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Posted (edited)
6 hours ago, CrashOverRide.308 said:

Man... I have had no time to hit the range yet. But im thinking about checking headspace before I head out. Theres a go and no go on brownell for $50

But i will post pictures of my build tonight. Its been awhile.

What barrel did you end up with? I am wondering if it's stamped .308Win or 7.62 NATO. The headspace gauges for the two chambers are a little different. I've found Go/No-Go/Field sets for the .308 and Minimum & Maximum gauges for the 7.62, as well as a Special .308 gauge 1.633" length which Brownell's says is also a "tight" 7.62 Match Gauge (7.62 standard Min is 1.634")

With a Go/No-Go/Field set, the BCG should chamber the Go, not chamber the No-Go, and if it chambers the FIeld gauge the weapon is dangerous to shoot.

On the 7.62, it should chamber the Min but not the Max.

Edited by Frankh252
Mistake
Posted
14 hours ago, Frankh252 said:

What barrel did you end up with? I am wondering if it's stamped .308Win or 7.62 NATO. The headspace gauges for the two chambers are a little different. I've found Go/No-Go/Field sets for the .308 and Minimum & Maximum gauges for the 7.62, as well as a Special .308 gauge 1.633" length which Brownell's says is also a "tight" 7.62 Match Gauge (7.62 standard Min is 1.634")

With a Go/No-Go/Field set, the BCG should chamber the Go, not chamber the No-Go, and if it chambers the FIeld gauge the weapon is dangerous to shoot.

On the 7.62, it should chamber the Min but not the Max.

The barrel is stamped .308 Win from schyulers arms. Can I use an empty 308 shell casing in place for the "GO" gauge?

Posted
1 minute ago, CrashOverRide.308 said:

The barrel is stamped .308 Win from schyulers arms. Can I use an empty 308 shell casing in place for the "GO" gauge?

Apologies for the bluntness, "NO!"

Cases are not a substitute for a "Go" Gauge, especially spent ones. Brass cases are purposefully undersized compared to Go gauges to ensure functionality. 

We STRONGLY encourage you to purchase a quality gauge set. We recommend Pacific Tool & Gauge. 

Posted
1 hour ago, FaxonNathan said:

Apologies for the bluntness, "NO!"

Cases are not a substitute for a "Go" Gauge, especially spent ones. Brass cases are purposefully undersized compared to Go gauges to ensure functionality. 

We STRONGLY encourage you to purchase a quality gauge set. We recommend Pacific Tool & Gauge. 

Don't apologize Nathan, that's a pretty serious thing not to be cutting corners! 

Posted

If you don't want to buy the gauges, take it to a gunsmith and have them check it for you.  It's money well spent.  Either way, don't short cut this step in the build.

Posted
1 hour ago, CrashOverRide.308 said:

Promise of my build.

Another thing. I purchased some dummy rounds. It picks up rounds when I charge the handle. But! When the bolt sits on the bolt catch and I press the catch release button. It doesnt pick up a round? 

   The Bolt stop is holding the Bolt on the Bolt Face ? & by the way, glad to see you are using a Dummy rounds instead of live ammo for testing .

  Is the Mag Catch tight enough & is the Mag caught with the Catch properly ? What manufacturer is the Mag Catch ? (DPMS/AR 15 or Armalite AR 10 )

Posted
1 hour ago, survivalshop said:

   The Bolt stop is holding the Bolt on the Bolt Face ? & by the way, glad to see you are using a Dummy rounds instead of live ammo for testing .

  Is the Mag Catch tight enough & is the Mag caught with the Catch properly ? What manufacturer is the Mag Catch ? (DPMS/AR 15 or Armalite AR 10 )

Yeah. Thank you. Dummies happen to be the safest :)

The bolt catch is holding the bolt. But once released it dont pick up the dummy round. Mag is caught with the catch good. It does what it does. When I push the mag release it releases mag. It holds but a little shaky? By not much but it'll suffice. Mag catch is DPMS I hope. I purchased it from Chris at central florida firearms. He says its the one for the blem up and lower receiver I purchased also from him on gun broker. 

Posted (edited)

     Some including me , use an Armalite AR 10 Mag Catch, it has a longer threaded stem & the Pad that holds the mag is a little larger , seen below at the bottom , DPMS is the top one. Longer Threaded shaft for the mag release button helps in proper tension adj.with some Lowers . The slightly larger Pad for holding the mag may help with stabilizing Mag in position . 

 LH1835.JPG

  What Mag brand are you trying ?

 What Buffer system are you using ? 

  Can you get some photo's of the Mag inserted into the assembled rifle with Dummy round in Mag. , with Bolt Stop engaged  , from the Port opening  ?

Edited by survivalshop
Posted
4 hours ago, survivalshop said:

     Some including me , use an Armalite AR 10 Mag Catch, it has a longer threaded stem & the Pad that holds the mag is a little larger , seen below at the bottom , DPMS is the top one. Longer Threaded shaft for the mag release button helps in proper tension adj.with some Lowers . The slightly larger Pad for holding the mag may help with stabilizing Mag in position . 

 LH1835.JPG

  What Mag brand are you trying ?

 What Buffer system are you using ? 

  Can you get some photo's of the Mag inserted into the assembled rifle with Dummy round in Mag. , with Bolt Stop engaged  , from the Port opening  

I am using 10, 20, 25 round PMAGS also using LR-308 buffer system from primary arms. 

Also have noticed now that it jams the dummy round once bolt is released. And when handle charged the catch doesnt engage to stop the bolt. Alot of times I have to push down on the catch release button.  Also, when I push the button to release the mag, most of the time it will also release the bolt catch? 

 

20160410_091844.jpg

20160410_092116.jpg

Posted (edited)

  The Barrel is missing .

  The Bolt  Stop has a lot of pressure on it from the Buffer Spring , with out the Mag holding Bolt Stop up there , it will probably not stay  . Check the movement of your Bolt Stop for burr's or stickiness .

Edited by survivalshop
Posted
12 hours ago, survivalshop said:

     Some including me , use an Armalite AR 10 Mag Catch, it has a longer threaded stem & the Pad that holds the mag is a little larger , seen below at the bottom , DPMS is the top one. Longer Threaded shaft for the mag release button helps in proper tension adj.with some Lowers . The slightly larger Pad for holding the mag may help with stabilizing Mag in position . 

 LH1835.JPG

  What Mag brand are you trying ?

 What Buffer system are you using ? 

  Can you get some photo's of the Mag inserted into the assembled rifle with Dummy round in Mag. , with Bolt Stop engaged  , from the Port opening  

I am using 10, 20, 25 round PMAGS also using LR-308 buffer system from primary arms. 

Also have noticed now that it jams the dummy round once bolt is released. And when handle charged the catch doesnt engage to stop the bolt. Alot of times I have to push down on the catch release button.  Also, when I push the button to release the mag, most of the time it will also release the bolt catch? 

56 minutes ago, survivalshop said:

  The Barrel is missing .

  The Bolt  Stop has a lot of pressure on it from the Buffer Spring , with out the Mag holding Bolt Stop up there , it will probably not stay  . Check the movement of your Bolt Stop for burr's or stickiness .

Alrighty. 

Will take a look at tonight. Will also make sure the barrel is installed as well. Thank you SurvivalShop.

Posted

Alrighty. 

You're right. The catch release opens when theres a mag sitting in. But it still doesnt feed the dummy round. When I charge the handle. The bolt stops half way and jams. With a little push from the handle hard enough it'll chamber but ither than that its still and issue... 

Any advice?

Posted

Are you letting the charging handle fly or riding it forward? I had this issue with a 5.56 build, I took off some fine burrs on the ramps and after cycling several dozen times the issue went away. Use PLENTY of lube!

Posted (edited)

  Check to make sure the Hammer is not hitting the Trigger's Disconnector , you will see a mark on top of the Disconnector where the Hammer is hitting it . You can remove the Hammer & see if the BCG travels properly with it removed .

 Make sure the Bolt Stop is sitting low enough in the Lower Receiver & not interfering with BCG travel .

Edited by survivalshop
Posted
On Monday, April 11, 2016 at 1:30 AM, jtallen83 said:

Are you letting the charging handle fly or riding it forward? I had this issue with a 5.56 build, I took off some fine burrs on the ramps and after cycling several dozen times the issue went away. Use PLENTY of lube!

 

On Monday, April 11, 2016 at 1:30 AM, jtallen83 said:

Are you letting the charging handle fly or riding it forward? I had this issue with a 5.56 build, I took off some fine burrs on the ramps and after cycling several dozen times the issue went away. Use PLENTY of lube!

Both. But I am running it dry. Im going to lube the hell out of it this weekend. And see how it runs. Been waiting for my head gauges come in before lubing it up and they're  finally here. Any steel mags you would recommend that will work with the matrix JT?

Posted

Here is one with the Go gauge in. Locked and flushed with upper. Which is also good. I guess its a green light to head on over to the range finally? 

I guess there were 2 ways of checking headspace. 1 taking the bolt apart and removing extractor and turning it into barrel? Then theres this one I tried. Not sure which is recommended but option 2 worked fine to me. 

Opinions anyone?

Will be shooting some cheap prv rounds I purchased from cabelas. Probably get a few boxes of Hornadys to see if it makes any difference.

20160419_012425.jpg

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