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Post by Jon on Apr 7, 2011 20:59:33 GMT -5
Richard. I will try to put out a better effort to find the tips. I thought the interest was gone so I didn't look real hard. I'm trying to straighten out years of od's and end's If I don't find them I'll give Dave a call or Grouse may have some laying around. I really like the look of the ones your working on now. Dave had told me in the past that he could custom make almost anything some one wanted. I never got in to price. His bullets seem to be popular with the b/p people. They just don't seem to like smokeless. Jon
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Post by Dave W on Apr 7, 2011 21:04:26 GMT -5
Al............Jon says he got some when he ordered the ones he sent me. So far, he has been unable to locate them as he said he would send them to me. Tar............I just took a 200 gr. Leheight that Jon sent me and turned the base flat. It reduced the weight to 189 gr. I then added some #9 lead shot and seated that NA Arms .22 bullet (30 gr.)...........then profiled the nose. Final weight? 222 gr. In my opinion, too much work for an already expensive bullet? Just putting in the insert and profiling is not bad. This can be done by anyone with a drill press. But the lathe end of it? I will not get to shoot these for two weeks since our range is being closed for excavation work on the 300 yard berm. Let me ask the board one question...............How much do you think a bullet........particularly a solid one (like brass or copper) will actually "obturate" inside a soft plastic sabot? I don't see a whole lot of obturation with jacketed lead bullets shot sabot less much less a solid in a sabot (based on the ones found in the dirt) Richard Count me as somewhat skeptical also about the obdurating. I have looked at blue Harvesters I recovered that were shot with the 195 BX and I could fold the petals up and other than the cup being expanded, they looked as though they had never been shot. Spent sabots with jacketed bullets looked as though there was some swelling where the base of the bullet would sit. Smoke posted some recovered sabotless bullets, didn't look like there was a lot of obdurating going on with those either. Edge has a picture of a bullet from one of his combos that completely contradicts what I just said. I think the bullet semi drilled the sabot, the expansion was enormous. Maybe he can post it again with the details. Probably numerous factors play into how much expansion we are actually getting. Pressure, pressure rise, jacket thickness come to mind. Wondering if running a saboted bullet down the barrel and measuring the sabot petal where the lands engrave the petals and then doing the same to a recovered spent sabot would shed any light or even be a reliable method to give some idea as to what actually is happening?
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Post by edge on Apr 8, 2011 7:50:17 GMT -5
No drilling at all Top picture shows the loaded relationship. ( sabot is prior to sawcutting for petal breaking ) The bullet is a 150 grain 8mm Sierra ProHunter shot from my custom 50 caliber Savage. The base is 0.250 thick. 4 Slight bumps are the sawcuts. Notice they do NOT go to the center which is the dimple from the drill. Original bullet on left. Right bullet recovered from buck. After I recovered this bullet I moved the petal break point to beneath the bullet base. edge.
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Post by rangeball on Apr 8, 2011 12:19:46 GMT -5
I think all you have to do when using the Excel program is to substitute your data in the C-3 to C-13. C-3 is pretty simple, bullet diameter. C-4 is overall length C-5 is meplate diameter, since you have a point that doesn't count so put 0.00 C-6 to C-8 deals with boattails you can just 0.00 C-9 is the type of ogive, this program only deals with tangent and secant, your bullet is a cone or spire point, I would chose tangent. C-10 is the radius of the ogive measured in calibers (bullet diameter), to get close you may have to plot this out on paper. For some reason if you input secant (which may be more accurate in this case) it doesn't ask for nose length or bearing length. C-11 asks for the specific gravity of the bullet, I'm not sure on the unit of measurement. Lead has a SG of 11340 kg/cu.m and copper 8930 kg/cu.m so it may be if you have a copper bullet 8.9. C-12 is your planned velocity in fps C-13 is air density, again I do not know what the measurement they ask for. ICAO standard is 1013.25 hPa @sea level with no humidity. Maybe the 1.018 is standard in PA. The program should calculate the rest. Thanks, that helped a ton. I was inputing the data in one of the empty columns. If I leave the nose profile as T and angle at the default in column C, which is of an existing .243 bullet I believe with a 2700fps muzzle velocity, it outputs the following data: Weight- 241gr S.D.- .216 BC- .43 Twist rate- 20.2 I believe if we did a straight cone nose profile the weight would be more where predicted at 237gr and the bc would be a bit less, but still way above what we have available now. Would help with twist rate a bit too. I plan to order some 110 copper rod and get some of these made. I can anneal them as well, if you think obturation from softer copper is of any real significance. I'd love to send some to you guys with PT equipment and extended range access. I have a 500yd range, but no PT.
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Post by rossman40 on Apr 8, 2011 13:53:28 GMT -5
What you have to watch for when ordering 110 copper is the temper. You can get it soft or annealed which will have a tensile strength of 32,000 and a yield strength of only 10,000, semi-hard which will have a tensile strength of 42,000 but the yield strength ups to 36,000 and then full hard which has a tensile strength of 50,000 and a yield strength of45,000. If your going to anneal it save the hassle and just order it soft. As long as you do not bend it ("work it") it should not harden much machining it on a lathe. An example is copper tubing, it is soft but once you bend it, "work it", bending it back is tough. The nose design is a critical factor in the BC. As I said before a straight cone is not always the best aerodynamically but it is the easiest to produce. A good read, en.wikipedia.org/wiki/Nose_cone_designJust a bit of history the big names in modern aerodynamics are Wolfgang Haack and Theodore von Kármán. Both set the pace before WWII. Von Kármán's top student was William Sears who was at one time the head of aerodynamics for Northrup. The flying wing which resulted in the later B-2 is some of his work. Another good source of reading, www.appliedballisticsllc.com/index_files/Articles.htmAnd if your a glutton for punishment look around this website (mostly in German) lutz-moeller-jagd.de/
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Post by rangeball on Apr 8, 2011 14:19:53 GMT -5
Thanks. I was searching high and low for a soft/annealed 110 source, but all I can find is 110 hardened. Do you know of a good source for it that sells in small quantities? I'm thinking to start with about 72" that should produce about 48 bullets based on the current set of specs.
I'll check the links out. I am now playing around with different secant and tangent angles. Reducing this to 1 which if I am understanding correctly would more closely mimic a straight cone, really hammers the predicted bc.
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Post by edge on Apr 8, 2011 15:05:56 GMT -5
The tangent and secant refer to a radii, and not angles.
A 1/2 caliber tangent would be a full nose radius.
edge.
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Post by edge on Apr 8, 2011 16:45:49 GMT -5
What you need to calculate is the difference between the OAL and the ogive and make sure you have at least 1 caliber of bearing surface!
edge.
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Post by rossman40 on Apr 8, 2011 17:01:25 GMT -5
I talked to my supplier and I can get it half-hard but finding it soft she said may be a problem. The reason being that it is so soft in the smaller diameters in bends too easy during shipping/handling. Her price to me for .5" dia 6' long $100. WW Grainger was $94.50 for full hard. Online Metals had it for like 1/2 the price but I have a hunch they have not updated their price sheet in a while. If you can get it in 7/16" your looking at maybe a 15-20% lower cost per foot over 1/2" to keep cost down. As you increase the tangent ogive radius the nose gets longer. You have to remember that it is measured in calibers so 1 would be .400 if you draw it out. A .5 would give you a round nose, What you have to watch is the Center of Gravity (CG), as the nose gets longer the CG moves to the rear. This makes the bullet more acceptable to wind gust and any hiccups during the transitional/intermediate ballistics phase, bad crown, effects of muzzle gases, the transition from a static CG to a dynamic one and in our case sabot separation will have a larger effect on accuracy. To counteract this on VLD/ULD bullets they lengthen the bullet, more weight, and also lengthen the boattail. But since we are dealing with sabots we have to have the flat base.
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Post by deadon on Apr 8, 2011 17:48:57 GMT -5
Would a happy medium be ojive #2 or do you have to make 50 of each and then do the accuracy testing In which case it may never happen
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Post by GMB54-120 on Apr 8, 2011 19:59:05 GMT -5
WOW, i didnt know copper was that much. I heard the new Hornady MonoFlex uses "Guilding Metal" <sp> which i assume is a copper alloy. Maybe it is a cheaper option. Ive talked to Dave at Lehigh before and he works with brass partially because he says its easier to work with on the lathe. I have no idea if its a special brass or....... He does occasionally make some copper bullets but atm Knight has him in high gear with several projects. Plus all the bullets for AlexArms and other companies. Later i will see if i can get some custom 40cals from him. Maybe his 200gr but "pointier" with a very small HP just to test and no BT. That might get upto 220gr+. Ive got some of his pointy 458 255gr and 300gr MATCH SOCOMS and they are kinda cool. Another thought is make a mold or mod one to the size/shape you choose and make the bullets from really hard lead like linotype <sp>, IIRC its like 24 BHN. A friend has a spire point mold (really pointy too) and ive got some of his really hard spire points. Ive been trying to get him to make it smooth sided. Just some random thoughts for testing a higher BC option.
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Post by rossman40 on Apr 8, 2011 20:43:51 GMT -5
You would probly need at least a 4 radius to get the BC over .300. That will be about a nose length of about 3/4". Another factor will be keeping the length to point where it will be able to shoot out of a 1:22 twist that most have.
You getting a headache yet Rangeball? Are these going to be cut on a CNC machine that you can program a radius nose?
Copper prices are crazy, they are up 25% just in like the last 9 months. The .5" dia 6' long was $70 last year.
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Post by edge on Apr 9, 2011 1:24:48 GMT -5
A meplat is not bad, just not too big!
Keep it small and it does not hurt much. With our diameters a 1/8 inch meplat is OK. IMO, you should work backward. Decide on the bearing length and subtract that from the maximum AOL. The balance is your maximum nose length.
The only thing you can do to shrink the nose is to increase the meplat!
Now for a tangent radius the calcs are easy. For a secant radius you can generally double the tangent but you will probably be a bit hit or miss as to whether the BC is higher than the tangent! The problem will be whether the shock wave separates from the bullet or it does not. Companies spend a lot of money testing so a tangent would be the easiest to try.
To calculate a radius when you know the chord and the height:
R= ( c^2 + 4h^2 ) /8h
So the nose will be 1/2 c; h is 1/2 the bullet diameter ( minus 1/2 any meplat )
To calculate a 0.450 bullet with zero meplat and a nose length of .625 the calcs are :
1/2 c = .625 h = .225
so
2c ^2 = (0.625 * 2) ^ 2 = 1.5625; h ^ 2 = 0.050625 ( * 4 = 0.2025 ); 8 * h = 1.8;
R = ( 1.5625 + 0.2025 ) / 1.8 = 0.980
So now you know that a .625 nose on a .450 bullet is a .980 inch radius or a 2.18 caliber radius depending on how you look at it.
Now if you had a 0.100 meplat then the radius will be 1.18 inches or 2.6 calibers.
edge.
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Post by Al on Apr 9, 2011 3:04:13 GMT -5
geesh Edge, might as well write the program ;D
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Post by edge on Apr 9, 2011 13:20:01 GMT -5
geesh Edge, might as well write the program ;D Actually, if you have an old computer that uses DOS you can download the OTHER program from the Lilja website and find that it was compiled by edge I think that I did that about 7 years ago and it does have some errors in it, but at the time it was state of the art! edge.
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Post by chuck41 on Apr 9, 2011 22:28:58 GMT -5
I have resized some of the Hornady .411" 300gr interlock bullets for use in my .40 sabotless. Not really too hard to do, but the end result is a bullet that is a bit heavy for my taste. I would definitely use them if I got a chance to hunt elk or bear with the ML-10 though. Fits really nice. I shot a couple with mild loads but haven't gotten the courage to do so with what most would consider full loads. I am a recoil-a-phobic and a 300gr bullet at 2400fps or so has a pretty good thump even in my 11# ML-10.
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Post by rossman40 on Apr 10, 2011 14:46:38 GMT -5
Maybe Chuck has the simple idea, take the Hornady 405 Cal .411 300 gr InterLock SP or FP and mill the soft point off and drill a hollow point (with a custom ground mill a one step operation). Then with a die from Corbin re-size, reform the nose a bit and with a nose punch in the die, re-form the hollow point to take a plastic tip from Dave at Lehigh or somewhere else. You would have to experiment on how much to mill/drill to get the proper weight and dimensions. With a collet set-up on a lathe or mill that operation would be very repeatable with precision.
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Post by edge on Apr 10, 2011 15:56:19 GMT -5
I have resized some of the Hornady .411" 300gr interlock bullets for use in my .40 sabotless. Not really too hard to do, but the end result is a bullet that is a bit heavy for my taste. I would definitely use them if I got a chance to hunt elk or bear with the ML-10 though. Fits really nice. I shot a couple with mild loads but haven't gotten the courage to do so with what most would consider full loads. I am a recoil-a-phobic and a 300gr bullet at 2400fps or so has a pretty good thump even in my 11# ML-10. High BC means mass! If you want a bullet with a high BC then You must remember that the BC is Form Factor times Sectional Density! These are truths that can't be avoided! Lead is heavy, and copper is less heavy. A copper bullet is lighter and needs more twist! IMO, lead is your friend.
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Post by jims on Apr 10, 2011 18:46:17 GMT -5
If we could get our hands on some spent uranium our hopes would be answered. ;D
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Post by Chris Champion on Apr 10, 2011 23:18:38 GMT -5
I have resized some of the Hornady .411" 300gr interlock bullets for use in my .40 sabotless. Not really too hard to do, but the end result is a bullet that is a bit heavy for my taste. I would definitely use them if I got a chance to hunt elk or bear with the ML-10 though. Fits really nice. I shot a couple with mild loads but haven't gotten the courage to do so with what most would consider full loads. I am a recoil-a-phobic and a 300gr bullet at 2400fps or so has a pretty good thump even in my 11# ML-10. This is the bullet in one of the links I put in the first post ;D Great discussion and ideas flowing here guys!! Keep it up. Hey Chuck...send me a few of those resized 300 grainers. I'll push em up to thumping level.
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Post by pposey on Apr 11, 2011 7:17:12 GMT -5
Would it not be hysterical to see a plastic tip on a hard cast lead bullet,,,,,,,,,
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Post by rossman40 on Apr 11, 2011 9:11:23 GMT -5
I think we have seen with the .451-2 and .458 bullets a factor with jacket and jacket thickness when shooting with a sabot. Straight lead bullets do not seem to do well if soft. Perhaps over obruation to the point where the bullet is knocked out of balance. Plated bullets with their .004-.008 jacket also fall to this maybe. Real thick jackets (.050") like the XTP Mag do not do as well as their thinner jacketed brothers. The Nosler Partition and Swift A-Frame may also do not so well with their thick jackets and a open base design. The Winchester Platinum Tip with it's open base didn't fair well ether IIRC. The thinner jacketed bullets (.018") like the Parker BE, Hornady .458 300gr and the Remington .458 300gr JHP seem to do well. Bullets with a medium thickness jacket (.035" or less) like the Barnes Original, SST/SW, regular XTP do alright. Solid bullets like the Barnes and Lehigh seem to be hit or miss, ether your gun likes them or it doesn't and with mine it seems to favor lead core bullets.
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Post by rangeball on Apr 11, 2011 9:11:33 GMT -5
You getting a headache yet Rangeball? I wasn't until I read edge's calculations post. I cried uncle Yes, I believe so. onlinemetals is what I had found, since soft/annealed is scarce I'll try to order to see I can get it for that price. If not, maybe order less. The plan is to have as few made as possible to satisfy pressure trace and bc determination requirements, reserving stock for revisions as necessary. My goal is to produce a higher BC bullet, not necessarily the highest bc bullet, in an effort to maintain fps and terminal performance. That chart you posted above is phenomenal. Really helps my perspective on things, no wonder they say a pic is worth 1000 words
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Post by rangeball on Apr 11, 2011 10:09:54 GMT -5
Would a happy medium be ojive #2 It doesn't provide much of a bc bump. I blew up and printed out the chart rossman posted above, and the barnes .40 fits the .28 bullet right on. Laying the barnes on this column, it looks to be a 3 ogive. Add a tip to it and it would fit the 3 profile exactly, and as is this bullet only has a BC of .19. I played with the lilja er I mean edge program with different ogives and the 8 maxes out bc, but I need to get into the program more to understand how long the bearing surface is at this spec. I don't think it's enough.
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Post by rangeball on Apr 11, 2011 10:31:45 GMT -5
What you need to calculate is the difference between the OAL and the ogive and make sure you have at least 1 caliber of bearing surface! edge. Thanks, learning every day I went back into the fine detail that the program generates and get the following specs for the design above, as well as a revised version to get the 1 caliber radius- Ogive-..8..........4 OAL-....1.38"..1.22" Nose-...2.7c... 1.9c BS-...... .6c..... 1.1c Weight-241... .242 BC-..... .430... .330 SD-..... .216.....216 Twist-.. 1:20....1:22
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Post by rossman40 on Apr 11, 2011 11:34:22 GMT -5
The chart actually came from a book/brochure written by Wallace H. Coxe and Edgar Beugless for DuPont back in the 1930s. They were both ballisticians working for DuPont at the time. What you did was lay the bullet on the chart to determine the ogive to insert the factor into their calculations to determine exterior ballistics (drop, drift and downrange velocities). The book is a collectors item and the charts were separate in a neat envelope with the DuPont logo. The book was ground breaking at the time (antique in todays standards) and their work is recognized today in Sierra's manuals. I feel sorry for Edgar, it is often referred to as the Coxe-Bugless chart, somewhere the first "e" got dropped out of his last name. I think from being left out when referenced in General Hatcher's notebook in 1947.
In todays world ULD bullets can have a radius of 14 calibers or more.
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Post by rangeball on Apr 11, 2011 12:50:05 GMT -5
Amazing... It's a great tool for sure, laying bullets on it tells one a lot. Looks like the sst and pointed barnes mz and thors are all 3, the barnes 275 tsx .458 is a 4. Plugging in the specs for the barnes .40 195 and I get withing a few grains of weight and a calculated bc of .195. This thing seems to be right on, great work edge
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Post by rangeball on Apr 11, 2011 15:07:35 GMT -5
I was taking another look at the parker 325 and it occurred to me that it seems to have a secant ogive, not tangent, so I went back to the excel program and came up with this-
Ogive-..T8..........T4.....S10 OAL-....1.38"..1.22"....1.32" Nose-...2.7c... 1.9c......2.0c BS-...... .6c..... 1.1c......1.3c Weight-241... .242..... 242 BC-..... .430... .330..... .387 SD-..... .216.....216..... .216 Twist-.. 1:20....1:22.....1:21
With secant I can get longer and higher bc in the weight range, but twist becomes and issue.
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Post by rangeball on Apr 12, 2011 9:00:59 GMT -5
Wayles, you mentioned in your thread you didn't want to butt in. By all means please do Your buddy sounds like the perfect guy with the time, talents, equipment and desire to get this thing moving. I'm in complete agreement with your thoughts on a final design. My goal with this so far has been to produce a solid prototype to see if it will shoot and what the real world bc is. I've been at 242 grains, but if it shoots had planned to introduce a nice size hollow point for expansion and a plastic tip to fill out the rest of the length. That should get the weight down a bit and hopefully not drastically impact bc. It will be a bit before my machinist buddy has equipment freed up to play with, so if you're buddy's ready to go, by all means full speed ahead
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Post by bigmoose on Apr 12, 2011 10:09:52 GMT -5
I just mic'ed a bunch of Barnes X bullets {all copper} 300gr. and 350, Un fired .458, fired .458 all shot with sabots. Excellent bullets for deep penetration
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