Free: Contests & Raffles.
Velocity is your best indicator of pressure. If your chronograph is accurate and reliable, I would go by the velocity more than anything else. If the book says 2700 is max, then stop when you get to that velocity. Having said that, the Hodgdon data I'm looking at shows 2773 with 46.0 grains of Varget (assuming you're talking about a 308 Win.) And Nosler data shows 2820 fps with 46.0 grains of Varget, and 165 grain bullet. Both of these sources are using a 24 inch barrel so if yours is shorter you couldn't expect to match their velocities. I certainly wouldn't push it much further as long as you're getting good accuracy. 2700 fps is plenty for a 165 grain bullet. Gaining 50 or even 100 fps won't make any significant difference in performance.
Quote from: bobcat on April 21, 2018, 09:14:29 PMVelocity is your best indicator of pressure. If your chronograph is accurate and reliable, I would go by the velocity more than anything else. If the book says 2700 is max, then stop when you get to that velocity. Having said that, the Hodgdon data I'm looking at shows 2773 with 46.0 grains of Varget (assuming you're talking about a 308 Win.) And Nosler data shows 2820 fps with 46.0 grains of Varget, and 165 grain bullet. Both of these sources are using a 24 inch barrel so if yours is shorter you couldn't expect to match their velocities. my most recent load build up i was hoping for 3100+ fps but 3050 proved most accurate. primers looked good, bolt lift was easy, and most important of all it was accurate. i might have to adjust my zero a little bit, but id rather do that than stretch brass life and safety.I certainly wouldn't push it much further as long as you're getting good accuracy. 2700 fps is plenty for a 165 grain bullet. Gaining 50 or even 100 fps won't make any significant difference in performance.Not sure if I follow you when your saying velocity is pressure. Take a round with any of the Hogdon powders and see where your max velocity is. Then try it with a double base powder such as Reloader or Vhitavouri and it will be much higher. Bolt lift, flat primers, ejector marks are signs I look for pressure.
Velocity is your best indicator of pressure. If your chronograph is accurate and reliable, I would go by the velocity more than anything else. If the book says 2700 is max, then stop when you get to that velocity. Having said that, the Hodgdon data I'm looking at shows 2773 with 46.0 grains of Varget (assuming you're talking about a 308 Win.) And Nosler data shows 2820 fps with 46.0 grains of Varget, and 165 grain bullet. Both of these sources are using a 24 inch barrel so if yours is shorter you couldn't expect to match their velocities. my most recent load build up i was hoping for 3100+ fps but 3050 proved most accurate. primers looked good, bolt lift was easy, and most important of all it was accurate. i might have to adjust my zero a little bit, but id rather do that than stretch brass life and safety.I certainly wouldn't push it much further as long as you're getting good accuracy. 2700 fps is plenty for a 165 grain bullet. Gaining 50 or even 100 fps won't make any significant difference in performance.
Another common misconcep tion is that case separations are caused by excessive pressure. Well, no. Over the decades I’ve encountered a number of cartridge cases that were the victims of hot loads. Some had odd marks on the case head, while others had primer pockets large enough for two primers – though no trace of a primer was left in the hole. Yet none of these cases showed the shiny ring of stretching, and their bodies hadn’t cracked anywhere. Instead, case separations are caused by (you guessed it) excessive headspace. Now, often cases with a shiny ring in front of the case head, or actual cracks in the same area, also have flattened primers, supposedly a classic sign of high pressure. I hate to break the news, but flat primers aren’t necessarily an indication of high pressure, or even a very good sign. The primer myth has been around long enough that Gen. Julian Hatcher warned against it way back in 1947, when his book Hatcher’s Notebook was first published. (This is one of the basic texts of rifles and ammunition, even today, and every serious shooter should own a copy.) Early in the chapter on headspace, Hatcher discusses wildcat cartridges: “Usually the originator of one of these cartridges had no facilities for taking pressures, and depended entirely on the notoriously unreliable [emphasis mine] method of judging pressures by the appearance of the primer.” But myths are much harder to kill than create, so some handloaders continue to believe they can divine pressure from a primer.When a rifle cartridge goes off, the primer is pushed backward, due to powder gas pushing through the flash-hole, so it would seem to make sense that a really flat primer indicates high pressure. Not necessarily. A really flat primer can also be caused by slightly excessive headspace. When the firing pin hits the primer, it drives the case forward. If there’s a little slop between case and chamber, the expanding powder gas first pushes the primer backward in the primer pocket. If the pressure is low enough, as with the .30-30 Winchester, the primers will remain slightly backed out of the fired brass. This is common in ancient and well-worn .30-30 lever actions.If the pressure is higher, however, as with the .30-06, the rear of the primer itself expands a little as it backs out, since it’s no longer supported by the primer pocket. In another micro-second the case itself is thrust back over the slightly expanded primer. At the same time, the case stretches a little bit, so the handloader also finds a shiny ring a half-inch in front of the case head. Our innocent handloader now sees what he thinks are two signs of high pressure, when in reality the only problem is oversizing the case. Primer cups also vary in thickness and hardness not just from brand to brand, but lot to lot. Add tiny differences in headspace, and trying to “estimate” pressures from primer appearance is like trying to make shrimp jambalaya out of tofu and spinach.Now, the case itself can show signs of excessive pressure. One of the virtues of brass is that up to a certain pressure it remains flexible, returning near its original shape even after an instant of very high pressure. This is why brass is used in cartridge cases: The brass expands firmly against the chamber walls as the powder gas expands, sealing the chamber. But if subjected to “excessive” pressure, brass doesn’t spring back after firing. Instead it starts to flow.The first sign of excessive pressure is a small imprint on the case head from the ejector slot hole in the bolt face. This can be misleading, however, especially in a new rifle, due to a little ridge left by machining around theedge of the ejector hole. This ridge will eventually wear away with use, but initially it can leave a definite mark on brass even when firing factory ammunition. Today’s brass is often hard enough that signs of real distressdon’t appear until the pressure is over 70,000 psi, above the long term limit of modern rifle steels.So even if your brass doesn’t show ejector-hole marks, it doesn’t mean the load is safe, no matter what your cousin Elrod claims. One of the classic examples is the 7mm STW, originally developed as a wildcat. Many early users of the STW claimedthey could push 140-grain bullets3,500 to 3,600 fps without any traditional sign of excessive pressure – and they were right. But when the folks at Remington tested their loads, they found pressures of 70,000+ psi, the reason factory 7mm STW ballistics were toned down considerably.
John Barsness explains it better than I do.Read the article beginning on page 68 here:http://www.tulprpc.org/attachments/File/Load_Development_May_11.pdfOr here's part of it:QuoteAnother common misconcep tion is that case separations are caused by excessive pressure. Well, no. Over the decades I’ve encountered a number of cartridge cases that were the victims of hot loads. Some had odd marks on the case head, while others had primer pockets large enough for two primers – though no trace of a primer was left in the hole. Yet none of these cases showed the shiny ring of stretching, and their bodies hadn’t cracked anywhere. Instead, case separations are caused by (you guessed it) excessive headspace. Now, often cases with a shiny ring in front of the case head, or actual cracks in the same area, also have flattened primers, supposedly a classic sign of high pressure. I hate to break the news, but flat primers aren’t necessarily an indication of high pressure, or even a very good sign. The primer myth has been around long enough that Gen. Julian Hatcher warned against it way back in 1947, when his book Hatcher’s Notebook was first published. (This is one of the basic texts of rifles and ammunition, even today, and every serious shooter should own a copy.) Early in the chapter on headspace, Hatcher discusses wildcat cartridges: “Usually the originator of one of these cartridges had no facilities for taking pressures, and depended entirely on the notoriously unreliable [emphasis mine] method of judging pressures by the appearance of the primer.” But myths are much harder to kill than create, so some handloaders continue to believe they can divine pressure from a primer.When a rifle cartridge goes off, the primer is pushed backward, due to powder gas pushing through the flash-hole, so it would seem to make sense that a really flat primer indicates high pressure. Not necessarily. A really flat primer can also be caused by slightly excessive headspace. When the firing pin hits the primer, it drives the case forward. If there’s a little slop between case and chamber, the expanding powder gas firstpushes the primer backward in the primer pocket. If the pressure is low enough, as with the .30-30Winchester, the primers will remain slightly backed out of the fired brass. This is common in ancient and well-worn .30-30 lever actions.If the pressure is higher, however, as with the .30-06, the rear of the primer itself expands a little as it backs out, since it’s no longer supported by the primer pocket. In another micro-second the case itself is thrust back over the slightly expanded primer. At the same time, the case stretches a little bit, so the handloader also finds a shiny ring a half-inch in front of the case head. Our innocent handloader now sees what he thinks are two signs of high pressure, when in reality the only problem is oversizing the case. Primer cups also vary in thickness and hardness not just from brand to brand, but lot to lot. Add tiny differences in headspace, and trying to “estimate” pressures from primer appearance is like trying to make shrimp jambalaya out of tofu and spinach.Now, the case itself can show signs of excessive pressure. One of the virtues of brass is that up to a certain pressure it remains flexible, returning near its original shape even after an instant of very high pressure. This is why brass is used in cartridge cases: The brass expands firmly against the chamber walls as the powder gas expands, sealing the chamber. But if subjected to “excessive” pressure, brass doesn’t spring back after firing. Instead it starts to flow.The first sign of excessive pressure is a small imprint on the case head from the ejector slot hole in the bolt face. This can be misleading, however, especially in a new rifle, due to a little ridge left by machining around theedge of the ejector hole. This ridge will eventually wear away with use, but initially it can leave a definite mark on brass even when firing factory ammunition. Today’s brass is often hard enough that signs of real distressdon’t appear until the pressure is over 70,000 psi, above the long term limit of modern rifle steels.So even if your brass doesn’t show ejector-hole marks, it doesn’t mean the load is safe, no matter what your cousin Elrod claims. One of the classic examples is the 7mm STW, originally developed as a wildcat. Many early users of the STW claimedthey could push 140-grain bullets3,500 to 3,600 fps without any traditional sign of excessive pressure – and they were right. But when the folks at Remington tested their loads, they found pressures of 70,000+ psi, the reason factory 7mm STW ballistics were toned down considerably.
Another common misconcep tion is that case separations are caused by excessive pressure. Well, no. Over the decades I’ve encountered a number of cartridge cases that were the victims of hot loads. Some had odd marks on the case head, while others had primer pockets large enough for two primers – though no trace of a primer was left in the hole. Yet none of these cases showed the shiny ring of stretching, and their bodies hadn’t cracked anywhere. Instead, case separations are caused by (you guessed it) excessive headspace. Now, often cases with a shiny ring in front of the case head, or actual cracks in the same area, also have flattened primers, supposedly a classic sign of high pressure. I hate to break the news, but flat primers aren’t necessarily an indication of high pressure, or even a very good sign. The primer myth has been around long enough that Gen. Julian Hatcher warned against it way back in 1947, when his book Hatcher’s Notebook was first published. (This is one of the basic texts of rifles and ammunition, even today, and every serious shooter should own a copy.) Early in the chapter on headspace, Hatcher discusses wildcat cartridges: “Usually the originator of one of these cartridges had no facilities for taking pressures, and depended entirely on the notoriously unreliable [emphasis mine] method of judging pressures by the appearance of the primer.” But myths are much harder to kill than create, so some handloaders continue to believe they can divine pressure from a primer.When a rifle cartridge goes off, the primer is pushed backward, due to powder gas pushing through the flash-hole, so it would seem to make sense that a really flat primer indicates high pressure. Not necessarily. A really flat primer can also be caused by slightly excessive headspace. When the firing pin hits the primer, it drives the case forward. If there’s a little slop between case and chamber, the expanding powder gas firstpushes the primer backward in the primer pocket. If the pressure is low enough, as with the .30-30Winchester, the primers will remain slightly backed out of the fired brass. This is common in ancient and well-worn .30-30 lever actions.If the pressure is higher, however, as with the .30-06, the rear of the primer itself expands a little as it backs out, since it’s no longer supported by the primer pocket. In another micro-second the case itself is thrust back over the slightly expanded primer. At the same time, the case stretches a little bit, so the handloader also finds a shiny ring a half-inch in front of the case head. Our innocent handloader now sees what he thinks are two signs of high pressure, when in reality the only problem is oversizing the case. Primer cups also vary in thickness and hardness not just from brand to brand, but lot to lot. Add tiny differences in headspace, and trying to “estimate” pressures from primer appearance is like trying to make shrimp jambalaya out of tofu and spinach.Now, the case itself can show signs of excessive pressure. One of the virtues of brass is that up to a certain pressure it remains flexible, returning near its original shape even after an instant of very high pressure. This is why brass is used in cartridge cases: The brass expands firmly against the chamber walls as the powder gas expands, sealing the chamber. But if subjected to “excessive” pressure, brass doesn’t spring back after firing. Instead it starts to flow.The first sign of excessive pressure is a small imprint on the case head from the ejector slot hole in the bolt face. This can be misleading, however, especially in a new rifle, due to a little ridge left by machining around theedge of the ejector hole. This ridge will eventually wear away with use, but initially it can leave a definite mark on brass even when firing factory ammunition. Today’s brass is often hard enough that signs of real distressdon’t appear until the pressure is over 70,000 psi, above the long term limit of modern rifle steels.So even if your brass doesn’t show ejector-hole marks, it doesn’t mean the load is safe, no matter what your cousin Elrod claims. One of the classic examples is the 7mm STW, originally developed as a wildcat. Many early users of the STW claimedthey could push 140-grain bullets3,500 to 3,600 fps without any traditional sign of excessive pressure – and they were right. But when the folks at Remington tested their loads, they found pressures of 70,000+ psi, the reason factory 7mm STW ballistics were toned down considerably.
