80% AR10 feed problems

[Whyl_e0921]

I built an AR10 using polymer80 lower . All went well all parts fit perfect only one problem. Will not cycle and not sure where the problem is. Fires good but will not feed second round also when I load just one round in magazine bolt will not lock open. Am suspecting buffer or buffer spring ? I have a Leapers UTG A2 full buttstock. Please anyone have any ideas ?

[sketch]

26 minutes ago, Whyl_e0921 said:

I built an AR10 using polymer80 lower . All went well all parts fit perfect only one problem. Will not cycle and not sure where the problem is. Fires good but will not feed second round also when I load just one round in magazine bolt will not lock open. Am suspecting buffer or buffer spring ? I have a Leapers UTG A2 full buttstock. Please anyone have any ideas ?

Ar 10 upper? Armalite? Is the 80% lower made to fit the upper? You say fit is good .. mag related ? Details bro? 

[98Z5V]

1 hour ago, Whyl_e0921 said:

 Am suspecting buffer or buffer spring ? I have a Leapers UTG A2 full buttstock.

That's  probaby an AR15 buffer in there, and way too long for a 308AR.

[Whyl_e0921]

DPMS upper also the spring and buffer for A2 buttstock are Leapers UTG mod# RB-T308B is supposedly 308 version. Any recommendations on which buffer spring to use

[98Z5V]

Specs first, on what you have. Preferably, with pictures.

Relaxed length on the spring, and number of coils.  Length of buffer.

That stuff has to come first for us to figure out that you're running - despite what any kind of product description states. You can never count on some dip-wad putting the correct parts in your shipment box.

So, pics and specs...  Help us help you...

[98Z5V]

Right on their own website, this model number or any combination of it, doesn't turn up anything...

I searched this exactly, and all combinations of it: Leapers UTG mod# RB-T308B

Disregard - manually hunting it down turns up this item, by part number:

https://leapers.com/prod_detail.php?mitem=acces&level1=&level2=&itemno=RB-T308FB&status=&mtrack=m

Edited February 12, 2017 by 98Z5V

[mineralman55]

How many rounds through it? Whose BCG and was it heavily lubed with oil? There may not be a problem. These take 100-200 rounds to break in. Patience.

[survivalshop]

 -Will the BCG lock back when manually charging action with an Empty Mag ?

 -Was the Upper purchased as a Complete Upper assembly or was it assembled by you ?

 -Need Photo of gas tube protrusion into Upper Receiver .

 -AS said above , Buffer spring length , Coil count .

 -Also as said above , Buffer length & Weight .

 -What Brand of Mag. used ?

[Whyl_e0921]

specs = spring 12.25 L  coil count 35 . Buffer  5.25 L not sure of weight. 

How many rounds thru 80. Using magpul magazines

if cycled manually yes bolt locks back. 

Lite lube

Purchased complete package from Daytona Tactical  (minus the lower). Originally came with collapsible stock . Replaced with A2 full stock buffer and spring included. Never fired with collapsible stock. 

[survivalshop]

Just pulled my DPMS Rifle Buffer system 

Spring length --12 1/2" long

Coil count -----  39  ( AR 15 Rifle has about 43 coils )

 Buffer length ----5 5/16" long  ( AR 15 Rifle Buffer 5 7/8 " )

 Buffer weight ----5.4 oz.

Edited February 15, 2017 by survivalshop

[survivalshop]

 Makes me wonder about the Gas Port in the Barrel or Gas Block fitment .

 Separate the Upper from the Lower & Remove the BCG & take a photo of how far the Gas Tube protrudes into the Upper Receiver .

 

 I count 37 coils from your photo .

Edited February 15, 2017 by survivalshop

[Whyl_e0921]

[survivalshop]

What length gas system is the Barrel ?

This is how it should look , we have seen some Factory DPMS Carbine gas systems that are close to yours & work , but its not right .

[shepp]

We ran into this problem not long ago I remember taking pictures to compare, but  I don't remember who had the issue

[98Z5V]

Buffer system is right, or very close, for a.308AR. 

That gas tube is too short - it should come back to the middle of the port opening for the cam pin, as seen is SS's photo.  In your photo, it only comes back to the very opening of that cam pin port cutout...

If it's midlength gas, you're screwed.  If it's Rifle gas or Carbine gas, you can pick up the Armalite AR-10 gas tube and correct this issue.  If you already have the Armalite AR-10-lengthed gas tube, that barrel is incorrectly made...

[Whyl_e0921]

First want to say to all of you  THANK YOU  for all the help . I guess I will check with my local gunsmith and see if this problem can be fixed . Also I will get in touch with DatonaTactical and see if they will fix problem.

Will post update in a few weeks hopefully this beast will be shooting properly.

Again Thank You

[Whyl_e0921]

After a trip to 2 of the local gunsmiths both of which said it was not my gas tube . One even had his own AR10 there in the shop for comparison. And gas tube was same position as mine . Anyways both seem to think was the buffer tube spring. So I purchased the spring which is longer then The one that came with my A2 stock. Long story short just got home from the range . AR10 is now perfect shoots great. With no more problems . Again thank you for all your input and advice

[survivalshop]

  Good to hear .  

[2Amickymouse]

AR10  clip dropping after firing first chambered round . I basically have a single shot AR10.

Gun was bought from old owner . Anyone have the same issue that can share about a fix ?

 

 

Edited January 18, 2021 by 2Amickymouse

[98Z5V]

Mag catch. First thing to look at.  Armalite AR-10 that you have?