Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Pressure signs/chronographing
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="travelr47" data-source="post: 206057" data-attributes="member: 5339"><p>I'm in agreement with 280Rem re velocity and the use of a chronograph to aide in determining pressure without pressure testing equipment. Some of the other comments</p><p>seem a bit scary though. There are a lot of variables that need to be recognized</p><p>and taken into consideration when working up any load, starting with the specific</p><p>firearm that's going to shoot the load.</p><p></p><p>If your load is below the maximum load listed and is chonographing from your rifle</p><p>at the maximum velocity, you've got a max load!</p><p></p><p>Changing from a standard primer to a magnum primer does not automatically increase</p><p>the pressure by 15% or anything else! In a variety of primer tests over the years that</p><p>I've read, including Barsness' in Handloader Magazine, where WW magnum rifle primers increased the pressure by 20,000 psi, while there was negligible difference between some other mfr's magnum primers from their respective standard primers. Maybe the results from Barsness' test only address the lot numbers of the primers he tested, maybe not. Regardless, it's always risky to generalize when we are only reloading for our specific guns.</p><p></p><p>Ken Waters in his "Pet Loads" book describes his method for measuring pressure without</p><p>the appropriate equipment, where he measures the case head with a micrometer of new</p><p>unfired brass, then again from factory loaded after it's been fired. The case head expansion measurement from the fired factory load he sets as "maximum". (Actually Ken measured the pressure ring just above the case head that is formed on fired brass. And it requires a micrometer to accurately take this measurement.) But Ken also chronographed velocity as well to balance out other indicators.</p><p></p><p>As mentioned above, another indicator that you're at maximum load is when adding a half grain of powder doesn't increase velocity. Not always, but usually. Some other indicators include enlarged primer pockets, blackened primers, blown primers, flattened primers, excessive case stretch requiring the cases to be trimmed after firing, as well as hard to open the bolt, etc.</p><p></p><p>Re Hodgdon and their list of maximum loads with their powder: Hodgdon definitely is listing MAXIMUM LOAD DATA, ALONG WITH EITHER PSI OR CUP MEASURED PRESSURES. I'd suggest if anyone thinks otherwise, a phone call to Hodgdon will quickly clear up the confusion. But again, that's only with their test barrels and components, and every bullet & powder mfr I know of repeatedly WARNS the handloader to work up their loads carefully and only using the load data these companies provide as guides and NOT just jump in and go to their maximum load data to start with!</p><p></p><p>I don't know of any rifle cartridges that use Bullseye or any other fast shotgun powders typically used for loading some handgun cartridges, when loaded with jacket bullets. I know a fella who loves to use BlueDot and GreenDot for "reduced loads" in some rifle cartridges, but even those powders are significantly slower than Bullseye! The only rifle cartridges I can think of that might use such powders are JDJ's Whisper cartridges. To suggest velocity should be discarded as a pressure indicator is simply a fool's folly. The Bullseye example notwithstanding. Everyone needs to be aware of every component's compatibility with the other components they're using to handload for any cartridge and NOT create a dangerous situation by mixing and matching capriciously. That includes the differences between 5.56x47mm military brass and .223 Rem brass; and, simply the volume capacity difference between one brand of brass from another brand, regardless of caliber. And how the various bullets, and their design affect pressures. Such as a Berger 168-gr VLD bullet (308-cal) versus someone else's 165- 168-gr of the same caliber.</p><p></p><p>Bottom line: Without the appropriate testing equipment to measure pressure, we have to rely on a variety of information to make an informed and reasonable assessment of whether or not we've reached a maximum load. To arbitrarily dismiss one form or another of data available to us is courting disaster.</p></blockquote><p></p>
[QUOTE="travelr47, post: 206057, member: 5339"] I'm in agreement with 280Rem re velocity and the use of a chronograph to aide in determining pressure without pressure testing equipment. Some of the other comments seem a bit scary though. There are a lot of variables that need to be recognized and taken into consideration when working up any load, starting with the specific firearm that's going to shoot the load. If your load is below the maximum load listed and is chonographing from your rifle at the maximum velocity, you've got a max load! Changing from a standard primer to a magnum primer does not automatically increase the pressure by 15% or anything else! In a variety of primer tests over the years that I've read, including Barsness' in Handloader Magazine, where WW magnum rifle primers increased the pressure by 20,000 psi, while there was negligible difference between some other mfr's magnum primers from their respective standard primers. Maybe the results from Barsness' test only address the lot numbers of the primers he tested, maybe not. Regardless, it's always risky to generalize when we are only reloading for our specific guns. Ken Waters in his "Pet Loads" book describes his method for measuring pressure without the appropriate equipment, where he measures the case head with a micrometer of new unfired brass, then again from factory loaded after it's been fired. The case head expansion measurement from the fired factory load he sets as "maximum". (Actually Ken measured the pressure ring just above the case head that is formed on fired brass. And it requires a micrometer to accurately take this measurement.) But Ken also chronographed velocity as well to balance out other indicators. As mentioned above, another indicator that you're at maximum load is when adding a half grain of powder doesn't increase velocity. Not always, but usually. Some other indicators include enlarged primer pockets, blackened primers, blown primers, flattened primers, excessive case stretch requiring the cases to be trimmed after firing, as well as hard to open the bolt, etc. Re Hodgdon and their list of maximum loads with their powder: Hodgdon definitely is listing MAXIMUM LOAD DATA, ALONG WITH EITHER PSI OR CUP MEASURED PRESSURES. I'd suggest if anyone thinks otherwise, a phone call to Hodgdon will quickly clear up the confusion. But again, that's only with their test barrels and components, and every bullet & powder mfr I know of repeatedly WARNS the handloader to work up their loads carefully and only using the load data these companies provide as guides and NOT just jump in and go to their maximum load data to start with! I don't know of any rifle cartridges that use Bullseye or any other fast shotgun powders typically used for loading some handgun cartridges, when loaded with jacket bullets. I know a fella who loves to use BlueDot and GreenDot for "reduced loads" in some rifle cartridges, but even those powders are significantly slower than Bullseye! The only rifle cartridges I can think of that might use such powders are JDJ's Whisper cartridges. To suggest velocity should be discarded as a pressure indicator is simply a fool's folly. The Bullseye example notwithstanding. Everyone needs to be aware of every component's compatibility with the other components they're using to handload for any cartridge and NOT create a dangerous situation by mixing and matching capriciously. That includes the differences between 5.56x47mm military brass and .223 Rem brass; and, simply the volume capacity difference between one brand of brass from another brand, regardless of caliber. And how the various bullets, and their design affect pressures. Such as a Berger 168-gr VLD bullet (308-cal) versus someone else's 165- 168-gr of the same caliber. Bottom line: Without the appropriate testing equipment to measure pressure, we have to rely on a variety of information to make an informed and reasonable assessment of whether or not we've reached a maximum load. To arbitrarily dismiss one form or another of data available to us is courting disaster. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Pressure signs/chronographing
Top