A little expertise needed. AR-15 issues

[Jared]

I purchased a Doublestar star-15 carbine from a guy on here and it was new, unfired. I broke the barrel in properly and am firing Remington 1st run 55gr. fmj ammo. I have experienced a couple of malfunctions from this rifle. The first was a feed problem when the next round to be fed via the feed ramps into the chamber, was jammed into the barrel extension and it drove the projectile itself into the case almost all the way flush. The round that mis-fed was the 10th round fired from a new magpul 30-rnd pmag that was initially loaded with 25 rounds. Could this be a magazine issue? Or possibly related to the second issue? The second issue is that I beleive the rifle is over-gassing. There are VERY strong pull marks from the extractor on the rim of the case, and the spent brass is ejected at least 5-6 feet from the rifle. Can this be remedied by a new, stronger buffer spring and heavy buffer? Any other thoughts? By the way, the rifle has been fired 120 times in total. I'm happy with the rifle otherwise and I'm not *****ing about the guy, he didnt screw me over or anything, I just wanna get this thing firing properly. Is it possible that since the gun is new, the barrel could be a bit tight, causing overgassing? I mean, I would think that it should be ok by now. Little help pls! Thanks!

 

[shooter521]

The first was a feed problem when the next round to be fed via the feed ramps into the chamber, was jammed into the barrel extension

Got pics of your feed ramps? The gun doesn't happen to have a standard barrel extension installed in a ramp-cut upper receiver, does it?

Can this be remedied by a new, stronger buffer spring and heavy buffer?

Can't hurt; conventional wisdom says to run the heaviest buffer that will allow the gun to cycle with the weakest ammo you expect to shoot (for most folks, that's Wolf). I run 9mm buffers (5.3oz) in all my carbines.

 

[AllenM]

I like to rule out the easy stuff first. I would try a differant mag.

 

[shooter521]

I like to rule out the easy stuff first. I would try a differant mag.

No harm in that, either. Just doesn't sound like a mag issue to me, since the mag in question is 1) a PMAG, 2) brand new, and 3) the problem isn't happening consistently.

My

 

[Jared]

I believe that the ramps and extension are right for each other... and the weakest ammo or the most common ammo for that matter would be 55gr rem umc fmj.

 

[bigus_D]

what is the discoloration on the feed ramps? looks like rust from here, though I suppose it could be a lube of some sort.

I'd imagine that if the chamber were in the same condition, shells could easily become stuck in there.

Note: I'm no expert!

 

[AllenM]

I still stand by my opinion

 

[shooter521]

Ramp arrangement looks correct; nice pics BTW!

So let's get back to basics. Dean Caputo (longtime carbine SME and former Colt armorer) says that the majority of AR function problems can be summarized by the acronym "MEAL".

Magazine - are you using mags of proven quality? Does the malfunction occur with different/multiple mags?

Extraction - does your carbine have the correct extractor spring and insert? Carbine length gas system should have a 5-coil spring and black insert (if necessary, an O-ring can be added at the base of the spring to improve tension). Does it have the correct recoil buffer and spring?

Ammo - is the ammo of known-good quality (i.e. have you had problems with it before? Have others?), and does the malfunction occur with multiple/different types of ammunition?

Lubrication - are you keeping the gun lubricated properly and frequently?

 

[boman]

one misfeed? I would keep shooting the rifle with this mag and others to see if it continues to misfeed. ---could have been one of those flukes since the barrel/upper combination appear to be correct.

There are VERY strong pull marks from the extractor on the rim of the case, and the spent brass is ejected at least 5-6 feet from the rifle.

. 5-6 feet doesn't sound unusual---extraction sounds solid---maybe that rem brass is exceptionally soft or the extractor has a burr on it? 223 chamber might extract a little harder? rough chamber?

Steve

 

[Jared]

If you look at the ramps at a different angle, the rust-colored material is actually copper from the projectile. I dont know why it looks like rust haha... I'll try some other mags I have 4 new in the plastic pmags w/ window and some milspec mags.. are there any other things I can do for reliability??

 

[kevinj110]

Wait Jared isn't your AR a mid length gas system. Get a heavier buffer.

 

[kevinj110]

Oh ya and get back to work.

 

[Steven]

I purchased a Doublestar star-15 carbine from a guy on here and it was new, unfired. I broke the barrel in properly and am firing Remington 1st run 55gr. fmj ammo. I have experienced a couple of malfunctions from this rifle. The first was a feed problem when the next round to be fed via the feed ramps into the chamber, was jammed into the barrel extension and it drove the projectile itself into the case almost all the way flush. The round that mis-fed was the 10th round fired from a new magpul 30-rnd pmag that was initially loaded with 25 rounds. Could this be a magazine issue? Or possibly related to the second issue? The second issue is that I beleive the rifle is over-gassing. There are VERY strong pull marks from the extractor on the rim of the case, and the spent brass is ejected at least 5-6 feet from the rifle. Can this be remedied by a new, stronger buffer spring and heavy buffer? Any other thoughts? By the way, the rifle has been fired 120 times in total. I'm happy with the rifle otherwise and I'm not *****ing about the guy, he didnt screw me over or anything, I just wanna get this thing firing properly. Is it possible that since the gun is new, the barrel could be a bit tight, causing overgassing? I mean, I would think that it should be ok by now. Little help pls! Thanks!

Sounds fairly normal for a new , tight AR. Not unusual to get a round jammed every now and then, but it should not be a constant thing.
5-6 ft sounds about right for ejection.
Have you checked the extractor for burrs , chips , ect.
Picture of the brass ejection marks ?
Clean the bolt, chamber very well, lube it up good,try some different ammo and get some miles on that thing.