Seeking Your Comments

[TC8500]

I was on the range yesterday developing a load for my 7X57mm TC Encore. I was shooting at 100 yards, the temperature was 70 degrees and sunny. These are the loads I shot yesterday. 150 grain Nosler BT, RP brass, Fed 210M primer. total COL is 3.00. The first load was with 46 grains of W760 which formed a nice tight group in the center of the target. Second load was with 40.6 grains of Varget, this load too formed a tighter group than the 760 and was centered in the target. The third group was with 49 grains of H4350, this load however formed a much more open group about six inches higher than the other two. None of the loads showed any signs of high pressure. So I'm asking for your thoughts on why the 4350 went much higher. Any and all comments are much appreciated.

 

[blarby]

Your gun/barrel does not like the pressure curve harmonics that 4350 at that charge provides.

All firearms are unique critters. Thankfully, you have two powders that tickle it just the way it likes.

 

[Grumulkin]

So I'm asking for your thoughts on why the 4350 went much higher. Any and all comments are much appreciated.

There are at least 3 possibilities:

1. The one I think is most likely is that the load is a little too light. This means there is a little more time for the barrel to rise under recoil before the bullet exits the bore. If this is the case, increasing the load will probably make the groups tighten and the impact point come down.

2. As the load is increased, there is a progression from tighter groups to wider groups and the impact point may become higher. So, maybe the load is a little too hot. The only way to know is to start low and work up.

3. It could be that IMR 4350 isn't a good choice for that cartridge/bullet.

 

[TC8500]

H4350 Comments

Much appreciated comments from both of you. I'll try another H4350 load by increasing a grain or two and see how it performs. H4350 produced a good tight group when I shot a 120 grain Nosler BT. So once again thank you.