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Post by rbinar on Jan 20, 2009 22:10:19 GMT -5
8-)This post is about the recent loads fired by Steve White from a 40 caliber rifle shooting the 200 grain SST bullet. The loads were with 86 and 89 grains of powder and reached speeds of 2890 and 3115fps respectively.
I see the need to provide some guidance regarding the pressure produced by these loads. I will attempt to estimate as well as measure loads to provide as much information as possible.
The first load was with 86 grains reaching 2890fps. For that load I have an estimated colume length of 2.85 inches. With a 23.35 in barrel the case water capacity is 93 grains and the expansion ratio would be 8.19.
The calcullator gives these results.
Pressure(CUP) 42892.642
Expansion Ratio (R) 8.190
W 93.000
F2 1.884
K1 19216017.236
K2 1.493
K3 668.670
I'm not completely sure of the powder colume length. If it's longer the pressure would be lower and the opposite is true as well. I also would take any advice on the function F2 as it has a number of deriving methods.
So again some real world numbers would be nice. Steve can you measure the colume? Mark be sure to check my math.
In time I will try the 3115fps load also but I want check this one for the present.
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Post by sw on Jan 21, 2009 8:10:12 GMT -5
I'll get the measurement. I've noticed, and am not surprised, that the 40 cal loads are very sensitive speed-wise to slight changes in the primer powder. Note, that this speed(3115'/sec) only had 1 chrono reading so we need to see if that was just an anomaly.
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Post by edge on Jan 21, 2009 8:42:32 GMT -5
Looks pretty close to my results using your powder column. ( I actually thought that it would be a bit longer which would lower pressures. ) FYI I have a predicted velocity of a little over 3,000 fps. Powley suggests a slightly faster powder if it were not duplex  edge. VELOCITY 2890 fps Chronographed PRESSURE 41535 psi AVG. PRESSURE 15099 psi Expansion Ratio ( R ) 8.182 W 93.33 F2 = 1.840 K1 = 18110867 K2 = 1.537 K3 = 670.245 IMR Powder Selector 129 IMR-3031 =135 IMR-4064 =120 |
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Post by ewc on Jan 21, 2009 8:52:04 GMT -5
I will take column measurements with the loads I have planned for today or tomorrow's testing.
The loads i have planned should not exceed the estimated pressure you posted above. I plan on checking Steve's load of 4350 and then trying RL19, 22, and 4831sc - all with 12 gr 4759.
I also agree with SW about the primer powder increases - speed really shot up with just a 4 gr increase of 4759 in one of my Varget loads.
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Post by dougedwards on Jan 21, 2009 8:57:45 GMT -5
8-)This post is about the recent loads fired by Steve White from a 40 caliber rifle shooting the 200 grain SST bullet. The loads were with 86 and 89 grains of powder and reached speeds of 2890 and 3115fps respectively. I see the need to provide some guidance regarding the pressure produced by these loads. I will attempt to estimate as well as measure loads to provide as much information as possible. The first load was with 86 grains reaching 2890fps. For that load I have an estimated colume length of 2.85 inches. With a 23.35 in barrel the case water capacity is 93 grains and the expansion ratio would be 8.19. The calcullator gives these results. Pressure(CUP) 42892.642 Expansion Ratio (R) 8.190 W 93.000 F2 1.884 K1 19216017.236 K2 1.493 K3 668.670 I'm not completely sure of the powder colume length. If it's longer the pressure would be lower and the opposite is true as well. I also would take any advice on the function F2 as it has a number of deriving methods. So again some real world numbers would be nice. Steve can you measure the colume? Mark be sure to check my math. In time I will try the 3115fps load also but I want check this one for the present. It is encouraging to see that these lighter bullets can be shot at speeds approaching 3,000fps without the neccessity of also increasing pressure to near 50,000 CUP in the smaller calibers. I am wondering about the relevance of the expansion ratio (for us lay people). Is this a ratio between the area of the barrel taken by the powder in reference to the total area of the bore of the barrel? Is 8.190 a number in the area that would be considered good? What if you had a longer barrel? Would that enhance or detract from the performance using this same load? Excuse my ignorance here as I have been a member of this board for years and have learned so much in reading the posts here. However I am still somewhat in the dark as to exactly how things work when we change things (barrels, powder, caliber, bullets etc). Your input is appreciated as always. Doug |
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Post by rbinar on Jan 21, 2009 10:35:55 GMT -5
I am wondering about the relevance of the expansion ratio (for us lay people). Is this a ratio between the area of the barrel taken by the powder in reference to the total area of the bore of the barrel? Is 8.190 a number in the area that would be considered good? What if you had a longer barrel? Would that enhance or detract from the performance using this same load? Excuse my ignorance here as I have been a member of this board for years and have learned so much in reading the posts here. However I am still somewhat in the dark as to exactly how things work when we change things (barrels, powder, caliber, bullets etc). Your input is appreciated as always. Doug Expansion ratio is probably beyond the consideration of the average shooter. However it is a considerable concern for those who want to be schooled enough to develop loads. There are many tools to work with but they all work on the principal of the powder turning into a certain amount of gas. Though different options are available the manner of estimating pressure I use compares the speed of the bullet to the amount of powder burned, the space it has to expand into (Case size), and area the bullet is accelerated in (barrel length). In simplest terms the expansion area is the amount of space in the case compared to the length (expressed as volume) of the barrel and case. The reason for this should be seen by simple logic. If you have a big ole case and a long barrel it should not take excessive pressure to reach speed. In this example time can be used instead of pressure. Whereas in reverse a small case and short barrel would take considerable pressure to reach comparable speed. In this example pressure is used to compensate for time. A noted difference in the 10ML (whatever the caliber) is the case. Normally the case is a fixed constant. All you need to know is the case volume expressed in grains of water (thus it is expressed in the program as W) and it would never change (there are exceptions). With our case every load has a different sized case. However the volume of the powder (in grains of water again) is the volume of the case. That's why the powder column length is required to estimate the pressure. It is also why every load has a different ratio and deciding if a given number (such as 8.19) is good or bad can't be stated except if the load is shooting to the desired pressure. One difficult thing to explain is how pressure relates to caliber. The volume of any case or barrel is a cylinder. Cylinders raise in volume according to the square of change in radius. That means if you double the size of the cylinder you increase the volume of the case by the square of 2 or 4 times the smaller cylinder. That means it essentially takes four times as much gas to reach equal pressure in an equal comparison We see this in the fact a given powder would make more pressure in a smaller caliber even if the bullet is lighter in weigh. But there is one constant. For our example the bullets must have the same diameter to weight ratio or sectional density for expected results. It would take consider more time and study to fully understand expansion ratio. However the information is available at given web sites for free so it is not beyond the average shooter who really wants to know. |
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Post by dougedwards on Jan 21, 2009 17:51:53 GMT -5
Wow.......looks like I have some studying to do. My concern is that with so many of us abandoning the 50 cal for the flatter shooting and lighter recoil of the smaller calibers that risks might be taken in ignorance. Ignorance in the sense of just not knowing enough to experiment with the unkown. For example.......if we can conclude that, in general, a 40 caliber muzzleloader is more accurate, flatter shooting and easier on the shoulder than a 50 caliber then what would prevent us from concluding that a 30 caliber or 25 caliber muzzleloader would be even more appealing?
I do know of at least one shooter who took the plunge of the then uncharted waters of .375 caliber and his frustrations ended in damage to his brand new barrel. It could have been worse. IMO we need education to make changes and move forward. The education that can be gathered from this forum is not only invaluable. It is also neccessary. I hope this doesn't ciome off as overly opinionated. It is written only out of concern for those like me who might be exhuberant about making a new discovery to the point of taking unneccessary risks.
Doug
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Post by sw on Jan 21, 2009 21:01:12 GMT -5
40 cal PacNor
11.0g 4759 + 75.0g H-4350 = 2.707" column length
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Post by rbinar on Jan 21, 2009 21:18:11 GMT -5
Wow.......looks like I have some studying to do. My concern is that with so many of us abandoning the 50 cal for the flatter shooting and lighter recoil of the smaller calibers that risks might be taken in ignorance. Ignorance in the sense of just not knowing enough to experiment with the unknown. For example.......if we can conclude that, in general, a 40 caliber muzzleloader is more accurate, flatter shooting and easier on the shoulder than a 50 caliber then what would prevent us from concluding that a 30 caliber or 25 caliber muzzleloader would be even more appealing? I do know of at least one shooter who took the plunge of the then uncharted waters of .375 caliber and his frustrations ended in damage to his brand new barrel. It could have been worse. IMO we need education to make changes and move forward. The education that can be gathered from this forum is not only invaluable. It is also necessary. I hope this doesn't come off as overly opinionated. It is written only out of concern for those like me who might be exuberant about making a new discovery to the point of taking unnecessary risks. Doug Doug I started this post for a bigger purpose. The fact you seem to know where I'm going before I get there is (in the words of another) "astounding". I show the first load because it is very close to ideal IMO. However looking at the second I didn't have such a great opinion. It is notable that when Steve fired the load he only shot once. Smart shooter don't stick their foot in a bucket and keep on walking. They know when to back up. There are signs of problems all over the place and I was wondering if anyone else was going to catch the problem. The first sign to me was when Steve reported large speed increases with slight changes in powder. There are a number reasons for this but this being a duplex load the signs point to only one thing and that is "booster saturation". Ugggg you say while asking, another one? Yes just when you think you know it all wham, that's when you realize all is not to be known. Booster saturation can be had when the booster powder has raised pressure to the point where more of it causes rapid changes in load conditions. This can be seen by this load moving from 2890 to over 3100fps with just 3 grains extra powder. That should be a sign to everyone within distance of the moon that the pressure was a lot higher. I'm sure as we move to a faster bullet this will be noted and an effort to have more powder in the load to reach 3100fps will be applied. But what would happen if load was being shot by a shooter with lessor eye for the unusual than Steve? Is there a possibility someone would decide I got 3100fps with this load and all is safe I can add 6 more grains of primary and 3 more grains of booster and be really fast? Well I certainly hope not but this points out the need for experience and knowledge at every level of development. When 45 and 40 caliber rifles were introduced I pointed out that load development was not for the mild of heart or mind. I am very thankful that over a period of years I've had input from some of the great minds of shooting and ballistic technologies. Even at that I know bad things can happen. The example of someone experimenting with a foreign caliber is a classical example. It is VERY hard to start with no information and get it right the first time. So don't. If you have never developed a load don't without the guidance of someone who can lead you safely and then let them pull the trigger. If you can't develop a load use only loads shot by others and are proven to be within a very safe limit. I know of some who are trying to shoot either .375 or .358 bullet in the 9.3 caliber barrel or bullets. It's a shame that time has not allowed me to work on loads for those chambers as yet. So know this! There is little or no connection for loads of a different caliber. The idea that that rifle shoots to this speed with that much powder is simply a problem waiting to happen. Even if you know the caliber well every attempt must be made to proceed with caution. |
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Post by jims on Jan 21, 2009 22:29:17 GMT -5
To rbinar: You never cease to amaze me with your understandings of powders and loads. Again you nailed it. I was one that experimented with loads in a .375 barrel. The saboted loads seemed more "forgiving", perhaps the sabot was a safety valve of sorts.
My trouble came in a sabotless load with a 286 grain Nosler 9.3mm (.366) bullet. I was in an area I should not have been with disastrous results. The barrel nut broke, the barrel bulged. No harm to me other than my pride and the barrel. I cut two inches off the breech and had it magnafluxed. It turned out OK but I have not really ventured back into those territories other than to fire a test load to make sure the barrel was intact. Still trying to come up with some loads. Overall my IMR 4350 seemed the "best", if that really is a correct term.
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Post by rbinar on Jan 22, 2009 0:17:32 GMT -5
To rbinar: You never cease to amaze me with your understandings of powders and loads. Again you nailed it. I was one that experimented with loads in a .375 barrel. The saboted loads seemed more "forgiving", perhaps the sabot was a safety valve of sorts. My trouble came in a sabotless load with a 286 grain Nosler 9.3mm (.366) bullet. I was in an area I should not have been with disastrous results. The barrel nut broke, the barrel bulged. No harm to me other than my pride and the barrel. I cut two inches off the breech and had it magnafluxed. It turned out OK but I have not really ventured back into those territories other than to fire a test load to make sure the barrel was intact. Still trying to come up with some loads. Overall my IMR 4350 seemed the "best", if that really is a correct term. Jims with that heavy of bullet I'd think you could shoot either about 50 grains (maybe slightly more) of Imr-4064 or around 70 grains of 4350. Of course I'd start with a little less and work up With a normal length barrel I'd think 4064 is good to about 2250 or so and 4350 to about 2400 fps all well within normal pressure limits. If your barrel is shorter now then the speed will be reduced accordingly. |
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Post by rbinar on Jan 22, 2009 0:20:12 GMT -5
40 cal PacNor 11.0g 4759 + 75.0g H-4350 = 2.707" column length This would raise the original prediction in the 2 to 3kcup range. I don't think we have to have much debate on the 89 grain load to know pressure would exceed 55,000psi |
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Post by sw on Jan 22, 2009 14:41:25 GMT -5
Concerning my load work up, this really is not the way to do it. I had less than an hour to sight-in the 223/WCE scope and unload my 3 MLers and test velocities of various loads. These loads would be best evaluated progressively upwards. I want a load around 42-44K and quickly found that 14/75 was way over - shouldn't have tried the 4 g jump of primer powder. 4 grains got over 250'/sec increase. I plan on testing VV-110 from about 9g to 12 or 13 with H-4350 from 75 -80gs. Likely 3000'/sec load -11.5g VV-110/ 78g H-4350. We'll see.
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Post by jims on Jan 22, 2009 17:03:46 GMT -5
I feel like I am horning in on this site talking about 9.3mm. I do not want to do that. I will put it on its own title page in the future. Craigf is putting some load information together on various calibers and I hope to have mine there as any assistance is appreciated. Some members here have already made suggestions. I can list later my speeds and powders both saboted and sabotless but will give time for the other information to get posted. Thanks to all out there that have offered guidance.
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Post by sw on Jan 22, 2009 21:13:46 GMT -5
I feel like I am horning in on this site talking about 9.3mm. I do not want to do that. You haven't bothered me . |
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