Advice on load workup

[omt223]

I just got my Bergara back from cutting the barre (from 26 to 22")
its a HMR that I changed the stock on (to a MC3 legend). 300 win mag
It has a mark 4 on it, stock trigger.

I have been getting 5 round groups that for the most part separate out into two acceptable groups but as a whole aren't.
I have about 8lb of surplus Wc857 that I have been messing with as well as some RL25, and 4831.
I am trying to work up loads with 180gr SSTs and 175 nosler CCs. I have some 220CCs but havent messed with them much.
I think I am about ~0.02 jump but dont have my gauge (gave it to a friend since I am in school, and of course ended up needing it)

I have been using CCI 200s; I do have some magnum primers but have been told they are largely unnecessary, maybe thats wrong.
As far as the powders, I have tried from 77gr up to 79 of 857; ~78 seemed to be the most promising but nothing special, 79 really opened up. Largely the same with the other powders.
I don't have the range for a proper ladder at my disposal within reasonable distance.

Here are a few of the targets, I have more but they are for the most part the same.

 

[JD284win]

Middle target wants to shoot good. Adjust seating depth .002 each way for .006 or work the powder up and down each direction by .3 grains. What caliber by the way?

 

[sedancowboy]

At those powder charges I always start with Mag primers. What Cartridge are you talking about?

 

[omt223]

At those powder charges I always start with Mag primers. What Cartridge are you talking about?

would help wouldnt it.
300 win mag

 

[JD284win]

That's a short barrel for a 300wm. May need a faster powder. Buddies 300wm with a 24" barrel. Had to ditch all the normal slower magnum powders and ran IMR4350 with 180gr Barnes. Man did she like the faster powder. Some were around 74gr if I remember right. In the neighborhood of 2980fps.

 

[omt223]

That's a short barrel for a 300wm. May need a faster powder. Buddies 300wm with a 24" barrel. Had to ditch all the normal slower magnum powders and ran IMR4350 with 180gr Barnes. Man did she like the faster powder. Some were around 74gr if I remember right. In the neighborhood of 2980fps.

Closest I would have to that is accurate 4064 or 4831

 

[imyourhuckleberry]

Middle target wants to shoot good. Adjust seating depth .002 each way for .006 or work the powder up and down each direction by .3 grains. What caliber by the way?

This^^^^^^ or try a different bullet weight.

 

[JD284win]

Closest I would have to that is accurate 4064 or 4831

That should get you close. Those were goto powders back in the day before h1000 and rutumbo and what not.

 

[omt223]

I have some H1000

That should get you close. Those were goto powders back in the day before h1000 and rutumbo and what not.

I have some H1000

 

[MagnumManiac]

Stick with 4831.
I bet the muzzle flash on that rifle is tremendous.
I have never seen a 300WM with a barrel shorter than 24", I know they exist, just have never seen one in use myself.
I hunted with a 24" barrel 300WM all throughout the early 90's, it was a flame thrower at that length.
RE22/RE25 will work well in that barrel length too.

Cheers.

 

[omt223]

Stick with 4831.
I bet the muzzle flash on that rifle is tremendous.
I have never seen a 300WM with a barrel shorter than 24", I know they exist, just have never seen one in use myself.
I hunted with a 24" barrel 300WM all throughout the early 90's, it was a flame thrower at that length.
RE22/RE25 will work well in that barrel length too.

Cheers.

I shot it in the evening the other day; it wasnt anything notable I thought

 

[L.Sherm]

I would definitely give H1000 and mag primers a go.

 

[Mike Matteson]

I shoot a 308 Norma Mag rifle in a 26" barrel, using H4350 @ about 75gr with a Fed 210 primer in Winchester Cases, and Nosler Accubond 165gr bullet. Develop 3300fps from the load. Very accurate, and have nock down several elk with it. No problem reaching out to 500+yds with it. Being it's a shorter barrel you may need a Mag Primers. H1000 is a very slow powder, and I feel it's great for longer barrel lengths or heavy loads. I would us caution on load development. The 75grs I stated above it hot, and primers are flat. The H powders are very temperature stable.

 

[JD284win]

I think H1000 is too slow for a barrel under 26". No saying it won't work. IMR7828 may land you in a good spot. Still a touch slow for a sub 24" barrel. Still think a 4350 or 4831 will be optimal in your barrel configuration.