Premature excess pressure signs in hand loads for my Bolt gun Grendel

[A5BLASTER]

I should have included that.
I had a Hornady 123 gr SST over 26.7 grains of Ramshot TAC at 2.306 COAL. (2.250 book max ) 1.892 CBTO using the Hornady bullet comparator. CCI #400 primer. This is when the pressure showed up. I'm shooting a 22" barrel. I used the Hornady loading manual for my data.
I generally begin my testing at around 75% book max. For this I started at 25.8 grains and was working up in .3 grain increments.

Thanks for the data. I agree with the others your at max for your rifle with that powder,primer setup.

[rickOshay]

This is why the use of a chronograph is highly recommended (if not essential) for reloading. Velocity is an indirect measurement of pressure.

[BLUESGUNNER]

This is why the use of a chronograph is highly recommended (if not essential) for reloading. Velocity is an indirect measurement of pressure.

You are correct. I should have set up my Chrony.

[LRRPF52]

For a soft CCI 400, your primer looks textbook, not that this means much.

The ejector swipe is more likely a result of a sharp edge on your ejector channel than anything, although I'd like to see what your velocity is.

Are you jamming the lands any with that long of a COL?

Does your dummy cartridge fall out of the chamber with gravity after being fully seated without the bolt?

In my Howa, I could load 140gr A-MAX to over 2.400" IIRC and it still didn't kiss, but each chamber may be sightly different.

[SightedIn]

I should have included that.
I had a Hornady 123 gr SST over 26.7 grains of Ramshot TAC at 2.306 COAL. (2.250 book max ) 1.892 CBTO using the Hornady bullet comparator. CCI #400 primer. This is when the pressure showed up. I'm shooting a 22" barrel. I used the Hornady loading manual for my data.
I generally begin my testing at around 75% book max. For this I started at 25.8 grains and was working up in .3 grain increments.

I had similar issues when doing COAL tests with SSTs. I went back to book spec of 2.250 and my issues went away. It was more accurate too.
Ssts like a jump

[CaptnC]

This is why the use of a chronograph is highly recommended (if not essential) for reloading. Velocity is an indirect measurement of pressure.

Yeap...IMO best answer so far...plenty of great suggestions too.

I've reloaded since the late 70 but had never loaded for a gasser. One of the first thing I worried about was going over pressure in the AR platform.

So my Magnetospeed goes on as soon as the rifle comes out of the case when I'm testing a new load.

I own 4...6.5 Grendel and the all like H335 with heavier bulet's (123gr class bullets) and Benchmark for lighter bullets (90 to 107gr).

[BLUESGUNNER]

Yeap...IMO best answer so far...plenty of great suggestions too.

I've reloaded since the late 70 but had never loaded for a gasser. One of the first thing I worried about was going over pressure in the AR platform.

So my Magnetospeed goes on as soon as the rifle comes out of the case when I'm testing a new load.

I own 4...6.5 Grendel and the all like H335 with heavier bulet's (123gr class bullets) and Benchmark for lighter bullets (90 to 107gr).

Thanks Capt for the response.