Issue fixed. (Can delete)

[kcstott]

I don't get it. Other companies make uppers, lowers, etc. you should be able to see and feel if the carrier is hitting or rubbing on either. Without something majorly wrong I can't see the lower causing ejection problems, I've made crazy out of spec lowers, and not had a problem lol. On one of my 308s it really needed to break in. There is a lot of lug surface there, any little burrs and sharp edges need to wear in before it is smooth. I was having the exact same problems, hell the first round just jammed in there. Sprayed it wet with lube, ran through 40-50 shots and now it is perfect.

You assuming he's mechanically inclined. Which from his posts is definitely not, (RUVALCABA This is not an insult it's just what it is)

He's having a hell of a time trying to figure out what the hell is going on. And after going to a few gun shops where some dip behind the counter that cant change his own oil but can give sound trouble shooting advice on firearms mis directs him sure I can see him being confused as hell.

Still want to see the upper

[kcstott]

Believe it or not.... After so many different parts replaced..... The upper receiver wasn't DPMS... Lower worked great and the no name(Sold to me from LCG) didn't line up straight across. causing the carrier to rub on the sides and slow down.... So now I have a upper that I can't use and would need to machine that one more to make it work correctly.... Thanks everyone for your feed back and help.

I'd like to see the upper in question. and if you don't want it $$$$

[bigcalidave]

I don't get it. Other companies make uppers, lowers, etc. you should be able to see and feel if the carrier is hitting or rubbing on either. Without something majorly wrong I can't see the lower causing ejection problems, I've made crazy out of spec lowers, and not had a problem lol. On one of my 308s it really needed to break in. There is a lot of lug surface there, any little burrs and sharp edges need to wear in before it is smooth. I was having the exact same problems, hell the first round just jammed in there. Sprayed it wet with lube, ran through 40-50 shots and now it is perfect.

[MIGUEL RUVALCABA]

Believe it or not.... After so many different parts replaced..... The upper receiver wasn't DPMS... Lower worked great and the no name(Sold to me from LCG) didn't line up straight across. causing the carrier to rub on the sides and slow down.... So now I have a upper that I can't use and would need to machine that one more to make it work correctly.... Thanks everyone for your feed back and help.

[ar15barrels]

Did load only one round at a time and noticed the brass just bounces around in side.
Almost like can't make it out the upper.

This is usually over-gassed.
In an overgassed situation, the bolt unlocks before the bullet makes it out of the barrel.
The extractor jumps the cartridge rim.
The chamber pressure in the barrel keeps the case in the chamber until the pressure in the barrel subsides.
As pressure is dropping, the case is freed from the chamber and pushed out of the chamber into the action where it bounces around.

Read this: www.ar15barrels.com/prod/operation.shtml

The correct solution for overgassed operation is to reduce the amount of gas getting to the bolt carrier group which will slow down the unlocking.
The "patch job" fix is to just increase extractor tension so the extractor does not jump the case rim.

[MIGUEL RUVALCABA]

I have two video clips of what it's doing now but don't know how to post them. Did load only one round at a time and noticed the brass just bounces around in side. Almost like can't make it out the upper. 26 rounds shot only 1 cycled correctly. I'd post video but don't know how sorry.

Response, BCG is starting to get some rubbing on the siding right before bolt. But think I'm going to just buy a stripped upper from Brownhells and if that doesn't fix it then buy JP adjustable gas system.

[kcstott]

So you should start trying what we told you systematicly going through your upper reciever

But if that picture you posted was normally it looks like a short cycle and you need to look at your gas system also check your bolt carrier for lopsided wear patterns that can cause binding too

^^^^this once again. You need to go through every thing.
In reality I'd ship it down to arbarrels and have Randal take a look at it. His time is worth the money. If you wanted someone a little closer there is Kendog on the board too but you'd have to ship as well.

[Central Coast Gunsmithing]

So you should start trying what we told you systematicly going through your upper reciever

But if that picture you posted was normally it looks like a short cycle and you need to look at your gas system also check your bolt carrier for lopsided wear patterns that can cause binding too

[Rock6.3]

So there is nothing wrong with your lower.
Now the problem is with your upper.

Are we still meeting at the range this weekend?

[MIGUEL RUVALCABA]

Well according to local shop my lower ACTUALLY is machined right fits and fired with him... I get all input on here but I'm just updating with what I get.. I was trying to save $ and get insight on here but I spent $ on three different gun smith and finally one here in Elk Grove stated lower wasnt to DPMS specs but upper receiver wasn't a DPMS nor any mas distributor he knew of. Hence shop that sold to me LCG is closed. So NOW BEING told to try a new low mass upper receiver. 😳🔫

[kcstott]

If you had said above that the rear lug pocket location in the lower would shift the upper, I would agree, but you specifically said FCG pocket...

Yep i did but I would consider it one and the same. although technically not.

[ar15barrels]

I had no idea about a "old style Armalite.

I did a google search to find a photo of the old style and new style 308 carriers and it turns out the damn photo was on my own website...

[ar15barrels]

No just that the rear lug pocket is typically machined with the FCG pocket

If you had said above that the rear lug pocket location in the lower would shift the upper, I would agree, but you specifically said FCG pocket...

[kcstott]

I'm trying to comprehend how moving the FCG pocket in the lower would move the BCG in the upper.
Have you compared the hammer width to the width of the hammer clearance cut inside the BCG?

Perhaps you are thinking of an old style armalite carrier with the really narrow clearance cut?
If the FCG pocket was grossly mis-located, the hammer would just strike the bottom of the carrier instead of the firing pin.

No just that the rear lug pocket is typically machined with the FCG pocket and if it was shifted over say .030" may cause a bind with the bolt rubbing the buffer tube. Yeah all your BCG now a days have a mile of hammer clearance. and you've been doing this far longer then me. I had no idea about a "old style Armalite.
but like I said that can't happen as the front lug would have to shift as well.

[ar15barrels]

The problem he describes leads me to believe the FCG pocket was machine off center and shifted the BCG over at the rear causing it to bind up.

I'm trying to comprehend how moving the FCG pocket in the lower would move the BCG in the upper.
Have you compared the hammer width to the width of the hammer clearance cut inside the BCG?

Perhaps you are thinking of an old style armalite carrier with the really narrow clearance cut?
If the FCG pocket was grossly mis-located, the hammer would just strike the bottom of the carrier instead of the firing pin.