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April 21st, 2024
Photo 1: Three Near-Equal-Weight 7mm Bullets with Different Shapes
TECH TIP: Bullets of the same weight (and caliber) can generate very different pressure levels due to variances in Bearing Surface Length (BSL).
This article, from the USAMU Facebook Page, concerns reloading safety. In the relentless quest for more speed and flatter ballistics, some hand-loaders load way too hot, running charges that exceed safe pressure levels. Hint: If you need a mallet to open your bolt, chances are your load is too hot. Stay within safe margins — your equipment will last longer, and you won’t risk an injury caused by over-pressure. In this article, the USAMU explains that you need to account for bullet shape, diameter, and bearing surface when working up a load. Don’t assume that a load which is safe for one bullet will be safe for another even if both bullets are exactly the same weight.
How Bullet Profile and Bearing Surface Affect Pressure Levels
Today, we continue our handloading safety theme, focusing on not inadvertently exceeding the boundaries of known, safe data. Bullet manufacturers’ loading manuals often display three, four, or more similar-weight bullets grouped together with one set of load recipes. The manufacturer has tested these bullets and developed safe data for that group. However, seeing data in this format can tempt loaders — especially new ones — to think that ALL bullets of a given weight and caliber can interchangeably use the same load data. Actually, not so much.
However, bullet designs include many variables such as different bearing surface lengths, hardness, and even slight variations in diameter. In fact, diameters can occasionally range up to 0.001″ by design. Thus, choosing untested bullets of the same weight and caliber, and using them with data not developed for them can yield excess pressures.
This is only one of the countless reasons not to begin at or very near the highest pressure loads during load development. Always begin at the starting load and look for pressure signs as one increases powder charges.
Bullet Bearing Surface and Pressure
Bullet bearing surface length (BSL) is often overlooked when considering maximum safe powder charges and pressures. In Photo 1, note the differences in the bullets’ appearance. All three are 7 mm, and their maximum weight difference is just five grains. Yet, the traditional round nose, flat base design on the left appears to have much more BSL than the sleeker match bullets. All things being equal, based on appearance, the RN/FB bullet seems likely to reach maximum pressure with significantly less powder than the other two designs.
TECH TIP: Bullets of the same weight (and caliber) can generate very different pressure levels due to variances in Bearing Surface Length (BSL).
 Bullet 1 (L-R), the RN/FB, has a very slight taper and only reaches its full diameter (0.284 inch) very near the cannelure. This taper is often seen on similar bullets; it helps reduce pressures with good accuracy. The calculated BSL of Bullet 1 was ~0.324″. The BSL of Bullet 2, in the center, was ~0.430″, and Bullet 3’s was ~ 0.463″. Obviously, bullets can be visually deceiving as to BSL!
Some might be tempted to use a bullet ogive comparator (or two) to measure bullets’ true BSL for comparison’s sake. Unfortunately, comparators don’t typically measure maximum bullet diameter and this approach can be deluding.
Note: Due to time constraints, the writer used an approximate, direct measurement approach to assess the bullets’ different BSLs. While fairly repeatable, the results were far from ballistics engineer-grade. Still, they are adequate for this example.
Photo 2: The Perils of Measuring Bearing Surface Length with Comparators
In Photo 2, two 7mm comparators have been installed on a dial caliper in an attempt to measure BSL. Using this approach, the BSLs differed sharply from the original [measurements]. The comparator-measured Bullet 1 BSL was 0.694” vs. 0.324” (original), Bullet 2 was 0.601” (comparator) vs. 0.430” (original), and Bullet 3 (shown in Photo 2) was 0.602” (comparator) vs. 0.463” (original). [Editor’s comment — Note the very large difference for Bullet 1, masking the fact that the true full diameter on this bullet starts very far back. You can use comparators on calipers, but be aware that this method may give you deceptive reading — we’ve seen variances just by reversing the comparators on the calipers, because the comparators, typically, are not perfectly round, nor are they machined to precision tolerances.]
Thanks to the U.S. Army Marksmanship Unit for allowing the reprint of this article.
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July 16th, 2023
Photo 1: Three Near-Equal-Weight 7mm Bullets with Different Shapes
TECH TIP: Bullets of the same weight (and caliber) can generate very different pressure levels due to variances in Bearing Surface Length (BSL).
This article, from the USAMU Facebook Page, concerns reloading safety. In the relentless quest for more speed and flatter ballistics, some hand-loaders load way too hot, running charges that exceed safe pressure levels. Hint: If you need a mallet to open your bolt, chances are your load is too hot. Stay within safe margins — your equipment will last longer, and you won’t risk an injury caused by over-pressure. In this article, the USAMU explains that you need to account for bullet shape, diameter, and bearing surface when working up a load. Don’t assume that a load which is safe for one bullet will be safe for another even if both bullets are exactly the same weight.
How Bullet Profile and Bearing Surface Affect Pressure Levels
Today, we continue our handloading safety theme, focusing on not inadvertently exceeding the boundaries of known, safe data. Bullet manufacturers’ loading manuals often display three, four, or more similar-weight bullets grouped together with one set of load recipes. The manufacturer has tested these bullets and developed safe data for that group. However, seeing data in this format can tempt loaders — especially new ones — to think that ALL bullets of a given weight and caliber can interchangeably use the same load data. Actually, not so much.
The researchers ensure their data is safe with the bullet yielding the highest pressure. Thus, all others in that group should produce equal or less pressure, and they are safe using this data.
However, bullet designs include many variables such as different bearing surface lengths, hardness, and even slight variations in diameter. In fact, diameters can occasionally range up to 0.001″ by design. Thus, choosing untested bullets of the same weight and caliber, and using them with data not developed for them can yield excess pressures.
This is only one of the countless reasons not to begin at or very near the highest pressure loads during load development. Always begin at the starting load and look for pressure signs as one increases powder charges.
Bullet Bearing Surface and Pressure
Bullet bearing surface length (BSL) is often overlooked when considering maximum safe powder charges and pressures. In Photo 1, note the differences in the bullets’ appearance. All three are 7 mm, and their maximum weight difference is just five grains. Yet, the traditional round nose, flat base design on the left appears to have much more BSL than the sleeker match bullets. All things being equal, based on appearance, the RN/FB bullet seems likely to reach maximum pressure with significantly less powder than the other two designs.
TECH TIP: Bullets of the same weight (and caliber) can generate very different pressure levels due to variances in Bearing Surface Length (BSL).
Bullet 1 (L-R), the RN/FB, has a very slight taper and only reaches its full diameter (0.284 inch) very near the cannelure. This taper is often seen on similar bullets; it helps reduce pressures with good accuracy. The calculated BSL of Bullet 1 was ~0.324″. The BSL of Bullet 2, in the center, was ~0.430″, and Bullet 3’s was ~ 0.463″. Obviously, bullets can be visually deceiving as to BSL!
Some might be tempted to use a bullet ogive comparator (or two) to measure bullets’ true BSL for comparison’s sake. Unfortunately, comparators don’t typically measure maximum bullet diameter and this approach can be deluding.
Note: Due to time constraints, the writer used an approximate, direct measurement approach to assess the bullets’ different BSLs. While fairly repeatable, the results were far from ballistics engineer-grade. Still, they are adequate for this example.
Photo 2: The Perils of Measuring Bearing Surface Length with Comparators
In Photo 2, two 7mm comparators have been installed on a dial caliper in an attempt to measure BSL. Using this approach, the BSLs differed sharply from the original [measurements]. The comparator-measured Bullet 1 BSL was 0.694” vs. 0.324” (original), Bullet 2 was 0.601” (comparator) vs. 0.430” (original), and Bullet 3 (shown in Photo 2) was 0.602” (comparator) vs. 0.463” (original). [Editor’s comment — Note the very large difference for Bullet 1, masking the fact that the true full diameter on this bullet starts very far back. You can use comparators on calipers, but be aware that this method may give you deceptive reading — we’ve seen variances just by reversing the comparators on the calipers, because the comparators, typically, are not perfectly round, nor are they machined to precision tolerances.]
Thanks to the U.S. Army Marksmanship Unit for allowing the reprint of this article.
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July 12th, 2022
It’s great to be able to access online load data for your cartridges. You can quickly get load data for a particular powder and bullet weight. However, there are times when we prefer to consult old-fashioned printed/bound load manuals. The primary reason is that manuals produced by bullet- and tool-makers will, for a particular cartridge, include data for powders from multiple manufacturers. Having a single source can save you time and trouble. For example, if you want to find 6.5 Creedmoor loads using H4350 (Hodgdon), Reloder 16 (Alliant), and N150 (Vihtavuori) you would have to visit three different powder-maker websites, one after another. OR you can pick up a modern load manual and find everything in one place.
There are many excellent printed load manuals on the market. We have used the Berger Manual, Sierra Manual, Speer Manual, Lyman Manual, and Hornady Manual. We like the Berger and Sierra manuals for match rifle cartridges, and the Lyman and Hornady manuals for hunting loads and pistol cartridges. Unfortunately, the popular binder-format Sierra Manual is currently back-ordered. But the excellent Nosler Reloading Guide 9 is back in stock at Midsouth for $28.99.
The Lyman Reloading Manuals have earn praise over the years:
“Every other reloading book I’ve used favors their own bullets over every other manufacturers. With Lyman you get an honest representation of a wide variety of different… manufacturers. [Lyman has] a ton of reloading data on just about any bullet style you can imagine. I’ve tried a wide range of their recipes and everyone I’ve tried has been spot on. The overall breadth of information this book covers is impressive.” Review by RangetoReal.com.
Along with the Lyman 50th Edition Manual, here are other recommended Reloading Manuals:
Here Are Four General Instructional Books That Cover Reloading Procedures:
POWDER BURN RATE TABLE
Here is the most recent powder burn rate chart from Hodgdon/IMR that we could find. Click links below to access printable PDF. Note, some readers have suggested a couple powder ranking issues in the table. However, this is the latest official version from the IMR website, released in November 2019.
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November 19th, 2021
Nosler now offers the Nosler Reloading Guide #9, the latest in a respected series of hardback Nosler load manuals. This 800-page guide covers 101 cartridge types. New in this edition you’ll find the popular 6mm Creedmoor, 6mm XC, 6.5 PRC, and 7.62×39, along with 20 Nosler, 22 Nosler, 24 Nosler, 27 Nosler and 33 Nosler. This new guide draws from thousands of hours in the Nosler Ballistic Lab, along with the experience of many respected experts.
The book is available now for $27.99 at Grafs.com. In addition, much of the book’s latest load data is available for free on the Nosler.com online LOAD DATA Center. But to get ALL the data, PLUS the technical articles, you’ll need to buy the book.
The Nosler Reloading Guide 9 Reloading Manual provides load data for 101 rifle and handgun cartridges with hundreds of new powder additions. A comprehensive data set for today’s reloader, this manual is current with every bullet that Nosler offers through 2020 from 17 caliber up to 458 caliber in the rifle section and 9mm up to 45 caliber in the handgun section. Nine new cartridges were added to this manual. These include: 20 Nosler, 22 Nosler, 24 Nosler, 6mm Creedmoor, 6mm XC, 6.5 PRC, 27 Nosler, 7.62×39 and 33 Nosler. Also new for the Nosler Reloading Guide #9 are cartridge introductions written by veteran outdoor writers and industry tech experts. The 800-page book also has helpful “how-to” sections such as “Getting Ready to Reload”.
Q. Why Buy a Book when Load Data is Available Online from Powder Makers?
There are good, solid reasons to buy print-format loading guides produced by bullet-makers. If you go to the Hodgdon online Reloading Data Center you’ll only find loads with Hodgdon, IMR, and Winchester powders — the key brands they sell. In a book such as this Nosler #9 or the Sierra Reloading Manual, you will find loads with a much wider selection of powders including Vihtavuori, Alliant, Accurate, Norma, Ramshot, and other brands. You won’t find a Reloder 16 or VV N140 load on Hodgdon’s website.
In addition, it is handy to have loads in a print edition which is easy to access on your load bench. You don’t need a computer or an internet connection. And using a book is often faster than a web interface when quickly scanning through a variety of bullet choices for a cartridge.
Along with the Nosler #9 Manual, here are four other recommended Reloading Manuals:
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July 27th, 2021
It’s great to be able to access online load data for your cartridges. You can quickly get load data for a particular powder and bullet weight. However, there are times when we prefer to consult old-fashioned printed/bound load manuals. The primary reason is that manuals produced by bullet- and tool-makers will, for a particular cartridge, include data for powders from multiple manufacturers. Having a single source can save you time and trouble. For example, if you want to find 6.5 Creedmoor loads using H4350 (Hodgdon), Reloder 16 (Alliant), and N150 (Vihtavuori) you would have to visit three different powder-maker websites, one after another. OR you can pick up a modern load manual and find everything in one place.
There are many excellent printed load manuals on the market. We have used the Berger Manual, Sierra Manual, Speer Manual, Lyman Manual, and Hornady Manual. We like the Berger and Sierra manuals for match rifle cartridges, and the Lyman and Hornady manuals for hunting loads and pistol cartridges. Unfortunately, the popular binder-format Sierra Manual is currently back-ordered. Get one if you can.
The Lyman Reloading Manuals have earn praise over the years:
“Every other reloading book I’ve used favors their own bullets over every other manufacturers. With Lyman you get an honest representation of a wide variety of different… manufacturers. [Lyman has] a ton of reloading data on just about any bullet style you can imagine. I’ve tried a wide range of their recipes and everyone I’ve tried has been spot on. The overall breadth of information this book covers is impressive.” Review by RangetoReal.com.
 Nosler #9 Manual Features New Cartridges
If you are looking for up-to-date cartridge/bullet/powder information, in late 2020 Nosler released the Nosler Reloading Guide #9, the latest in a respected series of Nosler load manuals.
This 800-page guide covers 101 cartridge types. New in this edition you’ll find the popular 6mm Creedmoor, 6mm XC, 6.5 PRC, and 7.62×39, along with 20 Nosler, 22 Nosler, 24 Nosler, 27 Nosler and 33 Nosler. This manual is a good resource for PRS shooters and hunters. The Nosler #9 book draws from thousands of hours in the Nosler Ballistic Lab, along with the experience of many respected experts.
The book is available for $28.99 at Midsouth or $29.95 on Amazon. Keep in mind that much of the book’s latest load data is available for free on the Nosler.com online LOAD DATA Center. But to get ALL the data, PLUS all the technical articles, you’ll need to buy the book.
Along with the new Nosler #9 Manual, here are four other recommended Reloading Manuals:
Here Are Four General Instructional Books That Cover Reloading Procedures:
POWDER BURN RATE TABLE
Here is the most recent powder burn rate chart from Hodgdon/IMR that we could find. Click links below to access printable PDF. Note, some readers have suggested a couple powder ranking issues in the table. However, this is the latest official version from the IMR website, released in November 2019.
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April 16th, 2021
Three near-equal-weight 7mm bullets with different shapes and bearing surface.
This article, from the USAMU Facebook Page, concerns reloading safety. In the relentless quest for more speed and flatter ballistics, some hand-loaders load way too hot, running charges that exceed safe pressure levels. Hint: If you need a mallet to open your bolt, chances are your load is too hot. Stay within safe margins — your equipment will last longer, and you won’t risk an injury caused by over-pressure. In this article, the USAMU explains that you need to account for bullet shape, diameter, and bearing surface when working up a load. Don’t assume that a load which is safe for one bullet will be safe for another even if both bullets are exactly the same weight.
Today, we continue our handloading safety theme, focusing on not inadvertently exceeding the boundaries of known, safe data. Bullet manufacturers’ loading manuals often display three, four, or more similar-weight bullets grouped together with one set of load recipes. The manufacturer has tested these bullets and developed safe data for that group. However, seeing data in this format can tempt loaders — especially new ones — to think that ALL bullets of a given weight and caliber can interchangeably use the same load data. Actually, not so much.
The researchers ensure their data is safe with the bullet yielding the highest pressure. Thus, all others in that group should produce equal or less pressure, and they are safe using this data.
However, bullet designs include many variables such as different bearing surface lengths, hardness, and even slight variations in diameter. In fact, diameters can occasionally range up to 0.001″ by design. Thus, choosing untested bullets of the same weight and caliber, and using them with data not developed for them can yield excess pressures.
This is only one of the countless reasons not to begin at or very near the highest pressure loads during load development. Always begin at the starting load and look for pressure signs as one increases powder charges.
Bullet Bearing Surface and Pressure
Bullet bearing surface length (BSL) is often overlooked when considering maximum safe powder charges and pressures. In Photo 1, note the differences in the bullets’ appearance. All three are 7 mm, and their maximum weight difference is just five grains. Yet, the traditional round nose, flat base design on the left appears to have much more BSL than the sleeker match bullets. All things being equal, based on appearance, the RN/FB bullet seems likely to reach maximum pressure with significantly less powder than the other two designs.
TECH TIP: Bullets of the same weight (and caliber) can generate very different pressure levels due to variances in Bearing Surface Length (BSL).
Bullet 1 (L-R), the RN/FB, has a very slight taper and only reaches its full diameter (0.284 inch) very near the cannelure. This taper is often seen on similar bullets; it helps reduce pressures with good accuracy. The calculated BSL of Bullet 1 was ~0.324″. The BSL of Bullet 2, in the center, was ~0.430″, and Bullet 3’s was ~ 0.463″. Obviously, bullets can be visually deceiving as to BSL!
Some might be tempted to use a bullet ogive comparator (or two) to measure bullets’ true BSL for comparison’s sake. Unfortunately, comparators don’t typically measure maximum bullet diameter and this approach can be deluding.
Note: Due to time constraints, the writer used an approximate, direct measurement approach to assess the bullets’ different BSLs. While fairly repeatable, the results were far from ballistics engineer-grade. Still, they are adequate for this example.
Photo 2: The Perils of Measuring Bearing Surface Length with Comparators
In Photo 2, two 7mm comparators have been installed on a dial caliper in an attempt to measure BSL. Using this approach, the BSLs differed sharply from the original [measurements]. The comparator-measured Bullet 1 BSL was 0.694” vs. 0.324” (original), Bullet 2 was 0.601” (comparator) vs. 0.430” (original), and Bullet 3 (shown in Photo 2) was 0.602” (comparator) vs. 0.463” (original). [Editor’s comment — Note the very large difference for Bullet 1, masking the fact that the true full diameter on this bullet starts very far back. You can use comparators on calipers, but be aware that this method may give you deceptive reading — we’ve seen variances just by reversing the comparators on the calipers, because the comparators, typically, are not perfectly round, nor are they machined to precision tolerances.]
Thanks to the U.S. Army Marksmanship Unit for allowing the reprint of this article.
Share the post "How Bullet Bearing Surface Length Can Affect Load Pressure"
January 6th, 2021
It’s great to be able to access online load data for your cartridges. You can quickly get load data for a particular powder and bullet weight. However, there are times when we prefer to consult old-fashioned printed/bound load manuals. The primary reason is that manuals produced by bullet- and tool-makers will, for a particular cartridge, include data for powders from multiple manufacturers. Having a single source can save you time and trouble. For example, if you want to find 6.5 Creedmoor loads using H4350 (Hodgdon), Reloder 16 (Alliant), and N150 (Vihtavuori) you would have to visit three different powder-maker websites, one after another. OR you can pick up a modern load manual and find everything in one place.
There are many excellent printed load manuals on the market. We have used the Berger Manual, Sierra Manual, Speer Manual, Lyman Manual, and Hornady Manual. We like the Berger and Sierra manuals for match rifle cartridges, and the Lyman and Hornady manuals for hunting loads and pistol cartridges. Unfortunately, the popular binder-format Sierra Manual is currently back-ordered. Get one if you can.
The Lyman Reloading Manuals have earn praise over the years:
“Every other reloading book I’ve used favors their own bullets over every other manufacturers. With Lyman you get an honest representation of a wide variety of different… manufacturers. [Lyman has] a ton of reloading data on just about any bullet style you can imagine. I’ve tried a wide range of their recipes and everyone I’ve tried has been spot on. The overall breadth of information this book covers is impressive.” Review by RangetoReal.com.
Nosler #9 Manual Features New Cartridges
If you are looking for the latest cartridge/bullet/powder updates, just last month (December 2020) Nosler released the new Nosler Reloading Guide #9, the latest in a respected series of hardback Nosler load manuals.
This 800-page guide covers 101 cartridge types. New in this edition you’ll find the popular 6mm Creedmoor, 6mm XC, 6.5 PRC, and 7.62×39, along with 20 Nosler, 22 Nosler, 24 Nosler, 27 Nosler and 33 Nosler. This manual is a good resource for PRS shooters and hunters. The Nosler #9 book draws from thousands of hours in the Nosler Ballistic Lab, along with the experience of many respected experts.
The book is available for $24.99 at Midsouth or $24.95 on Amazon. Keep in mind that much of the book’s latest load data is available for free on the Nosler.com online LOAD DATA Center. But to get ALL the data, PLUS all the technical articles, you’ll need to buy the book.
Along with the new Nosler #9 Manual, here are four other recommended Reloading Manuals:
Here Are Four General Instructional Books That Cover Reloading Procedures:
POWDER BURN RATE TABLE
Here is the most recent powder burn rate chart from Hodgdon/IMR that we could find. Click links below to access printable PDF. Note, some readers have suggested a couple powder ranking issues in the table. However, this is the latest official version from the IMR website, released in November 2019.
Share the post "Reloading Manuals — Top Choices for a Handloader’s Library"
December 11th, 2020
Nosler has just released the Nosler Reloading Guide #9, the latest in a respected series of hardback Nosler load manuals. This 800-page guide covers 101 cartridge types. New in this edition you’ll find the popular 6mm Creedmoor, 6mm XC, 6.5 PRC, and 7.62×39, along with 20 Nosler, 22 Nosler, 24 Nosler, 27 Nosler and 33 Nosler. This new guide draws from thousands of hours in the Nosler Ballistic Lab, along with the experience of many respected experts.
The book is available right now for $24.99 at Grafs.com. In addition, much of the book’s latest load data is available for free on the Nosler.com online LOAD DATA Center. But to get ALL the data, PLUS the technical article, you’ll need to buy the book.
The Nosler Reloading Guide 9 Reloading Manual provides load data for 101 rifle and handgun cartridges with hundreds of new powder additions. A comprehensive data set for today’s reloader, this manual is current with every bullet that Nosler offers through 2020 from 17 caliber up to 458 caliber in the rifle section and 9mm up to 45 caliber in the handgun section. Nine new cartridges were added to this manual. These include: 20 Nosler, 22 Nosler, 24 Nosler, 6mm Creedmoor, 6mm XC, 6.5 PRC, 27 Nosler, 7.62×39 and 33 Nosler. Also new for the Nosler Reloading Guide #9 are cartridge introductions written by veteran outdoor writers and industry tech experts. The 800-page book also has helpful “how-to” sections such as “Getting Ready to Reload”.
Q. Why Buy a Book when Load Data is Available Online from Powder Makers?
There are good, solid reasons to buy print-format loading guides produced by bullet-makers. If you go to the Hodgdon online Reloading Data Center you’ll only find loads with Hodgdon, IMR, and Winchester powders — the key brands they sell. In a book such as this Nosler #9 or the Sierra Reloading Manual, you will find loads with a much wider selection of powders including Vihtavuori, Alliant, Accurate, Norma, Ramshot, and other brands. You won’t find a Reloder 16 or VV N140 load on Hodgdon’s website.
In addition, it is handy to have loads in a print edition which is easy to access on your load bench. You don’t need a computer or an internet connection. And using a book is often faster than a web interface when quickly scanning through a variety of bullet choices for a cartridge.
Along with the new Nosler #9 Manual, here are four other recommended Reloading Manuals:
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January 11th, 2018
Written by Sierra Bullets Ballistic Technician Duane Siercks
One of the first things new reloaders notice is that load data varies between reloading manuals. The Sierra Bullets Technicians frequently get inquiries asking us to explain why the load data appears to be inconsistent. This article explains five key factors that can influence published load data.
Example of load data variances for two 168 grain bullets:
Here are five reasons why the load data varies:
The Bullet
Basically, the similarities in the .30 caliber 168 grain Match bullets (for example) end with weight and diameter. The bullets likely have dimensional differences such as bearing surface length. Bearing surface has a large effect on pressure and velocity. There are also differences in boat tail, flat base, ogive and over-all lengths, which each help determine the cartridge over-all-length (COAL). With different COAL’s, we can expect changes in pressure and velocity also. In some calibers there are differences in bullet diameter with different bullet manufacturers.
It is also worth noting that bullet manufacturers do not all use the same copper alloy for their jackets. This produces more or less friction that results in load pressures and velocities. The solid copper bullets also vary quite a bit in comparison to a lead core and copper jacketed bullet.
The Gun
Each gun is unique, even if you are using the same make, model, and caliber. Special consideration should be used to consider that not all firearm chambers are the same either, creating more variables that need consideration. There can be drastic differences in the throat length. This controls the amount of “jump” that a bullet experiences when the cartridge is fired.
The Powder
Within normal manufacturing tolerances, you can see some variation in a given powders burn rate between different lots of the same powder. So naturally when two different Manuals are produced, it would be doubtful that the same lots would be tested.
The Cartridge Cases
New cases are almost always near minimum specs in dimension. A load fired in a new case would likely have slightly more pressure that when fired in a re-sized case. This would certainly be true if we were loading into fire-formed cases that have had minimal re-sizing done. Fired cases that are full length resized most of the time be slightly larger than the new unfired cases. This gives you differences in case capacity. The same powder charge placed within a new case and a full length resized case will produce different pressure levels and probably different velocities.
Conditions
Temperature can cause pressure increases or decreases. Hot temperatures tend to cause pressures to increase, while cold temperatures will usually do the opposite. Humidity and altitude can impact pressures and velocities likewise.
Conclusion
As you can see, an amazing number of variables effect any load combination. With the differences in the manuals, you’re just seeing firsthand examples of what took place when the data was collected with that particular set of components and firearm. Think of a reloading manual as a report. In essence, a reloading manual says, “We tried this particular component combination, and these are the results we obtained.”
Remember that you may or may not reach the same maximum load safely. There is no “one load fits all bullets.” The minimum load data offers a safe place to start. The maximum load data listed should always be regarded as a safety guideline and not necessarily a goal! Your gun should shoot accurately without breaching the maximum load data. The best advice is: always start low and work your load up!
If you have questions about variances in load data or other reloading questions, please call our ballistic technicians at 1-800-223-8799 or send us an email at sierra [at] sierrabullets.com.
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June 5th, 2016
What’s the best book for folks getting started in metallic cartridge reloading? According to our Forum members, the best manual for “newbie” reloaders is the Lyman Reloading Handbook. In our Shooters’ Forum, a newcomer to reloading was looking for a basic reloading guide that also included load data. The most recommended book was the Lyman Handbook, now in its 50th Edition (just released). Along with “how-to” advice on reloading procedures, the Lyman Manual features cartridge specifications and load data for the most popular cartridges.*
Here are some comments from Forum members:
“The Lyman book is an excellent manual with a large section describing the process of reloading. I heartily recommend it. As a beginning reloader, you may want to consider purchasing more than one book in order to get different perspectives on the reloading regimen. One can never be too careful. A ‘minor’ mistake can be costly.” — Cort
“In my opinion, the Lyman Manual is one of the best for the beginning reloader since it covers all the basics and some advanced methods. If possible, you would be also well served to hook up with an experienced reloader, preferably a target shooter or long-range varmint hunter, who can also give you some very useful pointers on precision reloading.” – K22
Editor’s NOTE: K22 echoes the advice we give to new hand-loaders. We suggest that novices find an experienced mentor who can “show them the ropes” and guide them through the basics.
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Another gun blogger agrees that the Lyman Manual is a logical choice for new handloaders:
Carteach Review: The Lyman Reloading Manual
“[Lyman publishes] an excellent manual for any handloader, but especially for those new to the craft. Perhaps the best judgment of a handloader’s regard for a reloading manual is which one he chooses to give someone new to the fold. The needs of a new reloader differ from those of someone with long experience, and the right manual can set the foundation for years of safe procedures. Here is the one I choose to give a good friend embarking down the path:”
Carteach adds: “Lyman has always taken pains to provide very clear and understandable instruction on the basic process of reloading cartridges. The imaging is helpful and to the point. The load data Lyman provides is comprehensive, and [Lyman] takes the time to note special circumstances which new loaders need to be aware of. As example, the .30-06 section has some words regarding the M-1 Garand and its special needs. For someone who has never loaded for the Garand, these few sentences are golden!” |
*We recommend that you always double-check printed load data with the latest web-based data from the actual powder manufacturers. Powder properties can change. The most current powder data is usually found on the powder-makers’ websites.
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February 8th, 2016
We are often asked, “Can you recommend a good reloading book that picks up where the typical reloading manual leaves off — something that goes into more detail about the processes involved.” There is such a book, and it’s fairly recent: Metallic Cartridge Handloading: Pursuit of the Perfect Cartridge, by M.L. (“Mic”) McPherson. Released in 2013, this 425-page book goes into greater depth than McPherson’s popular intro reloading guide, Metallic Cartridge Reloading. McPherson’s latest reloading treatise covers all aspects of the reloading process: the cartridge case; maintaining, improving and loading the case; the seating and reading of primers; the loading of propellant; bullets and the loading of bullets; accurate load development; internal and external ballistics; bullet making and casting; and reloading presses.
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With hundreds of photos and illustrations, this book is a good reference for shooters getting started in precision reloading for accuracy. Compared to some other books on reloading procedures, McPherson’s new resource is more up-to-date, so it references more modern reloading tools and techniques. NOTE: This is NOT a reloading manual containing specific load data. Rather, it is a how-to book that covers the process of cartridge reloading from start to finish.
Reviews by actual book buyers:
A great resource for handloaders although a little technical for beginners. I have been reloading for 40+ years and picked up some good ideas. — Loren R.
This is a book intended for people who have been reloading for a while. The book contains very detailed information about reloading. — Kaj H.
About the Author, M.L. (“Mic”) McPherson:
Mic McPherson, Technical Editor of Hand Loader’s Digest, is the author of numerous firearms resource books including Metallic Cartridge Reloading and Accurizing the Factory Rifle. He has written scores of articles for leading gun periodicals including Precision Shooting, The Accurate Rifle, Rifle Shooter, and Varmint Hunter Magazine. Mic also served as an Editor of the 8th and 9th Editions of Cartridges of the World.
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May 21st, 2012
MidwayUSA has knocked $1.50 off the prices of LoadBooks reload manuals for three of the most popular centerfire calibers: .223 Rem, .308 Win, and .30-06. As discounted, these manuals now cost $5.49 (regular price $6.99). In addition, the most popular pistol load manuals are also marked down to $5.49 (9mm, .38 Spl, .357 Mag, 40sw, and .45 ACP, .45 Colt).
All of these caliber-specific reloading guides are packed with information from major US bullet- and powder-makers including Accurate, Alliant, Hodgdon, Hornady, IMR, Lyman, Nosler, RCBS, Sierra, Speer and Winchester. LoadBook manuals are printed on heavyweight paper and spiral-bound so they will lay flat on any surface. Most load manuals have about 54 pages. NOTE: since most of these manuals have not been updated within the last 5 years, you won’t find the latest bullet designs or recently-introduced powders such as Hodgdon Hybrid 100V or Alliant Reloder 17.
| .223 Rem |
.308 Win |
.30-06 |
1555 Tested Loads
58 Bullets, 40 Powders |
1940 Tested Loads
80 Bullets, 42 Powders |
2138 Tested Loads
83 Bullets, 59 Powders |
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