Am I the only one...

[Y-T71]

I was cleaning my Uberti "Smoke Wagon" this morning and noticed a difference in the thickness of the steel between the chambers from the rear of the cylinder to the front of the cylinder.





To my way if thinking, this means the chambers are NOT bored "straight" through the cylinder.

I've never noticed this before so I checked my other 3 revolvers (2 S&W 629's and a Ruger Security Six .357) and sure enough, the chambers were bored through the same; not "straight".

Obviously, as far as I'm concerned, it doesn't appear to have any effect on reliability or accuracy in the 30+years I've owned and shot revolvers, I just can't believe I've never noticed this before.

Does everyone else already know about this? (Boy am I going to be embarrassed if I'm the only one!)

Does anyone know why this is done?

It might be done for a reason that is blatantly obvious and I'm just a little slow

 

[aaaaa]

Perhaps because the bullet is smaller diameter than the case, so on the back of the cylinder the holes are slightly bigger to accommodate the cases? In other words, the chambers apparently do not extend all the way through the cylinder bores. Are you sure they are tapered or is there a slight edge where it transitions from chamber to bore part of the cylinder?

 

[Y-T71]

I think that's exactly what's going on! (And yes, now I'm embarrassed)

I just couldn't figure it out!

Thanks!

 

[earlthegoat2]

Do you see a step in the chamber?

 

[Y-T71]

Do you see a step in the chamber?

Sure do!

That's my answer!

 

[aaaaa]

Now that I go back, you can see the step in the second photograph.

 

[aaaaa]

This also explains why shooting .38 Special's shorter case cartridges in a .357 Magnum causes deposits in the chamber. Because the chamber part is wider than the bullet, so the bullet does not "clean" out the deposits from that wider part of the chamber where the longer case would sit. I never understood that before, but this thread got me to thinking. Same for .44 Special in a .44 Magnum gun.

 

[CraigC]

If you look at the chamber of anything that uses a heeled bullet, you won't see that step.

 

[Y-T71]

What's embarrassing is I knew about the chamber throats and how you get crud built up from shooting shorter cartridges in longer chambers and how some manufacturers bore the throats a smaller diameter than the bore leading to loss of accuracy and lead deposits in the forcing cone/barrel...

I just could NOT make the connection

In my defense though, I've been pretty "foggy" for the last couple of weeks (Dr's found leisons on my brain and think I might have MS)

Thanks for not making fun of me!!

 

[Kookla]

@Y-T71 hope everything checks out with you healthwise.

 

[Dave DeLaurant]

If you inspect some old revolvers chambered for cartridges that use heeled/outside lubed bullets, such as .41 Colt, the chambers come a bit closer to a straight-walled cylinder, though they usually still taper a bit inside front-to-back.

I understand Howell devised a 6-shot cartridge conversion cylinder for some models of cap and ball revolvers featuring a very slight angle to the chambers, in order to make enough room at the rear to accommodate the rims. They also make 5-shot cylinders without resorting to angled chambers.

 

[aaaaa]

If you look at the chamber of anything that uses a heeled bullet, you won't see that step.

meaning the bullet is wider outside it's case? That would only be specific calibers set up that way, like you cant do a heeled .38 special then shoot it out of a .357 magnum as it might act like a stuck bullet (squib) and blow up the cylinder. So are heeled bullets specific to certain calibers? Or do I need to be aware to avoid heeled .38 Special cartridges?

Heeled would only work in rimmed bullet since non rimmed use the case and step in the chamber to prevent the bullet from falling too far in?

 

[aaaaa]

What's embarrassing is I knew about the chamber throats and how you get crud built up from shooting shorter cartridges in longer chambers and how some manufacturers bore the throats a smaller diameter than the bore leading to loss of accuracy and lead deposits in the forcing cone/barrel...

I just could NOT make the connection

In my defense though, I've been pretty "foggy" for the last couple of weeks (Dr's found leisons on my brain and think I might have MS)

Thanks for not making fun of me!!

I hope that all works out well. No problem on the post, my thought process sometimes gets clouded, maybe from certain excesses in my teen years that are best left unsaid now.

 

[film495]

my only centerfire revolver is like that. I always assume the front of the chamber was narrower to align to the forcing cone better. if it didn't narrow I'd think you'd spit lead everywhere. .38 Special. drop a range rod down the barrel and check the cylinder alignments, it is usually really spot on, if it isn't you end up shaving lead. with straight cylinders that don't narrow, not sure how the alignment to the barrel would work not very well I imagine.

 

[Dave DeLaurant]

meaning the bullet is wider outside it's case? That would only be specific calibers set up that way, like you cant do a heeled .38 special then shoot it out of a .357 magnum as it might act like a stuck bullet (squib) and blow up the cylinder. So are heeled bullets specific to certain calibers? Or do I need to be aware to avoid heeled .38 Special cartridges?

Heeled would only work in rimmed bullet since non rimmed use the case and step in the chamber to prevent the bullet from falling too far in?

Rather than thinking of heeled bullets independently, think of them in terms of a heeled bullet/cartridge system. Their main advantage back in the day was that you could make the entire case a bit narrower for a given caliber -- that was a plus when converting a percussion revolver design to metallic cartridges. Also heeled bullets are less likely to telescope into their case in a tubular magazine. They are a nuisance, since their configuration means the bullet lube is exposed to dirt and debris; crimping is also more of a chore.



The only cartridge with a heeled/outside lubed bullet in common use today is the .22 S/L/LR. It offers no advantages and survives as a legacy design -- more modern rimfire cartridges like .22 WMR use inside lubed bullets.

 

[Driftwood Johnson]

Howdy

Here are the actual Sporting Arms and Ammunition Manufactures (SAAMI) specification drawings for the 45 Colt cartridge and chamber.

Notice the on the cartridge drawing the bullet diameter is less than the OD of the cartridge case. This is the case with almost all modern cartridges that have a bullet the same size as the inside diameter of the cartridge case.

Notice too, the step in the chamber where the diameter is reduced to bullet diameter is not a 90 degree angle. This is because revolver ammunition like this headspaces (seats) on the cartridge rim. There will always be a little bit of space between the end of the cartridge case and the narrower diameter of the chamber throat.






Here are some examples of Heeled Bullets. In other words, the rear of the bullet is slightly smaller in diameter than the rest of the bullet. The 'heel' is the same diameter as the inside of the case, but most of the bullet is the same size as the outside of the case. These particular bullets are heeled bullets I cast up for loading in the antique version of the 44 Colt. Has you can see, the outside of the bullets is the same diameter as the outside of the brass. Cartridges like this needed a different type of crimp, the crimp could not be formed with modern style crimp dies. Also, notice one groove for bullet lube is on the outside of the case. This was problematic because the soft lube used in these cartridges would attract contamination from dirt, pocket lint, and what have you.






The 44 Colt cartridge was developed for the Colt Richards Conversion. This Richards Conversion is pictured with 4 original 44 Colt cartridges. The Richards Conversion used the same cylinder as the original Colt 1860 Army Cap & Ball revolver. The cylinders of these revolvers had no narrow chamber throats, the chamber diameter was bored all the way through to where the nipples were located. So, practically speaking, the 44 Colt cartridge was a cartridge designed around a 44 caliber ball. I forget just now what the dimensions are, but I seem to recall the actual bullet diameter of the original 44 Colt cartridges was pretty much the same as 45 Colt, around .452 or so. But the brass was the same diameter as the bullets.






This is the cylinder from the Colt Richards Conversion. The rear of the cylinder, where the nipples were, has been machined away, leaving the .452 or so chambers bored all the way through.






44 Russian, the cartridge all the way on the left in this photo, is generally acknowledged to be the first production cartridge where the entire bullet was the same diameter as the inside of the brass case. The Russians specified this to Smith and Wesson for the Russian model revolvers Smith and Wesson was making for the Russian government. Left to right in this photo the cartridges are 44 Russian, 44 Special, 44 Magnum, and 44-40. All have bullets that are crimped inside the case.






Some more cartridges that had heeled bullets. Left to right, 44 Henry Rimfire, and two examples of 44 Colt. On the far right is an old 45 Colt case. Difficult to see, but the bullet is of the same diameter as the inside of the case.






Here is a Smith and Wesson #2 Old Army Tip Up revolver. The cartridges are 32 RImfire. Like most rimfire cartridges, they had a heeled bullet and the outside of the bullet was the same diameter as the outside of the copper case.






Difficult to see in this photo, but the chambers of this revolver were bored through all one diameter. Because the bullets were the same diameter as the copper cases, there was no step for a narrower chamber mouth.

 

[aaaaa]

Good to know if I buy any older model guns or conversions I can't necessarily just grab a box of modern ammo off the shelf.

 

[Jim Watson]

The internet is a great research tool, but it is hard to find out while you are trying to keep from drooling over that Gabbett Fairfax Mars in the store that 8.5mm cartridges are not readily available.

 

[Dave DeLaurant]

Just for grins, I'll mention a hybrid between outside and inside lubed bullets called the stop ring bullet. You see these used in some German cartridges like the 8.15x46R for single shot target rifles. The usual technique was to use the same case over and over during a competition, refilling powder between shots and either breech seating the bullet separately or just thumbing the bullet into the case without any crimp. Usually inside lubricated, but some designs had grooves on either side of the stop ring. I don't claim to fully understand the thinking behind these yet -- I've got a new book on the subject, but it's in German and slow going. One explanation I heard was that it helped address variances in non-standardized bore dimensions, but I'm not sure I buy into that.