Oh for Pete's Sake 

What a revelation to hear I ain't the only one.  I absolutely hate it when I lose an argument wid myself.  So dam'd demeaning.  And:

YES!!  I do shoot Pietta's.  When I had my Shingle out, I just plain began to really dislike Uberti Cap Guns.  I wasn't much happier with Uberti Open Tops but "that" is another thread entirely.  Anyway, I found Uberti to be a complete PITA to set up to run well for CAS.  Don't get me wrong, Pietta were/are not dead simple, but I like 'em better.

Everything I did was for maximum reliability.  As a self proclaimed, dedicated, determined and card carrying GAMER, my guns just had to be reliable.  There is a laundry list of changes I made/make, which include the switch to Slix nipples and lighter springs (speed dontcha know).  In the long run, matters not whatcha do, there is going to be the occasional train wreck with Cap Guns.  Nature of the beaste.  After all, nothing is perfect and MURPHY is always lurking just around the corner.

If not including a mechanical method to prevent caps/frags in the hammer channel, welding cup the face of the hammer is a necessity, then polish it like a mirror.  Not perfect, but better than nothing at all.

I would like to include, what we forget in today's world, when Cap Guns were KING, the caps in use were quite different.  More robust.  REQUIRING heavy Main Springs just for ignition.  Many folks seek to be able to run an entire match without a bit of attention to their horse pistols.  We must remember, a RELOAD in the age of Percussion was sure death.  The accepted percussion "reload" was to grab another fully charged gun.  Ergo, shooting with an "off the gun" reloading stand is perfectly acceptable.  Wiping the Cylinder Face, Barrel Breach and Arbor between stages insures a gun running just a smooth at the 10th stage as at the first.  Along with that I have also become a proponent of tight Barrel to Cylinder gaps (nother thread??)

NO NO NO NO 

NONE OF THE ABOVE.  I have no capability to load plastic or paper hulls.  So I load/run/shoot ALL BRASS MAGTECH.

Is that a vote of ONE??

I added your "category", sheeeeesh...

Now go vote.

Jim,
You'll find that when the next cartridge to feed to the lifter is stopped by the link, that it sits very straight in the magazine tube.  The magazine spring pushes on that bullet nose and it normally straightens up relative to the magazine axis after "bottoming out".  Most won't know this unless they have worked on the '92s and '94s and/or had to write up a Design and Function explanation as part of their training.  That cartridge could easily be nose to center of the tail on the cartridge in front of it.  The rest do sit helter skelter especially with bottle neck cases.  There are cutaway rifles with a slotted magazine tube used for training and understanding the workings and you can see that jumble of noses up and down or left and right beyond the first shell against the link.

I've read the discussions about the older cases having "rifle depth" pockets, the truth of the matter is that there was NOT a standardized primer to begin with, Everyone made or had their design made.  I knew someone who dissected a lot of shells and the primer thicknesses were all over the place.  They were being used in low pressure Black Powder shells and you could get away with almost any thickness.  Plus a lot of them were copper instead of the brass alloys used later.  Balloon head cases, primers all over the map, it wasn't until the 20th century it really stabilized.

~Mako

I'll admit my ignorance, I never knew 30-30 used large primers.  Obviously I never owned one nor reloaded it.  I had heard that they didn't have a problem with pointy bullets because the taper of the cartridges kept the bullet point from lining up with the primer in front of it.  I don't know if that part is true at all or not.  But thanks for edumacating me, Mako!

When I lay .30-30 cartridges out flat in a line (and I'm using factory cartridges for this test), the points don't line up with the center of the next primer (see picture below).  They kind of straddle the edge of the primer pocket.  I assume they'd be similar in a magazine tube, although it would be dangerous to take that assumption too far.  For instance, spitzer points could still find their way into the outer part of the primer and set it off.

These also don't really have "flat points" although they are recent (a few years ago) Remington factory Core-Lokt loads.  The box doesn't even say flat point (just "soft point").  About half of them seem to have a small flat meplat little more than half the diameter of a large rifle primer.  The other half are really more of a round nose.  Not a lot of consistency even in the same box of ammo.  Obviously Remington doesn't consider this a long-range or target cartridge!

So a flat point doesn't seem strictly necessary for the .30-30, but that doesn't mean it isn't necessary for other cartridges.

And every .30-30 case I've seen (or noticed, anyway) used large rifle primers.  But that doesn't mean that it always has, all the time.  For example, we usually think of .38-40 as using large pistol primers, but I have some old  Peters cases that are sized for small primers.  But I also have a box of Peters .38-40 with large primers.  I've also heard that .44-40 cases can sometimes be found with large rifle primer pockets, not large pistol.  (After all, it started out as a rifle cartridge.)  I've never seen or heard of that with .38-40 but it's probably possible.

But I digress.  However, I would be pretty surprised to find a .30-30 with a small primer pocket, and that may be part of the reason they're safe with some round-nose bullets (provided they're not too pointy).

Lonesome,
I can give you two sets of dimensions for S&W .45 ACP revolvers.

• I have had only one newer Model 25s with tight Ø.453 throat openings at the front of the cylinder, but most were Ø.454 
• I had fixed sight 1950 Model 22s with Ø.454 throat openings at the front of the cylinder.
• I have had Model 1955 S&Ws (later called Mod 25) with Ø.453 throats   (corrected per mister QUALITY CONTROL...AAAARGGGH)
• I currently have two unmounted spare cylinders for M1950, M1955 or Mod 25s (basically Model 22s or 25s) with Ø.454 openings   (corrected per mister QUALITY CONTROL...AAAARGGGH).  I have those spares because I used to fit an extra cylinder in .45 Colt to Model 25s, 1950s or 1955s, I have those two left, I may have cranes for them as well.  I would have to look.
• Most if not all of the .45ACP cylinders started out with a Ø.482 chamber opening at the rear
• The .45 Colt chamber is Ø.487 to Ø.489 at the rear depending upon the reamer and the Ø.454 throat is perfect for them.

In the S&W the .45 ACP chamber has the headspace step the case mouth butts up against, the .45 Colt chamber has the typical revolver leade and throat which is a gradual transition.

So there is no short answer for a S&W.  But all actually shot very well, I really couldn't tell much difference between the Ø454 and Ø.452 throats, especially with lead bullets.  Out of a Ransom Rest with match 185gr or 230gr jacketed bullets the accuracy might have been 1/2" better at 25 yards and at 50 it was a wash again.

As I said 30 or 40 years ago adding a .45 Colt cylinder was a common "conversion" or cylinder addition.  Finally S&W started making the 25 in .45 Colt, I don't know if you could get one with two cylinders except from the Performance Center and those were special order.

I don't know if you personally could tell the difference between the larger and smaller throats especially with Lead Cowboy loads, either way, enjoy them.

I can send pictures with gauge pins if you wish, but I'm not home for a few more days now.  I just have files on my drive I carry with me.

~Mako