[Flint Rock]

Let me tell you a little story. I bought myself a new Ruger SR 556 a while back. I really like the gun. A tad heavier than some, but not a problem. Anyway, one day on the range I heard something odd. I didn't think much about it and kept shooting. Then it happened again. The Ruger starting mixing in a two or three round burst every mag. Please be aware that my Ruger is not selective fire. The bursts starting coming more often, and getting longer. Four to six round burst started happening. Not really wanting to send the rifle back for repair for who knows how long, I replaced the entire trigger group with a Rock River 2 stage trigger. The rifle calmed down some, now it would limit itself to a two round burst about every mag or so. Well, I sent the gun back to Ruger. They replaced the sear disconnector and test fired it 50 times. All is right. Wrong. I went to the range to rezero sights and optics. Thirity rounds of slow fire zero work. Change mags. On about round two or three, I wasn't really counting, the gun became a runaway and dumped the whole mag. Soooooooo, the gun has gone back to Ruger for another repair attempt. My guess is the bolt or upper receiver is out of spec and the bolt is riding too high to reset the hammer. I guess we shall see. Has anybody else ever had something like this happen?

[neilage66]

Originally Posted by Flint Rock

Let me tell you a little story. {snip} Has anybody else ever had something like this happen?

One idea and one suggestion:

You may be bump firing the rifle unintentionally.

Hide yer dog.

[Txhillbilly]

Originally Posted by Flint Rock

All is right. Wrong. I went to the range to rezero sights and optics. Thirity rounds of slow fire zero work. Change mags. On about round two or three, I wasn't really counting, the gun became a runaway and dumped the whole mag.

I bet that got the Range Officer's attention,as well as everyone else.

Hope that Ruger can get it fixed in a timely manner for you.

[Tackleberry1]

I had a similar multiple round burst experience with my Bushmaster but it was not the rifle. I had replaced the factory trigger with a drop in Chip M Cormick trigger group and after about 300 rounds I began getting 2 to 5 round bursts.

I had my dealer "who sold me and installed it" replace it with a second but same model trigger group and have had no further issues.

Tack

[Flint Rock]

Originally Posted by neilage66

One idea and one suggestion:

You may be bump firing the rifle unintentionally.

Hide yer dog.

No. I'm not bump firing the gun. I can assure you that I have more than enough training and experience to properly and safely fire an AR, or just about any other gun for that matter.

[downsouth]

Flint Rock, be careful!

http://www.utahconcealedcarry.com/viewtopic.php?f=23&t=2132

[Paladin201]

Originally Posted by Txhillbilly

I bet that got the Range Officer's attention,as well as everyone else.

Yeah, and that can lead to some bad things. I'm sure everyone here knows the design of the AR trigger group is such that it can very easily burst or even go full auto if things aren't adjusted and timed right. I know a guy. I should say, I know of a guy. Don't know him personally. But he did a trigger job on his AR. Didn't like the long, creepy trigger pull. At the range it started letting off some 2 or 3 round bursts. Unfortunately for him, there was a LEO at the range who got his license number and made some phone calls. Later that day some ATF agents showed up at his home with a search warrant and confiscated the rifle. A couple of days later they came back with a warrant for his arrest. He learned that they had tested the gun at the lab and duplicated it's burst behavior. They also documented the fact that the trigger had been altered from its original configuration. He was charged with attempting to manufacture a machine gun. That's why I never modify the trigger group on an AR. I've had people come to me and ask me to de-creep or lighten the trigger on their AR. I tell them "leave it alone" and walk away.

P.S. Wrote this before I saw Downsouth's post. These scenarios are happening with increasing frequency.

[JonM]

atf has no tolerance for the honest law abiding citizen making a mistake. they will gleefully sell machine guns to murdering thugs but they will put grandpa in jail for having a shoestring and a gun at the same time...

send it back to ruger.

save all your correspondence with ruger.

[Flint Rock]

My Ruger has made two trips back to the Ruger factory for repair. Two times it has been "repaired" and sent back to me. Both times the "repair" didn't work and the gun would run wild. The gun would would pass a function check and the 50 round factory test fire, but whenever I spend some time and a few hundred rounds with the old girl.........well full auto runaway is sure to follow. I called Ruger customer service Saturday (after 3 full auto malfunctions in 200 rounds) and left a voice mail telling them the gun was still malfunctioning. Monday, Ruger was closed. Tuesday, Ruger customer service called and told me they were going to replace the gun.

The trigger group has been replaced three times. Nothing on the gun measures out of spec. I have been shooting AR's for 35+ years (military, LE, instructor) so it's not operator error.
I did find that the firing pin had come back so hard that it had bent the firing pin retaining pin. Actually the firing pin had stamped an impression into the retaining pin. I don't believe that was the problem, just a sympton of whatever the problem was/is. I would guess it is something ever so slightly out of spec in the bolt or bolt carrier.

[mjkeat]

This is why we have recommended against these levels of ARs. For the money you spent on it, less actually, you could be enjoying a quality AR at the range instead of standing in line at UPS.