denton
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You're absolutely correct. When working with efficiencies, energy is that natural metric, and in the range under discussion 10% is about right.
280 Remington
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cdb1
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I prefer a 24" barrel for 30-06 and .270 so if I had a .280 that's what I'd want. If I'd didn't have .270 and 30-06 I'd probably want a .280 but just don't see the need. Where my interest lies these days is in a cartridge slightly less powerful so 7x57 is what I'd like.
MachIVshooter
Member
So my .280 loads that run a bit faster than published data are "ridiculously hot", but your 7x57 loads that do the same are fine. Got it.
And I gave you the source for my load data, yet you insist that it isn't published. Sierra 5th edition manual, page 450. 150 gr. Gameking, 54.6 grs. IMR-4350. My measured velocity is higher than their published figure.
My 4831 load was worked up, and is only 2.5 grs. over the published data for a 145 gr. bullet in Speer #13. There is a lot of real world data out there for .280 Rem using heavy charges of 4831, some exceeding 60 grs. behind 150 or 160 gr. bullets. If you've spent much time at the reloading bench and then testing in the field, you should know tha 4831 is one of those powders that it's just about impossible to truly over-do in a .30-06 case. I get 3195 FPS average with that powder behind a 117 gr. Sierra in my 24" .25-06 with no pressure signs whatsoever and good brass life.
Meanwhile, you're claiming that you are getting >100 FPS over any published data I've seen in my books with your 7x57 with "room for another 100 FPS". Of course, you don't tell us what bullet or powder, so I can't compare it to my own results in either of my 7x57 rifles.
See above.
Yet in the real world with a real rifle, on December 31 2003 just outside of Masonville Colorado at an altitude of 5,600 ft an an ambient temp of 30°F, we shot 20 rounds loaded into Winchester brass with Winchester large rifle primers over a Gamma Master Chrony 12' from the muzzle and got an average velocity of 3,054 FPS.
Sometimes what you get in your own rifle is quite a bit different than published data in a manual. I've had some come out disappointingly low, and others that were quite a bit faster, like the IMR-4350 load in .280, or the 80.0 gr. charge of 4350 in my 8mm mag behind a 180 that should have been 3,150 FPS but chronoed 3,315 avg.
Llama Bob
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Generally pressure follows velocity. If your load is over velocity, it is probably over the pressure of the book load as well. In order to get the bullet to go faster, you had to push it harder. Of course this is useless information if the book load is not pressure tested, or is tested in CUP (code for "we have no clue what the pressure actually was"). But caution should be taken around unexpectedly speedy loads.
salt&battery
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I have an older nosler manual and IMR 7828 powder gave wicked velocity for the 280. a 175 bullet over 2800 fps but they used a 26" barrel
MachIVshooter
Member
Of course, which is why I work up with soft plain brass Winchester primers that will flatten or crater much sooner than thicker, harder nickel plated CCIs and others.
Book loads are pretty much always going to be conservative for obvious liability reasons, since variables like temperature or a half thou difference in bore/bullet diameter can have a significant effect on chamber pressure.
Not to encourage unsafe practices, but a seasoned reloader will know how far he can push the envelope in a given firearm. I won't put the same heavy .30-06 loads I run in a modern sporter through my M-1 Garand, M1903 or 03A4. And I wouldn't use loads seeing the kind of Velocity out of 7x57 that Denton is posting in my small ring Mausers.
Someone new to reloading should consult several manuals, start with starting loads, and work up toward max published data. That falls into the common sense category. Those of us who've been playing the game for many years know what to look for, and know that exceeding the SAAMI spec'd pressure by a little bit is not going to hurt a modern bolt action that can safely handle a proof load 50% & more over that number. We work up carefully and then back off if we start seeing poor brass life, flattened/cratered primers, ejector hole marks on brass, sticky extraction, etc.
All that said, once again, the load that Denton is poo-pooing is, in fact, a published load, both the powder and the specific bullet I used. It's not like I stuffed a solid copper TSX in front of that charge to see such velocity. And the chronograph is checked with CCI .22 LR standard velocity out of a 16" barrel to confirm that it is reading properly, as I've found that ammo to be very consistent and very close to the published velocity out of many different rifles over many different chronographs.
zb338
Member
If you are a "gun looney" as I and a lot of my friends are. You would buy a .280 and have
a gunsmith re-chamber it to .280 Ackley improved. Then you have a gun that shoots almost
magnum loads. All you have to do for brass is shoot the .280 cartridges in the Ackley and
they will fire form for you. If not then Nosler sells .280 Ackley Improved brass, ready to go.
Zeke
a gunsmith re-chamber it to .280 Ackley improved. Then you have a gun that shoots almost
magnum loads. All you have to do for brass is shoot the .280 cartridges in the Ackley and
they will fire form for you. If not then Nosler sells .280 Ackley Improved brass, ready to go.
Zeke
denton
Member
It's not up to me to tell you what you can or can't run in your own rifle. That's strictly your decision. What you can't do is represent a load that is "only 2.5 grains over a published load" as being typical or fairly representative. Well, I guess you can, because you did, but you're not going to get general acceptance.
Llama Bob is being more polite than I tend to be. Kudos to him for being gracious. The fact is that there are no magic barrels. Muzzle velocity is completely determined by the force of the gas as a function of time (longer barrel = more time), engraving force, friction, bullet mass, and a tiny contribution to angular momentum (and maybe some other minor factor I have forgotten). If your load is faster than "book", your pressure is higher than "book" (assuming the same barrel length and components). The laws of physics grant no exceptions. Tighter geometry gives higher pressures and velocities, and looser geometry gives lower pressures and velocities. Velocity very closely tracks pressure. Been there, done that with a chronograph and pressure measuring equipment.
Modern "book" loads are not more conservative because of liability issues. They are more conservative because we have better instrumentation, and have corrected some of our earlier hubris. The CUP system, as has been pointed out, is neither very precise nor very accurate. Both the piezoelectric and strain gauge systems are much better.
Gas cannot read a headstamp. It only "knows" the strength and thickness of the brass and steel that surround it. Regardless of headstamp, 7x57 and 280 (and 30-06 and others) have identical head dimensions and will withstand the same pressures in rifles with the same construction. Any pressure that the 280 will handle, the 7x57 will handle, given the same rifle design. If you want to fairly compare the two, you have to use comparable pressures. That is what I have done and what you have not.
In a 280 size case, a grain of powder is typically about 2,500 to 3,000 PSI and about 60 FPS, more or less. If you're 2.5 grains over a published load, you can estimate how much extra pressure your load is generating. If you like being 6-7.5 KPSI over the published load, you are certainly welcome to it.
Firearms typically have a generous safety margin. Odds are, you'll never need it. Most of us will go through thousands of rounds and never need to invoke that design margin. But if you do need it, you will tend to need it rather badly, and if it's not there for you, you'll probably be sad. You make your decisions, and you get the consequences that go with those choices.
With that, I'm done with this topic.
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Offfhand
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This is quite true, I had a .280 built on a Pre-M-70 Winchester action back in the /70's and another built on a 1909 action, when custom rifle makers were getting lots of orders for deluxe .280's. Here the one built on much modified Mauser.
MachIVshooter
Member
Given the number of folks out there posting .280 Rem loads with similar and higher velocities, I beg to differ.
So you claim to understand these things, yet try to demonstrate chamber pressure and muzzle velocity as simple linear correlatives. They are not. You know (or should, anyway) that the same rifle, case, primer & bullet at the same temperature can produce a lower velocity and higher chamber pressure with one powder, whilst achieving higher MV at lower chamber pressure using another. Yes, velocity is the product of acceleration over time. It is the acceleration component that you are oversimplifying, assuming a constant pressure.
Not arguing that the measuring is more precise today, but none of them publish data that is right up to the SAAMI max in their pressure barrels precisely because we live in an extremely litigious society. One grave injury or wrongful death suit because a published load blew up a rifle could close the doors of a bullet or propellant manufacturer with punitive damages in the 8 figure or higher range. We all know this.
Then you'll be happy to share your results with a strain gauge on a .280, yes? Because if you don't have those figures with the same controls you did for your alleged 7x57 testing, then we're back to comparing only book loads, and your higher-than-published velocity figures are out.
It'd also be great to hear about your set-up, so that we know it was done properly and thus able to produce accurate figures. Because if you glued that strain gauge on and proceeded to document without accounting for all variables from ambient temp to the thickness, alloy and temper of the barrel, your numbers don't mean a thing. Which, BTW, your pressures, even if accurate, are over the 51 KSI SAAMI max.
That is one of the most ridiculous statements I've read on this board concerning internal ballistics. Once again, you are assuming a simple correlative.
Thanks, dad. And exactly how many cartridges do you load for? How many guns have you built? Do you know things like the yield strength of common receiver and barrel materials such as 4140 steel or 416 stainless without having to go look them up? Understand the difference between shear strength, yield strength and ultimate tensile strength? If you want to continue with condescending admonishments toward someone who actually does understand what those safety margins are in hard numbers, you'd better be standing on solid ground.
cdb1
Member
To each his own. I've never loaded over max published loads and doubt I ever will. If I did I'd certainly never post the load on a public forum.
denton
Member
I did say I was going to put this down, and I will.
So you claim to understand these things, yet try to demonstrate chamber pressure and muzzle velocity as simple linear correlatives. They are not. You know (or should, anyway) that the same rifle, case, primer & bullet at the same temperature can produce a lower velocity and higher chamber pressure with one powder,
If you want to continue to live in that bubble, you had best not look at the attached image file, which is one of many I have done. This particular data is from an 8x57. The R^2 is over .99, which says it's very, very linear. Now if you want to make a multivariate model, and include primer and temperature and so forth, guess what? The pressure vs. MV component is still linear.
And exactly how many cartridges do you load for? How many guns have you built?
Irrelevant and condescending. The answer is, enough that I'd have to stop and count, and I'm not going to do that for you. And if it turned out that I was ahead of you in that department, would you say, oops, my bad? Probably not. While we're at it, how many pressure measuring systems have you designed and built from scratch? I've done one, though it's not the one I used for the attached graph.
Do you know things like the yield strength of common receiver and barrel materials such as 4140 steel or 416 stainless without having to go look them up? Understand the difference between shear strength, yield strength and ultimate tensile strength? If you want to continue with condescending admonishments toward someone who actually does understand what those safety margins are in hard numbers, you'd better be standing on solid ground.
Again, irrelevant and condescending. I do understand those things reasonably well, having professionally consulted on those issues, though I usually look up constants like Young's modulus when I need them.
Then you'll be happy to share your results with a strain gauge on a .280, yes?
If you think about it for a moment, you are the one who has a 280 load and no pressure data. If you had that, we wouldn't be using other sources, such as measurement labs and QuickLoad. All measurements and models are estimates. Some estimates are better than others. The quality of estimates we do have is adequate for the actual question at hand. Your load is not a typical or representative 280 load.
BTW, your pressures, even if accurate, are over the 51 KSI SAAMI max.
Well, yes they are. And in what way is that relevant? Are you asserting that 280 brass is somehow stronger than 7x57 brass? Would you feel better if I told you that I often form my 7x57 brass from old 270 brass?
It'd also be great to hear about your set-up, so that we know it was done properly and thus able to produce accurate figures.
Fair enough. I performed a full, formal Measurement System Analysis (something even SAAMI doesn't do). I controlled the temperature of the firearm and the ammunition in all key tests. I performed a multi-factor test to characterize the sources of variation in the test results. I researched needed constants to provide an accurate conversion from hoop strain to PSI. I carefully checked my results against accepted sources and against QuikLoad and found my results to be consistent in all respects. I was trained in the use of strain gauges by the same people who trained Dr. Lloyd Brownell, who did the famous series, Firearms Pressure Factors. So, having given you that, do you accept my results? Probably not. So let's talk about the quality of your pressure data....
It is the acceleration component that you are oversimplifying, assuming a constant pressure.
I have made no such assumption.
I could go on, but it is well past time to end this discussion.
So you claim to understand these things, yet try to demonstrate chamber pressure and muzzle velocity as simple linear correlatives. They are not. You know (or should, anyway) that the same rifle, case, primer & bullet at the same temperature can produce a lower velocity and higher chamber pressure with one powder,
If you want to continue to live in that bubble, you had best not look at the attached image file, which is one of many I have done. This particular data is from an 8x57. The R^2 is over .99, which says it's very, very linear. Now if you want to make a multivariate model, and include primer and temperature and so forth, guess what? The pressure vs. MV component is still linear.
And exactly how many cartridges do you load for? How many guns have you built?
Irrelevant and condescending. The answer is, enough that I'd have to stop and count, and I'm not going to do that for you. And if it turned out that I was ahead of you in that department, would you say, oops, my bad? Probably not. While we're at it, how many pressure measuring systems have you designed and built from scratch? I've done one, though it's not the one I used for the attached graph.
Do you know things like the yield strength of common receiver and barrel materials such as 4140 steel or 416 stainless without having to go look them up? Understand the difference between shear strength, yield strength and ultimate tensile strength? If you want to continue with condescending admonishments toward someone who actually does understand what those safety margins are in hard numbers, you'd better be standing on solid ground.
Again, irrelevant and condescending. I do understand those things reasonably well, having professionally consulted on those issues, though I usually look up constants like Young's modulus when I need them.
Then you'll be happy to share your results with a strain gauge on a .280, yes?
If you think about it for a moment, you are the one who has a 280 load and no pressure data. If you had that, we wouldn't be using other sources, such as measurement labs and QuickLoad. All measurements and models are estimates. Some estimates are better than others. The quality of estimates we do have is adequate for the actual question at hand. Your load is not a typical or representative 280 load.
BTW, your pressures, even if accurate, are over the 51 KSI SAAMI max.
Well, yes they are. And in what way is that relevant? Are you asserting that 280 brass is somehow stronger than 7x57 brass? Would you feel better if I told you that I often form my 7x57 brass from old 270 brass?
It'd also be great to hear about your set-up, so that we know it was done properly and thus able to produce accurate figures.
Fair enough. I performed a full, formal Measurement System Analysis (something even SAAMI doesn't do). I controlled the temperature of the firearm and the ammunition in all key tests. I performed a multi-factor test to characterize the sources of variation in the test results. I researched needed constants to provide an accurate conversion from hoop strain to PSI. I carefully checked my results against accepted sources and against QuikLoad and found my results to be consistent in all respects. I was trained in the use of strain gauges by the same people who trained Dr. Lloyd Brownell, who did the famous series, Firearms Pressure Factors. So, having given you that, do you accept my results? Probably not. So let's talk about the quality of your pressure data....
It is the acceleration component that you are oversimplifying, assuming a constant pressure.
I have made no such assumption.
I could go on, but it is well past time to end this discussion.
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MachIVshooter
Member
You brought it on yourself.
Within certain, very narrow constraints. I don't think I really need to explain that the pressure drops with the volume increase as the bullet travels down the bore, or that powder burn rate drastically affects chamber pressure, average pressure, exit pressure. Pretty sure everyone here understands that fast pistol powders in a large rifle round spells disaster, whilst slow rifle powder in a small handgun case results in dismal velocities and lots of unburned powder being expelled with the bullet. Same concept with different powders within a range suited to a particular cartridge, just less extreme results.
It's published load data from a reputable source. I gave you the manual and page number. It's also far from the only load you can find out there on the interwebz getting >3,000 FPS with a 150 grainer in the .280 rem.
Umm, how about because you're chastising me for a load that might be a few KSI over max, while touting yours that are definitely over by your own measurements. My beef is not with the figures, but with your hypocrisy.
If your contention is that the case head of the 7x57 is the same as .30-06 based rounds so it's fine, then another few KSI bringing the .280 up from 60 KSI is also A-OK in your book, since the .270 chambered in the same rifles with the same bolts has a max of 65 KSI.
What do you call this?
One grain won't even get the bullet out of the barrel, and a compressed load of 65 grains certainly won't see 3,900 FPS with anything but featherweight pills. Never mind that bullet weight is completely ignored in this silly paradigm, as is bore diameter, barrel length and every other variable that would minutely or drastically affect the outcome.
denton
Member
The kindest response is that you are being deliberately obtuse.
There are certain assumptions that almost everyone understands, such as "all other factors equal" or "over the range of interest". If you don't understand that, I don't have time to explain it all to you.
MachIVshooter
Member
The only assumption you should be making here is that in a bulletin board thread with dozens of participants and multiple conversations existing simultaneously, nothing is tacit.
MachIVshooter
Member
I appreciate where you're coming from, but there's useful information within the rancor.
If you find it distasteful, my apologies, but I'm not and never will be one to keep quiet when I see things that just aren't right. Y'all should know that about me by now
I don't find the information distasteful. I don't find the discourse distasteful. I find the unprofessional tone distasteful. We're all better than that and we need to watch out for each otherI appreciate where you're coming from, but there's useful information within the rancor.
If you find it distasteful, my apologies, but I'm not and never will be one to keep quiet when I see things that just aren't right. Y'all should know that about me by now
In this regard I have seen quite a few 280 AI factory rifles on GB. It is either popular now or becoming more so.
I weighed my Remington Mountain Rifle. It come to 7lbs 14 oz with 3x9 Leupold, sling and unloaded
SwampWolf
Member
I don't find the discussion to be "unprofessional", whatever that is. I'm actually finding merit in both sides of the "argument" and am finding the ongoing discourse interesting and informative.
SwampWolf
Member
If you really didn't care, I doubt you'd have taken the trouble to add this post to the discussion. No need to further complicate your life needlessly.
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