Anyone know how tight/loose the current crop of .45 R92 chambers are cut? I’ve got ~10yo R92 in .45 Colt that I like a great deal, but the chamber is cut so oversized that It’ll bulge cases to where they can’t be reloaded in some of my tighter-chambered revolvers anymore. I’ve been considering one of the Triple Blacks as a suppressor host.

I shot one the other day that belongs to my neighbor.  It was every bit as accurate as my Henry

My R92 .45/.454 does not have an oversize chamber.  I bought it in 2007.  I reload all my .45 brass and use it in one of my .45 pistols or rifle and have never had any that bulged.

I have thought about going with one of the .454 models because SAAMI specs for .454 chambers are considerably tighter than those for .45 Colt, but I have never seen a 16” threaded .454 model.

Mine is plenty tight

I have an EMF Hartford 45 Colt I bought in 2005.

It has a chamber cut loose like described, I reckon it's to aid in loading.

It bulges cases when I load hotter rounds.

Not bad at all when loading 255gr under 8gr of Unique.

I have a 16" Rossi M92 loaded in 44 magnum and it doesn't buldge cases, it's a newer one I bought in late 2015.
It kicks fiercely with magnums.

Some .45 Colt history is needed to understand the chamber dimensions,

The .45 Colt is a black powder era cartridge and black powder is notorious for fouling.

If you look at pistol class black powder cartridges like the .44-40, .38-40, and .32-20 you will note they all have a slight bottle neck, a slight body taper and a fairly substantial rim. That’s because these rounds were designed to be fired in lever action rifles like the Winchester 1873 and 1892, where they relied on an extractor engaging the rim.  

They also needed to limit has coming back into the the chamber and the action to minimize fouling.  The slight bottle neck helped the comparatively low black powder pressures quickly seal the case agains the chamber to limit gas moving back into the chamber and action.  The tapered body ensures that as soon as the cartridge case starts to move aft, it would be fully out of contact with the case walls reducing extraction effort.

These features also worked fine when these pistol class cartridges were used in companion revolvers.  

You see similar tapered bodies and in some cases bottle necks on the larger black powder rifle rounds for the same reason.


The .45 Colt however was designed specifically for the Colt Peacemaker and Colt wanted to get the largest possible .45 caliber case capacity in the smallest possible cylinder diameter.   Consequently given that design goal and the use of a rod ejector they used a very small diameter rim as all it had to do what provide head spacing. They also used a parallel wall cartridge case to maximize case capacity and thus powder capacity. It was after all intended to be the .44 Magnum of its day.

However, Colt was still concerned about possible stiff ejection and hedged its bets by tapering the chamber, from .4800” at the chamber mouth to .4862” at the bas e of the chamber, making it .0062” in larger in diameter at that point than the .480” diameter cylindrical case, and a steadily increasing taper along the body of the case from mouth to base.

Around 1900 Colt did start making the rim more substantial and that change along with the use of smokeless powder with greatly reduced powder fouling has made it possible to chamber lever action rifles in .45 Colt - something that was just not done or even possible in the black powder era.

However the tapered chamber persisted and continues to be the SAAMI spec.

It’s not an issue with the original 14,000 psi limits for the .45 Colt as the brass tolerates that well with minimal bulging and stretch.

However at 21,000-23,000 psi (.45 ACP and .45 ACP +P) pressure loads commonly used in modern .45 colt handloads in modern revolvers, case stretch begins to become a bigger issue and case life becomes much shorter.

At 30,000 psi “Ruger only” pressures case life is around is down around 7 reloads before you see spider cracks forming in the middle of the case body.

Marlin and Winchester Model 94s Wi I’ll tolerate 40,000 psi and the Rossi 92 and modern Winchester 1892 will handle 50,000 psi.  However if those chambers are cut to the standard SAAMI spec with .4862” at the base bulging and case stretch will be an issue.

But those chambers are not “loose”, they are cut to SAAMI spec.

When I load .45 Colt to those 30,000 psi and higher pressure levels I use a factory crimp die with a carbide sizer that sizes the case all the way to the case, and I don’t expect more than 4-5 reloads out of the case.


But frankly I rarely do that as if I want more performance a .44 Magnum or .454 Casull makes more sense.  But I normally don’t as a 255 gr bullet fired out is a Model 92 at even 30,000 psi pressures and relate velocities has fairly fierce recoil and at best mediocre accuracy.  If I need more punch I use a Model 94 in .38-55 in stored of trying to make the .45 Colt into something it isn’t.