Berger vld load troubles
Let me start off with describing my new rifle:
Remington 700 (trued/squared)
Mcmillan htg adj stock
broughton 5.75 24" 8 twist
tub recoil lug
american precision arms trigger guard
leupold mark 4 4.5-14
chambered .243 winchester
I am set on shooting berger 105 vld with h4350 and a federal 210m. I'm sure there are other choices out there but i have read enough people using these components and getting their rifles to shoot with enough tweaking. So with this rifle, i was hoping for pretty consistent .25 moa groups at 100 yards. I haven't even tried 100 yards yet because i have heard the bergers need to be shot out farther to stabilize.
I am using winchester .243 brass. I have trimmed all to length, uniformed the primer pockets, deburred the flash holes, and weight sorted.
The barrel has been properly broken in and had just over 100 rounds through it at the start of this testing.
Day 1: I went to the range to test seating length based off bergers recomendations. I started with 41 grains of h4350 and seating depths of .010, .050, .090, and .130 off lands. 5 shot groups each at 200 yards. none of the groups were that impressive but .090" was the best. I put 4 shots in about a 3/4" group and one flyer opened it up to about 2".
Day 2: I used the .090" seating depth and tested 39.5, 40.0, 40.5, and 41.0 grains of h4350 and i chronoed each shot.
39.5 g h4350: 2834, 2828, 2891, 2863, 2882 Average: 2860 ES: 63
40.0 g h4350: 2886, 2906, 2869, 2919, 2923 Average: 2901 ES: 54
40.5 g h4350: 2964, 2946, 2939, 2935, 2940 Average: 2945 ES: 29
41.0 g h4350: 2950, 2921, 2908, 2946, 2964 Average: 2938 ES: 56
41 grain load produced just over a 3/4" group with 4 rounds and a flyer opened it up to almost 3" group. This is the same load that produced the 3/4" group on day one but also with a horrible flyer. Also looking at the velocities it looks like 41 grains is pretty big spread. It had an ES of 56 but it was consistantly spread out over that distance where as 40.5 grains was very consistant with ES of 11 but one shot turned it to 29. So i was thinking that even though 41 grains of h4350 and seating depth of .090" shoots the best group, the velocities were kinda all over and both times testing it had extreme flyers. So it would seam that maybe there is an overpressure issue of some sort even though the brass isn't showing any. 40.5 grains shot a very uniform 5 shot group measuring about 1.25" which would be 5/8 MOA and the velocity was pretty consistant.
Day 3: I used 40.5 grains h4350 for the charge and .090" seating depth to start with to fine tune the seating depth. Today I tested .070", .080", .090", .100", and .110" and assumed that I would get my final load today. Figured one of these groups would give me a uniform 1/4 to 3/8 MOA group. (1/2" to 3/4" at 200 yards)
It was a little bit windy that day. Gusting between 7 o'clock and 5 o'clock. None of the groups where all that impressive, but .080" and .090" where noticeably better. The .080" measured about 1 5/8" and the .090" measured just under 1 1/2" group. Even if you take the wind out of it, the groups are still about the same.
The rifle was cleaned between groups and fouler shots as well. the barrel was always allowed to cool. Shot with a front rest and rear sand sock. I had a custom built .308 on a 700 action with a 20" 7.1 contour broughton built by the same smith. with 175 smk and varget with just a little playing with powder charge i was shooting groups under 1/4" moa.
So overall I am still not very satisfied with these results and feel like this gun is capable of better. I this about all i can really expect from winchester brass, not neck turning, not a tight neck chamber, and only a 5.75 contour barrel?