Standard vs Mag primers?

[xdeano]

How much different will switching from Fed210M to Fed215M primers do with velocity/pressure?

And should I back my charge off .3 grain or keep it as is and just shoot it? I'm pushing H1000.

I hear several different schools of thought on using mag primers. Most guys don't mess with their charges at all. But i've never used a mag primer so i want to be on the safe side.

Thanks in advance.

Deano

 

[wapiti25]

you should back off the charge. The std is 10 % but I have used less. Velocity and pressure are totally different measurments. You can not measure velocity and say that the pressure is ok. Pressure has a peak value and a curve that is pressure for a time. You can have a low velocity with high pressure. Velocity comes from the area under the curve without going above the limit of the gun and case. Most of the time when you run high pressure's by a small amount you expand the primer pocket and leave other marks on your case. Thecase is the gas seal of a firearm. When you vent high pressure gas you can do damage such as blowing up and destroying your gun, hurting you from flying pieces and gas. Your eyes are at the back of the bolt, guess where the gas from the chamber go? A blown primer can send the gas down the bolt raceway and into your face. Trust me I have had primers vent and it is not fun. I have had cases crack and it will scare the hell out of you (old rem-umatic 270 brass that was previously unfired cracked and vented gas on me) I had 2 out of 3 fail. I tossed the other 37 cases in the trash. Don't shoot with out reducing the charge when you change componets it will cost you 4 or 5 rounds to be safe is that too much to be safe? Thank you for asking, be safe and have fun.

 

[xdeano]

backing off 10% seems a little excessive if you ask me. I'm not a lawyer.

47.4g x .10 = 4.74g
47.4-4.74 = 42.66g

I think i started of my load test with regular primers at 44.0g and i was no where near max. I've ran it up to 48.5g of powder in said case with no pressure sign, just ran out of case capacity.

Any one else have any suggestions?

xdeano

 

[spclark]

For what cartridge & bullet? H1000's pretty slow stuff, suited for hefty case capacities. My take would be to back off maybe 1.0 grain then work up if need be if velocity proves lost.

 

[Nomad47]

Jsimonh and I have the exact same 284 barrel. And we run the same velocities with the same charge of RL-17. But when I tried H4831sc with 215Ms, I had to back off .5 grains compared to his load with BR-2s.

Here's a good read about primers. http://www.the-long-family.com/primer_study.htm

 

[xdeano]

Cartridge is 6slr. 105g hunting vld.
Thanks for the read nomad

Deano

 

[spclark]

Thanks for the link Nomad. Good read indeed.

 

[xdeano]

Nomad,

I just wasted about an hour on that site. That's some good stuff. A lot of useful stuff on there for QL, as well as the primers. I got my answer though, thank you.

With slower powders the Fed 215M Mag primer is better then a standard, for getting lower es/sd's, and better ignition. But with slower powders there will be a slightly higher pressure spike.

Good stuff.

xdeano

 

[Catfish]

One day last summer I had some free time so I did some primer test. I do not have a presure gage, so I used my Oler to check velocity. I would load 3 round ea. with 1 prime and did this with several different primers useing both standard and mag. I tried this with several different rounds use different burn rates of powder. I had 1 round that I got a standard deviation of 7 with with 15 rounds and 5 different primers a mix of standard and mag. I had one load that had higher velocities with st. primers than mags. and even had 1 load that was showing presure signs with std. pirmers and not with any of the mag. primers. After alot of thought I believe that the burn rate of the powder and the volume effect the varation in how primers act. One thing for sure, I was not able to tell untill after the were fired with my test, so I would recomand you always start low and work up a load every time you change primers.