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Magnum Primers in Standard Cartridges
- Thread starter GeauxTide
- Start date
RC20 said:According to Ramshot, modern ball powders do not require magnum primers.
Just for anyone reading this: Be aware that Western Powders (Ramshot distributors) are referring to modern formulations, specifically, and not to all modern powder production. I called Hodgdon one time and asked if modern H335 or BL-C(2) or H380 or the other St. Marks spherical propellants they distribute had changed since CCI first modified their primers to better ignite them (1989). They said, "no". The formulations they ordered were identical to the original chemistries developed in the 1960's.
Marco Califo
New member
So, what I gather from the last few posts means:
For: H335/WC844 use magnum primers.
For: TAC, magnum primers are not needed.
Since Western Powders also distributes AA2460 and AA2520, those also do not require magnum primers. But using magnum primers can be OK if loads are worked from reduced loads.
Correct?
For: H335/WC844 use magnum primers.
For: TAC, magnum primers are not needed.
Since Western Powders also distributes AA2460 and AA2520, those also do not require magnum primers. But using magnum primers can be OK if loads are worked from reduced loads.
Correct?
All a magnum primer needs to do to meet the definition is make more gas than a standard primer
Unclenick
Please provide your reference.
The heat energy produced by the primer determines "magnum" designation.
There is no standard I find for brisance.
Primers have little effect on gas volume in my testing.
Hence you will see no/ little change in velocity.
To increase velocity you have to burned more powder(to produce more gas).
Magnum primers simple have a longer penetration into the powder column increases the powder burn at start of ignition- this results in greater pressure.
One of the best discussions for layman on primers with additional reference can be found here http://www.sksboards.com/smf/index.php?topic=56422.0
be safe
Ruggy
be safe Ruggy
Marco Califo,
I don't believe that is necessarily correct, but I don't actually know. The Accurate powders are older than the Ramshot powders, but newer than the St. Marks powders. I do know I got a significant accuracy and SD improvement from deburring flash holes with Accurate 2520 in .308 Win, and that suggests it would also benefit from a magnum primer, but I haven't done the experiment.
Old Roper,
I don't believe Federal makes the #41. Speaking to CCI, they said it matched their CCI 450, except for having the wider anvil legs again. Federal also makes the GM205MAR match primer for the AR, but they told me they get military sensitivity from it by thickening the primer cup, which is a different approach. Also, it is a standard strength match primer and not a magnum primer as the #41 is. Though the two companies are co-owned, I don't believe either line has been changed to match the other in any way. Federal primers all use the hydroxide of lead styphnate as a sensitizer (aka, basic lead styphnate) where CCI does not, instead using normal lead styphnate.
I don't believe that is necessarily correct, but I don't actually know. The Accurate powders are older than the Ramshot powders, but newer than the St. Marks powders. I do know I got a significant accuracy and SD improvement from deburring flash holes with Accurate 2520 in .308 Win, and that suggests it would also benefit from a magnum primer, but I haven't done the experiment.
Old Roper,
I don't believe Federal makes the #41. Speaking to CCI, they said it matched their CCI 450, except for having the wider anvil legs again. Federal also makes the GM205MAR match primer for the AR, but they told me they get military sensitivity from it by thickening the primer cup, which is a different approach. Also, it is a standard strength match primer and not a magnum primer as the #41 is. Though the two companies are co-owned, I don't believe either line has been changed to match the other in any way. Federal primers all use the hydroxide of lead styphnate as a sensitizer (aka, basic lead styphnate) where CCI does not, instead using normal lead styphnate.
Marco Califo
New member
Thanks Unclenick. In 223 I have thousands of Tula 556m primers, so both TAC and 2520 will be set off by those, after working up loads. I did not know that about TAC not needing hotter primers, but all my SR are hotter.
Ruggyh,
Sorry I didn't respond earlier to your post. I hit the compose window before I read down that far, apparently, and just spotted your post on the reread. I'll hit your points here.
From Allan Jones, who used to develop primers (among other things) at CCI:
Mysteries and Misconceptions about the All Important Primer. In it, he points out:
and later:
"There are two ways to make a Magnum primer—either use more of the standard chemical mix to provide a longer-burning flame or change the mix to one with more aggressive burn characteristics. Prior to 1989, CCI used the first option in Magnum Rifle primers. After that, we switched to a mix optimized for spherical propellants that produced a 24-percent increase in flame temperature and a 16-percent boost in gas volume."
Obviously, by adding more mix, as in the first option, you also make more gas. The second option, which I have read elsewhere means adding fuel compounds but not additional sensitizing compound, also raises pressure. Heat and pressure go together, of course. But more specifically, as is also mentioned in the article, mild ignition often works well with a full case of powder (less empty space) but leads to delayed or erratic ignition with smaller charges. So the amount of empty space needing to be pressurized to reach the "boost" pressure mentioned by Jones is a factor. In fact, he specifically implies the claim not to require a magnum primer with some powders (like Ramshot) may be reversed by low load volumes. It's a useful read and I highly recommend it.
As mentioned before, heat and pressure go hand-in-hand. The erratic ignition of lower charges can be traced to extra space. That will, of course, drop pressure and temperature. As Jones said, one may achieve magnum status in primers by different methods. Thus, a hotter flame may achieve adequate boost pressure with less gas volume than a cooler flame does, but whichever way you achieve the pressure "boost" to avoid the powder squibbing out, you need to arrive at that. I don't believe either the pressure or heat content are fixed values in a table some as there is more than one way to skin this cat.
I believe you are referring there to the volume of gas made by the powder, and not by the primer, as I was. The powder gas volume is so much greater than the amount of gas made by the primer as to be a whole different discussion.
You can also do it by increasing the ballistic efficiency of the burn. Ballistic efficiency (BE) is the percent of the potential energy in the powder that is converted to kinetic energy in the bullet. For many common high power rifle cartridges, it is in the 25-30% range. Less than that for overbore cartridges, more for short pistol cartridges with their high expansion ratio's (relative to any given barrel length) and they vary with the powder and its burn rate.
One way to increase that efficiency is, as you say, to burn more powder. Most guns throw some minor percentage of powder out of the barrel unburned (sweep the dust from in front of the firing points at an indoor range and touch a match to it to see this) and if you get to higher temperatures and pressures earlier in the bullet's travel down the bore, you will burn the powder more completely and therefore will have burned more powder in the bore.
However, even if you work with a powder fast enough that it burns completely in the bore, if you burn that powder faster, earlier in the bullet's travel, the peak pressure goes up because you have more moles of gas in either the same or a shorter space. Assuming a bullet heavy enough not to get ahead of the powder gas evolution rate, the muzzle pressure does not go down because the total gas volume is the same, so you have raised the average pressure between peak and muzzle in the bore by increasing the peak value only, and with it the muzzle velocity goes up and the barrel time goes down and the BE increases. This is how Charles Petty got his charge of 24 grains of 10X to give a 55-grain V-max bullet a 5% velocity increase with a hot primer as compared to what he got with a mild primer gave him.
If, by "longer penetration" you mean the gas pushes further through the grains to light more powder surface area, you need to explain how you can make that happen without supplying more gas and pressure in the jet. If you've ever seen the yellow fused grains of a load that squibbed out, you will understand why minimum pressure has to be maintained. Most people are fooled by the fact powder burns without interruption out in the open, but there it has its oxygen supplemented by air. In confinement, powder requires adequate heat and pressure to maintain breaking down of its nitrocellulose and nitroglycerin to release oxygen. If the pressure is too low, a powder with a lot of deterrent at the surface is smothered and can't keep going.
Unfortunately, the first paragraph suggests Mr. Barsness doesn't quite understand what brisance is. He correctly says it is measured as a shattering effect. But it is actually an explosive material property measured for a standard sample weight of the material. Brisance speaks to power in the physics sense that more shattering of sand or of metal in the test is the result of a faster rate of delivery of the energy released by combustion. Another way to explain it is brisance is a measure of the suddenness of explosion in combination with the energy density of the standard sample weight of it.
If you go back and look at the early NT (non-toxic) ammunition made for .45 Auto, you found cases with a large pistol diameter primer pocket with a huge looking flash hole. The reason was the DDNT used as the sensitizer in NT primers has greater brisance than the lead styphnate used in conventional primers. It would release its energy so suddenly the gas could not escape through a standard sized flash hole before it had pushed the primer cup out of the pocket hard enough to mushroom and perhaps cause a gas leak. The larger flash hole lets the pressure in the primer pocket drop faster. But the total gas, flame and heat energy delivered to the powder was made the same as for a standard primer by adjusting the mix and its quantity. So it didn't affect the strength of the primer's ability to ignite the powder, despite its higher brisance.
In Allan Jones's example, which way you go about creating a magnum primer affects brisance. In the first method, brisance of the material is unchanged; the quantity is just larger. In the second the brisance is changed by altering the formulation.
Sorry I didn't respond earlier to your post. I hit the compose window before I read down that far, apparently, and just spotted your post on the reread. I'll hit your points here.
ruggyh said:Please provide your reference.
From Allan Jones, who used to develop primers (among other things) at CCI:
Mysteries and Misconceptions about the All Important Primer. In it, he points out:
"In addition to providing a spark to ignite propellant, it gives an initial boost in pressure to help the propellant reach a self-sustaining burn."
and later:
"There are two ways to make a Magnum primer—either use more of the standard chemical mix to provide a longer-burning flame or change the mix to one with more aggressive burn characteristics. Prior to 1989, CCI used the first option in Magnum Rifle primers. After that, we switched to a mix optimized for spherical propellants that produced a 24-percent increase in flame temperature and a 16-percent boost in gas volume."
Obviously, by adding more mix, as in the first option, you also make more gas. The second option, which I have read elsewhere means adding fuel compounds but not additional sensitizing compound, also raises pressure. Heat and pressure go together, of course. But more specifically, as is also mentioned in the article, mild ignition often works well with a full case of powder (less empty space) but leads to delayed or erratic ignition with smaller charges. So the amount of empty space needing to be pressurized to reach the "boost" pressure mentioned by Jones is a factor. In fact, he specifically implies the claim not to require a magnum primer with some powders (like Ramshot) may be reversed by low load volumes. It's a useful read and I highly recommend it.
ruggyh said:The heat energy produced by the primer determines "magnum" designation.
There is no standard I find for brisance.
As mentioned before, heat and pressure go hand-in-hand. The erratic ignition of lower charges can be traced to extra space. That will, of course, drop pressure and temperature. As Jones said, one may achieve magnum status in primers by different methods. Thus, a hotter flame may achieve adequate boost pressure with less gas volume than a cooler flame does, but whichever way you achieve the pressure "boost" to avoid the powder squibbing out, you need to arrive at that. I don't believe either the pressure or heat content are fixed values in a table some as there is more than one way to skin this cat.
ruggyh said:Primers have little effect on gas volume in my testing.
Hence you will see no/ little change in velocity.
I believe you are referring there to the volume of gas made by the powder, and not by the primer, as I was. The powder gas volume is so much greater than the amount of gas made by the primer as to be a whole different discussion.
ruggyh said:To increase velocity you have to burned more powder(to produce more gas).
You can also do it by increasing the ballistic efficiency of the burn. Ballistic efficiency (BE) is the percent of the potential energy in the powder that is converted to kinetic energy in the bullet. For many common high power rifle cartridges, it is in the 25-30% range. Less than that for overbore cartridges, more for short pistol cartridges with their high expansion ratio's (relative to any given barrel length) and they vary with the powder and its burn rate.
One way to increase that efficiency is, as you say, to burn more powder. Most guns throw some minor percentage of powder out of the barrel unburned (sweep the dust from in front of the firing points at an indoor range and touch a match to it to see this) and if you get to higher temperatures and pressures earlier in the bullet's travel down the bore, you will burn the powder more completely and therefore will have burned more powder in the bore.
However, even if you work with a powder fast enough that it burns completely in the bore, if you burn that powder faster, earlier in the bullet's travel, the peak pressure goes up because you have more moles of gas in either the same or a shorter space. Assuming a bullet heavy enough not to get ahead of the powder gas evolution rate, the muzzle pressure does not go down because the total gas volume is the same, so you have raised the average pressure between peak and muzzle in the bore by increasing the peak value only, and with it the muzzle velocity goes up and the barrel time goes down and the BE increases. This is how Charles Petty got his charge of 24 grains of 10X to give a 55-grain V-max bullet a 5% velocity increase with a hot primer as compared to what he got with a mild primer gave him.
.ruggyh said:Magnum primers simple have a longer penetration into the powder column increases the powder burn at the start of ignition- this results in greater pressure
If, by "longer penetration" you mean the gas pushes further through the grains to light more powder surface area, you need to explain how you can make that happen without supplying more gas and pressure in the jet. If you've ever seen the yellow fused grains of a load that squibbed out, you will understand why minimum pressure has to be maintained. Most people are fooled by the fact powder burns without interruption out in the open, but there it has its oxygen supplemented by air. In confinement, powder requires adequate heat and pressure to maintain breaking down of its nitrocellulose and nitroglycerin to release oxygen. If the pressure is too low, a powder with a lot of deterrent at the surface is smothered and can't keep going.
ruggyh said:One of the best discussions for layman on primers with additional reference can be found here http://www.sksboards.com/smf/index.php?topic=56422.0
Unfortunately, the first paragraph suggests Mr. Barsness doesn't quite understand what brisance is. He correctly says it is measured as a shattering effect. But it is actually an explosive material property measured for a standard sample weight of the material. Brisance speaks to power in the physics sense that more shattering of sand or of metal in the test is the result of a faster rate of delivery of the energy released by combustion. Another way to explain it is brisance is a measure of the suddenness of explosion in combination with the energy density of the standard sample weight of it.
If you go back and look at the early NT (non-toxic) ammunition made for .45 Auto, you found cases with a large pistol diameter primer pocket with a huge looking flash hole. The reason was the DDNT used as the sensitizer in NT primers has greater brisance than the lead styphnate used in conventional primers. It would release its energy so suddenly the gas could not escape through a standard sized flash hole before it had pushed the primer cup out of the pocket hard enough to mushroom and perhaps cause a gas leak. The larger flash hole lets the pressure in the primer pocket drop faster. But the total gas, flame and heat energy delivered to the powder was made the same as for a standard primer by adjusting the mix and its quantity. So it didn't affect the strength of the primer's ability to ignite the powder, despite its higher brisance.
In Allan Jones's example, which way you go about creating a magnum primer affects brisance. In the first method, brisance of the material is unchanged; the quantity is just larger. In the second the brisance is changed by altering the formulation.