Aero frustrations

[jander6442]

Ok building here and right out the gate.... Issues! Got and Aero m5e1 from Granite Ridge Oufitters and a Rainer Arms barrel 16" ultra match barrel.

This one https://www.rainierarms.com/rainier-arms-ultramatchtm-308-barrel-31 

The problem is the index pin on the barrel bottoms out before it reaches the feed ramps on the receiver. I personally think it's the upper out of spec. I can't confirm as I have nothing to compare it to and Aero is gone for the weekend. What are your thoughts? Thank you in advance.

[shepp]

Welcome to the forum, feel to tell us about yourself in the intro section

[Robocop1051]

Do you have a set of micrometers? Some measurements are going to be needed in this.

It would also help to see pics of the parts uninstalled. One pic of the barrel extension and one of the upper receiver threads.

[jander6442]

Sorry SheppI thought I did that already. Robot here's some pics thank you in advance. Measurements will have to wait until tomorrow I going to the range early so I need to get some sleep.

Edited March 25, 2017 by jander6442
Spelling

[jander6442]

One more

[survivalshop]

  Not familiar with that model of Aero Upper , so can say for sure how its set up , but one thing thats different with a 308AR verses an AR 15 , there is really no need for the M4 type feed ramps on the Upper Receiver . The 308 sits much higher in the Mag & feeds different , so if they even hit that part of the Upper receiver , there is something wrong to begin with .

  You will only know if someone here has a 308AR already assembled with that Upper Receiver type or by completely assemble the rifle & check Head space & check rifles Function with Dummy rounds .

 Is the Barrels Flange seated fully against the Upper receiver ?

[jander6442]

It sits completely against the index pin slot. I have read were others have used this barrel on m5 uppers. I got with aero and of course they are heading out the door for the weekend. Take a look at the pic where the barrel is in the upper and look how much I have to reach to the edge where the mag meets the bottom of the receiver. About .125 I'm guessing cause I need batteries in my gauge.

[guruofhotrod]

Here are a couple of pics of an Aero M5 upper (not an "E") showing the depth in wich the barrel extension should seat - also the barrel extension should measure around 1.240" from the end (where the lugs are) to the rear face of the flange. From the amount of mismatch you have it seems the indexing pin may not be seating correctly?  Hope that helps   

Edited March 25, 2017 by guruofhotrod

[jander6442]

Just got back from the range great day. Relieved a lot of stress. Thank you for the pics and the numbers guru. 1.24 it is from the extension flange to the lugs. Interesting enough from the receiver to the end of the barrel socket land. Just has to be the index pin groove on the receiver is out of spec. Let's Hope Granite Ridge Oufitters is appreciative of my situation so far on messenger and email they have been a Ghost.

[survivalshop]

  From what you are saying is ,the Alignment Pin is seating before the Barrels Extension flange is seating against the Upper Receiver ?

 Hard to compare two different types of receivers , but you would think they would line up the same , if machined correctly . 

9 hours ago, guruofhotrod said:

Here are a couple of pics of an Aero M5 upper (not an "E") showing the depth in wich the barrel extension should seat - also the barrel extension should measure around 1.240" from the end (where the lugs are) to the rear face of the flange. From the amount of mismatch you have it seems the indexing pin may not be seating correctly?  Hope that helps   

 Now that looks correct . Have you tried torquing this Barrel onto the Upper Receiver yet ?

Edited March 26, 2017 by survivalshop

[jander6442]

Yes. I did take his extension measurement and measured from lugs to flange same as guru's. Then measured the same 1.24 from receivers lug end to where the extension flange meet. The index slot has not been cut deep enough, length wise. I can see the amount needed has been borked  by cutting into the area that's threaded the  area that meets up with the flange seat on the receiver where the extension meets the receiver. 

Plus I can feel it wiggle and hear it bumping that land area in there. No I have not torqued it down yet I doubt I could get that much down it would mean smashing some aluminium, but I'm no expert. Granite Ridge website says 65lbs of torque IIRC.

Edited March 26, 2017 by jander6442

[guruofhotrod]

Or, the slot in the upper that accommodates the indexing pin may be cut too narrow for the pin or have a burr from machining preventing the pin from engaging.

[jander6442]

Nope proper width. No burrs, looked with a jeweler's glass. They started the machining of the slot to early as its cut starts on the threaded side, the same amount of space that's needed for a proper seating of the barrel. I could prolly finish it myself really it's only going to go as deep as the flange on the extension will allow.

I won't do that unless Granite Ridge wants to be non professional about it or Aero steps it up, but I would rather do a straight swap out with another upper. I have a feeling I got shipped a blemished.

[survivalshop]

 If alignment Pin is bottoming out before the Barrels Extension Flange Seats , probably Torquing it down will not help , only deepening that slot will get the Barrel where it needs to be .> I would let Aero take care of it , Call , email with photos , I don't see them having an issue with repairing or replacing . Your call .

[jander6442]

I'm talking right now with Granite Ridge. He suggested to tap the barrel. That's not going to work. So a replacement is going to be issued. For some reason if this happens again that index slot is going to get a little file treatment. Thanks to guru measuring the extension for me. I did find a DPMS blueprint to reflect that dimension. The saga continues. 

Meanwhile parts are showing up:

Aero m5e1 receiver set 12" handguard

Aero charging handle

Aero LPK

Rainier Arms 16" ultramatch barrel mid-length

Superlative bleed off gas block

Fortis RED muzzle break

Aero BCG Nitride

Larue MBT trigger, Larue grip

JP SCS kit

V seven liteweight buffer with end plate castle nut.

Stock TBD.

Prolly put a PA 1x8 scope on it with American Defense mount.

 

 

 

Edited March 27, 2017 by jander6442
More info

[guruofhotrod]

You're welcome! Glad to be able to help - hopefully the replacement upper will get you going, should be a sweet rifle, keep us posted

[jander6442]

I will. I couldn't be totally bummed. I got to shoot a Scar 17s this weekend. It was a birthday present I got last week. Some sweet shooting rifle right there.

[jander6442]

Update: Granite Ridge sent me a replacement upper (great customer service)... I have a feeling the first one would have worked. Never had to heat up a upper to get the barrel to seat before. With just a minute of heat from my heatgun it sat in wonderfully.

Headspaced a touch on the tight side (smithey said), but man the ejector on the Aero bolt is mega strong had to drop the bolt to get rounds into battery. Over all with 6 clicks on the gas block it shot everything I put in it. American Eagle did the best after a long break in procedure, about 1 moa after that @ 100yards, everything else a little over. I would have posted targets, but my range is in the middle of no-where and some locals were wondering the perimeter.

https://goo.gl/photos/36MrrVmSFjvKNnEZA

https://goo.gl/photos/SCihN57bdpsz6rGJ8

[survivalshop]

[beantown]

Nice job on the rifle build Josh. How did the muzzle brake do?

[jander6442]

The muzzle brake is sweet. I've used the Fortis on .223 although this has a more aggressive ports and slopes. I must say it would suck to be my range neighbor though. 

I'm using a JP timing nut and the barrel has a really long shoulder. It leaves a small Gap between the timing nut any ideas to take out the gap. If I was running suppressed it would be ideal, but I only run my blackout suppressed.

[survivalshop]

Crush Washer ? Or have a Spacer made up to the spec's you need .