Doughnuts on 300 Norma Brass - 1st firing!

[EXSOCAL]

I’ve been having nothing but fits over the last 6 months of reloading for my 300 Norma Mag. Everything on the rifle is as it should be - headspace checks out perfect, barrel is a 28” bartlein heavy Palma on a Defiance Deviant.

I started off trying new Norma brass with H1000 and 230 Bergers. The throat is set up so the bullets are at the lands and just about at the max mag length. Through this rifle, the seem to like a little jump so I set them .040 back. I did load workups with H1000 and Retumbo... from around 79 grains starting to 86 grains max. With the virgin brass I wasn’t seeing any major pressure signs until mid 85 grains and pretty consistent heavy bolt lift at 86 grains. MY OCW testing showed 83.6 grains of Retumbo was shooting lights out so I loaded up 20 rounds of new Norma brass for chrono work. After I was done, I noticed a slight doughnut had formed on ALL of the new brass. It was inside the neck and large enough to where a bullet could not freely slide into a fired case. I tried neck turning new brass, tried neck turning old brass, annealing, etc..... no luck.

Fast forward... I recently made the switch to Hornady brass and am not seeing any doughnut problems at all, but I am seeing pressure signs even at very minor loads. I get extractor marks down at 79 and 80 grains of Retumbo all the way to 85 grains, then I get hard bolt lift as before

Do I have a funky chamber or what is going on??? I’ve never run into anything lol this before.

Thanks !

 

[culater]

You might have to invest in one with the use of 300 Norma mag brass.

 

[Nieko]

I’ve been having nothing but fits over the last 6 months of reloading for my 300 Norma Mag. Everything on the rifle is as it should be - headspace checks out perfect, barrel is a 28” bartlein heavy Palma on a Defiance Deviant.

I started off trying new Norma brass with H1000 and 230 Bergers. The throat is set up so the bullets are at the lands and just about at the max mag length. Through this rifle, the seem to like a little jump so I set them .040 back. I did load workups with H1000 and Retumbo... from around 79 grains starting to 86 grains max. With the virgin brass I wasn’t seeing any major pressure signs until mid 85 grains and pretty consistent heavy bolt lift at 86 grains. MY OCW testing showed 83.6 grains of Retumbo was shooting lights out so I loaded up 20 rounds of new Norma brass for chrono work. After I was done, I noticed a slight doughnut had formed on ALL of the new brass. It was inside the neck and large enough to where a bullet could not freely slide into a fired case. I tried neck turning new brass, tried neck turning old brass, annealing, etc..... no luck.

Fast forward... I recently made the switch to Hornady brass and am not seeing any doughnut problems at all, but I am seeing pressure signs even at very minor loads. I get extractor marks down at 79 and 80 grains of Retumbo all the way to 85 grains, then I get hard bolt lift as before

Do I have a funky chamber or what is going on??? I’ve never run into anything lol this before.

Thanks !

SoCal, have you figured out your 300 Norma pressure issues? I have fought the same thing as you with my 300 n. No other cartridge has ever given me a problem. I have recently acquired Peterson brass which seems better (harder) however I'm still getting a sticky spot at the top of the bolt lift on 2+ reloads. No more donut like the Norma Brass.
I have tried 4 different sizing dies. 1st Forster, 2nd Whidden, 3rd Custom Whidden again, 4th Redding(best yet). I used a ptg reamer and feel the body by the case head is not being sized down enough to allow for "spring back".
This has been super frustrating, thinking of chambering a new barrel with different reamer.

 

[EXSOCAL]

I got so frustrated with burning my components up trying to figure it out, I took a step back for a bit but just recently started to revisit my issues. So far I've tried Hornady brass and Norma Brass. Surprisingly the Hornady brass gives me a bit better results over the Norma brass but I also ordered 100 pieces of the new Peterson stuff to try.

As for my pressure issues, I've looked at everything... At first I though the neck was too tight and the doughnut was the culprit. I tore the barrel off, checked the chamber, checked my reamers... nope neck was correct and there was no interference with the doughnut and the chamber. What was happening though is I wasn't dealing with the doughnut directly and just sizing over the top of it, hoping it would go away after the 3rd firing. This created a constricting ring inside the case mouth that I could feel when I was seating the bullet.... no bueno. I went back and annealed all my Norma cases and cut the doughnuts out. This worked for one more firing and the doughnuts were back.

After all of this I scrapped a bunch of Norma brass and gave the hornady stuff a try. No doughnuts with the Hornady brass and I was getting better velocity and accuracy. However, what I did end up with were several stuck cases. These guys really got stuck in there too. The M16 extractor on the defiance bolt played hell on getting em out but no luck. I would stick probably one out of 5 rounds. No other pressure signs at all, primers look great. The load was pretty mild pushing 225 ELD - M's at 2920 FPS. I noticed a shiny ring around the base of the fired brass maybe 75-100 thou up from the extractor groove. My calipers were showing this was approx. .004" high... I believe this is what is leading to the stuck cases now but I cant figure out what is causing this unless my PTG reamer is bad....

I love the Norma and the accuracy has been great, even on the bad days but I'm also thinking about exploring other options and maybe playing with the 338 lapua or 338 edge.

 

[Precision Underground]

I got so frustrated with burning my components up trying to figure it out, I took a step back for a bit but just recently started to revisit my issues. So far I've tried Hornady brass and Norma Brass. Surprisingly the Hornady brass gives me a bit better results over the Norma brass but I also ordered 100 pieces of the new Peterson stuff to try.

As for my pressure issues, I've looked at everything... At first I though the neck was too tight and the doughnut was the culprit. I tore the barrel off, checked the chamber, checked my reamers... nope neck was correct and there was no interference with the doughnut and the chamber. What was happening though is I wasn't dealing with the doughnut directly and just sizing over the top of it, hoping it would go away after the 3rd firing. This created a constricting ring inside the case mouth that I could feel when I was seating the bullet.... no bueno. I went back and annealed all my Norma cases and cut the doughnuts out. This worked for one more firing and the doughnuts were back.

After all of this I scrapped a bunch of Norma brass and gave the hornady stuff a try. No doughnuts with the Hornady brass and I was getting better velocity and accuracy. However, what I did end up with were several stuck cases. These guys really got stuck in there too. The M16 extractor on the defiance bolt played hell on getting em out but no luck. I would stick probably one out of 5 rounds. No other pressure signs at all, primers look great. The load was pretty mild pushing 225 ELD - M's at 2920 FPS. I noticed a shiny ring around the base of the fired brass maybe 75-100 thou up from the extractor groove. My calipers were showing this was approx. .004" high... I believe this is what is leading to the stuck cases now but I cant figure out what is causing this unless my PTG reamer is bad....

I love the Norma and the accuracy has been great, even on the bad days but I'm also thinking about exploring other options and maybe playing with the 338 lapua or 338 edge.

Sounds like there has to be something going on with the chamber.

 

[EXSOCAL]

Yup, agreed. The barrel is coming off for the second time. I'm going to set it back and re-chamber with a Manson reamer.

 

[bjay]

Im getting donut when using tight neck with short freebore forcing 230 boat tail seating below shoulder junction..whats your reamer neck diam and freebore?

 

[buffybuster]

Are you by chance using a bushing FL die?

 

[Shoots 700's]

Love to find out what your issues are. I am having to deal with the same issues only mine are in 6.5x47 Lapua.

 

[Aircraftmech76]

I inside neck ream all my precision brass before it's even fired. Have you considered going that route?

https://lewilson.com/inside-neck-reamer/

Cheers,

Kevin

 

[918v]

Sounds like a brass issue to me. It is thick all the way to the bottom of the neck. Only the neck walls are thin. When the brass flows, the thick shoulder brass flows into the neck forming the doughnut. Hornady brass sounds to be correctly made but heavier and or softer hence the ejector marks. Have you compared the weight of the Norma vs the Hornady brass or tested the water capacity?