newbie here, thnx in advance for any help received, a year ago I decided to purchase a Winchester 1885 highwall hunter in 300 wm, well unknowing to me they had only recently (2014) brought this caliber back along with 300 wsm and from my understanding only made 45 of each then discontinued production. my luck fall head over hills for a rare duck. well after three days of hair pulling research on the internet I found a 300 wsm at shedhorn guns I was also put on several lists in the event one popped up. I purchased the gun from shedhorn had it shipped to me and topped it with a vortex viper pst 6x24. very soon I realized ammo local on the shelf was a problem, I found one box of fusion 180 and at another place I found 1 box of 150 fusion, my plan from the beginning was to reload any way so no big deal, at the gun range both rounds shot plenty good to suit me and so back to the reload bench I go , and that's when it went down hill so far best groups ive loaded are 3-4 " using h4831 with 180 hornady sst and then imr4350 with hornady 150 grain gmx, ive tried every combo of charge and oal with very poor results. even discovered that hodgsons max load recommendation is over filling casing and that's when I decided to seek help hopefully from someone who has had success with this gun and caliber, again thnx in advance, wish I knew what was in the fusion cases?

You don't mention why you want to use your load. When it's for hunting: lots of data on .300 WSM in the Barnes Reloading Manual. My experience: when you can get a load with a Barnes bullet that gives a good group, you'll have a splendid round to hunt (your .300 will give satisfaction from small to big game from short to long distance).
So Barnes is where I would start (and afterwards I sure will try to get the same results with a cheaper round... even would try a reduced load with a home-made lead bullet because .308 is such a broad caliber to find bullet for)

and by the way: welcome in "nut-world" where nuts meet and Vince is serving beer while Suz is dancing on the pole...

Welcome bdriller,
Beer contains to much sugar and yeast, you are better off with a good scotch
I have never had much success getting the 300WSM to advertised velocities
Probably max 30/06 [advertised]
But I do have very accurate loads
My favorite powder is Win760 then 2209[H4350], 2208 [Varget] will give you the best muzzle flash ever, day time or night time. and RL17 gave a slight edge on velocity [not advertised] but I couldn't get a tight group
I have developed good loads for the following
180 Partitions, 165 Barnes TSX, 200 Woodleigh PP, 150 Lapua Mega, 150 Sierras, 150 Core Lock, 150 Taipan
Rifle is a Tikka T3, my best loads are under advertised max, but have traveled over searching for something but never found it.

I appreciate the response so far, I want a good round for deer at too long of a range not my desire on the range but it is what it is, far upper west texas so dang flat and no cover to speak of my buddy that lives there told me its so flat he once watched his dog run away for three days, 2ndary bullets will be used for fun long range plinking at 2'x3' steel targets starting at 600 yds and I cant tell you at this point where the fartherest target will be but im hoping for 1000 yds after lots of practice, really hope somebody chimes in with the same gun and caliber in case this gun has some funny characteristics.

Welcome aboard the best Hunting Forum on the web bdriller. Grab a beer and pull up a stump to the fire mate.

I can't help you with your calibre and load data, but as you have already seen, there are guys on here with the knowledge and experience and they are more than happy to pass it on.

Feel free to jump in with your experience as well mate.

Bdriller,
Does it group consistantly?
Or does the first shot go near where you want it and the rest wander off as the barrel heats up?
Scope mounts tight?
Scope actually holding zero? Maybe try another one and see what happens.
Are you flinching?
Weight of trigger pull, crisp or really creepy and heavy?
Rifleing in good condition?
Does the rifle fit you or are you hunched up or stretched out when you shoulder it.
Rifling twist what is it?
Are the holes in the target neat round ones or out of round?

Onto ammo, what press, dies, powder scale, primers etc are you using and what are your reloading processes.

We need all the above info to start. Distance trouble shooting, gotta love it.

dhc4 asked good questions. Did you use a chronograph so you can measure velocity dispersion? Did you measure distance to the lands? My initial guess is a concentrcity issue but more details are needed.

I've only ever developed hunting loads
For long range I'd look at the target pills
SMK's, AMax, Scenars or Bergers

all good questions, gun shoots a 1" group with federal fusion ammo in 150 grain and 180 grain I can alternate back and forth from factory to reloads the later shooting 4" groups ,yes on bullet depth have ran from .002-as much as .015 no improvement, barrel is not heating can wait 2 mins. between rounds and run 3 factory rounds back to back and group 1" loader is rcbs ,neck sizing only, deburr mouth mag primers I think hodgson data is bad because theyre max load compresses powder and when shell goes in barrel you cant close the chamber once I sorta forced closure and didn't shoot when I opend chamber bullet stayed stuck in lands and dumped powder down in gun mechanics, I assumed at that point that powder measure was wrong so I weighed a 55 grain bullet and a 150 grain bullet and scale was dead on. payed $ 45.00 a box yesterday for fusion ammo

barrel is 28" 10 twist , no have not chronographed not an issue with me at this point, am shooting gun on bench with sled, seen on here a fellow posted back in 07 he has the same gun and was reloading name craig hix, was hoping he might chime in .

Have to look it up, but a long time ago I read something about primers on the site of Barnes... something like "when you don't get teh velocity you expect, try .... primers" and it seemed to work that time. Sorry I forgot what kind of primers he recommended. I live in a country where 2-300 yards is considered to be a very long distance, so I'm not looking for maximum velocity.

And don't forget: some bullets need 2-300 yards to stabilize their flight. That kind of bullets can give a bad groupe at 100 yards and still a real good one at +300 yards (f.e. the .303 Br is a round that shows such unexpected things).

The harder it is to solve a problem, the more satisfaction when you get it solved...

From what I have read, the WSM has a very short lead, making bullet choice and seating depth pretty important. If you are overly compressing charges you may be experiencing bullet creep. This can be increased for rounds in the magazine as recoil adds to creep. A tight crimp helps but peak pressures can climb fast with such a combination. I had to lap the expander button in my 6.5 die as it left some cases with slack neck tension when using PRVI bullets.. Insufficient sizing could also cause neck tention issues I would try some loads in FL sized cases, starting charges and stick strctly to the OAL specs in your loading data. Measure the Fusions for another comparison.

GMX and Barnes bullets need to be at least 0.050" from the lands to avoid high chamber pressures. You likely have multiple issue compounding your situation. Make sure you check concentricity of your reloads. The only time my groups were that bad was when concentricity was off. You can do a quick check by rolling on a flat countertop. If you can see the tip of the bullet move, you have a concentricity issue.

Definately see wobble in tip when rolling, is neck crooked due to dyes?

Definately see wobble in tip when rolling, is neck crooked due to dyes?