seating depth and pressure

[vitaminado]

Hello
I'm reloading a 6.5 creedmoor with reloader 17 and berger vld hunting 140gr.
I've been doing the seat depth test.
I have found the best groups at 0.050 "and 0.130" from the lands.

At 0.050 I was able to easily reach 2800fps without any signs , but at 0.130 ", I have seen signs of pressure and have only reached 2680 fps.
I took 0.130 "because it gives me a better brass fill, but I don't get good speed.

I have read this in the forum:

My opinion and observation is that when the VLD's are seated deeper, they tend to slow down due to the absence of the pressure spike that occurs when the bullets starts out touching the rifling.

What can you tell me about this?
Thank you very much and greetings

 

[Bigeclipse]

What's happening is the bullet is being seated deeper into the case which will increase pressure inside the case (due to less open space in the case from the bullet) when the primer first fires. This is why you are seeing pressure signs earlier as .130 is seating pretty far back into the case.

 

[rsmithsr]

as in reduce powder and work up when making that big of a change in over all length.

 

[vitaminado]

I have also contacted Berger and they have answered the same as you.
I thought .130 would give me the same speed with a better box fill.
Everyday you learn something new

Thank you very much for the information