Question about my first AR

[42!]

So despite too many decade shooting I only got my first AR recently. Nothing too fancy, just something I bought, not built, an SA Saint Victor. But it's doing something weird that I'm guessing someone with more knowledge of the AR-15 platform has seen before. At first I thought it might be the ammo, the bulk Winchester 55gr 5.56, but over the weekend I had someone run 30 rounds through their AR and it seemed not to have any issues.
What's happening is that some of the time when it's fired the sound is unusually loud and there is a lot more flash. At first it was only every 5 to 10 rounds, but last time out it seemed like it got about half way through the 30 round mag and then it was every round.
I'm going to get a different ammo and see what happens, but I got a fair amount of this bulk ammo amnd, well, we all know what the ammo situation is right now.

What I'm hoping for is a "ya I've seen this lots of times and you just need to ..." kind of answer, but any ideas on what I should look for would help. Thanks

 

[Marty McFly]

Gotta be ammo. But I wouldn't worry if it cycles correctly.

 

[Buck F]

So despite too many decade shooting I only got my first AR recently. Nothing too fancy, just something I bought, not built, an SA Saint Victor. But it's doing something weird that I'm guessing someone with more knowledge of the AR-15 platform has seen before. At first I thought it might be the ammo, the bulk Winchester 55gr 5.56, but over the weekend I had someone run 30 rounds through their AR and it seemed not to have any issues.
What's happening is that some of the time when it's fired the sound is unusually loud and there is a lot more flash. At first it was only every 5 to 10 rounds, but last time out it seemed like it got about half way through the 30 round mag and then it was every round.
I'm going to get a different ammo and see what happens, but I got a fair amount of this bulk ammo amnd, well, we all know what the ammo situation is right now.

What I'm hoping for is a "ya I've seen this lots of times and you just need to ..." kind of answer, but any ideas on what I should look for would help. Thanks

I’m happy to test some of that stash of ammo you have...

 

[Tinkermatic]

Gotta be ammo. But I wouldn't worry if it cycles correctly.

My sentiments as well. So long as you’re not having functional issues, just a discernible difference in report, you should be fine.

 

[Marty McFly]

My sentiments as well. So long as you’re not having functional issues, just a discernible difference in report, you should be fine.

Oh what do you know tinker.
Oh wait you agree.
Nobody agrees with me
Im confused

 

[Tinkermatic]

Oh what do you know tinker.
Oh wait you agree.
Nobody agrees with me
Im confused

Deep breath, someone’ll be along soon to explain for us both.
It’s a magazine issue of course! Always the mags!

 

[Marty McFly]

Deep breath, someone’ll be along soon to explain for us both.
It’s a magazine issue of course! Always the mags!

 

[Tinkermatic]

Honestly though OP, grab some new ammo and you’ll start to notice subtitles between them and even within the same brand/box.
Here’s a question, are you using electronic ear pro?

 

[AHM]

OP's words frighten and confuse me...

...but did you clean it before the first time you ran it?

 

[jkelly1229]

Gotta be ammo. But I wouldn't worry if it cycles correctly.

Yup cheapo ass ammo usually something dirty like tula will do it. Unburnt powder in your break lights up.

Or you got really shitty ammo and it's under charged lol

 

[Marty McFly]

Honestly though OP, grab some new ammo and you’ll start to notice subtitles between them and even within the same brand/box.
Here’s a question, are you using electronic ear pro?

Yes. Its all about the subtitles....... sorry Dave. I'm done trolling . You know I like you

 

[cams]

Serious question not busting your balls, but what type of earpro are you using? I’ve seen lots of guys with the bigger ear muff styles trying to get a cheek weld and it ends up pushing the earpro up off their ear a little. Could that be the case?

 

[Tinkermatic]

Yes. Its all about the subtitles....... sorry Dave. I'm done trolling . You know I like you

Ah hell, I’m not even gunna change it.

Ammo subtitles, you know?!

 

[Marty McFly]

Ah hell, I’m not even gunna change it.

Ammo subtitles, you know?!
View attachment 453692

 

[mac1911]

is it this stuff, this stuff is all over the map I ran some over the crony along with other cheap offerings of m193/855 and the velocities are all over the place.? I agree check your ear protection "muffs" like to rid up.
are you running a 16, 18,20 inch barrel is your friends barrel the same length

 

[42!]

Serious question not busting your balls, but what type of earpro are you using? I’ve seen lots of guys with the bigger ear muff styles trying to get a cheek weld and it ends up pushing the earpro up off their ear a little. Could that be the case?

It's not me, others at the range hear the difference, it's NOTICEABLE. And the extra flash that come with it is impressive.

is it this stuff
View attachment 453699

Nope, no fancy "target". Just 1000 round brown cardboard, loose packed in a plastic bag.

Like I said, I was thinking ammo until it didn't happen in my older son's AR.

No functional issues.

And while I appreciate the offers to help me get rid of the ammo, my sons are way ahead of you on that.

In a week or two I'll have another platform to try, just waiting on that dam stamp.

 

[Coyote33]

Could it be that the barrel is heating up and doing something different with how it burns?

 

[92G]

That is most definitely not a firearm issue. It’s probably a nothing issue. How quiet would you like 5.56 to be? Your options are to run some of them over a chrono and/or pay attention to the ejection pattern which is an imprecise but legit indicator of pressure. Most likely explanation is some of those rounds are under-charged or the ammo you were sold isn’t WWB. Check the headstamp if you haven’t already.

 

[Bodhisattva]

What muzzle device are you using?

 

[jasons]

Have you tuned the Johnson rod for your ammo’s amplitivity factor?

 

[teamRR]

Assuming it's not how your electric muffs react or odd ammo, it would be a good idea to check headspace. Usually if ammo is that different it will have reliability issues IMO.

If you want another set of eyes and you are in the southern/seacoast nh area could take a look. Got gauges and stuff to check that too, other ammo, other ARs etc etc

 

[nutsym16]

Check the Johnson bar also

 

[cockpitbob]

Chamber throat a little short for the ammo? If the bullet is jammed against the lands chamber pressure will go up vs. the bullet having a few thou of running start into the lands. Maybe the longer cartridges in that plain brown box of bulk are causing the chamber pressures to spike.

ETA: or headspace like teamRR suggests. Here too, if the headspace is tight, the longer cases in the bulk ammo could have higher pressures.

Check the primers on the loud, flashy ones!

 

[Drix]

I've noticed sound profile differences with ammo, also noise differences with heat- I have an AR that loves spitting fire out of the ejection port after a mag or so.

Lastly, depending on the shooting stall sometimes my barrel doesn't get out beyond the stall and I can bounce sound differently. Try benching first, see if it helps, if not I agree, torque your johnson.

 

[Rocky Mosasaurus]

Damn, a Saint Victor, nice. The first AR I ever shot was a plain old SA Saint...the new Saint Victor line is badass. I would clean out the barrel with a bore snake, field strip everything and do a deeeeep clean. Afterwards do some smooth cadence shooting then mag dumps see if it happens again. Best of success with the Saint Victor, it’s a great rifle.

 

[jpm]

Damn, a Saint Victor, nice. The first AR I ever shot was a plain old SA Saint...the new Saint Victor line is badass. I would clean out the barrel with a bore snake, field strip everything and do a deeeeep clean.

This^^

But I'm wondering @42! if you are taking some time between shots perhaps? My thinking is that its pretty cold out these days and the powder in that ammo could very well be temperature sensitive. So your first 10-15 rounds are still kinda cold and less energetic until the gun heats up. And if you're taking time between shots, the chamber will be pretty toasty by then and heat up the round in the chamber making the powder more energetic when you finally fire it. That would increase the sound and the flash for sure.

Reloaders who like to run near max charge on their ammo will keep track of the time of year so they don't use a near max load they developed in the winter during the summer months and blow up their gun if the powder is temp sensitive.

 

[42!]

A couple good comments but some of you aren't reading, or maybe I'm not being clear.
The ammo is legit, sealed box from Shooters, headstamp matches. All from the same box. And Ammo was my first thought until the problem didn't happen in another AR.
What I describe happening is see and noted by all at the range, so this isn't my ears, or eyes, or some weird expectation of what an AR sounds like. And it's the first one I've owned, not the first I've shot. Seriously guys, I've been shooting since I was 13, thats forty years. There has been more than one AR in my hands. Although I do like the full auto SCAR more.
The rifle is completely stock and was new when I got it, also from Shooters.
Specs, muzzle device, here you go SAINT® Victor 5.56 AR-15 Rifle - Springfield Armory

I can't emphasize the difference between a "good" round and a "questionable" one. Everyone notices the change in volume and it's spitting fire. It's not subtle.

Otherwise it runs flawlessly, no ftf or fte and goes bang every time, a lot more carbon build up at the muzzle, but otherwise ok. And while I'm shooting a short range, the accuracy does not seem to be affected.

If it is just the ammo, it's the crappiest QC I've ever seen.

 

[jpm]

you could also take 10 or so rounds at random from the box and pull them apart and measure the charge in each. See if its consistent or not.

 

[drgrant]

It almost sounds like you had 223 and 556 mixed up in the same pile or something? lol

Then again I have seen some of that phenomenon, particularly with guns that had brakes or no flash suppression, etc.

 

[42!]

This^^

But I'm wondering @42! if you are taking some time between shots perhaps? My thinking is that its pretty cold out these days and the powder in that ammo could very well be temperature sensitive. So your first 10-15 rounds are still kinda cold and less energetic until the gun heats up. And if you're taking time between shots, the chamber will be pretty toasty by then and heat up the round in the chamber making the powder more energetic when you finally fire it. That would increase the sound and the flash for sure.

Reloaders who like to run near max charge on their ammo will keep track of the time of year so they don't use a near max load they developed in the winter during the summer months and blow up their gun if the powder is temp sensitive.

The barrel temp may be an issue, when I first noticed it it did seem to be more frequent after the first mag or two. Last weekend it seemed more consistent so I was thinking gas block issue, but like I said I don't have a lot of hands on with monkeying around with an AR. In the past it's been someone else's rifle so I was basically shooting it and handing it back. Last weekend was also all indoor so no major cold temps.