Anyone have a dimensional drawing for this case? Does it have a rebated rim? Must have if it is based on the 404 Jeffery case(?).

Thanks for any info.

Will,
You can get the drawing from www.ammoguide.com
2.85 long
2.387 to shoulder
.548 at case web
.532 at rim...

the 404 isn't rebated, the RUM cases are... as well as the WSM...

the best thing about the 375 RUM case is that's what you make 416, 458, and 470 AR Rounds from

For Ballistic Comparison CLICK HERE

Mike

Mike,
Your ballistic comparison data is all screwed up.

The "average employed bullet weight" is quite innovative, but you don't say what weight bullet was used, and seated to what depth to get the "water capacity" of the cases.

Your case capacities are absolutely wrong for water fill to case mouth.

You are using different bullet weights for the velocity and energy comparisons.

You don't specify barrel lengths used, not even an "average employed barrel length."

Ron,
Hornady heavy mags load the 375HH to 2700+

jeffe

Jeffe,
Weatherby loads the .375 Wby to 2800 fps with the 300 grain Nosler Partition (26" barrel) and there is still "powder shake room in the case."

Incorporating a proprietary compressed load method in with standard load data also is a screwed up method. Even if the Heavy Magnums did achieve what is claimed.

Also Jeffe, the energy quoted for the .375 H&H load does not compute for a 300 grainer at 2713 fps. Obviously a lesser weight bullet (270 grainer or 266 grainer average employed?) in the H&H while the .375 Wby is claimed to get 2701 fps with what must be a 300 grain bullet, or was it a 290 grain "average employed weight bullet?" Not appropriate for bar graphing with no explanation of load differences. I don't feel like back tracking the numbers to check the actual accuracy of the computations, but it must be done to understand the spin here.

Just a lot of methodological obscurity and inconsistency that make the comparisons pretty useless.

Selective data, old data, new data, fanciful data, pie in the sky data, all mixed up.

Needs sortin' out in a big way! Besides barrel lengths, a need exists to mention pressures and throats and COL's, etc.

Let me add a positive anyway: The pictures are pretty.

I agree with your points about the ballistic data, RIP. Too many variables missing and averaging across bullet weights gives meaningless data. It would be more useful (although not more accurate) to have averages by bullet weight instead of across the range.

That said, I quite enjoy the rest of the features of the site. particularly the dimension comparisons. Wish I had found the site before this morning (while searching for 416T cartridge drawings). Actually, it could have been quite handy for Saeed's cartridge guessing contest!

Cheers,
Canuck

quote:

Originally posted by Canuck:
Actually, it could have been quite handy for Saeed's cartridge guessing contest!

Cheers,
Canuck

Yes, you won the contest. How many years are we going to hear about it??

quote:

Originally posted by RIP:
Mike,
Your ballistic comparison data is all screwed up.

The "average employed bullet weight" is quite innovative, but you don't say what weight bullet was used, and seated to what depth to get the "water capacity" of the cases.

Your case capacities are absolutely wrong for water fill to case mouth.

You are using different bullet weights for the velocity and energy comparisons.

You don't specify barrel lengths used, not even an "average employed barrel length."

It helps if you read the accompanying descriptive text and understand the program. There isn't anything like the Ballsitic Comparison Tool anywhere else, so it pays to familiarize oneself before critisizing.

The values displayed are calculated from ALL LOAD DATA PRESENT. It combines all performance data using a complex averaging algorithm to create a single representative value for velocity, muzzle energy and bullet weight for each specified round. Otherwise, one cannot normally effectively compare cartridges they are not familiar with because one may be comparing a light load in one cartridge with a heavy load in another, or a heavy bullet in one case and a light bullet in another round. The Ballistic Comparison Tool "evens the field" as much as possible with a single "average" value for each parameter calculated from real-world values. It even adjusts for the situation where the listed load data for a round heavily favors lighter or heavier bullets.

A given cartridge should be able to propel the average listed bullet weight to the average velocity listed, and produce the average muzzle energy listed. that is the relationship of the values in the graphs. Note that the Ballistic Comnparison Tool also allows one to display the performance values of individual loads too (for example, to visually compare the "hottest" loads of 2 rounds), but the graphs then no longer represents an "average" performance for the cartridge, but the perforncae of an individual load.

Unfortunately, many loads do not include barrel length, otherwise I could calculate the average for that and include it also. But since barrel length has a relatively small effect on velocity (50fps or less/inch - which is why bullets from 2" snubbies are still QUITE effective), this parameter is less useful for comparison purposes. Gun-to-gun variations can cause a 20" barrel to produce the same ballistics as another 22" barrel, an effect that only complicates comparison.

As far as case capacity, the values listed are calculated from the case dimensions. Case capacity is another variable parameter that is not useful to attempt exact measurement - it is a "rough" value. The reason is that the amount of water that fills a case can vary considerably if the case is fired or not, how many times it has been fired (brass creep causes thinning of case walls) and which brand of case. Not all cases have the same wall thickness. Case capacity is a "rule of thumb" value, useful for comparison but little else. And the larger the case, the variation in measured case capacity increases. The advantage of the BCT's case capacity chart is that it displays a value for all rounds that is calculated with the same method. As such, it is extremely useful from a comparion point-of-view, which is the purpose of the tool.

Thanks for the chance to explain a bit about the Ballistic Comparison Tool.

Mike

quote:

Yes, you won the contest. How many years are we going to hear about it??

Did I ever mention that I used the gift cert at Mim's store to get a pair of Swaro 8x30 SLCs. I'll be eyein' up duggaboy's in style, in 34 days!

Cheers,
Canuck

Here's another, probably better example to illustrate the use of the BCT.

I suspect everyone here is familiar with the .308 and .30-06. perhaps less so the .30-06 Improved, but all cvan agree it is a .30-06 with improved ballistics. Here's the visuals...


The ballistic Comparison is HERE

Note that the program has "complex averaged" over 400 .308 loads to arrive at it's values. The .30-06, over 300 and the Improved only 2.

Yet, the charts (accurately) show the .30-06 having only a slight edge over the .308 and the Improved is considerably hotter. (Improved rounds are frequently pushed harder than conventional rounds due to their "top of the curve" nature.)

It also suggests the .308 and .30-06 are normally loaded with around 150 gr. bullets but the .30-06 Improved is comfortable and efficient with heavier bullets. The BCT also shows the relative case capacity differences between the rounds. Some may be interested that the case mods done to the Improved increase capacity by about 2 grains.

These differences present themselves even though the Improved has a lot less data to calculate with.

Now if you weren't familiar with these rounds, I suggest this display will give you a valid and fast sense of what those cartridges will do - a useful snapshot of relative performance. That's all the tool is designed to do and again, there's nothing like it anywhere.

Mike

quote:

Yet, the charts (accurately) show the .30-06 having only a slight edge over the .308 and the Improved is considerably hotter.

I suggest this display will give you a valid and fast sense of what those cartridges will do - a useful snapshot of relative performance.

I'm kind yes/no on this BCT. Maybe its good for novices? I dunno. I find it fairly meaningless, but maybe its because I understand how complex ballistics really are and am not comfortable with averaging apples and oranges (which different bullet weights are to me).

For instance, the comparison between the 308 and '06 is misleading IMHO. The 308 is very close to the '06 in lighter bullet weights, but the spread in performance widens considerably as you move up in bullet weight.

Averaging all the data loses all the utility, TO ME. Maybe others find it useful.

Anyway, I am not trying to be harsh about your site. I love it (I REALLY love the catridge dimension comparison). I just personally don't find the BCT meaningful or useful.

Cheers,
Canuck

and then when you take peak pressure into account, you get another story.

the 308 is loaded hotter than then 30-06, but that alone is not enough to make up for the cubic inches difference...

the improved version has t be loaded pushing max, as the users of those rounds typically are looking for max performance, and are loaded VERY hotter than saami 30-06...

This shows 55gr for the 308, 67 for the 30-06 and 69 )aint it 64?) for the improved... loaded at the same pressure, the 30-06 will always out run the 308, and for 2gr more case, as listed, i wouldn't bother with an improved.

jeffe

quote:

...Maybe its good for novices? I dunno. I find it fairly meaningless...

That's your right as an American!

Good for novices, yes. But it apparently also shows a few things to some experienced shooters too. On another busy forum, one poster was getting almost angry because of the comparison of his favorite .500 S&W Magnum with the (then brand new) .460 S&W Magnum. The .460 was already taking the spotlight from his baby, but then the BCT shows the .460 not only edges out the .500 in ME, it is developing as much at the muzzle of a pistol as a .308 Winchester in rifles...
CHECK IT OUT

And of course, the reason why is the .460's working pressure is 65,000 psi, in the realm of hi-performnce magnums. It's the Ferrari vs. the Buick syndrome. yeah, the Buick is big, but...

Should the BCT display pressure and barrel length too? Maybe. BCT is actually intended to be a good EXTERNAL Ballistics Comparison Tool (as are trajectory calculators). Pressure and barrel length relate to INTERNAL ballistics. That is a useful distinction to maintain sometimes, I think. The BCT is valuable for anyone interested in what can throw what downrange. Not so much how (although as noted, it does allow comparison of individual loads, too).

Problem is, many loads do not provide that info (barrel length and pressure) - how many of you know the pressure your loads are producing? But understand, the value of the BCT is that it derives it's answers from a real database of load data and it's got 9400+ loads in it right now (and growing). Do you know another tool that analyzes ALL AVAILABLE empirically-derived loads for a round, then calculates and displays these averages? (and it's not apples and oranges, it's physics that applies to all rounds. That comment is unjustified.)

If one has a selection of cartridges to purchase (settle on), chances are he/she will go through some kind of process like that at some point. It will be looking casually at the ballistics for the rounds in question and asking people for their opinions. This is a thorough and useful tool for such a process, especially whan hundreds of loads are available to analyze for performance.

It's calculates values represent ALL of the combined data of companies and individuals and includes the gun-to-gun variations of all the firearms used in the development of those loads. In terms of external ballistics, barrel length and pressure are meaningless. AmmoGuide's values are accurate because so many loads are available for calculation.

If you add your personal load data into AmmoGuide (paid subscribers only), it will be figured into the graphs too. The last 100 or so loads for the .308 have definitely nudged it up a little, but only a little. The more the better, as usual.

The BCT will eventually provide even more info, like highest and/or lowest peak value comparisons. But I don't like to sell vaporware.

I just wanted everyone to understand what it does after being critisized. Some of what has been suggested is not what the BCT was designed for. (And if I create a tool to also compare internal ballistics, it probably won't be FREE.)

Anyway, it is what it is.

Mike

quote:

Do you know another tool that analyzes ALL AVAILABLE empirically-derived loads for a round, then calculates and displays these averages? (and it's not apples and oranges, it's physics that applies to all rounds. That comment is unjustified.)

Actually I am Canadian, but despite that you are right, I do still have a right to my opinion.

Don't get me wrong...I am not trying to be overly critical or argumentative. I am just stating my opine, and to me comparing averages across bullet weights for each cartridge is comparing apples and oranges. A 30/06 with 150gr bullets is a much different beast than a 30/06 with 200gr bullets. I don't see much utility in an average employed bullet weight, and average velocity, energy etc flowing from that. First, it doesn't represent what the cartridge is capable of with different bullet weights, and it only shows which bullet weights the contributors of your database tend to prefer, which is completely subjective.

If you didn't average the bullet weights and instead sorted the data by cartridge and bullet weight, I'd find the data much more useful. I can appreciate the difficulty in that, however.

Again, please don't take offense. JMHO for your consideration. I am a fan of your website.

Cheers,
Canuck

The ultramag brass I've come across is 0.550" at the case head, and .532" at the rim, ie rebated to fit a belted mag bolt. The 404 Jeffrey is listed as 0.540" at the rim and case head.

Ultramag brass can sometimes function through a 404, depeding on how tightly the chamber was cut.

I've heard various reports of the ultramags, and later Winchesters short mags being based off of the 404 Jeffrey, and other reports stating that they were based off of a rimless rebated 348 Winchester.

Well said Canuck. The BCT is sillier than the "Bwana Saeed Index." Both are for the ballistically wet behind the ears. Fun parlor games. Of course, the BS Index, being less silly is more useful.

The pictures accompanying this BCT mumbo jumbo are pretty, however.

The dimensional data is limited, but a fun reference if I can't get to my books and brass.

Agree with Paul's points.

Manufacturing tolerances of brass and rifle chambers make for both tight and sloppy situations.

But, the RUM case is just a little too great in head diameter to be a true .404 Jeffery.

My .404 Jeffery brass is more like .542" to .543" in rim and head diameter.

Dakota claims .545" for their .404 Jeffery based offerings and it seemed to be about .544" to .545". Close enough to call it a Jeffery head and rim.