Question about 7RM reloading

[bstomper]

I am doing load development for my Winchester model 70 7mm RM. I am using Hornady brass, H1000 Federal 215m primers and 175gn Accubond LR bullets. Initial COAL is 3.360". I shot yesterday in -4c temps. The Nosler data says 65.5gns is max for the 175's and Hogdon and barnes say 64.5gns max at a COAL of 3.290". I am at 70.0gns and have no signs of pressure yet. No sticky bolt, no cratering on the primers but I can begin to see just a slight flattening of the primers. I am sitting around 2920 for speeds. I have a great accuracy node that is worth exploring at 68.2-2894fps, 68.4-2899fps and 68.6-2889. It confuses me a bit that I am 5gns above the stated max charge and not seeing pressure. Is this common? I could understand maybe a couple grains because of the longer COAL but 5 seems like a lot. I'm not to sure if I should continue to go up in charge weight until I see definate pressure signs and back down from there or just continue with the node at the 2890fps. Any help would be appreciated.

 

[GLTaylor]

My bet is you will see extreme pressure excursions at warmer temperatures. BE CAREFUL!
Would investigate good nodes at lower charges

 

[Dosh]

b, do you have an aftermarket barrel or the factory barrel?

 

[BallisticsGuy]

Don't look for max in the cold.

 

[bstomper]

My bet is you will see extreme pressure excursions at warmer temperatures. BE CAREFUL!
Would investigate good nodes at lower charges

That is also my concern. I ran into that issue with the load development on my 6.5cm

 

[bstomper]

b, do you have an aftermarket barrel or the factory barrel?

factory

 

[bstomper]

Don't look for max in the cold.

Good point. I should already know this because as I mentioned above, I ran into this doing load development on my 6.5cm and had drop to the next lowest node.

 

[bstomper]

Thanks guys, these were my thoughts also. I just needed some confirmation. I will explore the lower node.

 

[Gwine]

I agree, don't look for max in the cold. Be careful when it warms up even with H1000.

That said, I have a factory barreled 7RM that pressures up late. I'm currently running 4+ grains of 7828ssc over Berger's data for my combination of components. My speed is within 30fps of the Berger velocity at max. This was developed at 80*.

 

[bstomper]

I have more rounds loaded already at higher charge weights that I am going to pull the bullets on. Problem is I'm running low on bullets to do the next round of testing and won't be able to get any for a couple weeks. Will I get accurate results if I use the pulled bullets in the load development

 

[GLTaylor]

Yes. Just be very careful not to distress the tips or bearing surface.also re-size the case necks so neck tension is correct