that rounds get stuck at random, Any ideas ?

oil bolt and BCG....................run wet

oil bolt and BCG....................run wet

I striped the bolt cleaned it and lubed it and same thing, Its strange as it wasent doing this before i put it in the safe,  The only think i have done it mount a scope.

A previous poster asked if this is a rifle you put together or is it like a complete rifle from a company. Did you try cleaning the throat of barrel with a brush and then oil it up?

When you cycle rounds do u let the charging handle fly forward or you ease it into place?

When you say you apply pressure to charging handle, do you mean the bcg doesn't go into locked position or applying "pull pressure" to extract?

Check your extractor. Sometimes company's use both extra strength extractor spring and o ring. Both is not really necessary. If it has oring try remove it then cycle. Also check extractor for any burrs that may be getting hanged up on the round. Or maybe a burr on top the extractor that prevents going into locked position?

A previous poster asked if this is a rifle you put together or is it like a complete rifle from a company. Did you try cleaning the throat of barrel with a brush and then oil it up?

When you cycle rounds do u let the charging handle fly forward or you ease it into place?

When you say you apply pressure to charging handle, do you mean the bcg doesn't go into locked position or applying "pull pressure" to extract?

Check your extractor. Sometimes company's use both extra strength extractor spring and o ring. Both is not really necessary. If it has oring try remove it then cycle. Also check extractor for any burrs that may be getting hanged up on the round. Or maybe a burr on top the extractor that prevents going into locked position?

Its a complete upper that i purchased its a Core15,  It does it when i set the bolt slow or when i let it slam forward. the pressure is to the Charging handle to extract.

I also trteid loading a round without the lower attached and same thing, The bolt gets stuck (i pushed the bolt into position by hand)

Check your extractor. Sometimes company's use both extra strength extractor spring and o ring. Both is not really necessary. If it has oring try remove it then cycle.

Will do.

Hmmm. Check for burrs/ sharp pointy points on bolt lugs, barrel extension lugs, and upper receiver where the cam pin rotates/ cam pin itself should be smooth. Sounds definitely like binding, not a lubrication problem. Also if you have time to disassemble the bcg again, double check the cam pin hole and body. Make sure super smooth.

This probably isn't the problem, but check your gas tube. If it's crooked enough it could cause some binding. A good way to check is to somehow sharpie the gas tube and look for excessive rubbed off sharpie. This can help to see if something is horribly crooked? *shrugs*

Sorry I'm babbling so much.
Good luck and keep us updated.

Oh and the oring thing, Lmk if it has a blue(weak) or black (strong) insert. I assume it should have black since CORE15 made the upper. Most companies that use a black insert already using the stronger/longer spring. That's how they identify it sort of.

OKI, so i striped the BCG again, removed the extractor and had both the spring and the black o-ring, I removed the o-ring and function tested the rifle (Again) and it seems to be a lot easier to cycle, Its stil feels like its sticking tho. But maybe im just paranoid

Did it have the black insert? if it does, I say leave the o-ring off and fire. How many coils on that extractor spring? Or perhaps you have another ejector spring from another bolt to compare lengths?

How did the cam pin look? Smooth?
Upper receiver where the cut out for the cam pin to rotate looked clean (meaning smooth with no dents as well?)

Try feel those bolt lugs and barrel extension lugs too. Feel for burrs but be careful not to cut yourself.

I remember making my first ar15 I pieced together. It seemed a bit tight, but according to the barrel manufacturer it was because that my headspacing was on the tighter side. I had headspacing issues due to my bolt had Excessive NIb coating.  I had to polish and some wet sand with oil to get it to right depth.   After I fired some it seem to got a whole lot easier. If it helps, bolt face depth is .125".

I'm by no means an expert at all. I'm just looking at contact points and where metal rubs one another where it can cause resistance. Could it be your gas rings? I know that they go on a certain way. Sharp vs smooth edges. I totally forget which way is correct but that could cause drag and maybe scraping the inside of your bolt carrier? I guess you could check there to and be sure it's smooth as well and oil it up a lot just til you find the problem. YouTube or Google gas rings installation on the bolt. Also check those roll pins/ pinch pins (for the ejector and extractor) and ensure they are flushed with bolt.

How do the rims of the dummy and live rounds look after ejecting?  Chewed up?

Any scoring on the cartridge body like some crap got into the chamber?

How do the rims of the dummy and live rounds look after ejecting?  Chewed up?

Any scoring on the cartridge body like some crap got into the chamber?

Fine, No more marks or damage. Im tempted to take it to the range and see what happens, or at least let some one with more experience handle it and see if its just me being a pussy

Strange that it does it randomly and with live round as well as the dummy rounds.  Troubling with the live rounds more so. 

Do you feel it binding up anywhere in particular?  I assumed it was in how the bolt/locking lugs lock up, but do you feel dragging elsewhere? 

When you say it's stuck, it's it stuck to the point where you have to mortar the gun to get the bolt to move?  Just throwing stuff out here at this point to sort of try to eliminate things. 

If you could post a video of what you're experiencing, that would probably help. 

Do you feel it binding up anywhere in particular?  I assumed it was in how the bolt/locking lugs lock up, but do you feel dragging elsewhere? 

T'were me, I would chamber a round or two very slowly, feeling for any bumps or dragging as the bolt goes home and the round chambers.  Might illuminate where it sticks on the extraction.  Letting it slam home overrides any resistance with spring assistance, not present on extraction..

I like pressing the bolt into battery with my thumb, upper disassembled.  You can feel any rough spots, same with pulling the bolt back with the charging handle and not fighting the spring.  I like feeling the parts move.

If the rounds are hanging up, I wouldn't use live rounds to test things out. If there is a obstruction in the chamber or a hangup when sending home you could have a slam fire or out of battery kaboom.  Better have someone with experience look at it.