Straight wall principles with bottlenecks

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dfish1247

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Oct 29, 2022
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This seems the most appropriate place to ask this, if not, my apologies.

I asked in another thread using 223 as an example, but has anyone tried just going longer in case length while keeping the .378” rim diameter vs going the fatter .473” rim diameter trend we have now? It was a thought towards having higher velocity without the accelerated throat erosion.

Long story short, doing what straightwall cartridges done decades ago, 44 Russian, 44 special, 44 magnum, 445 supermag. Or 45/70, 90,110. They couldn’t go fatter in chamber, they drilled the chamber deeper.

Couple examples I could think of that certainly points toward the concept is 308 vs 30-06, 221 fireball vs 223 Remington. I asked about a 30-06 length but 223 case diameter cartridge, but maybe the 308 case length would be a better start.

What do you all think?
 
True, but that was not the question. How will a long skinny case cause less erosion than a short fat case loaded to give the same velocity?

I don't know an easy way to test it in the smaller calibers, the longest case I know of on the .223 head diameter is the .204 Ruger or maybe the 5.6x50 RWS. Would a .22x204 on the Gibbs pattern with straight body, short neck do to compare with a .22 BR, fudged to the same volume?
 
Every case of accelerated throat erosion and a barrel being “shot out” I’ve ever heard of or read involved a fat case with a small mouth. 220 swift, 22-250, 22 middlestead, 6x284, any of the short or super short mags.

What I don’t hear or read about as often are calibers where the shoulder to case mouth distance isn’t as large. 222,223,308, 8x57, 357, 44 mag. 30-06 won’t keep a throat as long as 308 will, I do believe more powder and pressure equals more sand paper effect.

My thought was to land closer to have your cake and eat it too(higher velocity plus better barrel life), instead of getting fatter with the case, get longer. Give the flame a straighter more unobstructed path out. Except the projectile for the would be comedian.

Stick with me here, you have 1000 cars on a six lane interstate doing 75mph, if you shrink to four lanes or shrink to two lanes, in the same amount of distance, which causes a bigger snarl? The six to two lane transition. Imagine the cars are burning powder and the case body is six lanes, the shoulder width is the transition, the mouth is the smaller amount of lanes.

I have a feeling this would follow the velocity difference between 308 and 30-06, which mentioned above, wouldn’t be worth the effort. Then again, a hot rod 350 legend type thing that wouldn’t beat you up,hmm.
 
Due to the primer being at the very back of the cartridge, long skinny powder charges do not ignite and burn as consistently as short fat charges. Small arms cartridges are too small to use priming systems that reach into the powder charge as seen with some much larger guns to facilitate uniform ignition and combustion.

Barrel damage is primarily due to pressure/temperature and velocity. The shape of the shoulder and throat have minimal impact on this
 
mcb said:
Due to the primer being at the very back of the cartridge, long skinny powder charges do not ignite and burn as consistently as short fat charges. Small arms cartridges are too small to use priming systems that reach into the powder charge as seen with some much larger guns to facilitate uniform ignition and combustion.

Barrel damage is primarily due to pressure/temperature and velocity. The shape of the shoulder and throat have minimal impact on this
Click to expand...
But, long fat charges(30-06, 300 win mag, 378 weatherby) do? Lrp vs srp obviously, but still. Priming system, I’m guessing you are hinting at the emulsion tube looking thing that goes up through the case.

The long skinny cartridges went under decades ago, but why? Other cartridges that performed better with what was available to work with at the time showed up. Steel technology is way better now vs the time of Carnegie.

As far as trying anything, that’s best left to a lab.
 
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Jim Watson said:
Hey, I know. Try it out and you tell us. Like the 7mm family? OK, here is the .28-30 Stevens, load it with smokeless and see how much longer the barrel lasts.

View attachment 1181466
Click to expand...

The Drilling/ Bochbusche (combo gun ) cartridges of old 9.2x72R, 9.2x74R, etc. did this specifically, and like the .28-30, for the purpose of putting more powder behind a bullet for the caliber without increasing case diameter. Even the Holland & Holland mags did so by using a very shallow angle shoulder compared to the Win. and Why. Mags of the '50s and WSM mags of the 'aughts'. I haven't noticed really bad throat erosion in the 9.2 rifle barrels in the drillings I've looked down the barrels of.
 
Drillings don’t get shot as much as a bolt action owned by a recreational shooter.

Although Elmer Keith had a .500 NE that showed visible erosion in the right barrel but not in the left. Lots of safaris, but not many follow-up shots required.
 
mcb said:
Due to the primer being at the very back of the cartridge, long skinny powder charges do not ignite and burn as consistently as short fat charges.
Click to expand...
Bingo. The issue of long, skinny cartridges was resolved in the 19th century in favor of shorter, fatter bottlenecked cases that held the powder closer to the primer.

The primary factor in barrel wear is the expansion ratio, which is based on case volume and bore volume. Large cases with small bores are hard on barrels.
 
Fun consider if nothing else.....in concept you could kinda compare any of the straight (ish) walls to a bottle neck round with similar powder capacity and bore diameter, and make an edjucated guess.

The 9.3x74 and the 9.3x62 would probably be good ones to compare, the 74 has a capacity advantage.
Youd need guns that could take equal load pressure, and alot of time energy and money....
 
dfish1247 said:
Every case of accelerated throat erosion and a barrel being “shot out” I’ve ever heard of or read involved a fat case with a small mouth. 220 swift, 22-250, 22 middlestead, 6x284, any of the short or super short mags.
Click to expand...
Overbore cartridges are those with a relatively large case volume or case capacity, coupled with a relatively small diameter bullet
Click to expand...

https://en.m.wikipedia.org/wiki/Ove...s are those with,in metric or imperial units.. The case volume or case capacity and barrel bore area can be mathematically related to obtain a case volume to bore area ratio in metric or imperial units.
Click to expand...
 
I’ve dug around some to no avail, but long skinny’s won’t light all the powder well supposedly. How does 30-06, 300 weatherby light theirs? Does a large rifle primer have that dramatic a difference in power vs a small rifle primer?

Anywho, how about wear on a 445 super mag vs a 44 mag? Any firsthand accounts? That, and the 44 vs a 444.

This is just a discussion on the idea, would the juice be worth the sqeeze?
 
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.308 Norma said:
I'm guessing you meant 45/70, 45/110, right? I'm not sure I've ever heard of a 90/110, but it sure enough would be bigger around than a 45/70. ;)
Click to expand...
The commas are for the part after the slash, though leaning on the space bar one time after the comma after the 90 would have made it clearer, an "and" or an "or" would have helped, and typing them out in full would be best.
 
dfish1247 said:
I asked in another thread using 223 as an example, but has anyone tried just going longer in case length while keeping the .378” rim diameter vs going the fatter .473” rim diameter trend we have now? It was a thought towards having higher velocity without the accelerated throat erosion.
Click to expand...
.222 Magnum.
L to R .222, .223, .222 Magnum. The neck length for the .223 is shorter than the .222s but otherwise they just are steps. The .223 is the youngest.
222_family.jpg
 
I don’t think you are thinking this through all the way. The reason 22-250, 6.5-284 and 220 Swift are barrel burners is because they are magnum overbore cartridges. They burn a lot of powder and create a lot of heat to move those projectiles very fast. Making them straight wall with the same capacity would not change the effect.

Take 44Mag vs 444 Marlin. A 44Mag throat will last a lot longer because it operates with less powder, less pressure and less heat. With the same amount of rounds fired a 444 will show more throat erosion than a 44 mag.

I think the biggest reason the longer straight walls weren’t seen as “barrel burners” is because back in the black powder era those are from, the only way to get more speed was to increase the capacity thus lengthen the case. So that’s what they did. But even so those early elongated cartridges never created enough high pressure and high heat.(At least compared to modern smokeless cartridges) to cause those throat issues.

The reason short and fat is all the rage now is because a short powder column burns significantly more consistently compared to longer cartridges, thus more accurate(There are other factors such as shorter actions are stiffer.) Check out what the benchrest shooters are using. I guarantee not one of them is using a long action cartridge. Yeah a 300 win mag or the Weatherby Mags are fine cartridges, but now days Short Mags, PRC’s or most Short action cartridges get the same job done more efficiently and generally more accurately.
 
Given the recent post about shooting range floors catching fire makes me wonder if anyone has researched where the tipping point is concerning barrel length vs powder charge. There has to be a lot of un-burned powder leaving the barrel even with normal loads. At some point the law of diminishing returns will kick in.
 
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