Earlier this year, I was talkng to a guy at the range who was running a DMR setup of some flavor. He mentioned that he really liked N133 with the 75/77 grain bullets in 223 due to the low SDs. As I had quite a bit on hand and it is a powder that is readily available, I thought I might give it a try.
Vihtavouri does not show data for the 77 SMK, but has loads for the similar bullet weights, between 17-21.9 grains of powder. I tried 20, 21, and 22 grains. The day I tried the 22 grains, I was at the range with a friend who had his new Garmin chrono. With only 5 test shots, the load showed promise, 3 of the 5 shots had identical velocity.
Before I made another load, I put together some data in Gordons Reloading Tool. It showed that 22.5 grains should still be under max pressure, so I bumped the load up another two tenths to 22.2 grains.
Today I tried that load with another friend’s Labradar and the 75 grain RMR blem. 2778 FPS out of a 24" 1:7 Krieger barrel, with the 10 shots providing an SD of 9.3. That’s good enough for most of the shooting that I do, but I might weight sort some brass and bullets to see if I can squeeze a lower SD out of that load.
Also, Gordons shows burnout at 9.4", so it may be a good powder for the shorter barrels.
The groups today were with blems, so not the best for testing accuracy. I shot them in two 5-shot strings. Both groups were in the .7s at 100 yards, with one group having a low flyer that put it at 1.1"
I plan on putting together some 77 SMK loads which will really show the accuracy better.
The first load with 22.0 N133 used CCI 450 primers, LC brass that had been fired in that gun once already.
The 22.2 N133 load was with Federal 205 primers. It also used LC brass, but were range pickups so the headspace wasn’t ultra consistent. This load showed a little bit of primer flattening, but I was shooting in direct sun and temps in the 90s. Worst case scenario with a 223 chamber.
Hottest to coldest goes:
Winchester (all types)
Federal (all types)
CCI (all types but the military equivalents)
Remington are the coldest across the board.
I remember German Salazer pointing out the the Remington (I forget which designation) primers defeated the purpose of the Palma brass because they were so hot, it was like a Large Rifle Primer.
Federal primers usually goose my velocities compared to the WOLF SRM. But WIN seemed to just play nice with everything.
I honestly don’t have too much experience with CCI 400s.
I have a 25 year old box of Winchester large rifle that I am still burning through. Nowadays, I shoot mostly small rifle- CCI BR4 and 450 for 223, 6BR, and 6x47L.
The Federal 205 on hand are used in standard pressure 223 loads with faster powders. Last year I was speaking to a high level benchrest shooter. He claimed that primers didn’t matter all that much in 6PPC and was running the 205 with N133. He was shooting 100 yard groups that were in the .1s so it obviously was working for him.
I do have a stash of Wolf and Tula primers but haven’t really seen a need for them. The Tula have thinner cups and only hold up in standard pressure loads.
My friend was playing with his phone skope adapter while we were at the range today. I should have tried to shoot a 5-shot group, but ended up moving to other targets on the range.
Today, I was mostly shooting my 223AI, but near the end of the shooting session, I got out the 223 and shot at some 420 and 545 yard targets with the 75RMR/N133 load. At 420, there is a steel coyote with a steel flipper of the vitals. Holding for a 5 MPH crosswind, I hit it 5 times in a row. Then dropped two on the hanging chicken at the same distance.
I’m loving that VV powders haven’t priced jumped like some of our old go-to choices. I was able to grab a few pounds todays for under $40/pound. I think even TAC costs more locally.
