300 Norma Improved. Load testing, info, and builds

[matt_3479]

I just did some pressure testing on my first 300 norma mag. I had the 215's at 3160fps without any significant pressure. Slight ejector marks, easy bolt lift, no cratering

 

[rpierce]

depending on the barrel length and powder used thats do able. another thing to remember though is that virgin and once fired brass won't exhibit much pressure signs until your at very high velocities. once that brass is fired several times though it will definitely have the tell tale signs of pressure. increased bolt lift/clicks etc. ive had 215 bergers over 3275 fps on once fired brass and still have easy bolt lift in a 26" barrel. that brass at several firings wouldn't come close to that velocity without bolt clicks though.

 

[matt_3479]

depending on the barrel length and powder used thats do able. another thing to remember though is that virgin and once fired brass won't exhibit much pressure signs until your at very high velocities. once that brass is fired several times though it will definitely have the tell tale signs of pressure. increased bolt lift/clicks etc. ive had 215 bergers over 3275 fps on once fired brass and still have easy bolt lift in a 26" barrel. that brass at several firings wouldn't come close to that velocity without bolt clicks though.

well I'll keep an eye on it. It was virgin brass. I looked back and they were actually at 3189fps. It looked like a node around there though (3160area) and another closer to the 3065 FPS range. So will focus on the lower node for now.

 

[rpierce]

that 3065 would be a good one to focus on for now, especially if the barrel hasn't sped up either. last thing you want is to be on a upper node and have the barrel speed up a bunch on ya lol. there is a very accurate node with n570 and 215s at 3180-3200 in the improved version.

 

[North Idaho Hunter]

@rpierce i have also seen the affects of pressure showing on 3x fired brass when virgin & once fired showed nothing. I quickly dropped to a lower node after reviewing the ladders.

thoughts on this? i just chopped them both up as an anomaly. but if you have a better idea as to why this happens i'd love to hear it!

 

[Rhovee]

The brass isn't fully formed to the chamber on AI cartridges until 3 ish firings.

 

[rpierce]

yep. ryan hovee's correct. not 100% formed.

 

[North Idaho Hunter]

Ahh, that makes sense then! Running into that with a 338 rogue and 22-250 ai

 

[naja302]

So should we just be randomly firing the brass 3 times and then start load development?

 

[rpierce]

So should we just be randomly firing the brass 3 times and then start load development?

no. you can do load development before then. just realize that the top node going mach chicken that you reach on once fired brass isn't going to be able to be used on brass fired more than 3 times.

 

[Rick Richard]

Just got past the 100 round count on my Ryan Pierce 300 NMI today so ready to start load development With N570 and 230 Berger Hybrids. Corn is up too high to do ladder testing at distance so going to try the velocity ladder test to find a node. Hope that works to get me in the neighborhood since my elk hunt is three weeks away.

 

[naja302]

Ok, I'll make sure I stay below Mach Chicken

 

[Shane Lindsey]

No man, Bust them chickens...

 

[Rick Richard]

Went out today to do that velocity ladder test. I think I found a node. Going to go out tomorrow and see if it repeats. Meanwhile. I had some rounds loaded up to fireform and what a surprise...Shot unbelievable and repeatable groups. Heck, might decide to shoot that load.