Issues? Baffled

[Lr-308FUn]

Hello, 
I did a content search and couldn't really find my issue. Now to start things out here are the build specs. 

Upper Receiver: Caliber 308 Winchester
Aero M5 Upper with Aero upper parts kit. 
Lantac Mil-spec BCG for 308 with Springco extra power extractor spring
Aero Breach charging handle
Faxon 308 pencil rifle barrel, rifle length gas system/ gas port drilled out to .101" from original .089", using Armalite rifle length gas tube.
Aero Precision adjustable gas block
Precision Armament M4-72 muzzle brake
UTG Pro M-LOK handguard
Lower Receiver: 
Aero M5 lower with Aero M5 lower parts kit
Hyperfire Enhanced duty trigger 
Aero M5 Enhanced buffer kit with Springco Orange spring/ Expo Arms 2.5" 5.3 oz buffer 
MFT Battlelink extreme duty butt stock 
2-25 round Magpul magazines 
2-10 round Magpul magazines
Had the issues describe below with all 4 magazines when using brass case ammunition, so I ruled out the magazines. 

Now, my issue is, this rifle will fire and without issue feed steel case ammunition of any kind. But when I try any brass case ammo, I get FTF, FTE, stove pipes you name it. I am at this time at a loss. I timed the adjustable gas block using 7.62x51 NATO ammunition since it's the lower power of the two. I got it to fire and lock back on one round, then opened up the gas block two more turns to ensure proper functioning. Tested again 3 more times with only one round and locked back each time. When loading my 2-Magpul 10 round magazines fully with the same 7.62x51 NATO spec ammunition it would start having the issues described above. 

I did use 4 different types of brass case ammunition, Military grade 7.62 M80 ball 146 grain, Winchester M80 FMJ, Federal 150 grain soft point and 150 grain PMC Bronze FMG. Now with the soft point ammunition I could understand since some semi-auto Lr-308/Ar10s won't feed it well due to the soft lead tip. But I was having the same issue with all the brass case ammunition in either 7.62x51 or 308 Winchester. 

When I would put Wolfe, Tulammo, or any steel case rounds in either magazine the rifle would feed all 10/25 rounds with errors.  As soon as I went to brass case it would have the issues again stated above. I even opened up the gas block fully and would still get this issue with brass case ammunition only. I have tried everything to get this build to be as reliable using brass case as it is with steel case. 

now could my issues possibly be with too much spring? I have been thinking about trying a standard 308 carbine spring with the 5.3 oz buffer and see if that might help with the dwell time. The ejection pattern with all ammunition is around 1 O'clock using current setup. I am also installing a different extractor claw that I had from an Aero Precision BCG. I am sure that it is gassed properly and can't figure out why it will only feed steel case ammunition of any brand flawlessly. Any suggestion will be helpful. 
 

Again, things I am going to try, different buffer spring same buffer, different extractor with same Springco extra power extractor spring. The get some of the same ammunition and try again. 
Thank you, 

Lr-308FUn

 

Edited November 12, 2022 by Lr-308FUn
new information added

[308USK]

Standard spring with 5.3oz buffer, open gas block WIDE OPEN to start, then dial in after issue is resolved.

[Lr-308FUn]

Thanks, will try this have a standard spring installed and 5.3 oz buffer. 

[308USK]

3 hours ago, Lr-308FUn said:

Thanks, will try this have a standard spring installed and 5.3 oz buffer. 

Best of luck!

I had issues after the build of my LR308; had to drill the gas port to fix...but in the process, I removed my JP SCS and got a stock Armalite spring and 5.3oz buffer to ensure 'standard' parts blah blah blah.  Once I got the gas side squared away (drilled out, open up gas block wide open, confirmed proper cycling, adjust gas block down for proper timing, then re-install the JP SCS and verify cycling is still proper (it was) and voila).

Will keep the stock spring & buffer for any other LR308/AR10 builds I do. 

[98Z5V]

On 11/12/2022 at 9:56 AM, Lr-308FUn said:

When I would put Wolfe, Tulammo, or any steel case rounds in either magazine the rifle would feed all 10/25 rounds with errors.  As soon as I went to brass case it would have the issues again stated above.

Any of that steel-cased ammo lacquer coated?  If so, that stuff will gum up your chamber.

[Lr-308FUn]

Nope none of it is, I've tuned the gas block to lower powered 7.62x51 and it will lock back on one round fired. But won't feed a full magazine of any brass case but will on same setting feed steel case fine. 

 

[308USK]

4 hours ago, Lr-308FUn said:

Nope none of it is, I've tuned the gas block to lower powered 7.62x51 and it will lock back on one round fired. But won't feed a full magazine of any brass case but will on same setting feed steel case fine. 

 

None of my business, but why are you shooting steel cased ammo?  (just a personal curiosity; every type of steel cased ammo has been nothing short of $h!t for M4/LR308 for me).

Now, for a thought to help (maybe):
Do you have a digital caliper?  If so:
1) Measure the case width of the steel ammo, record the measurement
2) Measure the head width of the steel ammo, record the measurement
3) Measure the case width of the brass ammo, record the measurement
4) Measure the head width of the head ammo, record the measurement

With the information above, you might be able to ascertain why the steel ammo is working properly and the brass ammo IS NOT.  Best of luck.

[Lr-308FUn]

I have been shooting steel case ammunition for decades with no issues ever. This is why this this baffles me.

I have set the gas block to steel case 308 Winchester, locks back on one round fired, does the same with brass case, but when I load the magazine with brass I get malfunctions but not with steel case. 

[98Z5V]

8 hours ago, Lr-308FUn said:

I have set the gas block to steel case 308 Winchester, locks back on one round fired, does the same with brass case, but when I load the magazine with brass I get malfunctions but not with steel case. 

Do you have different settings on the adj gas block for steel, then brass? Or leave the gas block the same?