300wsm load advice (hunting load)

[PBking51]

Quick background: I hunt primarily woods with <130 yards and on occasion post up in a field or two where I have a good rest but have not yet had to take a shot on a whitetail outside of 500 yards.
I primarily use a 30-06, but have had great success with the 300 WM out to 400 yards using factory federal premium nosler 180 TBBC. I had a knack for the 300wsm and want to get a go to load worked up so I can feel comfortable sending in my data to get my cds turret made for my vx5hd 3-15x44 scope. The rifle is a Christensen Arms Ridgeline. My hunting rounds in other calibers have all been loaded using FL dies with minimal experimentation. For 300wsm I am using a forester neck bushing bump die with a .333 bushing. Norma Cases, 180gr sciroccos, cci LRM primers and hybrid 100v powder.

When I first seasoned the barrel I used mild charges of H4350 and had small groups but velocities south of 2850 fps with 180gr SGKs.

I wanted to use this powder and get as close to 3000fps with the sciroccos. I found that 64gr gets me to 2995 (4 shots) with a SD of 2.25! This is .004 from Jam and shoulder bumped 5 thousandths. 1st 2 shots from a cold bore are on the money (though I will be using a 200 yard zero) and the rest are seen in the picture. I'm sure it's just me and not the barrel heating up that has the other 2 shots not in that group. My question is, what effect would neck sizing to .335 or .337 have on the group? I do not own any bushings and before I spend the $30 on bushings I figured I'd ask here. I figure that because the Standard deviation is so low I just risk loosing velocity from having less neck tension.

I'm sure I am just being picky as this is a 2" dot at 100yards from sandbags and if I was a better shot on paper this group would be smaller but as I have an abundance of sciroccos I figured might as well have all data perfect to make the most of the cds turret and finally break free from Kentucky windage.

 

[Orr89rocz]

Have you tried different powders? I never used 100v Or 180 swifts, but with 180 berger elites and reloader 23, it shoots lights out. 3063 fps out of mine.
and they are jumping a mile from mag length lol.

have you done a variety of seating depths and charge weights? Does cold bore hits always group tight, like first two shots? Always consistent? If so that may be just rifle heating up, and for hunting rig, first shot it always cold

 

[Kurz]

My question is, what effect would neck sizing to .335 or .337 have on the group?

Before I started questioning the use of different bushings, I would measure the neck diameter of my chamber in the rifle then measure the neck diameter of my loaded cartridge with the bullet of choice seated.

Once I established the proper neck size, then I would work on seating depth and powder charge.

Hybrid 100V is an excellent powder, cool burning and consistent. It will not yield the highest velocities because it burns cooler.

 

[dkhunt14]

It may not have any effect on group by going to a bigger bushing. At 100 yards with a hunting rifle, I doubt you will see much difference in group. My Norma cases run about .015 to .016 on neck thickness. With a .308 bullet a loaded round would be. 338 to .339. With your .333 bushing you will have about .005 to .006 sizing. That is pretty much.

I like a lot of hold on my 300 WSM target rifles and also for hunting guns. I would try the .335 bushing and see if it makes a difference. Another way you could lighten tension is to skim neck turn them. That would make them more concentric and lighten the tension with the same bushing. If you take off .001, it would be the same as going to the .335 bushing. Matt

 

[Badhabit]

I would start adjusting seating depth in .003 increments. Just needs tuning.

 

[INTJ]

I agree with the others. Don't fuss over neck tension. As long as you have at least .003 you are fine in a hunting rifle. Don't bump you shoulders quite so much, .003 is about right.

Experiment with seating depth. I typically start a 30 cal hunting rifle at .020 when finding the powder charge, then I'll check seating initially at .015, .020, .025, .030. Maybe then I'll check .040, .050, .060

 

[JFrank]

Im uncertain of a disadvantage to having .003 bullet hold or more but i am certain that too light .002 or less makes my rifles unhappy.
YRMD

 

[PBking51]

Thank you all for the comments and knowledge. I think I will have to take it out to 300 and see what groups look like before I play anymore.

I am not used to this CA action as even with no round or a factory species round there is a bit of resistance on the bolt close. I may have seated it back a little farther than necessary because of this, but I know I might be able to come out another .002 at best. With that neck tension and those bullets I still think chambered rounds were still getting pushed back due to the scirocco having a long bearing surface.

 

[Orr89rocz]

It may want to be jumped more. Try .010 off .020 off and .030 off