308 Loads not chambering in AR, need advice

[mehavey]

If the case headspace is long, that bolt slamming home will forcibly
collapse the shoulder and bulge the body transition juncture.
What was then a length problem . . .
...is now a diameter problem.
(Correctomundo, HiBC )

Voila ! Stuck case.
Mortared Rifles R`Us dance immediately follows
(I see it all the time as an RSO.)

Hard bolt going home is the acid test.


.

 

[Metal god]

I do not see advantage in initially using the bolt carrier and assist.

I do it that way for these types of specific test to not allow exactly what Mehavey is pointing out . I've actually run test checking how much the shoulder is set back by the BCG slamming the cartridge into the chamber ( 5.56 chambers ) My test showed as much as a .002 shoulder set back each time the same cartridge was chambered to a total amount of .005 set back . Which at that point the shoulder stopped being set back . Note these were cases I sized to be .003 short of fired cases . I did not see the same set back on factory rounds but they were already .006+ short of fired cases to start .

I even sized cases .002+ longer then my fire formed cases to see if letting the BCG fly home would still allow the case to be chambered , It did and the case was hard to extract , Not slam the stock on the bench hard but the bolt was binding for sure . Note I first tested the long cases by trying to chamber them as described earlier and they would not . However the force of the BCG slamming them into the chamber bouncing them off the chambers shoulder set the cases shoulder back enough to allow the bolt to go into full battery .

Well that was a bit long winded to say , easing the the BCG home and tapping into full battery avoids the case being damaged and sticking in the chamber because it it does not fit . If the case does not fit in the chamber tapping the forward assist will not allow it to chamber , Letting the BCG slam home can and often will . Doing it that way allows you to see if the case fits without needing to mortar it out if it does not .

 

[44 AMP]

OP states gun has never been fired. SO, Presumably new and under warrantee.

Reloads get stuck. Factory ammo get stuck. There are only two possibilities.

One, the owner is doing something drastically wrong...

two. there is something wrong with the rifle.

New, under warrantee, the rifle needs to go back to the maker, period. No handloading "work arounds" should be needed, nor should the owner try to fix anything himself, or take it to a local gunsmith. It should go back to the manufacturer for evaluation and repair. And it should be on their dime, including shipping both ways.

Call them, and get a ticket/shipping label, and send them the gun. Avoid further speculation until you get the gun back and see if they fixed it.

And, get some decent, consistent brass while you're waiting! Just don't load it until you have the rifle back to check it in.

 

[Metal god]

New, under warrantee, the rifle needs to go back to the maker, period. No handloading "work arounds" should be needed, nor should the owner try to fix anything himself, or take it to a local gunsmith. It should go back to the manufacturer for evaluation and repair. And it should be on their dime, including shipping both ways.

I agree completely . I once sent back a new Del-Ton 316 because on the first range trip it was doubling . Sure I could have just switched out the FCG or played with individual parts until I got it right . However I figured a brand new rifle should not have any issues so I sent it back . It was returned with a note stating the disconnect and hammer were out of spec and replaced . It has work flawlessly since .

I agree there should be no need to fix or create a work around on a brand new firearm .

 

[mehavey]

I was under the impression factory ammunition fit fine:

...found a box of PMC FMJs sitting around and purchased
them at an inflated price. Wouldn't you know, it chambers.

...
then suddenly something factory got stuck again.

Pounding the hell out of my Smith right now as we speak.
A factory round even got stuck.

I'd sure like to know the "history" of that 2nd round....

 

[44 AMP]

I agree there should be no need to fix or create a work around on a brand new firearm .

There should be no need, because if there is a need, then we (the consumers) didn't get the functional firearm we paid for.

And additionally, even if the fix is a small thing and one we could easily do, we should NOT fix it (on a new, under warranty gun).

If we, or out gunsmith fixes, then the factory A) usually doesn't even know they have a problem, and B) cannot and will not fix the problem.

Calling them, telling them there was a problem and that you fixed it simply does not make the impression that sending a gun back for them to work on does. In order to meet their obligation (functional firearm) and having to spend time and money fixing something that should have been done before the gun went out the door to be sold gives them incentive to find, and then fix whatever is going wrong that allowed defective product to reach the market.

 

[Unclenick]

- That bump-over feel indicates "cam-over"

The bump indicates the ram has begun to push on the die mouth and stretch the frame as you described. But most presses these days have stops that prevent actual camming over, which is where the press handle stroke keeps moving through the point where the ram reaches the top of its travel and starts down again before the handle reaches its stop. Designers have stopped making them because the mechanical advantage approaches infinite leverage at the top of ram travel too many presses have been damaged by ham-handed users who screw a sizing die in too far and then force the press through cam-over. I have only one press that will truly cam-over, and it's an old Lyman Spartan press.

 

[9mmSkeeter]

UPDATE

Not to revive a zombie thread but I’ve got an update. After 4 months at S&W, they sent back my rifle.

Replaced upper receiver, barrel, and bolt. How did it even leave the factory? Holy s—t. That’s like a whole new rifle. Marked as “misfires, misfeeds.”

My thread here also explains that it didn’t feel quite right out of the box.

I haven’t tested it yet but overall for ARs I can’t solidly recommend a brand new S&W based on my experience. You may disagree and that’s okay, but if someone were to ask me personally, this would be my story.

 

[44 AMP]

Replaced upper receiver, barrel, and bolt.

this makes it seem like all those parts were bad, but I doubt that was the case. i think the most likely reason was simple economics. Replacing the entire upper was probably faster and therefore cheaper than taking the time to track down the specific individual flaw(s) and fixing just those parts.

Glad you got your gun back, and I hope it works when you test it. It should. If not, S&W should get it again.

Happy New Year!

 

[Unclenick]

Yes. When parts are replaceable, substitution is the fastest route to resolving a problem, and the factory is usually the only repair agent who has enough parts to do it that way. Back in the early '80s, I returned a Charter Bulldog to the factory because it could barely stay on a paper plate at 25 feet. When I got it back six or seven weeks later, the paperwork said the frame had been twisted (likely from an over-torqued barrel during assembly) so they replaced it. The factory has (or did then, anyway) the ability to destroy a frame and reissue the serial number, and that appeared to be what they had done. In the process, they'd managed to change all the other parts as well. I knew that because the original had some oddities like misaligned hammer spur grooves, that were no longer there. So, apparently, they shot some guns until they found a good one and reissued the serial number, and sent me that one. It went from the previous poor performance to staying under two inches at 25-yards. Totally surprising for an inexpensive 3" gun with fixed sights.

The bottom line, the factory has the maximum repair power for a stock model gun, always. The only drawback is, for liability reasons, if you have had trigger work done, they will most likely put it back to factory specs before returning it to you. That's one thing your local gunsmith won't do.