Cold Temperature Ignition - LRP vs LRPM

[Buttermilk]

Is it possible that N555 is sensitive to location inside the case relative to primer?

While I do not know, Ii suspect you used a powder that is sensitive to positioning inside the case, relative to primer locations.

If N555 is sensitive to it's location relative to primer, particularly a weaker less intense primer, then getting it closer to the primer via filler, would explain positive ignition under those conditions.

The use a powder that isn't sensitive to positioning inside the case such a H4895, as it can be loaded at 60% of max loads with no issues, might make the results interesting with regards to ignition.

 

[cbuck516]

Is it possible that N555 is sensitive to location inside the case relative to primer?

While I do not know, Ii suspect you used a powder that is sensitive to positioning inside the case, relative to primer locations.

If N555 is sensitive to it's location relative to primer, particularly a weaker less intense primer, then getting it closer to the primer via filler, would explain positive ignition under those conditions.

The use a powder that isn't sensitive to positioning inside the case such a H4895, as it can be loaded at 60% of max loads with no issues, might make the results interesting with regards to ignition.

Thanks for the data point. I will see if I can find some H4895 to test. I was not aware that there were any powders that worked well with super low case fill, but now that you said that, trail boss is popular for subsonic loads and that has to be an incredibly low case fill %.
In my case, I am doing testing specifically around a 300 magnum platform so there is a certain range of powder speeds that would never make sense in real load development. N550 is right at the edge of ridiculous for a 300 PRC, but there is some published data for it on the manufacturers website so it isn't totally insane. Just poor case fill.

 

[memtb]

Again, interesting. I'm excited to see the results of your next test. I'll stay tuned.

Here's a question…could you shoot large pistol magnum primers in a rifle cartridge or even a magnum cartridge?

Again, this is what I've read……possibly on the internet, so it's validity cannot be questioned!

It's my understanding that the primer cup is thicker/harder on rifle primers. In fact, my 460 S&W requires a rifle primer……likely due to it's high pressure.

I also believe that the large pistol primer is not as tall as a large rifle primer.

I'll have to research the small primers! memtb

 

[memtb]

Here's an article that ya may find interesting and informative! I haven't read the article……it may show everything I previously wrote to be Bull excrement! memtb

Mysteries And Misconceptions Of The All-Important Primer - Shooting Times

By Allan Jones Most component primers have a little disk of paper between the

www.shootingtimes.com

 

[Grizzly60]

Here's an article that ya may find interesting and informative! I haven't read the article……it may show everything I previously wrote to be Bull excrement! memtb

Mysteries And Misconceptions Of The All-Important Primer - Shooting Times

By Allan Jones Most component primers have a little disk of paper between the

www.shootingtimes.com

Interesting article. And it didn't make you out to be excrement.

 

[Buttermilk]

Thanks for the data point. I will see if I can find some H4895 to test. I was not aware that there were any powders that worked well with super low case fill, but now that you said that, trail boss is popular for subsonic loads and that has to be an incredibly low case fill %.
In my case, I am doing testing specifically around a 300 magnum platform so there is a certain range of powder speeds that would never make sense in real load development. N550 is right at the edge of ridiculous for a 300 PRC, but there is some published data for it on the manufacturers website so it isn't totally insane. Just poor case fill.

Hodgdon has a pdf file on their website detailing the use of H4895 in reduced loads for recoil reduction. Basically if you can find data for the cartridge using H4895, you can load 60% of max charge for a reduced recoil load. Since H4895 isn't sensitive to location in the case relative to primer location, it works well for that application.

Not sure how applicable it would be for your particular study. Worth consideration however.

 

[Seabeeken]

Great info!!
Powder selection makes a big difference I suspect.
Throughout the 80's I fired hundreds of rounds in my 243 Win in all types of weather with 100gr Hornady and CCI 200 with 35.5 gr of IMR-3031which gave about 74% case fill and never an issue. The rifle shot amazing at all times.
I also shot N-550 for several years in my 338RCM with CCI 200 primers without any issues but as you indicated, the case was full.

I should add that the only issues I did have was in my 243ai with W-760. It would show normal pressures and then suddenly large pressure spikes. I never used it again after that and never will

 

[Beluebow]

Thanks for sharing your results!

The ignition system and primer type and depth are gonna play a huge roll in what fires/hang fires/no fire.

The three cases in the first pic look like light strikes to me?

 

[Buckbandit]

Thank you for sharing your test. Very interesting so please keep it up. Instant or regular grits? Asking for a friend

 

[memtb]

Thank you for sharing your test. Very interesting so please keep it up. Instant or regular grits? Asking for a friend

Nothing instant is good…….make mine regular! memtb