magnum12pm
Member
I was wondering, any reason you can not substitute small magnum primers for the regular small primers? I can get the magnums for 30.00 dollars a thousand.
Primer question
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magnum12pm
Member
I was wondering, any reason you can not substitute small magnum primers for the regular small primers? I can get the magnums for 30.00 dollars a thousand.
In my area the regular small and large pistol primers are sold out and only magnums are available. I have read differing opinions at other sites; some saying never to subsitute while others claim they use the magnums, but with reduced powder loads.
tbury
Member
Not a direct answer to you question; but winchester large pistol primers are for either standard or magnum loads. Some say that magnum primers increase the velocity and/or pressure for a given load. I have not tried it but that is why most people suggest backing down to starting loads and working up carefully to where you want to be velocity-wise.
Steve C
Member
If you read the manuals they say that you can substitute mag primers for standard primers but as with any change in components you should work up your loads again IF they are at maximum levels. If you are loading light loads at or below start level then a primer change to magnums will have little effect.
To be candid, internal ballistics (what happens when the bullet is still in the gun) are freaking unbelieveably complicated.
So the only generic answer is "It depends."
As already stated, for medium loads with medium powders, dropping back a little and retesting loads is all that is needed.
For odd powders and marginal loads, there can be problems with substituting primers either way. Even temperature can be a factor.
So the only generic answer is "It depends."
As already stated, for medium loads with medium powders, dropping back a little and retesting loads is all that is needed.
For odd powders and marginal loads, there can be problems with substituting primers either way. Even temperature can be a factor.
OP
magnum12pm
Member
I always load my practice rounds light. I can't see any reason to load max just to shoot practice rounds at paper target 25 to 40 foot. I think I will go with the magnum primers and work up the loads from minumum to mid loads as usual. That is until the craziness stops around here!
keppelj
Member
For accuracy you want the smallest primer that will ignite the powder: Small is better. Also magnum primers will increase your load effectively by at least 1/2 grain.
Skip Sackett
US Veteran
This is the best answer possible with the little bit of information given.
Maximum charge of Bullseye in a 357mag with a .1gr (tolerance of most powder measures)overage and you could end up with parts flying all around you as you shoot! (Just kidding!
Seriously, fast powders with magnum primers are a catastrophe waiting to happen in my world. Do it in a Glock with an unsupported chamber and WHOOHOO, you will have parts flying around!
If it were me, use the recipe, wait it out, regular primers will come back. Then, stock up on them, have a bunch of brass, powder and bullets on hand and stock up, dude! Did I say "THEN?"
Alk8944
US Veteran
What with the component situation what it currently is, this may not be the best time to be experimenting too much. That said, most of what is said, and everyone "knows" about load variations as a result of primer changes are worth just as much as most other "common knowledge". They are mostly what has been repeated over and over by gun writers for decades and are based more on "it sounds right to me" rather than actual evidence based on experimentation. This goes for what is said on the subject in all reloading manuals too.
The only way to know what will happen with a particular powder with different primers is to pick a load, any cartridge, bullet and powder, but all the same with only the primer being changed. .357 in an "N" frame is a good place to start, using a charge weight which is known to be below "maximum" by at least 5%. Actually a 158 LSWC with 13.5 gr. 2400 would be an excellent load for this purpose. Load at least 10 rounds with each of several different primers, standard, magnum, and small rifle, and different brands of each, depending on how comprehemsive a comparison you wish to make. 20 rounds or more will result in a more statistically significant sampling, the more the better even as many as 100 or more of each.
Fire your loads over your chronograph on the same day, within a reasonable time so the temperature is constant within a few degrees, and from the same gun. If you have chronographed several samples of a particular load previously you will have a good starting point for comparing the differences you might observe with everything being apparently equal but from different samples. It is not uncommon to see average velocity vary by 20-30 FPS or more between 10 round samples, even if fired from the same batch of ammunition. ES and SD can vary also.
Now, considering all the information you have as a base, shoot your loads, all with each primer in one string. When done compare Mean (average) Velocity, ES and SD for all the different primers. When this is done, and remembering that pressure equates to velocity, and the converse, see what the results were. I can confidently predict you will be surprised by what you find. "Common Knowledge" says the magnum primers will give higher pressure (velocity) than standard, and the small rifle even higher than the magnum. 'Taint necessarily so. What you will find is the standard will give higher, lower or virtually identical results to both the magnum and small rifle primers. SD and ES may be higher or lower too. Remember, that any difference as a result of the primer must be greater than the difference of identical samples fired at either different times or even consecutively for the difference to indicate a significant difference in any parameter.
Other things you may see that don't appear to be logical are that the ES and SD are higher/lower between samples, and that this parameter does not equate to the mean velocity. Higher mean velocity may have a lower or higher ES/SD.
Hopefully this makes some sense to you. Remember also that the result is only entirely valid with that powder and lot, and the specific lot number of each different primer. This will not mean that a particular primer type and a different powder will always give similar results.
How do I know this? I am not guessing. Over the past 20 years I have shot literally thousands of rounds over my Oehler 35P. I have made just this comparison quite a few times with several cartridges. I have usually been comparing two specific primers such as SM and Small Rifle, but have done LP/LPM too. Sometimes I have gotten lower velocity with a SPM compared to SP, but higher ES and SD. Sometimes velocity has been higher. This goes for SR/SP or SR/SPM comarisons too. There were variations in those parameters which are usually taken to indicate the consistency of a load, the ES and SD, but I have NEVER seen what could be considered as a statistically significant variation in velocity.
Just one other small point about primers. Notice above that I have tested Small Rifle primers in several revolver cartridges, mostly .357 Magnum. Even though I have been a practicing gunsmith/police and military armorer for many years I do not tinker with the mainspring in any of my revolvers, there just isn't any reason to in most cases. With stock springs I have literally NEVER had a mis-fire as a result of using a small rifle primer in a revolver cartridge. This included several thousand rounds of .32-20 in several S&W and Colt revolvers, all primer brands, and more years than many of you have been alive. Leave the mainspring alone and the strain screw tight and rarely will you have a mis-fire which can be blamed on a "Hard" primer.
The only way to know what will happen with a particular powder with different primers is to pick a load, any cartridge, bullet and powder, but all the same with only the primer being changed. .357 in an "N" frame is a good place to start, using a charge weight which is known to be below "maximum" by at least 5%. Actually a 158 LSWC with 13.5 gr. 2400 would be an excellent load for this purpose. Load at least 10 rounds with each of several different primers, standard, magnum, and small rifle, and different brands of each, depending on how comprehemsive a comparison you wish to make. 20 rounds or more will result in a more statistically significant sampling, the more the better even as many as 100 or more of each.
Fire your loads over your chronograph on the same day, within a reasonable time so the temperature is constant within a few degrees, and from the same gun. If you have chronographed several samples of a particular load previously you will have a good starting point for comparing the differences you might observe with everything being apparently equal but from different samples. It is not uncommon to see average velocity vary by 20-30 FPS or more between 10 round samples, even if fired from the same batch of ammunition. ES and SD can vary also.
Now, considering all the information you have as a base, shoot your loads, all with each primer in one string. When done compare Mean (average) Velocity, ES and SD for all the different primers. When this is done, and remembering that pressure equates to velocity, and the converse, see what the results were. I can confidently predict you will be surprised by what you find. "Common Knowledge" says the magnum primers will give higher pressure (velocity) than standard, and the small rifle even higher than the magnum. 'Taint necessarily so. What you will find is the standard will give higher, lower or virtually identical results to both the magnum and small rifle primers. SD and ES may be higher or lower too. Remember, that any difference as a result of the primer must be greater than the difference of identical samples fired at either different times or even consecutively for the difference to indicate a significant difference in any parameter.
Other things you may see that don't appear to be logical are that the ES and SD are higher/lower between samples, and that this parameter does not equate to the mean velocity. Higher mean velocity may have a lower or higher ES/SD.
Hopefully this makes some sense to you. Remember also that the result is only entirely valid with that powder and lot, and the specific lot number of each different primer. This will not mean that a particular primer type and a different powder will always give similar results.
How do I know this? I am not guessing. Over the past 20 years I have shot literally thousands of rounds over my Oehler 35P. I have made just this comparison quite a few times with several cartridges. I have usually been comparing two specific primers such as SM and Small Rifle, but have done LP/LPM too. Sometimes I have gotten lower velocity with a SPM compared to SP, but higher ES and SD. Sometimes velocity has been higher. This goes for SR/SP or SR/SPM comarisons too. There were variations in those parameters which are usually taken to indicate the consistency of a load, the ES and SD, but I have NEVER seen what could be considered as a statistically significant variation in velocity.
Just one other small point about primers. Notice above that I have tested Small Rifle primers in several revolver cartridges, mostly .357 Magnum. Even though I have been a practicing gunsmith/police and military armorer for many years I do not tinker with the mainspring in any of my revolvers, there just isn't any reason to in most cases. With stock springs I have literally NEVER had a mis-fire as a result of using a small rifle primer in a revolver cartridge. This included several thousand rounds of .32-20 in several S&W and Colt revolvers, all primer brands, and more years than many of you have been alive. Leave the mainspring alone and the strain screw tight and rarely will you have a mis-fire which can be blamed on a "Hard" primer.
Landric
Member
Fantastic post Alk8944!
This question comes up a lot, and there are a lot of different answers.
Luckily for me I have the right primers for the job, having just happened upon them in various places recently (I really picked the wrong time to run out of components). However, in the event that I need to use a primer other than what a recipe calls for this is great info to have.
At the moment even magnum primers seem pretty thin in the wind, but I have noticed that they are at least somewhat more available. I'm tempted to pick some up just to try out.
This question comes up a lot, and there are a lot of different answers.
Luckily for me I have the right primers for the job, having just happened upon them in various places recently (I really picked the wrong time to run out of components). However, in the event that I need to use a primer other than what a recipe calls for this is great info to have.
At the moment even magnum primers seem pretty thin in the wind, but I have noticed that they are at least somewhat more available. I'm tempted to pick some up just to try out.
TSQUARED
Member
I once mistakenly purchased some Fedral SP Magnum primers instead of the normal SP variety. I used them in very mild loads of 40 S&W (155 gr. FMJ at 725 fps) before I found out my mistake. I chronographed the same load with both primers and found that the SPM primers produced an additional 10 fps which I do not believe was statistically significant. If I had made the same mistake with full power loads I probably would have pulled the bullets.
OP
magnum12pm
Member
Thanks for the informative post Alk8944. I just returned from the range after testing different primers. My revolvers are all 357 magnums. I am loading 38+P+ Specials, really had no concern of over pressure on these loads. However just to be on the safe side I loaded them in 357 cases. What I wanted was 38 +P+ loaded in 357 cases to minimize the chance of someone putting them in a 38 revolver. I don't have a chrono so, I loaded my magnum primed and regular primed in the gun three of each just to see if recoil or report was noticable, it was Not! Infact if I load anymore of these I will bump it up a couple of tenths. I realize ballistics are a little more complicated than my unscientific tests. But I believe if you do not push the max load of a receipe, there is little chance of over pressure on a magnum revolver, using 38+P or +P+. I also measured each powder charge by hand instead of runner through the powder drop of the Dillion 550. The American select powder is not the best metering powder for the Dillon, not nearly as good as say finer grained powders like Tite Group, which I use most often. I thought I would try the American because it was only 76.99 for eight pounds. I just have to watch my powder charge more closely than Titegroup. I wanted to charge by hand to take that varible out of the testing.
Berry's plated 158grn. Bullet
5.1 grn. American Select Powder
Federal Small magnum primer
OAL 1.580
Berry's plated 158grn. Bullet
5.1 grn. American Select Powder
Federal Small magnum primer
OAL 1.580
Hook686
US Veteran
I use magnum primers with Unique and 2400 sometimes with my .357 magnum. I drop the load I use .2 grains (about 2%) when I do. I shoot a S&W 686 and a S&W 627PC. I have experienced no problems that I am aware of, but then I use light to mid range loads from the manuals. I do not think I would do this if I loaded towards the max. load end.
Sunkist
Member
I asked the same question recently. I got an answer from an experienced reloader that used the load in question successfully for over 30 years. The loads were minimal- no problem. Then I went back to my Lyman Cast Bullet Handbook for .357 loads and realized that all the loads used CCI 550 aka small pistol magnum primers. It has velocities and pressure readings. It's a trusted source. Check it out-you may find your load there. If not, you got excellent advise above. Good luck!
