.264WM/140 VLD Load Development (M70)

[benchracer]

I completed load development with Berger 140 VLD's and Retumbo in my .264 Winchester Magnum. The rifle is a South Carolina-produced Winchester Model 70 sporter in factory trim. The first target is the seating depth test. The second target is the powder charge workup. I still need to chrono the final load (69.9 grains) and verify it at longer range.

I am also working with RL-33 and will post the final results when I have them.

 

[somerumfun]

Any pressure signs? 70 grains appears to be over Max in the Hodgon data room.

 

[benchracer]

No pressure signs. Actual max in my rifle is quite a bit higher than where I am loading, but there is not enough headroom to reach the next higher accuracy node.

Quickload shows 82 grains as the default setting for .264 Win Mag case capacity. My actual measured case capacity, using Nosler brass, is 87.8 grains, which is why my actual max is so much higher than shown in book data. I did some careful load work to confirm this for myself.

This is a good example of why careful testing, real-world measurements, and generating real-world data is an important habit for any handloader. So many people think they can shortcut the process by using someone else's load data. Such thinking is wrong, unwise, and unsafe.

 

[RT2506]

It goes to show you that no two rifles are the same. I have a custom Shilen barrel 264 Win mag that has a TIGHT chamber and with 130 gr Accubonds 66.5 grs Retumbo is my max load. 67 grs left ejector marks on the rim.
I use WW cases with the bullet 20 thousands off the lands and average 3350 fps from the 27 3/4" barrel.

 

[benchracer]

RL-33 did not perform well in my rifle. It was shooting 2"+ groups @ 100 yards. I didn't bother to keep any targets or photograph them. I suppose I could experiment with different primers, but I have a very good load using Retumbo and don't want to waste any more barrel life chasing a load with another powder.

For this rifle, my load development will end here.

 

[barefooter56]

I completed load development with Berger 140 VLD's and Retumbo in my .264 Winchester Magnum. The rifle is a South Carolina-produced Winchester Model 70 sporter in factory trim. The first target is the seating depth test. The second target is the powder charge workup. I still need to chrono the final load (69.9 grains) and verify it at longer range.

I am also working with RL-33 and will post the final results when I have them.

benchracer,
69.9 or 69.3 grains? Which one have you settled on?

 

[benchracer]

69.9 is the load I am going with, pending verification at longer range. During my pressure limit workup, 70.0 grains clocked 3156 fps, so I am expecting 3150ish muzzle velocity. Will be interesting to see what the ES and SD numbers look like.

 

[barefooter56]

69.9 is the load I am going with, pending verification at longer range. During my pressure limit workup, 70.0 grains clocked 3156 fps, so I am expecting 3150ish muzzle velocity. Will be interesting to see what the ES and SD numbers look like.

benchracer,
69.9 looks like a winner. But 69.3 shows a really good horizontal. You may want to run them both over the chronograph and see which one has the lowest SD. SD is a good indicator of vertical dispersion and we feel it is the more important of the two measurements between ES & SD. What chronograph are you going to be using?

 

[benchracer]

benchracer,
69.9 looks like a winner. But 69.3 shows a really good horizontal. You may want to run them both over the chronograph and see which one has the lowest SD. SD is a good indicator of vertical dispersion and we feel it is the more important of the two measurements between ES & SD. What chronograph are you going to be using?

I appreciate your advice regarding ES and SD. I will check both loads to see what the numbers have to say. I use a Magnetospeed chronograph.

Both the 69.3 and 70.2 groups show the same lack of vertical, with one shot falling well out of the group horizontally. In both cases, I am confident that I did not pull the outlying shot. For that reason, I am leaning more toward the 69.9 powder charge. Chrono data may well yield some answers.

 

[barefooter56]

I appreciate your advice regarding ES and SD. I will check both loads to see what the numbers have to say. I use a Magnetospeed chronograph.

Both the 69.3 and 70.2 groups show the same lack of vertical, with one shot falling well out of the group horizontally. In both cases, I am confident that I did not pull the outlying shot. For that reason, I am leaning more toward the 69.9 powder charge. Chrono data may well yield some answers.

benchracer,
The Magneto Speed chronographs are great! Please let us all know what you find! Have a great weekend!

 

[lee31]

I run 70 grains of Retumbo with the 140 vld hunters out of my 264 . It gives me 3279 fps with a es of 16 or 17. I recently shot my best 500 yard group the other weekend just under a inch. But I must have got a hotter batch of retumbo I had some ejector marks on some of the cases. I have also run 77 grains of H870 gives me 3225 with a is of 27 fps at 500 the groups hang around 3.5inches with this powder. Here's a pic of the group I shot . Hope I can duplicate this tomorrow . There's a local 500 yard shoot tomorrow. I have won it the last two years with my 264.

 

[benchracer]

I loaded five rounds with the 69.9 grain charge of Retumbo and fired them over my chronograph. Average velocity came in a hair over 3200, with a min of 3184 and a max of 3225. ES was 41 and SD was 15. This load ended up being about 50 fps faster than I had expected. I think I am going to back down to 69.3 and re-test.

 

[barefooter56]

I loaded five rounds with the 69.9 grain charge of Retumbo and fired them over my chronograph. Average velocity came in a hair over 3200, with a min of 3184 and a max of 3225. ES was 41 and SD was 15. This load ended up being about 50 fps faster than I had expected. I think I am going to back down to 69.3 and re-test.

Benchracer,
You may want to work down in 1/10th grain increments to the 69.3 just to see what may be there. Lets try to get that SD down a bit more. You will notice it in the vertical stringing on the target. Keep us in the loop please! And pictures would help.

 

[benchracer]

Benchracer,
You may want to work down in 1/10th grain increments to the 69.3 just to see what may be there. Lets try to get that SD down a bit more. You will notice it in the vertical stringing on the target. Keep us in the loop please! And pictures would help.

I just shot those rounds across the chrono. I wasn't shooting for groups, so there aren't any targets or pics to be had. I am expecting the node to appear in the vicinity of 3150. If that is correct, I believe the ES and SD numbers may reflect that. It will be a few days before I can test further.