338 Luapa questions

[jamiebob]

I loading 300 smk with retumbo and fed mag primers Lapua brass, Fl sized with .365 bushing Seated to 3.650 and shot out of a sako trg 42 1-10

Just not sure what load to use? What i should be getting for fps and how much is this going to change when it gets hot out.
Was shooting a 5f at about 2900 feet.
92gr of retumbo = avg 2684fps 3 shot group size @ 300 yards = .426 Moa 5 shot = 1.647 moa (used on taget program)Pulled one on that group. (Group was 2.534" wide and 1.575" high)


93.5gr retumbo = avg 2791fps 3 shot group size @ 300 yards = .575 Moa 5 shot = 1.027 moa (Group was 2.817" wide and 3.077" high)

 

[redbullitt]

Re: 338 Luapa questions

For me, a lot of that would come down to what the groups actually looked like (ie how much vertical) and what the conditions were when they were fired. I would not put too much into chasing velocity; just find the one that seems to work the best. If it turns out being a slower load, then consider trying another powder.

It is helpful to record the velocities from a string of rounds. When you are getting where you want to be for a load, usually the SD will drop and be consistent.

For velocity, I am getting right around 2800 with the 300 smk (28inch barrel, 1200ish elevation)and reloder 25.

With regards to temperature, if you are on the high end of a load in the cold, there is a good chance the heat will bring in some pressure signs. The milder load you listed would more that likely still be just fine.

Were I you, I would go with the load that is the most consistent in terms of velocity, vertical spread etc. Soo honestly I am liking the size of that first one.