First, what brand of brass are you using? And what is your seating depth?

The data on Nosler's website is with Nosler brass. Nosler/Norma brass is fairly thick and heavy, so the internal case volume is generally less than a Winchester or Hornady brass, for example. So, the 65.5 grains in a Nosler case compared to a Win case, this would be a much lighter charge weight.

If your seating depth is seated out close to the lands, you are increasing the internal case volume. So you can run more powder in the case at the same pressure.

So, in combination of the brass and seating depth, you could easily need to add a few grains to get your speed up.

Ok. What is your coal?

Take one of your fired cases before resizing or decapping and weigh it then fill it with water and weigh it. The difference is your case capacity to use in quickloads.

You're about .060" over book listed max, so that will reduce your pressures some. Hornady shows 64+ grains of powder, also for a max.

I done load development on the 7mm Magnum with RL19 and 139 SST Interbonds and came across a nice group at 65.5 grains at 3,090 fps. last week on a dry hot day. Nosler manual says 65.5 grains, WMLR primer and at 3,318 fps with a 140 grain bullet, of course different manuals may have different data, but this load is at 3,090 fps which is very slow. So I input all the data, including H20 case fill, in Quickload to see pressure and the max pressure is 61,000 psi and my 65.5 grain load pressure is 46,500 psi. It could be due to chamber size, slower burn rate on powder or maybe short bearing surface on the SST bullet. The 65.5 grain load shot nicely but I would like a little more speed. So I ran a ladder test this morning and it was very humid and wet:

66.0 - 3,062 fps
66.4 - 3,089 fps
66.8 - 3,116 fps
67.2 - 3,136 fps
67.6 - 3,176 fps
68.0 - 3,150 fps
68.4 - 3,184 fps
68.8 - 3,221 fps
69.2 - 3,239 fps

No pressure on brass. Book max is 65.5 grains and this ladder highest charge is 69.2 grains of RL-19 ( 3.7 grains over max ) and still have not achieved 3,300 fps yet. Is it possible to continue charges up to 70.2 grains which will be predicted at 56,000 psi (which is well under max pressure of 61,000 psi.) and right at the node of 1.1905 with a 26 inch barrel at a velocity of 3,300 fps.

What would you folks advise I do?

Is the velocity loss between 67.6 and 68 from things starting to expand that we’re not before? I’ve always been curious about this phenomenon. At least that’s what I’m going to call it until I understand it.

I've heard multiple explanations but none of it was rooted in cement. I know which explanation I believe. I don't have enough evidence to open my mouth though and potentially make a fool of my self. Maybe someone here can shed some light.

I've heard multiple explanations but none of it was rooted in cement. I know which explanation I believe. I don't have enough evidence to open my mouth though and potentially make a fool of my self. Maybe someone here can shed some light.

I would not take Quickload as the gospel either. They are calculated guesstimates only. Lots of different things determine actual pressures.

I would not take Quickload as the gospel either. They are calculated guesstimates only. Lots of different things determine actual pressures.

Here's a sign of over pressure.