Is this normal for how the chamber should look?

[Arktikos]

I tore into my 454 this afternoon and while under the light and in the vice I took some photos of the chamber, particularly what looks to be a little relief around the outside edge. It is very slight, and goes about 270 degrees. Being that this is such a high pressure caliber is this cause for concern?

[Missionary]

Good morning
That is some good photografy.
Is this a used rifle ? Was this rifle purchased from someone you know ?
This looks to me as a follow up procedure to the chamber after it was cut.
I have never owned a chamber reamer that would make a cut like that. I could duplicate that extra cut with a Dremel or a cone shaped stone held at a slight angle. I can see someone doing this to improve feeding. Possible there was some rough edges.
Safety Take a car tire. Tie that rifle to the tire. Tie a long enough heavy string to the trigger. Point muzzle in a safe direction. Load a max loaded cartrige (factory if you have one. Mark the case head so you will know how the case was orientated to the chamber). Touch it of from behind a post,tree, wall or a thick bodied freind. Slowly eject the brass. Any tough lever pressure needed ? With a micrometer measure the case head for any deformity.. out of round ?
If nothing is out of the ordinary I would shoot it. This is how we test unknown rifles of dubious quality. Cartridge or muzzleloader.. when in dought trust Goodyear.
Mike in Peru

[pricedo]

Looks like a chamber that has been "repaired" by someone using a dremel tool to facilitate ammo feeding.
There was a post or two on another thread discussing the exact same methodology being used by Rossi CS (customer service) to fix feeding problems in a gun returned for repairs.
454 rifle chambers are "tight" for a reason.
That reason is that the chamber wall needs to support the cartridge case from rupturing under 60K+ psi of pressure during the firing cycle.
If the chamber wall is dremeled out so that it doesn't sufficiently support the brass case under the tremendous pressure of a full power load the gun turns into a shrapnel spewing grenade.
Perhaps this gun was returned by a previous owner and Rossi CS got their hands on it or a previous owner dremeled the chamber himself ??
The "fireworks" would happen if the chamber was sufficiently weakened when a full power load was fired.
You could perhaps get away with firing 45LC or low powered 454 Casull loads.
If ammo won't feed in a normal 454 chamber you don't change the chamber.........you change the ammo.
92s are somewhat ammo sensitive .........that's the nature of the beast..........you have to tailor the ammo to the gun and not the converse especially at those pressures.

[Arktikos]

Good morning
That is some good photografy.
Is this a used rifle ? Was this rifle purchased from someone you know ?
This looks to me as a follow up procedure to the chamber after it was cut.
I have never owned a chamber reamer that would make a cut like that. I could duplicate that extra cut with a Dremel or a cone shaped stone held at a slight angle. I can see someone doing this to improve feeding. Possible there was some rough edges.
Safety Take a car tire. Tie that rifle to the tire. Tie a long enough heavy string to the trigger. Point muzzle in a safe direction. Load a max loaded cartrige (factory if you have one. Mark the case head so you will know how the case was orientated to the chamber). Touch it of from behind a post,tree, wall or a thick bodied freind. Slowly eject the brass. Any tough lever pressure needed ? With a micrometer measure the case head for any deformity.. out of round ?
If nothing is out of the ordinary I would shoot it. This is how we test unknown rifles of dubious quality. Cartridge or muzzleloader.. when in dought trust Goodyear.
Mike in Peru

That's a great idea with the tire. so far haven't had any trouble with the 45 colt rounds I put through it. This gun was purchased as a new gun from a gun dealer here locally. We pulled it out of the box, took it out of the plastic with the usual oil and grunge. It seemed new to me. When it was removed from the box the recoil pad fell off as whoever assembled it never put the screws into the wood. This doesn't seem like the work of someone with at Dremal as it is very uniform and a very slight angle. It was difficult to get the camera in the right angle but the chamber opening doesn't look oval shaped at all.

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[Ranch Dog]

I think it is normal Ark. There must be a certain amount of chamber relief or a straight wall cartridge would never be able to chamber in the R92, only small bottle neck cartridges. The radius of relief I see is consistent and polished. Here is my rifle.

chamber_relief.jpg

This is nothing like the hack jobs I've seen done in Florida, it is the relief cut during manufacturing and is normal.

[Arktikos]

I think it is normal Ark. There must be a certain amount of chamber relief or a straight wall cartridge would never be able to chamber in the R92, only small bottle neck cartridges. The radius of relief I see is consistent and polished.
This is nothing like the hack jobs I've seen done in Florida, it is the relief cut during manufacturing and is normal.

I kinda figured this was the case. I was looking at my Marlins and didn't see this but with each of them, 45/70, 45 Colt, and 44 mag there is something unique to where there isn't the need for relief in order for reliable cycling. In the 44mag and 45 colt the chamber size is much larger than they are in revolvers, I have always figured they made them that way because of ease of chambering. I guess the brass can handle that with the pressures those calibers normally have. I did have one failure with the 44 mag with factory Winchester, a split down the side of the case. With the 45/70 that cartridge has a slight taper to it which has the same effect as a bottleneck for feeding purposes it seems to me anyway. I am "relieved" to hear this is the same as your rifle and it makes perfect sense for just a slight relief perhaps a very uniform .005 radius at the edge of the chamber (just an estimate).

[Model 52]

Do you have a picture of a fired case? As long as the case is not bulging it's not really much of an issue.

[Arktikos]

Do you have a picture of a fired case? As long as the case is not bulging it's not really much of an issue.

I just went and closely examined some 45 Colt cases I shot using 325gr bullets and 18.2gr of Lil'Gun and could see no bulge what so ever. These cases look pretty much identical to those fired through the Ruger BH, and completely unlike those fired through my large chambered Marlin. Since this chamber relief would effect the case back in the web I suspect this wont be a problem on the stronger Casull brass, but as of yet don't have actual experience. I'm likely to never put a lot of rounds of full house loads through this gun anyway as I don't enjoy high recoil all that much but do very much want to know that if I fire one at a charging brown bear and end up getting killed it will be because of poor marksmanship and not from gun parts found inside my cranium!

[pricedo]

If the brass is not expanding too much and being excessively worked during the firing/resizing cycle leading to incipient case head separation you are very likely OK.
It did look like someone had slightly belled the throat of that chamber in the original photo.
Maybe it was more polish & smoothing (during throat of the chamber burr removal) than cut (actual removal of metal) by a gunsmith or someone else who knew what they were doing.
If the cartridge wall bases aren't experiencing excessive expansion due to lack of chamber support when firing maximum loads it appears you are OK.
Easy enough to measure base of unfired new case and compare to fired (not re-sized) max load case using a regular case length caliper/gauge.
There are other clues.
Are you trimming a lot of brass during the case length trimming operation?
If you are the brass might be excessively expanding in an unsupported area.
"Brass flow" will eventually weaken the case in the unsupported area as it becomes thinner and thinner leading to eventual rupture.

[Arktikos]

If the brass is not expanding too much and being excessively worked during the firing/resizing cycle leading to incipient case head separation you are very likely OK.
It did look like someone had slightly belled the throat of that chamber in the original photo.
Maybe it was more polish & smoothing (during throat of the chamber burr removal) than cut (actual removal of metal) by a gunsmith or someone else who knew what they were doing.
If the cartridge wall bases aren't experiencing excessive expansion due to lack of chamber support when firing maximum loads it appears you are OK.
Easy enough to measure base of unfired new case and compare to fired (not re-sized) max load case using a regular case length caliper/gauge.
There are other clues.
Are you trimming a lot of brass during the case length trimming operation?
If you are the brass might be excessively expanding in an unsupported area.
"Brass flow" will eventually weaken the case in the unsupported area as it becomes thinner and thinner leading to eventual rupture.

I always am aware that the things I buy, as "new" could have been returned, refurbished and resold and that I could be a victim of that bad company practice. So all I as a consumer can do is check for clues. some of the clues from my 92 were made available to me right when the box was opened, which looked like a NEW box that hadn't been opened as of yet with the S/N on the end of the box label. Second was the plastic the gun was in, which also appeared to be unopened. When it was opened (by me as the shop owner was on the phone) the first thing that happened was the recoil pas which was on the butt stock just fell off. The screws had barely been started into the wood, likely a common thing for a rifle production line to overlook, but a very UNLIKELY thing for a previous owner to have taken out and fired without a recoil pad (or at least attempted to) before returning it for a faulty feed. As for the chamber itself, not having anyone elses to compare, except now for RD's which appears to have the same thing, it doesn't look like an experienced Walmart greeter that was earning extra money on the side as a gunsmith at the Rossi Florida operation had ever come in contact with this gun. I can't prove that beyond a shadow of a doubt, but I am satisfied myself that I have one that made it straight to my arms from Brazil without any other people with Dremel tools getting near it! As for brass expanding that is a good thing to watch. As I understand it, brass around the web that is stretching thin will get shiny and that is a dangerous clue. Is that correct? I need to go reread my Lyman book again as I am a pretty inexperienced reloader with only a few calibers and 2 years of experience. As for shooting max 454 Casull loads, I think that is going to be a one shot thing with the brass and then relegate it for plinkers or something..