Ongoing issues....extraction/ejection?

[82Trooper]

So after another disappointing day at the range, I return here looking for some advice. Regular readers will know I recently replaced the barrel on my first ever L1A1. It also has an aftermarket receiver cover, to mount a reflex sight. Last weekend, I had some feed issues, and basically it jammed almost every shot.
My untrained eye did not notice anything glaringly wrong, other than a few misshapen cases after ejecting.
I took her home, field stripped and cleaned everything. I replaced the inner and outer return springs, as well as the gas piston spring. Then I returned to the range this past Friday. I seem to have made my issues worse. The cases are very disfigured and dented.
Here is what I did, to try and pinpoint where the issue was:
-Tried 2 different kinds of ammo, both "new" manufacture, not reloads. One Malaysian surplus, and the other factory Winchester.
The gas adjustment set at 5, then up to 2.
-Several different magazines, to include a plastic, Moses machine Works aftermarket item.
-Pretty consistently the rifle locked partially back, after trying to eject, the photos show the spent rounds, mostly when I manually ejected them.
- Any helpful thoughts and diagnosis?

Information

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[browningautorifle]

Looking at the pic you see concentric circles in the chamber and again on the casing. I wonder if you need a spot of machine paper polishing on a drill mandrell to sort that. I wonder if the cases are being held a bit... Could also be a tight chamber. The mouth looks like the Breech Block and Carrier are smashing and holding them to create a stoppage when it fires. A chamber should be a mirror mostly, it won't take much. You shouldn't need to set the gas down when the rifle's clean. That can create another problem, like a broken ejector.

[Paul S.]

One of the cases has a long scratch on it. The scratch can be seen in the picture of one case being extracted from the chamber. That makes me wonder if there isn't something in the chamber that is dragging on the case and scratching it. My suggestion is as above, polish the chamber. Also, thoroughly inspect it for burrs or debris.


The case neck deformations are probably being caused by them striking the aftermarket top cover (soft brass meeting hard steel with force).

[mrclark303]

I would agree with Jim, a careful chamber polish is in order, then get some brass down range to bed her in.

[82Trooper]

So is a "careful chamber polish" something a gunsmith needs to do? Or is it a do-it-myself with a drill or a Dremel? I don't mind nuts, bolts and threaded stuff...but sanding or grinding sounds a bit intimidating.
This is the area we are referencing with the "concentric" circles"?

[CINDERS]

You can see all the beltings the cases have done on the upper receiver to the rear of the ejection port and along the top of the ejection port I am with Jims summation that the rough chamber is holding the rounds and its taking more push from the rod to get the case moving hence the rounds are being slammed out as the bolt body literally takes off on the ejection cycle and causing the dents and scratchings on the cases. As Paul S noted.
If your unsure about polishing it take it to a gunsmith for peace of mind.
I have used (on a 303) 1200 grit Wet & Dry little bit of RP 40 and a rod with a slot in the top so you make a sort of flapper and away you go with a variable battery drill your only polishing not trying to remove scads of material slow & steady
Your only trying to get the majority of the chamber polished so no need to go into the neck section just the main body. try the original upper after the chamber polish then put the after market back on and see if the brass gets hammered when the cycle works as it should.

[Bruce_in_Oz]

I notice that the extractor is the very early pattern with the "extra" bit on one side. These were declared obsolete and were to be replaced on inspection, starting in the late 1960's, if I recall my notes correctly.

A scored or rough chamber will mark the sides of the brass case, but will not mangle the end of the necks. I'm guessing an "aftermarket" barrel: all but the earliest Lithgow rifles had hard-chromed chambers and eventually fully plated chambers and rifling. A small dab of cold blue will tell. If the blueing paste darkens the chamber, it is not chromed. Chambers should be smooth, but NEVER highly polished. The idea is for the expanding case to "grab" the chamber walls briefly at the highest pressure stage, but as it contracts, to "let go" enough to be easily extracted. A mirror sheen will not allow this "grab" and thus MOST of the pressure will be directed into the face of the bolt / breech block; NOT a good thing.

Have you tried firing it with a standard dust cover? If cases are still being heavily dented at the end of the neck, something else is wrong. A bit of flattening is not all that unusual if the cases are spinning back and hitting the body, but I don't recall ever seeing a bunch of necks looking like yours.

If it has NEVER worked properly, check the two nested return springs inside the butt. One is supposed to be RH twist, the other left hand. This is so that the inner and outer coils do not "bind" when the return spring assembly is compressed as the tail of the carrier pushes it back. Don't laugh, it happened in real life with some Lithgow production and there was an official instruction to strip and examine a large batch of rifles in a certain serial number range to ensure they had the correct components. It is just possible that some errant springs escaped the weeding out of the spares stocks, as well. While you are checking springs, make sure that the spring for the body locking catch is SHINY; either black or "natural. If it has a dull, non-reflective surface on the coils, it is probably one of the dreaded phosphated ones, which are known to crack and fail. Thus it must also be replaced with a "shiney" one.

Happy building and shooting.

All we have in Oz are the memories and a few faded photos and documents.

[mrclark303]

Yep, 1200 grade, I would recommend you then shift to super fine grade.

Like most of these jobs, take your time, all you are looking to do is reduce the resistance.

A friend of mine drilled out the primer pocket of an unfired case, fixed a piece of welding rod and just used an automotive cutting compound with no paper abrasive.

Remove a 'gnats knacker' until she fires as intended.

[CINDERS]

BIO has it right the S/A's are but a faded memory that I seriously doubt will ever be in the hands of legal shooters again, thanks to JWH who acted unconstitutionally removing them from us, what a maggot...........

[browningautorifle]

I'm guessing an "aftermarket" barrel:

Bruce, this is the one he had a long thread about replacing the barrel. It's brand new...

sanding sounds a bit intimidating.
This is the area we are referencing with the "concentric" circles"?

Yes, that was what I was talking about. If worried then a gunsmith can do a chamber polish, it should be his bread and butter. Like Cinders says, a drill on low and steady with a mandrell of wood dowel and paper around it, wrapped opposite to the spin. Light oil but oil it for sure. Just do a few seconds and clean and examine. You'll see a difference. A gunsmith could do it in minutes, but shouldn't have you watching...that's when things go wrong for sure. It really is simple to do...fine machine paper.