Chamber cast VS COAL/ CBTO Gauge

[Wolfdog91]

So another question. What benefits is a person getting doing a chamber cast vs just using a CBTO/COAL gauge and slugging OTHER THAN getting some slugging out the way and having a 3D model ? Like unless you have some mystery gun and your trying to figure out the caliber I personally,don't really see much of an advantage. Now I may be 100% wrong idk hence why I'm asking. I've always just used a fire formed split case with the bullet I'm using .

https://i.postimg.cc/hzdbXmKw/IMG-20211102-225428875.jpg (https://postimg.cc/hzdbXmKw)

Pull it out some take a measurement, chamber it ,take another measurement, do that a half dozen or so times average it out and boom ,got my hard jam ( being where the ogive of my bullet is contacting my lands and is being pushed back into the case) and I just work back off of that going in five or ten thousands increments till I hit a node or what ever you wanna call it. And if I wanna see what my bore is I can just slug it with a round ball right ?
Now I understand another big thing is doing it to see how much free bore you have. And from my understanding,again I may be wrong here, free bore is just the space you have between your case mouth and your rifling ,right ? Or something along those lines. If that is the case you kinda doing that anyhow by using the gauge to find your hard jam so, idk I just don't see an advantage. Again may be wrong but hence why I'm asking. So, what's the advantage of there is one ?

[oley55]

If Marshall Stanton of Beartooth Bullets is to be believed, the throat dimensions/bullet fit do matter in regards to best accuracy. To quote,
"There is no substitute for proper bullet fit if precision and accuracy are your goal. Generic sizing will produce generic performance".
I have a copy of his book:
Beartooth Bullets
Technical Guide
A Comprehensive Guide for Unsurpassed Performance Using Cast Bullets
by J. Marshall Stanton

I am referring to it more and more often, but my original purchase years ago was in regards to fire lapping. I just did a pound cast of my Savage/Criterion chamber a couple weeks ago following his directions. A must have book written in a "hands on" easy to read and understand style. The Beartooth Bullets site is still up, but there is some question as to whether they are still in business or not. I would call them in advance of ordering the book if you are so inclined.

https://beartoothbullets.com/bulletselect/index.htm
https://beartoothbullets.com/contact/index.htm

[MostlyLeverGuns]

While a pound cast or cerrosafe cast may be helpful for odd and unusual rifles or rifles that are not caliber stamped, TO ME for normal factory rifles it is a waste of my time. For those who can only get to a range every couple of weeks or less it might be yet another way to play with your guns. Knowing chamber length can be helpful for trimming or NOT trimming brass. Using a neck diameter plug (NOE) in a case or a slit piece of case neck slid over a bullet seated in a shortened case can give chamber length. Throat diameter - I just start with a .310 for a new 30 cal - .308, .300 Savage, 30-06, 30-30 and SHOOT - of course I have my own range, but a test with a few different diameters at 100 yards gets there very quickly. The rifle action and magazine length limits COAL (cartridge overall length) and the ejection port can also limit COAL, you may have to eject a round WITHOUT firing. Jamming a bullet into the rifling can provide better accuracy, but can you eject the unfired cartridge without pulling the bullet and dumping powder into the action? Even if throat diameter is known, chamber neck diameter my limit usable bullet diameter. Knowing all the measurements is a nice exercise but the only real test is SHOOTING. There are established 'NORMAL' diameters that provide good starting points with or without knowing all the dimensions of that 30-30 or 308. It may be interesting but chamber casts are not needed to assemble accurate handloads.

[charlie b]

Unless you believe there is something wrong with the chamber of your firearm there is not really a reason to do a cast of the chamber. It is a means to obtain your throat/bore dimensions, which is what you need.

But, a 'pound cast' (not shoved all the way down the bore) will tell you what the throat and bore dimensions are, which are critical to good cast bullet shooting, ie, to decide on the dia of your cast bullets.

The CBTO gauge will allow you to get a repeatable bullet seating depth. For cast bullets I frequently just use COAL measurements. Jacketed I use the Hornady comparator.

[GregLaROCHE]

I’ve slugged a few bores, but I’ve never done a pound cast. Never thought I need to. I check for overall cartridge length, by taking the boolit I will be loading and pushing it in against the lands. Then I put a dowel or brass rod down the muzzle and mark it at the muzzle. Next remove the boolit, close the bolt and push the dowel down to the bolt face and mark it. Measure t distance between the two marks on the dowel and that will be your maximum overall length. Often people reduce the length by a couple of thousandths.

[Dusty Bannister]

As above, about as simple as it can get. No special tools, just a caliper and take notes for the reloading log. Works with cast, jacketed, powder coated, never tried paper patched though.

[Mr Peabody]

Marshall Stanton sold the site a few years back. I haven't been able to buy any of his products for quite awhile, a shame too.