AR help please!!

Maximcan

Maximcan

CGN Regular
Rating - 100%
130   0   0
Location
North Vancouver BC
Hey Gents,

I have a problem that someone on here might help me fix.

I have an 20" AR15 upper that, for some reason, won't feed 5.56 The barrel says it's chambered for it and 223 rem works (once in a while I need to use the forward assist)
To shoot my 5.56 i have to drop a round into the chamber and close the bolt on it.

The barrel and reciever are brand new, the bcg is not.

HELP....please!! I want to have fun without hitting that damn forward assist!!

Need help not smart ass comments like the last time I asked for help, please


Thanks guys
 
Check the overall length of the 5.56 cartridge compared to the .223. It might be a bit longer. I had that problem on a couple of my AR platforms and now I have to push the bullet in a bit on the 5.56 stuff.
 
start with the easy fix first,try a different magazine if you haven't already.if that doesn't work check the chamber with a borescope.sometimes there is a burr or a sharp edge which prevents easy chambering.223 and 5.56 are the same dimensionally,btw.does the bolt cycle properly on an empty chamber?let us know what's up.
 
I know the rifle that Maximcan has & was there to test fire . bcg cycles fine with empty chamber , feeds .223 95%of the time . when using .556 , will feed until the last 1/4 " . then will not go any more .
 
My bolt carrier will hang like that if I don't lube it, Or use oil. I lube the rails (and a little on the outside edges of the locking lugs) on m BCG with Lucas red-n-tacky now and it closes all the time. Even when I try to get it to hang up like it used to do. (Norinco cqa, and federal .223, sorry no 5.56 on hand)
 
Got to be factory, if he was qualified to reload for an AR, he would not be asking this question. No offense to the Op.

New or Used? Is on my mind. Last time I bought a used upper of the EE, it practiacally falling apart and needed a thorough going over with the ol' torque wrench.

If it's new, don't pick at it too much. Should have some reasonably drawn facsimile of a warranty.
 
In other news, off the top of my head, 5.56 is suppose to be a heavier duty brass, which means thicker walls, which could mean a thicker brass at the neck, which means when the identical 224 bullet is forced into said neck it turns out to be just a touch wider then a 223 round.

A 5.56 chamber is suppose to have wider tolerances so that everything fits always and guns keep running against all odds.

Try this, rig up what I like to call a Wildcatters No-Go gauge. A little trick the old timers taught me to make sure cases formed from other calibers are safe to fire.

Take a small piece of scotch tape, apply it around the circumference of the neck, so that it does not overlap, of one of the 223 rounds you've been firing. (The 223 not the 5.56.)

They try to chamber that round into your rifle, in a safe place, like at the range pointed downrange, and do not fire it of course.
See if that round now jams up like the 5.56.

If it does, it's cause you have too tight a throat. That tape simulates the amount of relief your case neck needs to expand and release the bullet.
In fact, if it does not chamber smoothly with the tape, you throat is too tight by some standards and can cause an unsafe spike in pressure as the bullet cannot leave as smoothly. If that's the case, I would not attempt shooting any hot match rounds in there anytime soon.
 
fred0000 said:
How much effort is needed on the forward assist to close the bolt the rest of the way?
Click to expand...

Foward assit will not completely close the bolt . Have to hand load the cartridge into the chamber then the bolt will close , gun will fire , casing will eject , bolt will grab new cartridge but not close . Start all over again .
 
canadiantbone said:
Foward assit will not completely close the bolt . Have to hand load the cartridge into the chamber then the bolt will close , gun will fire , casing will eject , bolt will grab new cartridge but not close . Start all over again .
Click to expand...

Is it hard to close the bolt when you do this ? have you tryed different Magazines?
 
Check your ejector/spring. How hard is it to push in by hand or with a tool?

If when you insert the round in the chamber and close it from locked open, it might have enough force to push the ejector pin in but when you try from a magazine, the momentum of the bolt closing slows down just enough that it hangs up.

Don't really know why it would do it with 5.56 and not .223 unless the chamber is not cut right or maybe has a short throat?/...I dunno
 
well ok here is a longshot.is it possible that the rim of the 223 brass is thinner than the milspec 5.56.if it is then you may have a problem with the extractor,or more specifically the problem may be the spring/donut setup under the extractor.in cool or cold weather you may have to remove the rubber donut thing because it won't allow the extractor to ride over the rim on the feedstroke.try it and post results please.
 
Check your gas path. Not enough gas will provide performance you described. If piston (rather than gas impingement), ensure selection knob is at full gas position. Misaligned gas block (partially closed orifice) will do that too.
 
You must log in or register to reply here.
Back
Top Bottom