magnum primer comparison
- Thread starter mveniot
- Start date
ultimate_monkey
CGN Ultra frequent flyer
- Location
- victoria BC
as always, work up to the load. federal primers are quite soft. but there has been alot of talk due to the winchester primer cups splitting
Are you planning on loading some cases at the max listed in the data and going to town?
This can produce a load at the max pressure, or below it, or above it. There is no way to tell.
There are many things that can effect the actual pressure that will make things different in your rifle from the rifle they used to generate the published data.
This can include:
-chamber dimensions
-throat dimensions
-bore dimensions
-groove number
-brass thickness
-brass hardness
-neck tension
-bullet construction
-copper hardness in the bullet
-lead hardness in the bullet
-different burn rates from the "same" powder, lot to lot
-different primer intensities (even from the "same" primers, from lot to lot)
-chamber headspace
-ambient temperature
-ambient pressure
-barrel length
and many other variables that you can't possible compensate for.
To develop a "max load" the safe way is to begin at the start load, work up, check velocity with each increase in powder, and stop when you reach the published max velocity. Though this isn't a sure-fire way to determine when you've reached max pressure, it is as good an estimation as your average shooter can get outside of a lab. That's not to say if you go a smidge above the max rated pressure for a cartridge, your rifle will explode. Most modern firearms are made much stronger than they have to for liability reasons. Most guns are proof tested at the factory using cartridges that are 125-160% max pressure and rifles that can't handle that obviously don't get sold (since there isn't much of a rifle left). That's not to say that running regular loads above max rated pressure is good for your rifle or safe in the long-term.
I have a 308 with a particularly tight chamber that reaches max published velocity half way between starting and max loads. I tried going 3/4 up the scale and the cases started to stick in the chamber. I concluded that because of specific factors with my rifle, it produced max velocity/pressure with lower loads than the average 308 rifle. I also have rifles that produce lower than expected velocities with even max loads. Due to specific characteristics of these rifles that are different from the test rifles used to develop the data, they produce lower pressures.
If you use a consistent set of components, keep them consistent, develop a max load, and keep everything as consistent as you can, it doesn't matter if you use a Win primer instead of a Federal (or Rem, or CCI, or S&B, or any other brand). Consistency is key.
As ultimate monkey mentioned, some lots of Winchester magnum rifle primers have had a lot of splits at even moderate pressures. This can lead to gas cutting on your bolt face as the high pressure gas shoots out of the split primer. Some theorize that Winchester might have missed an annealing step with certain lots making them harder and more brittle. I have 2000 WLRM primers and I'm not sure if they are effected or not so am only using them for cast loads at greatly reduced pressures. All my full power and accuracy based reloads are done with CCI primers.
This can produce a load at the max pressure, or below it, or above it. There is no way to tell.
There are many things that can effect the actual pressure that will make things different in your rifle from the rifle they used to generate the published data.
This can include:
-chamber dimensions
-throat dimensions
-bore dimensions
-groove number
-brass thickness
-brass hardness
-neck tension
-bullet construction
-copper hardness in the bullet
-lead hardness in the bullet
-different burn rates from the "same" powder, lot to lot
-different primer intensities (even from the "same" primers, from lot to lot)
-chamber headspace
-ambient temperature
-ambient pressure
-barrel length
and many other variables that you can't possible compensate for.
To develop a "max load" the safe way is to begin at the start load, work up, check velocity with each increase in powder, and stop when you reach the published max velocity. Though this isn't a sure-fire way to determine when you've reached max pressure, it is as good an estimation as your average shooter can get outside of a lab. That's not to say if you go a smidge above the max rated pressure for a cartridge, your rifle will explode. Most modern firearms are made much stronger than they have to for liability reasons. Most guns are proof tested at the factory using cartridges that are 125-160% max pressure and rifles that can't handle that obviously don't get sold (since there isn't much of a rifle left). That's not to say that running regular loads above max rated pressure is good for your rifle or safe in the long-term.
I have a 308 with a particularly tight chamber that reaches max published velocity half way between starting and max loads. I tried going 3/4 up the scale and the cases started to stick in the chamber. I concluded that because of specific factors with my rifle, it produced max velocity/pressure with lower loads than the average 308 rifle. I also have rifles that produce lower than expected velocities with even max loads. Due to specific characteristics of these rifles that are different from the test rifles used to develop the data, they produce lower pressures.
If you use a consistent set of components, keep them consistent, develop a max load, and keep everything as consistent as you can, it doesn't matter if you use a Win primer instead of a Federal (or Rem, or CCI, or S&B, or any other brand). Consistency is key.
As ultimate monkey mentioned, some lots of Winchester magnum rifle primers have had a lot of splits at even moderate pressures. This can lead to gas cutting on your bolt face as the high pressure gas shoots out of the split primer. Some theorize that Winchester might have missed an annealing step with certain lots making them harder and more brittle. I have 2000 WLRM primers and I'm not sure if they are effected or not so am only using them for cast loads at greatly reduced pressures. All my full power and accuracy based reloads are done with CCI primers.
You don't 'do' a max load for anything. You work up to it from the starting load. You do not pick a load and hope. However, if you change one component, in published data, you will get different results. Not dangerous result though.
I'm seeing Winchester ammo recalls, none of which are recent, but nothing about primers. Their site seems to be down at the moment too.
I'm seeing Winchester ammo recalls, none of which are recent, but nothing about primers. Their site seems to be down at the moment too.
LUTNIT has a great post (nicely done). The issue isn't which primers you use but how the primers, powder, and bullet work in your gun....as many have said start below, load up, watch for pressure signs (read up on that) and when you get to the velocity you need, stop.
WLRM primers will work just FINE - go ahead and use them but start 20% below maximum loads listed and work up. Your gun will be unique and you'll have to do some loading and shooting (hooray!) to learn what it likes.
This isn't cooking - you can't just follow the recipe and get the expected outcome nor is it nuclear bomb making - relax, be sensible and patient....this stuff is very much a discovery.
WLRM primers will work just FINE - go ahead and use them but start 20% below maximum loads listed and work up. Your gun will be unique and you'll have to do some loading and shooting (hooray!) to learn what it likes.
This isn't cooking - you can't just follow the recipe and get the expected outcome nor is it nuclear bomb making - relax, be sensible and patient....this stuff is very much a discovery.
