Berger (in an ad in Shooting Industry Magazine (http://fmgpublications.ipaperus.com/FMGPublications/ShootingIndustry/SI0119/?page=82), “the ELR Match Solid Bullets are available in .375 caliber with 379 and 407 gr offerings.” SKU'd up here - https://www.precisionreloading.com/cart.php#!ca=.375&l=BG
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Berger .375 solids on the horizon
- Thread starter ELR researcher
- Start date
I would be more excited if they were lead core jacketed hollow points like the vld bullets. would be more cost effective . they know that technology very well.
Sure why not ? Then they could lie about that as well. lol ( g1 b.c. )
Not many companies have the manufacturing capabilities to make a bullet that long combined with the larger diameter. It would be nice though.
Like Dave has indicated, companies are limited by machinery. The stroke length is an issue in being able to create long bullets over about 1.800" or so. Also, the ELR market is currently very small compared to other markets and it boils down to economics.
No and no bc is way to low candaleverse cause way tomuch of a bc drop. design getting bc by weight from a long bearing surface then attempting to reduce that is the wrong thought
Still waiting to hear if Berger is going to make a heavier .338 bullet. Something aroung 325 grains in a lead core bullet
I was granted a US utility patent (9,857,155 B2 on January 2, 2018) on a monolithic rifle bullet design which this new Berger bullet resembles to a rather startling degree. That design effort required 5 years of work. I offered my bullet design to the president of Berger a couple of years ago only to be summarily dismissed, saying Bryan Litz was their ballistician and they were not going to make copper bullets anyway. A paper of mine describing the design of my ULD bullet has been posted here in your Sniper's Hide "Resources" section since last Spring. While I do not intend to enforce this patent against Berger, I am fairly sure they will not be able to patent it themselves. I plan ultimately to place my patent into the public domain to prevent others from patenting its features to the detriment of the shooting community. I wish Berger and Bryan Litz good fortune and appreciate their valuable work in promoting the art and sport of ELR shooting.
Dan Warner is currently making a batch of prototypes of the latest Mark IIb design of my copper ULD bullet in 338-caliber for test-firing. That 338 bullet will weigh 246 grains and will be 1.910 inches in OAL. Based on my current research into the Interior Ballistics of Copper Bullets (PDF attached), I had to modify the bullet's afterbody design slightly. The OD of the gas-sealing rear driving band has been increased from 0.3382 to 0.3386 inches to promote better gas sealing in the barrel. The MkIIb bullet is now base-drilled using a 1/8-inch drill to a depth of 0.400 inches in order to port the base-pressure internally for better gas sealing in the barrel (similar to the old Minie-ball). The base of the boat-tail is now radiused at 0.300-inches (convex) to minimize bullet destabilization while traversing the muzzle-blast zone. I believe the 10.2-gr weight penalty for base-drilling will be a good trade for "perfect" gas obturation in the 338 rifle barrel which expands by 1.3 thousandths of an inch in internal diameter at the point of peak base-pressure during firing with a peak chamber pressure of 60,000 psi. The improved gas sealing of this bullet design should facilitate achieving "single-digit" extreme spreads in muzzle velocities, even at very high launch speeds. The G7-referenced BC of these 246-gr copper ULD 338-caliber bullets is estimated at 0.433.
My 375-caliber Mark IIb copper ULD bullet will weigh 335 grains and be 2.118 inches in OAL. My 375 bullet should have a G7 BC of 0.481. At this relatively light weight, my monolithic copper bullet can be fired much faster and still achieve single-digit spreads, which is critical in ELR shooting. From 375 barrels rifled at my recommended 7.0 inches per turn, the initial gyroscopic stability will be 3.1 for hyper-stability in a standard sea-level ICAO atmosphere. There is no reason to consider gain-twist barrels for firing my bullets made from tough "half hard" copper. Because of its better aerodynamics, my bullet will have a much greater maximum supersonic range than the new Berger 375's fired from the same cartridge. The relative performance of these bullet designs in subsequent transonic ELR flight remains to be seen; but the heavier, blunter-nosed Berger bullets might well be superior there. From the press-released photo of the lighter Berger 375 bullets, I see several design errors and trade-offs which I chose not to make. It is most unfortunate for all concerned that Berger chose not to work openly with me in developing their new monolithic copper bullet design.
Jim Boatright
Dan Warner is currently making a batch of prototypes of the latest Mark IIb design of my copper ULD bullet in 338-caliber for test-firing. That 338 bullet will weigh 246 grains and will be 1.910 inches in OAL. Based on my current research into the Interior Ballistics of Copper Bullets (PDF attached), I had to modify the bullet's afterbody design slightly. The OD of the gas-sealing rear driving band has been increased from 0.3382 to 0.3386 inches to promote better gas sealing in the barrel. The MkIIb bullet is now base-drilled using a 1/8-inch drill to a depth of 0.400 inches in order to port the base-pressure internally for better gas sealing in the barrel (similar to the old Minie-ball). The base of the boat-tail is now radiused at 0.300-inches (convex) to minimize bullet destabilization while traversing the muzzle-blast zone. I believe the 10.2-gr weight penalty for base-drilling will be a good trade for "perfect" gas obturation in the 338 rifle barrel which expands by 1.3 thousandths of an inch in internal diameter at the point of peak base-pressure during firing with a peak chamber pressure of 60,000 psi. The improved gas sealing of this bullet design should facilitate achieving "single-digit" extreme spreads in muzzle velocities, even at very high launch speeds. The G7-referenced BC of these 246-gr copper ULD 338-caliber bullets is estimated at 0.433.
My 375-caliber Mark IIb copper ULD bullet will weigh 335 grains and be 2.118 inches in OAL. My 375 bullet should have a G7 BC of 0.481. At this relatively light weight, my monolithic copper bullet can be fired much faster and still achieve single-digit spreads, which is critical in ELR shooting. From 375 barrels rifled at my recommended 7.0 inches per turn, the initial gyroscopic stability will be 3.1 for hyper-stability in a standard sea-level ICAO atmosphere. There is no reason to consider gain-twist barrels for firing my bullets made from tough "half hard" copper. Because of its better aerodynamics, my bullet will have a much greater maximum supersonic range than the new Berger 375's fired from the same cartridge. The relative performance of these bullet designs in subsequent transonic ELR flight remains to be seen; but the heavier, blunter-nosed Berger bullets might well be superior there. From the press-released photo of the lighter Berger 375 bullets, I see several design errors and trade-offs which I chose not to make. It is most unfortunate for all concerned that Berger chose not to work openly with me in developing their new monolithic copper bullet design.
Jim Boatright
I like your comments but don't worry i wont be using there solds any way too much money for what you get there bc would need to be way higher to get me to pay that much for there solids
Don't misunderstand, BAGW, I really want Berger or anyone else to build and market my bullet designs, or variations of them, successfully. I doubt that any CNC-turned copper bullet can be made from quality half-hard copper and sold for less. On the other hand, by insisting on "going it alone," Berger seems determined to rediscover for themselves what I have already learned. I always publish my findings for anyone to use freely. I only ask for proper attribution when others use my work.
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its funny you should say that ( attrbution) that is . I have given tons of designs and ideas to many of people and companies . that's all that most of the time i have ever wanted and next to never get it. people like to claim credit for others work and designs . that's this industry thanks for all that you have done for the guys like me and many others if you ever want to pair up with us on anything just ask thanks James
Here is an edited version of yesterday's paper on how copper bullets work in the rifle barrel compared to lead-cored bullets. I doubt you can find this information elsewhere. I tried to write this paper for riflemen as well as mechanical engineers to understand. I think this paper could be added to the Sniper's Hide Resources section.
EDIT: I updated the attached paper one more time.
EDIT: I updated the attached paper one more time.
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I have a couple of questions for Mr Boatright. At what point do you see the greatest increase in diameter of the barrel during the obturation process, behind the bullet or in the middle of the shank? The second question is not the degree of expansion at a given pressure a function of the barrel thickness all the factors being equal?
The 246-gr and 250-gr bullets in my 338 LM example calculations have moved only 3.2 inches from their starting positions when they experience their peak base-pressure. The timing, bullet position, and percent of peak chamber pressure for this peak base-pressure event vary with caliber, cartridge, bullet weight, powder type and charge, and shot-start pressure required. QuickLOAD displays the base-pressure graphically as one of its options.
The maximum internal barrel expansion would occur at this point of peak base-pressure behind the bullet inside a barrel of typical steel construction and outside profile. The maximum amount of internal expansion is proportional to the peak pressure inside the barrel, but is non-linearly related to barrel wall thickness at that location. More wall thickness produces less expansion, but not linearly with that thickness. The internal expansion is typically 3 to 5 times greater than the amount of outside expansion of the barrel at that same point (which is also non-linear with wall thickness). Examine Lame's Equations for "thick-walled" pressure vessels to see these non-linear relationships. Wall thickness would be Ro-Ri. We only use wall thickness directly in Lame's Equations for "thin walled" pressure vessels IIRC. A "thin-walled" pressure vessel has a wall thickness of less than 10 percent of its OD. That is, Ri must be at least 90 percent of Ro, as near the muzzle end of a fine upland hunting shotgun barrel, for example.
Riflemen should understand that the residual tangential stresses (hoop-stresses) implanted in any button-rifled steel barrel cancel about the first 20 ksi to 25 ksi of any and all pressures subsequently applied internally. This is quite similar to the "autofrettaging" of artillery tubes during manufacturing.
An important point that few riflemen have realized is that the peak pressure inside the barrel is the sum of the peak gas pressure (51 ksi in our example) and the peak radial contact pressure of the bullet inside the barrel (24.6 ksi here). This summed peak internal pressure of 75.6 ksi exceeds the peak chamber pressure of 60 ksi here, and should always be kept below 100 ksi for steel rifle barrels. The rear-most full diameter portion of the bullet is the point of application for both internal pressures experienced by the barrel steel. I term this infinitesimally thin rear-most cross-section of moving bullet material the "obturating disc" inside the "obturation aperture" moving down the barrel with the rifle bullet.
I hope this answers your quite pertinent questions, George F.
Jim Boatright
The maximum internal barrel expansion would occur at this point of peak base-pressure behind the bullet inside a barrel of typical steel construction and outside profile. The maximum amount of internal expansion is proportional to the peak pressure inside the barrel, but is non-linearly related to barrel wall thickness at that location. More wall thickness produces less expansion, but not linearly with that thickness. The internal expansion is typically 3 to 5 times greater than the amount of outside expansion of the barrel at that same point (which is also non-linear with wall thickness). Examine Lame's Equations for "thick-walled" pressure vessels to see these non-linear relationships. Wall thickness would be Ro-Ri. We only use wall thickness directly in Lame's Equations for "thin walled" pressure vessels IIRC. A "thin-walled" pressure vessel has a wall thickness of less than 10 percent of its OD. That is, Ri must be at least 90 percent of Ro, as near the muzzle end of a fine upland hunting shotgun barrel, for example.
Riflemen should understand that the residual tangential stresses (hoop-stresses) implanted in any button-rifled steel barrel cancel about the first 20 ksi to 25 ksi of any and all pressures subsequently applied internally. This is quite similar to the "autofrettaging" of artillery tubes during manufacturing.
An important point that few riflemen have realized is that the peak pressure inside the barrel is the sum of the peak gas pressure (51 ksi in our example) and the peak radial contact pressure of the bullet inside the barrel (24.6 ksi here). This summed peak internal pressure of 75.6 ksi exceeds the peak chamber pressure of 60 ksi here, and should always be kept below 100 ksi for steel rifle barrels. The rear-most full diameter portion of the bullet is the point of application for both internal pressures experienced by the barrel steel. I term this infinitesimally thin rear-most cross-section of moving bullet material the "obturating disc" inside the "obturation aperture" moving down the barrel with the rifle bullet.
I hope this answers your quite pertinent questions, George F.
Jim Boatright
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Thank you very much for such a detailed and thoughtful response. I take it that the bullet is fully in the rifling at the time it experiences the maximal pressure. It is interesting that there seems to be a "sponge" effect seen in the steel as is apparent from the disproportionate expansion of the lumen of the barrel and the outside. Seems like the steel is actually compressed in the immediate vicinity of the surface experiencing the pressure. Is that true?
Yes, that is correct, George. Steel is very elastic with a modulus of elasticity (E) of 28.5 million psi for stainless alloys to 30 million psi for plain carbon-steel. I used 29 Mpsi which is about right for high-alloy steels like 4340 which is a great barrel steel. Yes, the bullet was engraved by the shot-start pressure which is only about 5 percent of the peak base-pressure.
By the way, that large 1.3 thousandths of an inch internal diameter expansion at peak base-pressure initiates a strong shear-wave (internal pressure expansions) which travel up and down the barrel at 10,630 fps in 4340 steel. This wave reflects from each end of the barrel. Best accuracy occurs when the muzzle end is not being expanded by this S-wave at the instant of bullet exit.
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I feel it is important to comment that one must understand alloy properties as far as sheer and tensel strength are measured by a quantified millage. and catastrophic falure is diifferent all togather and is directly influenced by how thick the alloy is . if alloy was subject to strictly its property rating then tanks and battle ships could be paper thin so don't think its ok to build big stuff on thin tenons and smaller shanks I have a general rule of .240 to .245 tenon wall thickness or thicker and a shank of .300 per side as a minimum on all my builds as a guideline for safe margens . thanks James for your comments
The most highly stressed steel around the chamber swell is the steel forming the chamber walls immediately surrounding the middle of the powder column in the loaded cartridge. That is why conformal piezoelectric pressure transducers are placed there. Al Harrell, retired mechanical engineer from Lawrence-Livermore Labs, has a color-fringe image of stress levels in the steel surrounding the chamber area and front ring of a 308-based cartridge being fired in a Remington 700 bolt-action on his website, <VarmintAl.com> . I collaborated on that study. He used his own fully dynamic finite element analysis program. I hand-calculated matching tri-axial von Mises stress values at key locations.
We also jointly recommend polishing the chamber walls highly in bolt-actions rifles so that the bolt-face carries all of the bolt thrust instead of stretching the brass case walls so as to share some of that axial loading. The idea of roughing the chamber walls to prevent case extraction problems came from P. O. Ackley in the 1950's. He was converting military surplus bolt-actions to firing more powerful hunting cartridges, but failed to comprehend the bolt-face "stiffening" available by simply blueprinting the action for full contact of the locking lugs. If just one out of two lugs is initially bearing in the receiver, the bolt-face is initially only half as stiff as it was designed to be. I trust that everyone here understands this pretty well from chambering powerful cartridges in shoulder fired rifles. Al likened Ackley's idea to protecting your car's chrome bumper with its brass radiator core.
Jim Boatright
We also jointly recommend polishing the chamber walls highly in bolt-actions rifles so that the bolt-face carries all of the bolt thrust instead of stretching the brass case walls so as to share some of that axial loading. The idea of roughing the chamber walls to prevent case extraction problems came from P. O. Ackley in the 1950's. He was converting military surplus bolt-actions to firing more powerful hunting cartridges, but failed to comprehend the bolt-face "stiffening" available by simply blueprinting the action for full contact of the locking lugs. If just one out of two lugs is initially bearing in the receiver, the bolt-face is initially only half as stiff as it was designed to be. I trust that everyone here understands this pretty well from chambering powerful cartridges in shoulder fired rifles. Al likened Ackley's idea to protecting your car's chrome bumper with its brass radiator core.
Jim Boatright
