reduced 300 win mag innacuracy?

[hillbillydruggist]

I loaded some reduced TRAIL BOSS loads with Hornady 150gr bullets, CCI mag primers and it worked out great! then I used Remington mag primers, same powder load and 168 sierra game king bullets, and I had horrible accuracy like 12 inch spread at 100 yds. does this make sense?

remember I am an idiot, thanks


(was about 2 inches with Hornady)

 

[INTJ]

I would check to make sure everything is as it should be on the rifle. Scope screws are tight, actions screws, etc. Then I would shoot the Hornady load again to make sure it still groups okay. If it does, then you’ll just have to play with the Gameking load. I have not messed with reduced loads, but I have seen a rifle vary from 1/2” to 4” as I messed with loads.

 

[Ledd Slinger]

Changed primers and bullets and accuracy changed??? Of course that makes sense. You changed two major components in the recipe.

Tho 12" group does sound a little excessive...

If you want to reduce the power of the 300 win mag, you might as well shoot something smaller like a 308 win

 

[dolek]

Did you have the 150s at max(25.5 Trail Boss(?)) ? That's a pretty big difference in bullet weight to use the same charge .Also,are the bullets same design...FB or BT ?

I have had much better luck with reduced loads when using the 60 percent formula for H4895 . Just throwing that out there. Another thing, in my experience seating depth plays a major role in reduced loads accuracy .I usually find the velocity/recoil I want and tweak the accuracy with seating depth.

 

[hillbillydruggist]

Was the same powder charge, hornady was not boat tail, same Oal

Thanks

 

[dolek]

Was the same powder charge, hornady was not boat tail, same Oal

Thanks

OK,I can now see why such a dif in accuracy .You have big variables there,18 grain dif in bullet weight is big if using the same reduced charge . BT and FB factors in also,along with seating depth,both for jump/jamb and how much of the case capacity is used up by powder/bullet . I have had success from a jump of 70 all the way to a jam of 5 with a 30-06 , all depends on the combo . You should be getting close to what you already get with full strength loads when it comes to accuracy .

 

[Zero333]

I've read Flat Base bullets are much better for subsonics.

 

[918acton]

When loading Trail Boss for subsonic, I have placed cotton balls on top of the powder charge before I seat the bullets. The cotton balls will hold the powder in place for more consistent ignition and the cotton balls burn instantly. I have used this method to improve accuracy with different subsonic loads.

 

[DirtySteve]

Using a 300 WM to shoot subsonic seems a bit odd to me. I mean the thing is designed to shoot big bullets fast. You would be better suited with a 300 Black Out which was designed to be shot subsonic. Plus you can load it up to 30-30 performance...