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  #1  
Old 03-11-2018, 10:27 PM
Tysoncrosby21 Tysoncrosby21 is offline
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Default Sport 2 won't cycle?

Recently ground down the front sight and installed a midwest industries free float. Everything went back together perfectly, took it out and shot about 150 rounds with zero problems. Cleaned everything up and reassembled after shooting.

Next time I went out it wouldn't cycle. To the point where it wasn't even extracting the spent case.

So, I took everything apart and retorqued the barrel nut, reinstalled the gas tube and pin, took the bolt apart and completely cleaned everything. It is still short cycling but now it will extract but won't pick up the next round out of the mag.

Same ammo and mags I've used previously with zero problems. Weird that it went from perfect function to not cycling without doing anything to it.

Any ideas?
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Old 03-12-2018, 12:01 AM
TX-Dennis TX-Dennis is offline
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Sounds like a gas issue. I'm no expert, but perhaps the gas block shifted a bit after you ground down the front sight? It wouldn't take much to cause a problem.
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Old 03-12-2018, 12:26 AM
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Do you have pics of the gas block?
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Old 03-12-2018, 06:45 AM
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Quote:
Originally Posted by Tysoncrosby21 View Post
Recently ground down the front sight and installed a midwest industries free float.
Next time I went out it wouldn't cycle. To the point where it wasn't even extracting the spent case.



Any ideas?
Yea, ya screwed somethin' up..
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Old 03-12-2018, 06:55 AM
MichiganScott MichiganScott is offline
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Any ammunition changes? Factory vs. handloads?
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Old 03-12-2018, 08:22 AM
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Potentially your gas ring slots on the bolt body got aligned, allowing too much gas to escape to push the bolt carrier out of battery etc. Or your rings are worn out causing same malfunction. Or you screwed something up on the gas block.
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Old 03-12-2018, 09:15 AM
bamashooter bamashooter is offline
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Sounds like you have enough gas to extract but not enough left over to feed. Remove upper. Leave bolt in and charged.

Blow through the muzzle to make sure you have good flow and no blockage. If that's good:


Remove bolt. Plug the gas tube end with your finger and blow hard into the muzzle. There should be zero air coming out at the the gas block. Ring alignment should make no difference.

If it passes the blow test, check for leakage around the gas key and make sure the key screws are secure.

Possibly another issue but likely gas-related.
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Old 03-12-2018, 09:40 AM
Tysoncrosby21 Tysoncrosby21 is offline
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Not questioning any advice, I'm pretty sure it's a gas problem. Just wondering how the gas block could move or shift when It is pinned in place.

I'll check the Rings on the bolt, but probably just going to call Smith.

Also, the rifle cycled fine for about 300 rounds after the handguard swap. It was cleaned and put in storage and the next time I got it out it started doing this. It didn't happen first time out after grinding the sight and it didn't happen mid session either. The rifle went from fully functional, to its case and next time out non functional.

Last edited by Tysoncrosby21; 03-12-2018 at 09:43 AM.
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Old 03-12-2018, 10:09 AM
cyphertext cyphertext is offline
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I doubt Smith will help you... at least not on their dime due to the changes you made.

These are only some ideas... just spit balling...

Did you shave a little too much off the gas tube? Perhaps you got too close and there is a small crack or pinhole allowing gas to escape?

Do you have another bolt that you could try? If another bolt works, that eliminates the thought above and points towards the gas key on your bolt... If a second bolt fails, that points back to gas block and gas tube.

I agree that it is strange that it worked after you initially made your changes, but now doesn't.
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Old 03-12-2018, 12:33 PM
Tysoncrosby21 Tysoncrosby21 is offline
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I know I didn't go too far on the gas tube. I made 100% sure of that. Watched a bunch of "how to" videos.

I don't have another bolt to try and don't know of anyone with an AR that I could borrow one.
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Old 03-12-2018, 12:45 PM
Tysoncrosby21 Tysoncrosby21 is offline
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Sorry double post, just checked the screws? that hold the gas key in place. One is wiggling around and loose like crazy. Can I fix that? Or should I leave that to Smith.
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Old 03-12-2018, 12:58 PM
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Get the correct low profile GB and give it a try. Might get a gas tube for grins.
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Old 03-12-2018, 01:13 PM
Tysoncrosby21 Tysoncrosby21 is offline
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Talked to Smith, they'll warranty it even if the modified gas block is causing the issue.

So, that's nice.
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Old 03-12-2018, 03:15 PM
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Quote:
Originally Posted by OldSarge21 View Post
Potentially your gas ring slots on the bolt body got aligned, allowing too much gas to escape to push the bolt carrier out of battery etc. Or your rings are worn out causing same malfunction. Or you screwed something up on the gas block.
The rifle will in fact cycle perfectly with only one gas ring. The extra ring is for redundancy.
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Old 03-12-2018, 05:05 PM
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Quote:
Originally Posted by Tysoncrosby21 View Post
Talked to Smith, they'll warranty it even if the modified gas block is causing the issue.

So, that's nice.
Didn't you say though that the gas key was loose? The gas key is on the bolt, not the block.

Either way, if you can't do testing yourself, send it back to S&W and let them look at it if they'll warranty it.

And yes, the whole bolt ring thing is pretty much a wives tale with them being lined up and the gun not cycling.
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Old 03-12-2018, 05:21 PM
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Quote:
Originally Posted by Tysoncrosby21 View Post
Sorry double post, just checked the screws? that hold the gas key in place. One is wiggling around and loose like crazy. Can I fix that? Or should I leave that to Smith.
If it isn't stripped and you have a torque wrench, you can fix it. That screw should have been staked though so it wouldn't back out.

Glad to see that Smith will help you out with it if you send it in.
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Old 03-12-2018, 05:42 PM
Tysoncrosby21 Tysoncrosby21 is offline
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I might try to get those out and replace/seal and retorque them and see what happens.

Also, yes I said the key. It never crossed my mind to check it because I hadn't made any modifications to that part. So, once somebody suggested to check it I did and low and behold, screw loose.

Neither of the screws on the bcg appear to be staked. The one wiggled free and the other took almost no pressure to break loose.

Last edited by Tysoncrosby21; 03-12-2018 at 05:54 PM.
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Old 03-12-2018, 11:35 PM
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Yeah, those screws shouldn't ever come loose. If they did, that's definitely a warranty issue. This is what it should look like:


The staking is very obvious and deep. So, if it's not there, and the gas key is loose, that will definitely cause your issue. I'm glad S&W is going to fix it up for you.
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Old 03-13-2018, 06:04 PM
Tysoncrosby21 Tysoncrosby21 is offline
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Yeah, it doesn't look like the gas key screws were torqued or staked. The front one is sheered off and broken down into the spot it attaches and the rear one is rattling.

Got a couple extra hundred bucks from a winning casino weekend. Is it worth snagging an AIM Nickel BCG for 120? Primarily to fix this issue, also to have a 2nd bcg on hand to possibly diagnose problems.

Last edited by Tysoncrosby21; 03-13-2018 at 06:10 PM.
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Old 03-13-2018, 10:53 PM
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If by "nickel" you mean Nickel Boron, I would say yes, it's worth it.

Personally I like the Fail Zero NiB BCG myself: http://www.primaryarms.com/failzero-...-fzm16-4-01-nh

Yes, it's more, but if you're not going to get it replaced for free, you might as well get the best. So, get an actual upgrade.
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Old 03-13-2018, 11:14 PM
Tysoncrosby21 Tysoncrosby21 is offline
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Pretty affordable for a NiB, I'll spend the extra 30 to get a good one.
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Old 03-13-2018, 11:55 PM
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Personally, I would just get a quality BCG, like one from BCM... just the standard BCG, no special coatings needed.
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Old 03-14-2018, 09:26 AM
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Yeah, the only thing with the nickle boron is it cleans up real nice and easy, but other than that a standard qaility BCG is just fine.
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