In prep for my 7mm Rem Mag cartridge custom loads and my fall Newfoundland Moose hunt I had some difficulty getting Reloader 22 powder for reloading my 7mm Rem Mag.
Accordingly, I purchased some available Vihta. N560 Powder that Nosler had listed for 7mm Rem Mag with Nosler 175 grain ABLR’s with a 24 inch barrel and 9 twist.
Its burn rate is near to RL 22. My rifle is a 26 inch barrel and 9.5 twist. Subtle differences in length and twist can shift ideal powder burn rate preferences to one side or another. You just have to find the sweet spot and the powder.
Early N560 Powder results showed extreme spread (ES) and standard deviation (SD), at lower velocities, were excellent, thus I continued working up the load.
Many handloaders have found that some rifles with 9.5 twist rates do not like the 175 grain bullets’ accuracy but so far my rifle likes them with this N560 powder.
As those who experiment with loads are aware, powder, can and does vary from lot-to-lot, thus backing off to starting loads and working up slowly is best. Observing the cartridge case and resulting primer can tell quite a bit as you approach a max load. As you incrementally approach hotter loads, the primer will begin to flatten into a pancake.
I try to avoid what some call “sticky bolt”, a term for supposedly “manageable” over pressure. So far so good.
As I load each round, I use a sharpie pen to write the powder name, grains, and bullet type/weight used on the brass.
I have achieved the near to 3000 fps under preliminary testing at an outside temperature of 45ºF and cartridge and primers look flatter but normal. First 3 shot group was just 1.0 inches at 100 yards.
Next is to check for Extreme Spread and Standard Deviation below with Labradar data.
| Browning X-Bolt Speed 175g ABLR w/Viht N560 Powder 65.7g OAL 3.440 | |||||||
| Outside Temperature 48F | |||||||
| Total number of shots | 3 | ||||||
| Group 1 inch | |||||||
| Units avg velocity | fps | ||||||
| Units distances | yd | ||||||
| Units weight | grain (gr) | ||||||
| Stats – Average | 2974.61 | ||||||
| Stats – Highest | 2987.57 | ||||||
| Stats – Lowest | 2961.27 | ||||||
| Stats – Ext. Spread | 26.3 | ||||||
| Stats – Std. Dev | 13.16 | ||||||
| Shot ID | V0 | V25 | V50 | V75 | Proj. Weight | Date | Time |
| 1 | 2961 | 2925 | 2889 | 2851 | 175 | 4/2/2023 | 11:28:09 |
| 2 | 2975 | 2934 | 2896 | 2859 | 175 | 4/2/2023 | 11:28:39 |
| 3 | 2988 | 2945 | 2905 | 2866 | 175 | 4/2/2023 | 11:29:17 |
JBM Ballistic Data indicates 1891 ft-lbs delivered at 600 Yards, 10 mph crosswind moves the bullet 17 inches left or right. At 500 yds delivers 2100 ft-lbs and 11 inch crosswind. At 400 yds delivers 2330 ft-lbs and 7 inch crosswind.
Next is to practice at those distances and collect real field data to see what limitations surface. More to come!
Good Hunting!
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