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Sampo
09-29-2012, 14:55
I recently completed this build:

http://www.glocktalk.com/forums/showthread.php?t=1432247

Finally got out to shoot and thought I was gonna lose it!!!

Issues:

Firearm will not cycle a complete magazine, it essentially turned into a single action shooter. I load a full mag, cycle charging handle, chamber loaded and ready, pull trigger...bang...pull trigger again....nothing....cycle CH, load new round, pull trigger....bang....pull trigger.....nothing.... This happens about 95% of the time. The other 2.5%, I am able to run a full mag with no issues. The other 2.5%... FTE galore, I actually had to position the end of the CH against a shooting bench as counter pressure to pull back on the CH to clear the chamber (spent casing).

Ammo:

Mixed variety of Wal-mart offerings; Tula, Rem, Federal...

I've tried to self diagnose my issues and come up with it being either a gas/pressure or buffer/spring issue. Can't find a concrete solution though. :crying:

Details on upper:
http://www.midwayusa.com/product/951250/del-ton-ar-15-dissipator-a3-flat-top-upper-assembly-556x45mm-nato-1-in-9-twist-16-rifle-length-heavy-contour-barrel-chrome-moly-matte-with-a2-handguard-flash-hider

Details on LPK:
http://palmettostatearmory.com/index.php/ar-15-05/lower-parts/complete-psa-ar15-lower-moe-edition.html

Keoking
09-29-2012, 14:58
My Olympics Arms has been 100%. :tongueout:

Enough of me being a dick. I have no idea what is wrong with your rifle, but I hope someone can get you sorted out with a minimum of hassle. Good luck.

theundeadelvis
09-29-2012, 15:08
Is the spent casing being ejected? What magazines are you using (tried a variety?)? What weight buffet do you have?

Sent from my Galaxy Nexus using Tapatalk 2

Big Bird
09-29-2012, 15:14
Could be lots of things. You have a rifle length gas system using a heavy buffer. That could be the problem. You could have a rifle length spring in your buffer tube...that could be a problem (too long). Your gas tube might not be lined up with your gas key on your bolt. The gas key might be loose. The front sight base might not be aligned with the gas port. The gas port might be too small.

Any number of things...

Put a single round in a magazine and fire it. Does the bolt lock back? If not you have a gas issue somewhere.

Sampo
09-29-2012, 15:17
Both, casing will eject with no follow-up round being loaded, when the spent case does not eject, I get the crazy FTE. Mags were Pmags and standard GI metal mags with green/black followers.

AK_Stick
09-29-2012, 15:20
what is "the crazy FTE"


if you're having to mash the CH to open the bolt, your ammo/chamber is suspect.

Mayhem like Me
09-29-2012, 15:25
Do the simple test bb asked, single round in magazine see if it locks back on the bolt, if not you are. Under gassed.. Does not matter what else you do that is the first diagnostic to try.

Mayhem like Me
09-29-2012, 15:29
After reading the build I am gonna say that it is most likely a gas issue a rifle system on a 16 inch is a recipe for not working right....at least in 5.56 /223.
Can you make it work probably, but 16 works best with a mid..in 5.56


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Sampo
09-29-2012, 15:49
Pic of the buffer and spring...

FTE- Failure to Eject/Extract

Single round shot will lock the bolt back.

Compared the buffer and spring to those of my S&W M&P15 16" carbine length gas system and as far as I can tell, they're the same.

Cole125
09-29-2012, 16:06
Well first I would try a lighter buffer, if that does not work then it is a problem with the gas system.

I had the same issue with a PSA upper I bought, gas port in the barrel and gas block were not lined up causing that exact problems you describe.

Mayhem like Me
09-29-2012, 16:14
Pic of the buffer and spring...

FTE- Failure to Eject/Extract

Single round shot will lock the bolt back.

Compared the buffer and spring to those of my S&W M&P15 16" carbine length gas system and as far as I can tell, they're the same.

Important question did the bolt lock on the bolt face or carrier.
If it locked on the bolt face check for extractor tension if it seems weak go with the Bravo company upgrade.



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Hour13
09-29-2012, 17:34
Pic of the buffer and spring...

FTE- Failure to Eject/Extract

Single round shot will lock the bolt back.

Compared the buffer and spring to those of my S&W M&P15 16" carbine length gas system and as far as I can tell, they're the same.

This is part of the issue... sort of. A rifle-length gas system uses a rifle-specific buffer. However, it goes a bit deeper.

Rifle gas system on a 16" barrel is a bad mix IMO. Post gas-block dwell is WAY too short. The pressurized gasses that cycle the action come into play between the time the bullet passes the gas port, and the time it exits the barrel. Once the round exits the barrel, so does the pressure.

This is why carbines benefit greatly from H-buffer(over-gassing due to long dwell time). Mid-lengths typically run just fine with a standard buffer, and so on.

This is also why "mock Dissy" ARs exist. FSB in the rifle position, but the gas block is a low-pro, in the mid-length position, hidden under the handguards. Gives you the cool looks and longer sight radius of the Dissy, but it'll actually run worth a damn.

A true Dissipator has to be a perfectly tuned symphony of buffer weight, properly pressured ammo, etc, or it'll just suck. Even at it's best, 50/50 chance it'll suck anyway.

If you want to get your's running correctly, I'd install a complete rifle system(buffer, spring, tube & stock), then load it up with quality ammo in the P-mags, and give it a try.

:wavey:

Walt_NC
09-29-2012, 17:38
Probably a dumb question but have you checked your gas rings? I had the same problems you're describing on an SBR - blown gas ring was the culprit.

Sampo
09-29-2012, 18:14
Will the MOE stock fit on a rifle length buffer tube? Is the diameter the same as a mil-spec tube? Checked the gas rings, eveything looked 10-4.

Hour13
09-29-2012, 18:32
Will the MOE stock fit on a rifle length buffer tube? Is the diameter the same as a mil-spec tube? Checked the gas rings, eveything looked 10-4.

No, it's a completely different tube.

This is the MOE rifle stock...

http://dsgarms.com/ProductInfo/MAG404-BLK.aspx

You might want to swap the H-buffer for a standard one first, couldn't hurt to try!

But odds are good this system will continue to give you issues.

..

Hour13
09-29-2012, 18:36
Hopefully Plank will see this and jump in, he may have a solution I have not thought of yet.

:dunno:

mvician
09-29-2012, 18:39
First "review" on Delton's page


Had Problems with it.... September 27, 2012
Reviewer: MJShea from Lancaster, PA United States
I Can Not,,, Repeat CAN NOT... Recommend that you combine this with a carbine lower. I experienced nothing but Short Stroking, Jams, and Failure to Lock Back on the last shot. To get the delton dissipator to work properly this is the combination it took: Rifle length buffer tube and stock, standard carbine spring, and standard carbine buffer. The weapon is now performing flawlessly with any kind of ammo I throw into it. No short stroking, no jamming, and no failure to lock back on the last shot... This includes Russian steel case ammo. It was ordeal to get there, and cost me a lot more than I wanted to spend. I would love to give this a better review as I really like the rest of the products that I have bought from del-ton, but this one is a head-ache. Del-ton should make this product with a mid-length or carbine system under the rifle handguard.


http://www.del-ton.com/Custom_Upper_p/cu112.htm


Now I can't agree with him running a rifle receiver extension with a carbine spring and buffer, but something isn't right.

mvician
09-29-2012, 18:44
From Delton's Blog



Currently at DTI, our dissipator style of AR-15 rifle (a 16” barrel with a rifle length gas system) has a true rifle length gas system. Many other manufacturers build this style of AR-15 with a mid-length gas system under the handguards using a low profile gas block; a front sight base (that does not serve as a gas block) is then installed at the typical “rifle-length” location. The main advantage of this style would be the very long sight radius. Possible negative aspects include the weapon being a bit “muzzle heavy” and limitations in ammunition selection (see next paragraph).

Many things can affect the cycling and reliable operation of an AR-15. Multiple variations from the original design have created real benefits for some applications. However, these variations may require additional modifications...or they may create new limitations. Having a mid-length gas system on a 14.5” or shorter barrel, or a rifle length gas system on a 16” barrel (true dissipator) can necessitate an ammunition selection that produces higher pressures. This is due to the distance for the gas pressure required for cycling to travel before most of it escapes out of the muzzle behind the projectile. Some of the less expensive ammunition may use lower quality gunpowder that burns inconsistently; this can result in gas pressure that is inadequate for proper cycling. The weight of the bolt carrier and buffer also play an important role in the cycling of a weapon, so the right combination is necessary for peak performance.
Hopefully, this post has answered some basic questions about the various gas systems of the AR-15 rifle. Thanks for reading our blog; if you have any questions related to the AR-15 or any of our products, please contact us and we will be glad to assist you.


http://blog.del-ton.com/2012/01/ar-15-gas-sytems-and-operation.html

Airhasz
09-29-2012, 19:36
OP i hope you get you problem straightened out quickly, but I would then sell the weapon or designate it to range use as I would never again trust it in a patrol/defense situation...get you a Colt...good luck

Sampo
09-29-2012, 19:44
10-4 Airhasz.

Took the buffer apart, and got this...

Those that have suggested a lighter buffer, how many weights would you leave? 1-2?

I'm gonna jump on the horn with Del-ton come Monday and see what they say. Til then, a little in house "tweaking".

mvician
09-29-2012, 19:56
You just can't remove one of the weights in the buffer.
PM me your address and I'll send you a carbine buffer.
It is a lighter weight than the H buffer.

Sampo
09-29-2012, 20:04
PM sent...

Just for shiggles, what would happen if I did? Wear and tear on BCG, buffer tube/spring?

mvician
09-29-2012, 20:11
PM sent...

Just for shiggles, what would happen if I did? Wear and tear on BCG, buffer tube/spring?

The weights would just slam back and forth into each other, and wouldn't really "buffer" correctly.

PM replied to :supergrin:

surf
09-29-2012, 21:08
Generally people do well with builds when sticking with reliable combo's / manufacturer parts, but when you go off the board a bit and have issues, trouble shooting is not fun for someone new.

Most has been mentioned already but you are 99% likely undergassed. The simple one round test will more than likely show this. The reason it ran at times was probably due to the different loads that you fired. Hotter loads would run better but even your failure to eject was still due to a short stroke where the carrier does not go all the way to the rear to eject and strip a new round. Overall a rifle length system on a 16" barrel is a bad idea. Dwell time after the gas port is too short. Also you really should be running a rifle extension, spring and buffer, or you should go with something along the lines of the Vltor A5 extension, spring and buffer set up. These changes will provide the most reliability across the ammo spectrum, but you may still want to stick with hotter loads. Even then there is no guarantee.

WoodenPlank
09-29-2012, 21:29
While it isn't a surefire error (specs can differ slightly between brands), I'd suggest swapping recoil springs out. I counted yours at 39 coils, whereas the carbine spring in my SBR is 37. If your could are tighter spaced, and the spring is the same compression weight, it *should* be fine - but I'd suggest getting a spare and swapping it just to be sure.

An over-long recoil spring can definitely cause (or at least contribute) to the issues you are describing.

Also, next time you go test. document what types of ammo do what. If Federal XM193 runs fine, but Tula does not, that goes a long way to being sure of the issue.

Sampo
09-30-2012, 07:45
Found this, would this be a reliable solution? I know nothing would be 100% until I tried it.

http://palmettostatearmory.com/index.php/magpul-moe-rifle-stock-kit.html

WoodenPlank
09-30-2012, 09:28
Found this, would this be a reliable solution? I know nothing would be 100% until I tried it.

http://palmettostatearmory.com/index.php/magpul-moe-rifle-stock-kit.html

Until we can help you identify the problem, nobody can really say if that kit will provide a fix.

Get back on the range, try some of the troubleshoot steps that were suggested, and get back to us.

Sampo
10-20-2012, 14:48
I just wanna give a shout out to all those that provided feedback... mvician, thanks for the buffer.

I am now have about 500 trouble free rounds through this sucker! Not one single malfunction out of this bad boy. I've shot a mixture of Tula, Rem, and Fed. rounds. After a few trips to the range in an attempt to trouble-shoot my issues I broke down and contacted Del-Ton.

Lauren with Del-Ton was an absolute pleasure to deal with, out standing customer service!

I explained what was going on and they sent me a label and it was shipped out. 3 business days later, Lauren called and told me they had found some fouling/stoppage inside the gas tube, and that they had replaced the gas tube and that the upper was in the mail.

I was a little embarrassed :embarassed: since this seemed like a relatively easy fix to a major problem, but oh well.

I really appreciate everyone's input and feel I've learned just a little bit more about this rifle platform (which can't hurt :thumbsup:).

Thanks again guys and gals!!!

mvician
10-20-2012, 16:15
Glad you got it straightened out.

JBJ16
10-20-2012, 17:58
Happened to my friends M4forgery. He had 95% failure to extract/eject and had to position the CH on the table edge to pull the casing out.

Did this simple test. Disassembled the upper from the lower. Dropped first a 5.56mm round into the chamber, there was some resistance. Round did not drop in smoothly.

Next dropped a .223 Rem round in the chamber, this one went smooth. Turned out, his barrel was chambered for a .223rem.

So far he had no problems when using only .223 Rem rounds.