Loading down a 300 win mag to 308 speeds

[Never Forget]

I know, why would I want to do that? I shoot a steel silhouette match and my 300 win mag did a number on the targets so I'd like to try and load them down to about 2600ish with 168 BTHP. I was thinking about using Varget because I have a ton of it. Thinking about shooting a OCW test from 45 to 52 grains in 1 grain increments and see if I can catch some sort of a node. If I can get 1 1/2 moa accuracy I'm more than fine for what we are shooting, currently my gun does better than 1/2 moa all day with full power loads.

Does anyone see a problem doing this?

Normally I run my AR10 for this match but want to play in the bolt gun class for fun, this is just club level have a good time and bragging rights shooting, nothing serious.

 

[M14AMU]

Buy another rifle...in .308 Winchester!

 

[mmcu]

Try a H4895 reduced load.

Here's the link to Hodgdon's H4895 reduced load information: https://www.hodgdon.com/wp-content/uploads/2016/11/h4895-reduced-rifle-loads.pdf

 

[Prose]

H4895 is the ticket. I use it for reduced and fire forming loads from .17 - .458 caliber. No problems with this powder in any cases outside of the 25-06.

Varget is a decent option, but H4895 is the most consistent and the load data is precise.

 

[Never Forget]

That's awesome, thank you. Fortunately I just got an 8 pounder of H4895 so I'm set.

 

[Zero333]

I've loaded reduced loads with h4895 and it works wonderful.

 

[HTSmith]

After successfully loading down a 30/06 to 30/30 levels for my son's first deer rifle, I gave the 300 Win Mag a similar go. For that particular rifle, it didn't work for me. It loved a case full of slow burning powder and nothing else (that I could find). I was using 4064, so maybe the 4895 will work better. Please report back on your results.

 

[mongo chicago]

Be careful. Downloading too much can be as dangerous as overloading.

 

[Never Forget]

Worked great, tried H4895 from 42 grains to 55. 42 to 45 was too lite, didn't even push the shoulder forward with sporadic and really inconsistent chrono readings. 49 to 52 gave me between 2450 and 2525 consistently which is exactly what I was looking for. 5 shot groups were 1" at 200 yards with 49 grains and still under 2" at 52 grains, more accurate than I need for the type of match I'm shooting. I'm going to run 49 grains, recoil is like a 243 with that load and the muzzle break.

 

[mmcu]

Glad to hear that it worked out for you!

 

[Prose]

Thanks for reporting back.

 

[Clark]

300WM 125 gr nos bal tip moly 66 gr IMR4166 3374 fps chrono 22" Krieger barrel on 91/30 mosin nagant

One could do the same velocity with H322 in a 308.

 

[DRNewcomb]

Stick with extruded powders, which have easier ignition characteristics than ball. Use a charge that fills the case at least 1/2 full. Try to keep the rounds pointing up or horizontal (not down) when loading the chamber, so that the charge stays in contact with the flash hole.

 

[hogan]

Why not consult a few loading manuals and get a consensus on lowest velocities at bullet weight you're interested in?

The Lyman Cast Bullet Handbook #4 is very good source for cast bullet loads and how-tos. No reason to risk detonation by loading mouse loads in a magnum case without proficient guidance.

 

[Zero333]

Some of us knew H-4895 was the ticket for you.

Thanks for following up on this thread. I'm sure there is plenty of folk who will stumble on this thread after googling "reduced 300winmag loads"

 

[ImBIllT]

There are published loads of H380 running under 2800 in the Win Mag, and a few loads over 2800 in the .308. H4895 is right there too. Use magnum primers with ball powders.