[AMG Nate]

I am using Hornady factory loads 200gr SST. The gun has been blowing primers out the back of the cases on a consistent basis. I sent the gun back to S&W. They said “repaired yoke and replaced cylinder stop.” Just took the gun to the range and it is STILL blowing primers. The range didn’t have any .460 ammo in stock for me to try something different. As you can see in the pic, I fired 20 rounds and the primers that are crooked, missing, or have a dark ring show how many failures I had. WAY too consistent to “accept” it and move on.

I am going to email hornady with the lot number and see if there might be an issue with the lot I have. But I am still leaning towards a problem with my gun.
Anyone have ideas as to why there’s clearly an excess pressure issue going on here?

 

[SidecarFlip]

Don't look like excess pressure to me. The primers are not cratered. I'd say the pockets from the factory are either too loose or the flash hole is too big.

I'd take one (or more of the spent cases), decap them and insert new primers and 'feel' how they seat. I'd also look at the flash holes and compare the holes to a shell that the primer didn't lift on, but I strongly suspect the pocket are too loose from the swaging process.

As a rule I never use Hornady brass in 460 to reload. I don't much care for it in general. I use Starline instead or Jagerman. Not the first issue with Hornady factory loads or brass. Hornady ran a huge lot of 338 Lapua cases and factory loads that had the cases splitting when fired.

I did break in my 460 with the 200 grain Hornady flex tips (1 box), but they don't perform to my expectations. I had zero issues with primer lift, still have that fired box in the armory. I do load 300 grain .452's in hollow point but I prefer Swift A Frames over anything.

 

[SidecarFlip]

You need to learn to reload and build your own. Lesser calibers are fine for factory stuff, but the 460 Magnum isn't really.

Again, no excess pressure, just poor manufacturing tolerances and poor QC. In reality, excessive pressure would show up on the case sides, not the base and would cause hard extraction.

Just because it's 'factory made' don't make it good. It makes it mass produced that is all.

 

[AMG Nate]

You need to learn to reload and build your own. Lesser calibers are fine for factory stuff, but the 460 Magnum isn't really.

Again, no excess pressure, just poor manufacturing tolerances and poor QC. In reality, excessive pressure would show up on the case sides, not the base and would cause hard extraction.

Just because it's 'factory made' don't make it good. It makes it mass produced that is all.

It is hard to eject the spent brass. I have to hit the plunger on the table. Which lead me to believe too much pressure. Hopefully Hornady will make it right since I’m sitting on so much of this ammo.

 

[SidecarFlip]

Not a plunger, plungers are for toilets. It's a shell extractor and hitting it on a hard surface to eject a spent case is not the thing to do. If anything, use a soft face mallet to tap it and tap it squarely.

I'm curious. Have you ever shot anything but the 200 grain flex tips in it? By that I mean a different bullet entirely, as in a shorter case?

Reason I ask is because shooting a smaller (shorter) case bullet will cause the end of the chamber to get a carbon ring in it and that will create a hard extracting 460 case .

I occasionally experience hard ejection myself but I only shoot handloads and I tend to jack them up to maximum loads.

Hornady don't make it a habit of even loading to maximum powder loads.

If you have shot shorter cases, I suggest you clean each chamber carefully and not with Hoppe's because that won't get the carbon out. You need to carefully clean each chamber with a potent carbon remover like Sweets or BTE.

 

[AMG Nate]

I have JB paste. That seems to get carbon fouling out of bores very well... is it acceptable to use on the chambers?

 

[mrerick]

There is clearly excessive space between the frame and the cylinder rear face. How wide is the barrel to cylinder gap on your revolver?

It could well be that the barrel set back in the frame is inadequate, leaving too much space for the cylinder to fill between the rear of the barrel and the frame's cylinder face at the rear of the cylinder.

In the firing cycle, the high pressure generated by the powder will seal the case against the cylinder wall, holding it in place as the high pressure gas pushes the bullet out of the case mouth, into the cylinder gap and then into the leades of the barrel's rifling. During this high pressure pulse, the primers are being pushed back against the rear face of the frame. There is too much space allowing the position of the rim to be anywhere between the back of the cylinder and the frame face. When the cartridge is ignited while the rim is against the cylinder rear face, the primer can be pushed out into that space, stopping against the frame. The gap is too large.

Get back in touch with S&W CS and ask them to re-evaluate your revolver.

 

[SidecarFlip]

I have JB paste. That seems to get carbon fouling out of bores very well... is it acceptable to use on the chambers?

Yes

 

[SidecarFlip]

There is clearly excessive space between the frame and the cylinder rear face. How wide is the barrel to cylinder gap on your revolver?

It could well be that the barrel set back in the frame is inadequate, leaving too much space for the cylinder to fill between the rear of the barrel and the frame's cylinder face at the rear of the cylinder.

In the firing cycle, the high pressure generated by the powder will seal the case against the cylinder wall, holding it in place as the high pressure gas pushes the bullet out of the case mouth, into the cylinder gap and then into the leades of the barrel's rifling. During this high pressure pulse, the primers are being pushed back against the rear face of the frame. There is too much space allowing the position of the rim to be anywhere between the back of the cylinder and the frame face. When the cartridge is ignited while the rim is against the cylinder rear face, the primer can be pushed out into that space, stopping against the frame. The gap is too large.

Get back in touch with S&W CS and ask them to re-evaluate your revolver.

Marc:

First thing I'd do is make sure the bores are clean and free from any carbon buildup that will impede case movement.. If that don't alleviate the issue then the frame to cylinder space needs to be set back a couple thousands. I'm wondering if the OP banging the extractor rod on a table to extract stuck cases aggravated the face to cylinder clearance? Not having the pistol in hand, it's only conjecture on my part.

Me, I'd start with the easy part first (making sure the bores are clean and carbon free. If it was a face to cylinder issue, ALL the cases should have popped primers, not just a few. IMO, the pocket retention is loose in the case and the dragging case in the bore is magnifying the condition.

I've never cared for calibers that allow multiple loadings to be fired, especially loadings with shorter cases because that makes it easy to develop a carbon buildup at the end of the bore where a longer case will go... Sometimes, cheaper alternative (lesser cartridge, especially shorter case length) can cause issues. Why I asked if the OP had shot a diminutive load prior to the 460 / 452 bullets.

My 460 never sees anything but 460 cases. I see no reason to shoot anything else. The recoil isn't that bad, in fact, it's less than my 44RM in both lateral and vertical (muzzle climb planes).

 

[SidecarFlip]

Yes

Let me expand on that a bit... Use a tight fitting mop with the paste and burnish the bores carefully, observing each one to make sure the carbon is removed. The 460 cylinder is tight to begin with (mine is / was).

 

[mrerick]

What is observed (only some of the primers back out) is what cued me into problems with the barrel to cylinder gap.

If the cylinder is set too far forward, there will be excess space between the rear cylinder face and the frame. The cartridges that happen to have their rims up against the rear cylinder face will blow out their primers through the gap up to and against the frame. The cartridges that happen to have their rims up against the frame will keep their primers in place.

During ignition, the case will be up against the cylinder wall and won't be moving. The different primer backout positions will be caused by where the rim sits at the moment of ignition.