308 AR10 Build Info/Picture Thread

[jLorenzo]

How fucked am I? Aero rifle length gas tube, aero enhanced upper, Rainier Match 18" rifle gas. The gas tube has a slight shoulder that wont let it go into the upper any further. I have a SA adjustable block coming tomorrow but this shit doesn't look right to me.

Also heres a borescope of the barrel, only ran 2 patches of patch out through it, no scrubbing or anything. Looks like I'm gonna scrub some.

 

[msgriff]

How fucked am I? Aero rifle length gas tube, aero enhanced upper, Rainier Match 18" rifle gas. The gas tube has a slight shoulder that wont let it go into the upper any further. I have a SA adjustable block coming tomorrow but this shit doesn't look right to me.

Also heres a borescope of the barrel, only ran 2 patches of patch out through it, no scrubbing or anything. Looks like I'm gonna scrub some.

You can measure the gas tube to see if it is in spec or if it's the upper. Mil-Spec gas tubes are 0.180" (+/- 0.001") OD for the larger diameter area.

Additional specs not related to your issue: 0.170" (+/- 0.004") for the smaller diameter area, which extends 2.33" from the flared end. The OD spec for the flared end is 0.1800" (-0.0006").

There are heavy wall gas tube that are not Mil-Spec, that doesn't look like one of them. I don't know what Aero specs for the gas tube opening of their Enhanced uppers, but their anno is thicker than most.

 

[357Max]

A drill bit will fix that in 2 min.

 

[Cascade Hemi]

How fucked am I? Aero rifle length gas tube, aero enhanced upper, Rainier Match 18" rifle gas. The gas tube has a slight shoulder that wont let it go into the upper any further. I have a SA adjustable block coming tomorrow but this shit doesn't look right to me.

Also heres a borescope of the barrel, only ran 2 patches of patch out through it, no scrubbing or anything. Looks like I'm gonna scrub some.

Take a 35cal bronze brush, spray it down with FreeAll (or equivalent penetrating oil), and run the brush down the bore (back and forth) 100 times. Reapply the oil every 10 to 20 strokes. When you're done, scrub (sawing motion) the bore with a 30cal patch wrapped around a nylon 30cal brush, using Iosso or JB. One or two total passes. Most of that will clean up.

Return and replace the gas tube.

 

[jLorenzo]

Used Freeall and bronze brush. little better, if it shoots, good if not its going back. That is all I really care about.

 

[jLorenzo]

A drill bit will fix that in 2 min.

I hoping to not have to take a drill to my brand new stuff, perhaps I will though. Not before I try another tube.

 

[JR1200W3]

The bore on that barrel doesn't look awesome but I don't think it looks atrocious either. If you're talking about the horizontal/ perpendicular tooling marks, while not pretty, I don't think it will make the barrel shoot poorly. The brown discoloration is puzzling, possibly alarming. Is that the solvent you used?

My Ultra Match looks just like a polished button rifled barrel. Which it is. What you're seeing is what I think you get at that price point. I'd definitely just shoot it and see how it does. The good news is the gas port doesn't look too bad. I'd watch that with a borescope and see how the port erosion looks over time.

 

[Cascade Hemi]

The bore on that barrel doesn't look awesome but I don't think it looks atrocious either. If you're talking about the horizontal/ perpendicular tooling marks, while not pretty, I don't think it will make the barrel shoot poorly. The brown discoloration is puzzling, possibly alarming. Is that the solvent you used?

My Ultra Match looks just like a polished button rifled barrel. Which it is. What you're seeing is what I think you get at that price point. I'd definitely just shoot it and see how it does. The good news is the gas port doesn't look too bad. I'd watch that with a borescope and see how the port erosion looks over time.

I believe what you're seeing is left over lubricant from the buttoning process. It gets pressed into the metal and takes some time to come out. Pretty sure a little Iosso or JB will take it out, although it'll come out when he shoots it.

 

[jLorenzo]

I got a new gas tube and cleaned the hole in the upper extension with a 22 cal bronze brush and it finally went together. I now have 2 extra tubes though. Time to build more I guess.

 

[x248716x]

How fucked am I? Aero rifle length gas tube, aero enhanced upper, Rainier Match 18" rifle gas. The gas tube has a slight shoulder that wont let it go into the upper any further. I have a SA adjustable block coming tomorrow but this shit doesn't look right to me.

Also heres a borescope of the barrel, only ran 2 patches of patch out through it, no scrubbing or anything. Looks like I'm gonna scrub some.

is the tooth on the barrel nut touching the gas tube? IIRC, it helps to time the barrel nut, even though the gas tube sorta clears the teeth. just to give it maximum clearance. But it's been a while since I assembled mine (Aero enhanced M5 upper).

 

[jLorenzo]

is the tooth on the barrel nut touching the gas tube? IIRC, it helps to time the barrel nut, even though the gas tube sorta clears the teeth. just to give it maximum clearance. But it's been a while since I assembled mine (Aero enhanced M5 upper).

I thought maybe but no you dont have to fit the tube through the teeth with the enhance upper. The tube will clear no matter what. The hole the tube goes in needed brushed out really well. Real tight before I brushed it out.

 

[jLorenzo]

I think the Rainier match is going back, 2 handloads 175 nosler CC w/42.5gr of Varget, 155 SMK with 42.8gr AR comp. I don't see this breaking in or settling down to anything I would be impressed with.

 

[JR1200W3]

I think the Rainier match is going back, 2 handloads 175 nosler CC w/42.5gr of Varget, 155 SMK with 42.8gr AR comp. I don't see this breaking in or settling down to anything I would be impressed with.

JC, that's bad

 

[ALPHADOG]

1. Aero Upper 6.5 CM 24”, SS, Hvy BB .930 dia. At Muzzel, 1-8 twist
2. Aero M5 Lower
3. JP Bolt Carrier
4. JP .308 High Pressure Bolt
5. Giselle Buffer Spring
6. Radian Trigger
7. Radian Charging Handle
8. Juggernaut Hellfire System
9. Aero Lower Parts Kit
10. Precision Armament M11 Muzzle Brake
11. Magpul PRR Gen 3 Stock
12. Hogue Grip
13. Area 419 12” ARCA rail
14. Leupold MK5 HD 3.6x18
    

 

[jLorenzo]

JC, that's bad

To be fair I did my zeroing on that tatget so a few of those that are way out are from that but still it wasnt even really grouping half the time.

 

[JR1200W3]

To be fair I did my zeroing on that tatget so a few of those that are way out are from that but still it wasnt even really grouping half the time.

Just curious, why you didn't buy the ultra match version?

 

[jLorenzo]

Just curious, why you didn't buy the ultra match version?

The match had a couple people in the reviews claiming good results. Probably shouldve gone with the ultramatch. Not really a fan of flutes either

 

[Cascade Hemi]

The match had a couple people in the reviews claiming good results. Probably shouldve gone with the ultramatch. Not really a fan of flutes either

Post some pictures of your upper build. Groups like that suggest interference between the gas block and rail, or gas tube and upper. Even the worst barrels will normally print under 2".

I've said it elsewhere, Criterion is the best deal going. The one I bought is immaculate inside and has a gas port that looks reamed. I caught it on sale for roughly $300 here: https://ar15discounts.com/products/...08-m118-hybrid-stainless-rifle-length-barrel/

 

[jLorenzo]

Post some pictures of your upper build. Groups like that suggest interference between the gas block and rail, or gas tube and upper. Even the worst barrels will normally print under 2".

I've said it elsewhere, Criterion is the best deal going. The one I bought is immaculate inside and has a gas port that looks reamed. I caught it on sale for roughly $300 here: https://ar15discounts.com/products/...08-m118-hybrid-stainless-rifle-length-barrel/

I checked all that, plenty of room with the handguard. Gas tube it not binding or anything. The bipod was kid of rough and I can tell that large framer gassers are probably the hardest to shoot well. Even still I can shoot pretty well with my SPR. Lots of follow through. One or two of the groups was 2ish" but not even close to consistently.

I did start with the gas block wide open and worked my way back after each 5 round group. Needed to come back a decent amount before I stopped getting ejector smears/burrs.

Remember some of those way out shots were from zeroing the scope. it came off a gun with a 20 moa rail and the windage was like 5 mils off on the new gun.

 

[SolidCopper]

If you’ll humor me, my experience with large frame gassers is that one really has to have their fundamentals dialed in consistently to shoot them well. Also, I discovered my gas gun doesn’t like a bipod. It bounces all over hell and creation and doesn’t group for shit. I chalk this up, partly, to the nature of the bipod/hand guard/barrel nut relationship. Once I started using a bag for a rest and really got my body position and head/eye position correct and consistent, my rifle showed its quality. It could be that none of this applies to you and if it doesn’t then just ignore me.

 

[jLorenzo]

If you’ll humor me, my experience with large frame gassers is that one really has to have their fundamentals dialed in consistently to shoot them well. Also, I discovered my gas gun doesn’t like a bipod. It bounces all over hell and creation and doesn’t group for shit. I chalk this up, partly, to the nature of the bipod/hand guard/barrel nut relationship. Once I started using a bag for a rest and really got my body position and head/eye position correct and consistent, my rifle showed its quality. It could be that none of this applies to you and if it doesn’t then just ignore me.

I'm sure you're right.

 

[jLorenzo]

The Rainier went back, I am going to bite the bullet and go Krieger. Can anyone speak to the difference in the breech and neck length and diameter they offer? I assume shorter is more of a match chamber and longer leaves more room for functioning?

 

[JR1200W3]

RTR .308 Match 18"

craddockprecision.com

 

[NHPiper]

Seekins SP10 6.5CM

S&B PMII 5-25

Sig 7.62Ti

Vortex Impact 4000

L3 CNVD-LR