I use 74 gr of IMR 4831 behind 180gr Nosler Partition in my A-bolt. I'm getting 3050 fpswith consistent 3/4 - 1 inch group. My best is 3/8" but I think that was an accident.

I have used this same load in my Remington (Hart 1:12 barrel) with great results. This is one of those classic "do all" loads.

I can't get Nosler partitions to group in my gun (Win m-70)at all. I can shoot the 180 rem core locks with 75 gr. IMR 4831 less than an inch all day. switch to the partitions and groups go to 2.5 " They work fine in my buddies Rem 700

I think you will love the Pro Chrony. I had a Winchester 7MM Mag that would drop off quick when it reached a certain load. Just couldn't burn any powder efficiently.

Did it have a heavy bolt lift or pressure signs at that point? I know something is burning or I wouldn't have the heavy bolt lift.

bigcountry,

I have worked with .300 Win Mags and 180 grain bullets for about 13 years now. This past fall I found the best load I have ever tried in the guns I have loaded for. The load consists of:

New Winchester Brass
Federal 215M primer
76.0 grains of RL22
180 grain Nosler Accubond
Bullet is seated .015 from the lands
Average velocity for 5 shots in 70 degree weather - 3,184 fps.
Average velocity for 3 shots in 20 degree weather - 3,150 fps.

I am going to attempt to attach various targets from the day I worked up the load, and then a picture of my sight in verification target prior to my hunt this past fall.











Here is the sight in verification target. This was shot in rainy, breezy conditions and about 50 degrees.

300, thats the load I used. I found heavy bolt lift at 77gr. I am shooting a 180gr bullistic tip however. But very simular results.

bigcountry,

I too tried 77.0 grains when it was ~20 degrees outside. No obvious signs of pressure...except the chronograph - 3,248