magnum rifle primers
- Thread starter NHSHOOTER
- Start date
Generally, yes. It might be a good idea to back off 1/2 gr from your previous loads at 1st just to check for excessive pressure. But you can probably use the same exact load as before. It's just a good idea to back off a bit and work back up just to be sure. If you have a chronograph you could see 20-25 fps more speed, and I wouldn't be surprised if you find the loads with magnum primers more accurate.
No you should not substitute them. Yes you can use them, but you should work your load back up from start and will have a new load with that primer.
I think about powder primers and bullets the same, change any one of the 3, and you should work it up from start again.
Glad you got some primers.
I think about powder primers and bullets the same, change any one of the 3, and you should work it up from start again.
Glad you got some primers.
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Rather than work up new loads, why not see if you can find someone to trade you standard large rifle primers for the magnums?
Somone out there has standard and needs magnums.
Yes, you can use them, safely by working up your loads all over again, but if you can trade them to someone, you'll both be happy, and its a lot less work...
Somone out there has standard and needs magnums.
Yes, you can use them, safely by working up your loads all over again, but if you can trade them to someone, you'll both be happy, and its a lot less work...
unless you are on the ragged edge just shoot them. You may have to adjust your charge by .1 gns but that would be about it. I have tested this in both large and small primers and found negligible differences in velocity. In fact in two of my tests Federal blue box primers produced higher velocity's than CCI magnums both large and small. That was in a .223 77 gn bullet and .260 Remington 140 gn bullet
If you are really nervous drop .3 gns then work up. I am not saying there is no difference in brisience, just not enough to make more than 10 -20 FPS difference depending on the primer you are comparing it. That is from my semi scientific testing
If you are really nervous drop .3 gns then work up. I am not saying there is no difference in brisience, just not enough to make more than 10 -20 FPS difference depending on the primer you are comparing it. That is from my semi scientific testing
If you can find someone locally to trade with that would be beneficial.
In trading though you are subject to whatever brand the other person has. Several of my more accurate rifles have a certain affinity to a certain primer in a given load.
Short of trading your magnum primers off you can rework your existing load OR switch to a powder that is more consistent with a magnum primer and utilize them as they were intended to be loaded.
Three44s
In trading though you are subject to whatever brand the other person has. Several of my more accurate rifles have a certain affinity to a certain primer in a given load.
Short of trading your magnum primers off you can rework your existing load OR switch to a powder that is more consistent with a magnum primer and utilize them as they were intended to be loaded.
Three44s
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I use the rule of thumb to take 5% off the powder charge and work back up. This is because Charles Petty did some testing in Handloader in 2006 with the 223 Remington in which he got additional velocity equivalent to what about a 5% increase in powder charge would have produced. That's the most difference I've ever seen a primer make. There is no rule that applies perfectly all the time, though. When German Salazar's Rifleman's Journal was still up, he had some large primer tests in 30-06 that produces, IIRC, less than 20 fps average difference, so kind of in the noise. There are even some situations in which magnum primers decrease velocity depending on the ignition characteristics of the powder involved, whether or not the space was small enough for the primer to start unseating the bullet before the powder burn really got underway, etc.
One thing I've done before is look up a load in Hodgdon's data and divided the difference between the minimum and maximum load velocity by the difference in the minimum and maximum powder charge. This gives you fps/grain in that load region. I multiply that by 0.05 to get the number of fps I expect to lose if I don't change the primer. I can then download 5% using the magnum primer and if the first few shots produce that projected reduction, then I say it is making no significant difference to velocity and move the load back up to where it was before. But if it is not producing that much reduction, I divide the difference in the velocity I am getting and the velocity the old load got by that fps/grain number to get how much to increase the powder charge to get back to that original velocity and increase the charge only by that much.
That may seem complicated, but it saves a lot of test shots. Ten with the reduced charge gives me a mean velocity that is usable for that purpose and that's it. It is more precise if you have a few of your old primers to load up to get your velocity comparison under the same conditions.
I use the rule of thumb to take 5% off the powder charge and work back up. This is because Charles Petty did some testing in Handloader in 2006 with the 223 Remington in which he got additional velocity equivalent to what about a 5% increase in powder charge would have produced. That's the most difference I've ever seen a primer make. There is no rule that applies perfectly all the time, though. When German Salazar's Rifleman's Journal was still up, he had some large primer tests in 30-06 that produces, IIRC, less than 20 fps average difference, so kind of in the noise. There are even some situations in which magnum primers decrease velocity depending on the ignition characteristics of the powder involved, whether or not the space was small enough for the primer to start unseating the bullet before the powder burn really got underway, etc.
One thing I've done before is look up a load in Hodgdon's data and divided the difference between the minimum and maximum load velocity by the difference in the minimum and maximum powder charge. This gives you fps/grain in that load region. I multiply that by 0.05 to get the number of fps I expect to lose if I don't change the primer. I can then download 5% using the magnum primer and if the first few shots produce that projected reduction, then I say it is making no significant difference to velocity and move the load back up to where it was before. But if it is not producing that much reduction, I divide the difference in the velocity I am getting and the velocity the old load got by that fps/grain number to get how much to increase the powder charge to get back to that original velocity and increase the charge only by that much.
That may seem complicated, but it saves a lot of test shots. Ten with the reduced charge gives me a mean velocity that is usable for that purpose and that's it. It is more precise if you have a few of your old primers to load up to get your velocity comparison under the same conditions.