AR-15 failing to go into battery

[swampratt]

Possibly out of spec, and the bolt is riding a bit too low in the races of this upper

Right on the money I say.

Is the bolt thick enough at the bottom to take some off of it.
5-10 thousandths may do it.

Or are your plans to send it back to the manufacturer.

 

[Perplexed]

Right on the money I say.

Is the bolt thick enough at the bottom to take some off of it.
5-10 thousandths may do it.

Or are your plans to send it back to the manufacturer.

I bought the upper at least a year ago and just got around to using it, so I’ll try polishing the bottom of the bolt I want to use in this AR and see if that doesn’t help. I’ll post an update.

Thanks for all the comments, folks.

 

[leemozoid]

Update: I swapped out the barrel for another one, and still had the same issue of the bolt not going into battery with a loaded magazine. It would strip and partly chamber the round, but go no further. Dropping the magazine and recharging the bolt would result in the bolt chambering the round properly and going into battery. With an empty magazine, the bolt would go into battery when I released it.

The mystery continues, but now I’m looking hard at the side charger.

Have you tried loading your mags with just 28 rounds?

 

[swampratt]

He tried with 2 in the magazine post 1.

If I load two rounds into a magazine and charge the AR, I have the battery issue, and if I remove the magazine and charge the AR again, the bolt chambers fine. When I reinsert the magazine with one round in it, and fire the AR, the bolt ejects the spent round and chambers the next round but will not go fully into battery.

 

[RickN]

But, but, ARs do not have problems anymore!

 

[Perplexed]

But, but, ARs do not have problems anymore!

This was the first issue in eight AR’s I’ve built or bought

 

[Perplexed]

Well, I finally figured out the issue.

And boy, do I feel like a dunce. But in the interest of educating the public, I’ll admit to my major brain fart.

In their literature, NFA says their side charging upper will work with any milspec BCG. That’s where I thought to myself, “That sounds great, I’ll order one and try it.”

What I failed to notice was the very next part in the product description. “Replace the cam pin with our modified cam pin…”

Not only that, but I didn’t notice the supplied modified cam pin that was in the shipping box - in a bright yellow zip loc bag, no less.

So just now I swapped out the cam pin with NFA’s pin, and tried chambering a round from a fully loaded mag.

It worked. Chambered, fully in battery, and all. The next few rounds were chambered as well as I ejected each in turn. Now I need to drive out to the range when I get a chance and try the AR.

Time to go sit in the corner with one of those tall, conical hats.

 

[wawazat]

At least you came back and shared the solution. If this thread pops up in the search results of someone else with a similar issue, maybe it will help them out.

 

[Snattlerake]

Update: I swapped out the barrel for another one, and still had the same issue of the bolt not going into battery with a loaded magazine. It would strip and partly chamber the round, but go no further. Dropping the magazine and recharging the bolt would result in the bolt chambering the round properly and going into battery. With an empty magazine, the bolt would go into battery when I released it.

The mystery continues, but now I’m looking hard at the side charger.

Not for nothing but here goes. Are the magazines the right caliber? 6.8 SPC will allow the 5.56 load but it damn sure won't feed and acted exactly what you are telling us.
I purchased an AR from a member here and he "threw in" 5 magazines. I purchased the multi 5.56/223 caliber instead of the AR10 308 for the same money. The 5.56 had better quality innards. The seller said, "Take that box of magazines with you." pointing toward a small box of newish looking mags.
He said he built the rifle himself and test fired a mag, cleaned it, and set it back. I can't get anywhere to fire it for over a year and finally get to shoot it. I chambered a round with the charging handle and it went boom and immediately hung a round above the gas tube. I of course took my time getting it out and checked the tube for bends and creases and propper insertion into the BCG. I tried again and stove piped one with a jam halfway into the chamber.
Frustrated, I cleared it and brought it home checking clearances and reading about adjustable gas blocks assuming that was the cause and put the rifle up again. Screwing around using one of the gimme magazines as a template for a shelf system for storage, I noticed it said 6.8. on the follower and remembering in 1976 the AR magazines had a ballistic missile looking follower with the pointy end toward the front to show 18 year old mamma's boys which end of the round goes to the front. I looked at the side of the mag and it too said D& H Tactical, 6.8 SPC.


Well %^&*ING - A!!!!

I had some old military M-16 mags and drove out to the farm. Brrrrp. As fast as I could pull the trigger the rounds just left the weapon.

 

[O4L]

Well, I finally figured out the issue.

And boy, do I feel like a dunce. But in the interest of educating the public, I’ll admit to my major brain fart.

In their literature, NFA says their side charging upper will work with any milspec BCG. That’s where I thought to myself, “That sounds great, I’ll order one and try it.”

What I failed to notice was the very next part in the product description. “Replace the cam pin with our modified cam pin…”

Not only that, but I didn’t notice the supplied modified cam pin that was in the shipping box - in a bright yellow zip loc bag, no less.

So just now I swapped out the cam pin with NFA’s pin, and tried chambering a round from a fully loaded mag.

It worked. Chambered, fully in battery, and all. The next few rounds were chambered as well as I ejected each in turn. Now I need to drive out to the range when I get a chance and try the AR.

Time to go sit in the corner with one of those tall, conical hats.

I'm glad that you figured it out.

Now that you mention it, it seems like I remember reading something like that about the cam pin when using a side charger.