Failure to Eject

[SoMD_Gen4]

You're using an AR-10 recoil spring and not an AR-15 recoil spring? Yes, there's a difference and using the AR-10 spring in an AR-15 does exactly what's happening to your rifle. Did you put the lower together yourself?

Yes, I put the whole thing (upper and lower) together myself. I got the buffer tube assembly from Cromwells. I believe it was labed AR-15?

 

[TrappedinMD]

Id call the manufacturer of the gas block and ask them about using a free floated foreend.

 

[BradMacc82]

OP, I'm willing to bet cold $$$ that it's likely just a misaligned gas block.

When you put it together, did the edge of the block sit flush against the cut in the barrel? Because if it did, the gas port is likely covered.

 

[SoMD_Gen4]

OP, I'm willing to bet cold $$$ that it's likely just a misaligned gas block.

When you put it together, did the edge of the block sit flush against the cut in the barrel? Because if it did, the gas port is likely covered.

What do you mean the "cut" of the barrel. When I assembled it, the block sat up snug to the ridge that prevents it from going any further toward the upper. I think you are right though, and I believe it was probably aligned, and then when I tightend the set screw it may have shifted. After I rebuilt it yesterday, I am anxious to get it to the range to test it again. If it fires and ejects without issue, than we were right.

 

[ThawMyTongue]

What do you mean the "cut" of the barrel. When I assembled it, the block sat up snug to the ridge that prevents it from going any further toward the upper. I think you are right though, and I believe it was probably aligned, and then when I tightend the set screw it may have shifted. After I rebuilt it yesterday, I am anxious to get it to the range to test it again. If it fires and ejects without issue, than we were right.

Most barrels are cut with a handguard cap in mind between the FSB and the shoulder of the barrel. Often when using a gas block without the handguard cap you must account for the thickness of the missing cap. So the gas block would not be directly against the shoulder for correct alignment. I can't remember the thickness of the cap off the top of my mind...

You can see the placement of the handguard cap in this pic...

 

[CrawfishStu]

I see where you said which handguard and which barrel. Which gas block? You seem like you know enough for this to be a silly question......but it isn't an adjustable block like the wilson low profile is it?

 

[jonnyl]

What do you mean the "cut" of the barrel. When I assembled it, the block sat up snug to the ridge that prevents it from going any further toward the upper. I think you are right though, and I believe it was probably aligned, and then when I tightend the set screw it may have shifted. After I rebuilt it yesterday, I am anxious to get it to the range to test it again. If it fires and ejects without issue, than we were right.

this may be the issue as others are saying. There's supposed to be a gap there that allows for the handguard cap. You can kinda see it in this pic.

 

[FlatsFlite]

Gas block + 101

Remove the set screw furthest from the muzzle. In that (set screw) hole you should see a machined dimple into which that set screw fits. If you do not see that dimple, the gas port is blocked. Loosen the set screw and slide the bass block until you see that dimple.

Most people screw up by sliding the gas block until it stops then tighten it down. Most likely you'll have a 1/16" gap.

 

[BradMacc82]

I'm at work on my phone, so I can't post pics. But the block should be spaced off the barrels "seat" by only a few hundredths of an inch, to account for the handguard end cap.

 

[SoMD_Gen4]

I see where you said which handguard and which barrel. Which gas block? You seem like you know enough for this to be a silly question......but it isn't an adjustable block like the wilson low profile is it?

No it's a Spike's Tactical Micro .750" Gas Block.

The specific set up was off of AimSurplus.. http://www.aimsurplus.com/product.a...+Barrel+w/+pinned+Mid-Length+LPGB&groupid=573

 

[jimbobborg]

Yes, I put the whole thing (upper and lower) together myself. I got the buffer tube assembly from Cromwells. I believe it was labed AR-15?

I asked for an AR-15 carbine spring at a local shop and got an AR-10 spring instead. They look exactly alike until you put them next to eachother.

 

[SoMD_Gen4]

Gas block + 101

Remove the set screw furthest from the muzzle. In that (set screw) hole you should see a machined dimple into which that set screw fits. If you do not see that dimple, the gas port is blocked. Loosen the set screw and slide the bass block until you see that dimple.

Most people screw up by sliding the gas block until it stops then tighten it down. Most likely you'll have a 1/16" gap.

Yeah, that makes sense. The problem is with this gas block there is only one set screw. Behind that set screw is a pin that is pushed through to the otherside which fits in a groove on the bottom side of the barrel. It's almost a anti-rotation type of pin I would assume to keep the gas port un-obstructed.

 

[armed ferret]

are you sure the gas tube is aligned properly?

i helped another forum member assemble an AR upper, and he did the gas tube install. he put it in upside-down, so the hole on the gas tube was facing upward. turned his gun into a really nice single-shot rifle.

 

[SoMD_Gen4]

are you sure the gas tube is aligned properly?

i helped another forum member assemble an AR upper, and he did the gas tube install. he put it in upside-down, so the hole on the gas tube was facing upward. turned his gun into a really nice single-shot rifle.

I didn't pay attention when I disassembled and rebuilt it but if this is what happened to me that I'm gonna kick myself in the balls....not saying it is what I did but it'd be hilarious if it was

 

[John from MD]

I didn't pay attention when I disassembled and rebuilt it but if this is what happened to me that I'm gonna kick myself in the balls....not saying it is what I did but it'd be hilarious if it was

Your probably won't think it's too funny after that first kick.

John

 

[Ab_Normal]

It's a mid-length gas system on a 16" barrel. The barrel is a Spikes FN 16" CHF 1:7, 5.56 NATO

Do you have the correct length gas tube?

 

[SoMD_Gen4]

Do you have the correct length gas tube?

Yep. Appreciate all the good responses, I will report back after I hit the range hopefully sometime this week to try the "rebuilt" first build!

After all is said and done, if it works like it should, it's been an awesome learning experience and I will know more about my rifle then if I just bought one off the shelf.......and knowing is half the battle haha

 

[BradMacc82]

If you ever want to learn more than you'd think is possible in a short amount of time - watch Clandestine build one up.

Man taught me a few tricks I never would've thought of.


(I swear to god that better not wind up in the 'Out of Context' thread.)

 

[clandestine]

If you ever want to learn more than you'd think is possible in a short amount of time - watch Clandestine build one up.

Man taught me a few tricks I never would've thought of.


(I swear to god that better not wind up in the 'Out of Context' thread.)

 

[Rattlesnake46319]

If you ever want to learn more than you'd think is possible in a short amount of time - watch Clandestine build one up.

Man taught me a few tricks I never would've thought of.

Showed ya where the lube goes?


Dammit, that was supposed to go in the out of context thread.