Home Forums Hunting & Shooting Ask The Gunwriters Mr. Howell, A question on the efficiency of short cases

Am I correct in assuming two different case designs, and everthing else being equal, that it is the amount of powder and load density that determines the bullet velocity?

If that is so, and the load density is the same between the 300 Win. Mag. and one of the short short mags. now in vogue, if all else about the rifles and bullets are identical, won't the velocity difference between the two rifles be theoretically only due to the amount of powder being burned in the case ?

How can the hype about the short cases claiming better velocities than the old magnum cases be correct?

I am not a fan of efficiency � maximum velocity per grain of powder � since it requires the highest of peak pressures, which erode throats faster than less-efficient loads erode them.

I prefer (and design) cartridges that produce high velocities at lower peak pressures � which means burning slightly more powder (higher velocities) in significantly larger cases (lower pressures).

For example, compare the loads for the .300 Savage and the .30-06 in any loading manual, and you'll see that in a .30-06 case, you can load submaximum loads that (a) use more powder than the .300 Savage (but less than maximum for the .30-06) and (b) produce higher velocities than top (high-pressure) loads in the .300 Savage. Starter-level loads in the .30-06 are low-pressure loads that often produce higher velocities than top loads in the .300 Savage.

Likewise the .30-06 and any .300 magnum. Charges slightly heavier than top .30-06 loads can exceed .30-06 velocities from .300 magnum cases, at lower pressures.

Efficient? No.

Barrel-friendly? Yes!

The short, fat cases require top pressures � exactly the opposite of what I prefer and recommend.

Look at this another way:
For higher velocities, you have to burn more powder or burn a given amount at a higher peak pressure.
The smaller cases have to increase pressures to get comparable velocities. Larger cases can use a little more powder � but not enough more to make pressures high � to produce higher velocities at lower pressures.

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AMEN Sir, AMEN. You have my vote! Why put alot of time and money in a good barrel to see it gone in less than a 1000rds. This has ben going on for ever it seems. The 22/250's sweet spot is gone in less than 600rds. The list goes on it would seem for ever with grossly overbore cap ctgs. Why is this need for speed? I believe it is bought at a price much to high to pay. Does it start with the idea of the mystical all around rifle? I guess the only people who believe in that is the guy getting ready to make his next purchase. Look at all the popular ctgs out in the world that ignore the rules of good ctg. design and have stayed popular. The 243 WIN, 6mmREM are fine examples of the shooting publics understanding of what is good and bad in ctg. design. It seems when a shooter starts to worry about vaporizing bullets, stickey bolt lift, push seating primers with his fingers and eatting up his bolt face, he is most happy?

I think there is the "wow" factor. We all like to buy the "latest, greatest". In the world of firearms, it's all been kinda done before, so the manufacturers have to walk close to the edge to even claim something is truly "better".

The second factor is that, sadly, very few people, outside of a very few core competitors and dedicated varmint hunters, shoot enough to even wear out a 22/250. If you are only going to fire 100 or maybe 200 shots from your 30 cal in this life time, does it really matter that the bore will be gone at 700 shots? If a person shot an elk and a deer per year, plus five sighters, that's 100 years in the field before the accuracy starts "going". Even then, it is probably plenty accurate for another 100 years on big game.... JMO, Dutch.

Ken's comparison brings to mind tow 416s, one a remington and one a rigby. the rigby has the big, fat case with lower preessure. I asked the question one day, if velocity and bullet weight are the same, would recoil be higher in a high pressure round like the 416 rem compared to the 416 rigby. the answer I was told was that pressure did not make much of a difference in recoil.

Well, after reading Mr. Howell's remarks, I went to the Hodgdon site to look at pressure for various cartridges. I thought I was on to something until I noticed that the new cartridge pressures are listed in PSI and the older cartridges are CUP. Mr. Howell, how can we convert CUP to PSI for comparisons?

Ken,
While I savvy your stance, it seems like stepping over a dime to pick up a nickel.

Since you used the example of the 300 savage and the 30-06, I'll use that for my example.

How many rounds before either round burns out a barrel? 15,000 20,000 ? Let's just assume 15,000 rounds for the sake of argument.

The difference in a load of H4895 pushing a 150gr bullet in the two cases is about 7 grains. The 30-06 gets slightly more velocity, but I can re-do this using a reduced load to more closely match if you wish. Of course I can also do the same comparison with larger cased rounds, and the differences are more stark.

Now, take that 7 grains of powder, over 15,000 rounds, and you get roughly 15 pounds of additional powder burned over the life of the barrel. That 15 pounds cost roughly $270.00 retail, or about what it would cost to have a new Douglas barrel installed, or several factory take-offs.

In my view, your argument that it makes more sense to burn more powder in a larger case in order to save the barrel (and I can only assume that this is an economic decision) makes little sense given the facts.

Even if the 30-06 barrel lasts longer than the 300 Savage, it would have to last SIGNIFICANTLY longer before it becomes economically feasible to apply your logic. That is not an assumption I can make given that the 30-06 would burn an additional 105,000 grains of powder through the barrel over the same number of shots.

I would contend that the overwhelming majority of casual and sporting shooters would never approach burning out a barrel in either chambering mentioned.

For competitive shooters, who would likely shoot enough to wear out a barrel, recoil is an issue. This is exactly why they use small cases at high pressures. Physics dictate that the less mass moving out the barrel the less recoil. Adding more powder to get the same velocity makes no sense for them either.

For varmint hunters (myself included) there is even another consideration. When I go out, I tend to haul several hundred rounds with me. I can haul roughly 50% more 223 rounds in the same volume and weight as I can 22-250 rounds, regardless of whether the 22-250 would produce lower pressures. Add that to the economic advantage of saving several grains of powder per shot, for the same performance, and it is a no brainer for me. I'll pick the 223 every day of the week and twice on Sunday.

Now I'm not arguing the fact that larger cases at lower pressure make for safer, more amiable rounds to shot and reload, I just don't buy the economic argument.

Replacing a barrel is a right-now, full-price outlay. And the new barrel requires a new process of getting acquainted � more time, more money, often at an inopportune time. It's easier by far to buy powder a jug at a time over the years.

Compare, for example � How much will your "$100,000" house actually cost you in thirty years of monthly mortgage payments? How much would you save by paying cash up-front? How much easier and more practical is it to make many smaller incremental payments over a much longer time?

Besides, the dollar thing is only a part of the matter. Lower pressures make better sense in other considerations as well.

Buy or don't buy my criteria, as you prefer. I've just told you how I think. I don't sleep any better or any worse on the basis of whether you agree.

And I don't recommend dining close behind male cattle, in any guise, in any pasture � even if the patties look like chocolate and smell of mint.

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Ken,
A little pissy today, aren't you?

Even your money over time analogy doesn't work. $270 several years from now is worth a whole lot less than $270 now. If we want to figure in the time value of money, my argument makes even more sense.

If I took the purchase price of 15lbs of powder, purchased over two or three years, and put each of those expenditures in a bank account bearing interest, the resulting balance at the end of the time frame would be more than $270, even though I only put $270 in from my pocket. That interest alone could account for any additional cost of "a new process of getting acquainted ".

Do you also feel like the IRS is doing you a favor by collecting your taxes throughout the year, rather than collecting them all on Aprill 15th?

So, if we are arguing economics, and that was your only argument in the original post, then the only logical recommendation would be to buy the smaller cased chambering. Put the money saved in powder consumption into a bank account, and buy yourself a heck of a nice new barrel when you wear yours out.

Interesting points CAS.

No. Just not interested in arguing.

About anything.

If that's your dance, find another partner.

I was asked a direct question. I gave a direct answer. The End

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CAS are you shooting a stelite lined barrel? If you are thinking about machinegun barrels then 15 to 20,000 rds is on the low side. Even on most moderate pressure ctg. the throat is usually gone by 2000rds on the barrels all the rest of us shoot. Yea I've keep them alive longer because the accuracy was still there (on a few). It just takes forever to get them clean again.

3sixbits,
The only way to shoot out a 300 Savage, 308 Win, or 30-06 barrel in 2000 rounds would be to shoot as fast as you could load and pull the trigger.

I have it on good authority that the military has some of their 7.63 Nato barrels going strong WELL in excess of 20,000 rounds. Some of these barrels are Remington, some are Schneider, and some are Rocks.

Hell, I've got a 22-250 (supposedly a wicked barrel burner) with more than 3 times your magical 2000 rounds that will still punch groups WAY under 1 MOA.

Dogzapper has said that his 223 AI has a boatload of rounds thorugh it (I can't recall exactly how many) and it still shoots more than acceptably.

Well, it seems Ken's done on this one, but I'll add some thoughts. First, I haven't seen anything about the WSM beating the WinMags. Seems the concensus is that they can match their 2.5" counterparts in light-med weight bullets, and come close in the heavier bullets.
As for the question of efficiency, well, you can see there's an number of things at which to be efficient. There's certainly powder grain per fps, there's trips to stores looking for rounds, rounds per barrel accuracy, etc. I have to agree with CAS (or whoever it was) that most of us don't shoot out barrels, not in the calibers the WSM's are chambered in. And if you're a serious competitor, then, yeah, you have a different set of cost/benefit data to sort through. For the average hunter/shooter, any round can be made easy on the barrel, or hard on the barrel. A case that will shoot a bullet the same speed as a larger case (alebit at a higher pressure) will have a little less recoil, so there's that efficiency level as well.
One thing is for sure: TINSTAAFL!!
You gotta figure what you're willing to give to get what you want. The rest is just doing the math.

I put some 400 rounds thru my 300 SAUM just working up a load!

[quote]3sixbits,

I have it on good authority that the military has some of their 7.63 Nato barrels going strong WELL in excess of 20,000 rounds. Some of these barrels are Remington, some are Schneider, and some are Rocks.


I did'nt know the military shot a smoothbore event? <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

If you're talking 7.62 NATO barrels being sniper rifles that's one thing. If you're talking machine gun barrels, that's a whole new deal. I've shot M240G and M249 SAWs and we changed barrels after so many rounds. I don't know the ins and outs of them, but they can(and have) take alot of abuse.

Macrabbit, sure you did. But you aren't trying to tell us you are "normal" are you?

Heck, I shot out a 7mag barrel entirely working up loads. People tell me I'm "special", too.... LOL! Dutch.

That's my take on the matter as well. Heck, if a couple of bucks one way or the other made a difference, I'd have a room full of .22 rimfires and be happy.

To me, barrels are like tires on a car. They will eventually wear out. The only way NOT to wear them out is to leave them in the garage. And like tires on a car, I can abuse them by taking off like a drag racer and stomping the brakes all the time, or I can ease out and then come to a gentle stop. I'm gonna get where I'm going either way.

And even though I try to be easy on the barrel, that's not my major concern. Every time you let loose 65,000 psi you're pounding the bolt lugs just a leetle harder. A throat burning out is a few bucks. A bolt in my face would really hurt.

If you're working at the edge of the safety zone, every time you change powder lots, or primer lots, or ANY component in your 65,000 psi load, then unless you religiously go down 10% and work back up, your 65,000 psi load just might become a 75,000 psi load. A lot of RL-22 surprised the hell out of me in this exact manner.

Without pressure testing equipment, are you SURE you're 65,000 psi load isn't really 69,000 to start with?

I've always liked the idea of getting a bit more than you need and run it at no more than about 90-95% of capacity, this in rifles, cars or any mechanical device. The loss of 5% of performance is more than made up for by the gain of (pulling a number out of a dark orifice here) say 25% or even 50% greater longevity.

There's a joke told by Robert Duvall in the movie "Colors" that ends with the punch line, "No, let's walk down there and **** them all!"

The older I get the more I see the wisdom in that philosophy.

Dr. Howell, thanks for your prompt reply. I understand from this note and previous ones you've written that you like larger cases and lower pressures but I am having a hard time answering my question from your answer. It's probably because I am a bit short in the mental division. If you would be so kind as to indulge me, I sure would appreciate the answer put in different language so I might better understand the pros/cons of these new short cases. If you'd like not to express your answer at any further length, I'll understand. No problem.
Thanks