Powder speed and barrel length play in. I did testing with mag primers and lots of spread in my ES and SD. I have found that I typically don’t have good luck with mag primers in anything shooting less than 70 grains of powder. Check or the article, similar findings to mine.
I was surprised at how good the Norma brass has been. I typically run Lapua but they are not playing the short mag game yet, so I went with 100 pieces Norma. No culls, no complaints. That being said. I have emailed Lapua. They essentially said they have had lots of inquiries, especially on he 7 SAUM so in the future they could start producing it so fingers crossed
Played with the load today. Shot over my chrono and by my buddies labradar. Found my best load for the 162's. 3210 fps average with 13 ES and 6 SD according to the LabRadar. 3218 fps average with 12 ES and 6 SD. This was at 64.1 grains of H-1000 .005 off the lands. Shot 2 groups of 0.25" @ 100 and one group of 0.20". Going to 1,300 yards next weekend will report back after that.
The 65.5 grain load (same as the 3327 load from last week) was 3301 FPS average 31 ES and 13 SD with Labrador and 3319 with 28 ES and 13 SD on my chrono. So no malfunction on the chrono's part. Just a slick barrel I guess. 3 groups were all between .3 & .45" No pressure signs at all.
Going to go with the 3210 load due to the group size and SD. Loading up 50 for next weekend. The other 50 will by my 180 Eld load going 2930. Depending on how they perform I'll narrow down to the more accurate load then try for 1,760, 2,000 and 2,500.
I have been shooting a 7mm saum for years. I currently have 7 barrels chambered and ready to go for my 2 full custom 7mm saums. I have also shot out several . I change my own barrels etc. I say this to prove how familiar I am with this cartridge . Speeds of 162 grain bullet at over 3300 is either from an extra long barrel 32-34 inches, a result of a faulty chrono or excessive pressure. I would hate to see people try to duplicate that speed as it would be down right dangerous. I am sure you will hear from others.