Cratered/bulged primers, who's getting them?

[funflyer]

Funflyer,
     This stuff needs to be going to Big Green.   We are spinning our wheels
here.   Actually, Big Green needs to be liaising with us on these issues.
But they will undoubtedly say we are amateurs.
Blackie

Blackie, I'm sure Remington designers and engineers would tell us there is absolutely nothing wrong the pistol and we're overthinking things. Yes It works (mostly) but as we all know it can and should work better. So, at this point I'm just treating the pistol like the novelty it is.

[Engineerpower]

I can tell you with certainty that every engineer wants to produce the best design they can, and will push up against the limits of their available resources to do so. The design lead may have been aware of primer flow, but had to prioritize some other design feature over refining the interplay between extractor and case.

The extractor is spring loaded, so I don't think it's going to prevent the round from being fully chambered once the slide is in battery. During firing and extraction, the case will recoil rearward into the extractor, giving it those marks on the chamber of the extractor groove, but the extractor has plenty of give to move out of the way and prevent interference with the breechface. I would see this as a non-issue, as the engineer team will be more focused on the firing cycle than the appearance/condition of fired cases. I doubt cosmetic appearance and reloadability of fired cases weighs very heavily on manufacturers; just look at what HK roller-locks do to their brass, or how many designs that headspace on the rim don't mind the case stretching out.

They definitely shot for the minimum-side of the chamber spec. Chambers will wear looser, though, never tighter. My guess would be that this was a conscious decision to prevent a negative experience from loose chamber and loose or out-of-spec cartridge. Much better to have difficulty chambering a large round than easily chambering anything.

Also keep in mind that this is a small, almost all-metal pistol with a sub-$300 price. There's only so much development time that Remington engineers were afforded for the effort. Don't let the perfect be the enemy of the good.

[R51Fan2017]

Funflyer,
     This stuff needs to be going to Big Green.   We are spinning our wheels
here.   Actually, Big Green needs to be liaising with us on these issues.
But they will undoubtedly say we are amateurs.
Blackie

Blackie,

We aren't engineers. If we were, MAYBE, just MAYBE Remington would listen and give a crap. But we are nobodies in their eyes. Sad. 

[R51Fan2017]

The extractor is spring loaded, so I don't think it's going to prevent the round from being fully chambered once the slide is in battery.

Actually Cameron, that is incorrect. Remington didn't use a spring, they used a plastic ball for lack of better words to function as the spring for the extractor. It's springy enough to make the extractor work. Why they did this instead of a real spring, I will never know. Go look at your manual in the back with the exploded view. You will see what I am talking about.

[Chokejug]

Sorry, but if it functions as a spring, then it must be a duck!
In this case, a compression duck, umm, I mean spring.  (got confused there for a second) 

A spring doesnt have to be steel or even metal.

I think Cameron is dead on here.

Next question, please, anybody with one of the old model 51s in either caliber, can you tell us what their fired primers look like?

As I understand, the breech block does move a fraction and then stops for a split second.  I think that is where the very center of the primer has a chance to expand backwards.

Over pressure would expand, dead FLATTEN, the whole back side of said primer face.  Even to completely "fill in" that gap, the chamfer between the primer and the case head.

Here, we still have a very pronounced, triangular gap all around the outside of the primer circumfrence and the matching one in the inside edge of the primer pocket.

Over pressure, and subsequent metal flow would virtually fill that tiny gap completely tight.

[Chokejug]

That said, I just went and looked at 46 of my "picups".

44 brass and 2 steel cases.

Now, 41 of those brass cases showed little or nothing, visible or feelable, (with a finger nail), while 3 showed and felt, the very center, including the firing pin indentation raising slightly up out of flat.  Just a tiny, tiny nipple like rise.
However, both steel cases showed the same type protrusion.  Not surprising to me.

There is a completely different elastic modulous between brass and steel.
And the hardness, (work hardness), of brass varies as well.

Hard brass has lots of "spring back", after firing.
Firing pushes everything out tight against the chamber walls of course.  Hard brass shrinks back almost to it's prefired dimensions, while soft brass will tend to flow more easily and end up closer to the chamber walls, (if not stick, at least temporarily), and steel much more so. (Steel has much less rebound in every case).

I would guess the cartridge walls are sticking to the chamber walls in some differing amounts, allowing the primers to gain some extrusion when stuck tight, and none when the hull moves freely back with the breechblock.

Steel, the worst, softer brass a little less and quite hard brass, back to almost its original dimensions. (Too many of those, without anealing, and it will crack/split.)

I have found similar type primer deformation in some loads/brands with some autoloading shotguns.  Switch loads or fire the same loads in a break open gun, and it no longer shows up.

[funflyer]

That said, I just went and looked at 46 of my "picups".

44 brass and 2 steel cases.

Now, 41 of those brass cases showed little or nothing, visible or feelable, (with a finger nail), while 3 showed and felt, the very center, including the firing pin indentation raising slightly up out of flat.  Just a tiny, tiny nipple like rise.
However, both steel cases showed the same type protrusion.  Not surprising to me.

This is my point, some pistols show no primer anomalies when many others do. Choke, could you see any indication of the extractor making contact with the forward side of the extractor groove on the brass cases that have normal primers? Also, any chance you could measure the distance from the breech face to the extractor hook with a feeler-gauge?

[R51Fan2017]

This is my point, some pistols show no primer anomalies when many others do. Choke, could you see any indication of the extractor making contact with the forward side of the extractor groove on the brass cases that have normal primers? Also, any chance you could measure the distance from the breech face to the extractor hook with a feeler-gauge?

Todd,

My cases are showing the extractor mark on them too. Just noticed.

[funflyer]

This is my point, some pistols show no primer anomalies when many others do. Choke, could you see any indication of the extractor making contact with the forward side of the extractor groove on the brass cases that have normal primers? Also, any chance you could measure the distance from the breech face to the extractor hook with a feeler-gauge?

Todd,

My cases are showing the extractor mark on them too. Just noticed.

I think we're going to see all of them like this. It appears to be by design. The extractor pushes forward on the case to ensure it headspaces off the shoulder, keeping it fully seated in the chamber. The extractor can be polished to allow it to move more easily when the case recoils into the breech face. If you look at it closely you can see just how rough the casting is.

[Engineerpower]

The extractor is spring loaded, so I don't think it's going to prevent the round from being fully chambered once the slide is in battery.

Actually Cameron, that is incorrect. Remington didn't use a spring, they used a plastic ball for lack of better words to function as the spring for the extractor. It's springy enough to make the extractor work. Why they did this instead of a real spring, I will never know. Go look at your manual in the back with the exploded view. You will see what I am talking about.

Yep, that caught me off-guard too. I wasn't expecting an elastomer spring, but can't knock them for trying something different. May have to look at getting a couple more as spares, and/or drilling out for a normal extractor spring.

Kinda like the Viton o-rings on the Remington 1100; I was a little surprised the first time I tore mine down and found a semi-critical component made from what I would consider a consumable material.

[Rocky150]

Huntsville produces brass cases that appear all normal.

RRR

[R51Fan2017]

Yep, that caught me off-guard too. I wasn't expecting an elastomer spring, but can't knock them for trying something different. May have to look at getting a couple more as spares, and/or drilling out for a normal extractor spring.

Kinda like the Viton o-rings on the Remington 1100; I was a little surprised the first time I tore mine down and found a semi-critical component made from what I would consider a consumable material.

How long do you think an elastomer is going to last? My estimation is that it won't be as good as an old fashioned spring.

[funflyer]

Yep, that caught me off-guard too. I wasn't expecting an elastomer spring, but can't knock them for trying something different. May have to look at getting a couple more as spares, and/or drilling out for a normal extractor spring.

Kinda like the Viton o-rings on the Remington 1100; I was a little surprised the first time I tore mine down and found a semi-critical component made from what I would consider a consumable material.

How long do you think an elastomer is going to last? My estimation is that it won't be as good as an old fashioned spring.

Sean, I plan on taking out the extractor to mod it when I get and test my new barrel so I will see what the "pencil eraser" looks like when I remove it at that time. My experience with elastomers has been that they seem to take a "set" much sooner than a good ol spring will. Cameron may be right and a conventional spring replacement might be required at some point.

[Zenshot]

It could be that the Pedersen device does not work well with a spring setup on the extractor. Or maybe a spring would get fouled by carbon too quickly on the Pedersen device. It's certainly a different animal than other semiautos.

[R51Fan2017]

It could be that the Pedersen device does not work well with a spring setup on the extractor. Or maybe a spring would get fouled by carbon too quickly on the Pedersen device. It's certainly a different animal than other semiautos.

Anybody here got an original model 51 to compare with??