Early pressure signs - 300 Norma Mag - why???

[EXSOCAL]

I’ve been Reloading precision rifle ammo for about 10 years now, and I’ve never had so many problems as I have had with the 300 Norma mag. Pretty much everything I load for it shoots very well but I run into premature pressure at low powder charges. My load development for the 225 grain ELD-M started at 79 grains of H100 and went up to 85 grains. I had a good accuracy / pressure node at 81 grains but almost every case comes out with a nice ejector mark and flat primer. These are chronographing at 2904 and hold 1/3 MOA out to 300. Rifle is a custom build on a Defiance action with a 9 twist, 28” Bartlein. Norma Brass is once fires with a .002 shoulder bump and .001” neck tension, bullets seated .020” off. Anything above 82.6 grains and I get heavy bolt lift and this continues to 84 grains.

I was thinking the H1000 was too fast for my long fast twist barrel so I gave Retumbo a shot. I did a pressure test starting at 78 grains and ending at 85 in .5 gr increments. I ran into ejector marks at 80.5 grains and moderate bolt lift at 82 grains where I was getting 2914 fps with the 225 ELD.

Anyone else experince silimar issues??? I expected more velocity out of this round considering my pet load for my 300 win is running a 215 Berger Hybrid at 2850 with 75.3 gr H1000.

ive heard the Norma Brass can be soft but this is rediculous... what am I missing here???

I was doing a test test to work up a hunting load with the 200 Barnes LRX and could only get 2940 without pressure (81.4 gr H1000 / .050 jump).

Obviously 2900 with the 225 ELD M that shoots 1” groups at 300 is a solid load but I expected a bit more... Are my expectations too high?

 

[MtnCreek]

First thing I would check is to see if the necks have enough room to release the bullet. See if a bullet slides freely into a fired case neck.

 

[Beneviolence]

One thing I had with a 338LM was excessive headspace that allowed the rear of the case and primer to extend rearward until it hit the bolt face and I had signs of pressure (hard to lift bolt, cratered primers, ejector mark) early on. One telltale sign for me that suggested it was excessive headspace was the brass length increased quite drastically from a single firing. Meanwhile, my 6.5CM brass actually shrunk the first 2 firings.

 

[DeerSniper72]

I’ve been Reloading precision rifle ammo for about 10 years now, and I’ve never had so many problems as I have had with the 300 Norma mag. Pretty much everything I load for it shoots very well but I run into premature pressure at low powder charges. My load development for the 225 grain ELD-M started at 79 grains of H100 and went up to 85 grains. I had a good accuracy / pressure node at 81 grains but almost every case comes out with a nice ejector mark and flat primer. These are chronographing at 2904 and hold 1/3 MOA out to 300. Rifle is a custom build on a Defiance action with a 9 twist, 28” Bartlein. Norma Brass is once fires with a .002 shoulder bump and .001” neck tension, bullets seated .020” off. Anything above 82.6 grains and I get heavy bolt lift and this continues to 84 grains.

I was thinking the H1000 was too fast for my long fast twist barrel so I gave Retumbo a shot. I did a pressure test starting at 78 grains and ending at 85 in .5 gr increments. I ran into ejector marks at 80.5 grains and moderate bolt lift at 82 grains where I was getting 2914 fps with the 225 ELD.

Anyone else experince silimar issues??? I expected more velocity out of this round considering my pet load for my 300 win is running a 215 Berger Hybrid at 2850 with 75.3 gr H1000.

ive heard the Norma Brass can be soft but this is rediculous... what am I missing here???

I was doing a test test to work up a hunting load with the 200 Barnes LRX and could only get 2940 without pressure (81.4 gr H1000 / .050 jump).

Obviously 2900 with the 225 ELD M that shoots 1” groups at 300 is a solid load but I expected a bit more... Are my expectations too high?

I’m on the other side of the spectrum. I’m shooting berger 245’s using RL-33 and RL-50 lapua brass with cci 250’s. I’m getting 2900+ FPS with both and not seeing any signs of pressure at all. Which is a bit concerning with a bullet this heavy. Sounds like a bloody canon going off I’m a bit nervous as to wether I should continue on with the ladder test any further. I’ve heard mumblings of the 300 Norma having over pressure issues. I wasn’t sure if that was due to a lack of pressure signs.