264 High Pressure Issues Part II

[TC8500]

I posted a few weeks ago concerning high pressure signs in my 264 using 61 grains of H4831 with a 140 grain Nosler Partition. I received very good advice and recommendations on how to correct the high pressure.

I went back to square one and started all over on working up a load. I stared by using the following data which is posted on the Hodgdon website.

Remington Brass
H4831 Powder
Federal 215 Primer
120 Grain Nosler BT
OAL: 3.250

I loaded 5 rounds with 60.6 grains, 5 rounds with 61 grains, 5 rounds with 62 grains and 5 rounds with 62.5 grains. The max load listed is 64.5 grains.

I went to the range this morning and had no high pressure signs from any of the loads. The group size @ 100 yards for 60.6 was 1.75" for 61 it really tightened up to .68", for 62 it started to open back up to 1.50" and finally the 62.5 group opened up even more to 2" with the rounds climbing high and to the right. I now have a good 120 grain load and will start the same process on developing one for 140 grain load. Once again a big "Thank You" to all of you for helping me sort out the high pressure issue.

 

[loadedround]

Please explain what you mean by "high pressure signs". I didn't see your first post.

 

[gamestalker]

I would try experiementing with your OAL, working up closer to the lands specifically. You might find that the heavier powder chages that were not holding as tight a group will suddenly begin to cooperate. You powder choice is an excellent one and offers plenty of potential at the upper end of the data if you get up a little closer to the lands.

 

[TC8500]

The pressure signs shown with the 140 grain bullet were primers that were heavily cratered and in one round the primer was completely blown from the case. The OAL was 3.310 and the max OAL measured for this rifle is 3.410 which was done by seating a 140 Nosler Partition in the lands and the running a cleaning rod down the barrel until it touched the bullet and marking it. The bullet was the removed and the bolt closed and the rod run down until it touched the bolt face and marking the cleaning rod. The distance between the two marks measured 3.410

 

[Caddisflied]

You're wise to use caution when loading for the 264 Mag.
Pressures can jump quickly with that round for some reason.
I never got within 2 grains of a maximum load when I loaded for my 264.

 

[jerkface11]

4831 is TOO fast. Go to a slower powder. Try H1000 or H870 or retumbo. I use surplus IMR5010 in mine with 160 grain bullets.

 

[NCsmitty]

I now have a good 120 grain load

You cannot base a load on the results of a single 5 shot group. You'll need to run at least 3, five shot groups with that load to say that it is consistent.
The more you have to average, the more it gives you a picture of it's actual potential.

120gr Nosler ballistic tips can be accurate, but on larger game, can fragment at 264 WinMag velocities. You should take a look at the Nosler Accubonds or the Hornady interbonds, as they will expand without fragmenting, which is important out of magnum cases.



NCsmitty