Thread: My first load development

Originally Posted by grandpamac

Greetings Remmodel7,
I have not found ejector hole marks all that reliable as an indicator of pressure. There can be a slightly rough edge around the hole that makes a mark at normal velocities. Another rifle may show no mark, or any of the other "pressure signs" but expand the case head beyond further use with one shot. I've seen both. In the second case the claim was really good velocity with no pressure signs. Old data that had not been pressure tested was a culprit here as well. Velocity is easily the best indication of pressure that can be used by handloaders. Actual tests of velocity loss v barrel length reduction have shown 20 to 30 fps loss per inch for standard calibres with the smallest cases losing the least. I would figure on 20 fps per inch for your Grendel. Hodgdon/ADI book data for the Grendel is for a 24" barrel so 80 fps would be right.
Regards Grandpamac.

@grandpamac.
Yes sorry 24” from adi book. From the top of my head I think max load was 2460fps so I'm guessing I should be in the high 2300?
Was hoping for better then that.
I had read that the Grendel being such a short case burns all it's powder and Max velocities can be reached from as little as a 14" barrel.
Ideally I want to use 8208 as my powder but as you will all know it's bloody hard to find anything at the moment. Or if you do in the car of powder get it to you.

Originally Posted by Remmodel7

@grandpamac.
Yes sorry 24” from adi book. From the top of my head I think max load was 2460fps so I'm guessing I should be in the high 2300?
Was hoping for better then that.
I had read that the Grendel being such a short case burns all it's powder and Max velocities can be reached from as little as a 14" barrel.
Ideally I want to use 8208 as my powder but as you will all know it's bloody hard to find anything at the moment. Or if you do in the car of powder get it to you.

Greetings Again Remmodel7,
Max was 27.5 grains of Benchmark for 2,460 fps. You are 0.5 grains below that. Calculating the velocity per grain using the start and max loads gives 94 fps per grain gives 47 fps loss. About the only cartridge that gives max velocity with a 14 inch barrel is the .22 Long Rifle RF so you will loose velocity from the 20 inch barrel. 4 inches at 20 fps per inch (a conservative estimate) gives another 80 fps loss gives a corrected velocity of around 2,330 fps for 27 grains and around 2,380 fps for 27.5 grains. Whoever said max velocities could be achieved in a 14 inch barrel must have a degree in wish full thinking. Only a chronograph will tell you the truth. If you want more velocity a lighter projectile would be needed. Around 2,400 fps with a 123 grain pill is a pretty decent load though.
Regards Grandpamac.

Originally Posted by grandpamac

Greetings Again Remmodel7,
Around 2,400 fps with a 123 grain pill is a pretty decent load though.
Regards Grandpamac.

yes its right up there with a 7.62x39mm LMFAO.......

Originally Posted by Remmodel7

@grandpamac.
Yes sorry 24” from adi book. From the top of my head I think max load was 2460fps so I'm guessing I should be in the high 2300?
Was hoping for better then that.
I had read that the Grendel being such a short case burns all it's powder and Max velocities can be reached from as little as a 14" barrel.
Ideally I want to use 8208 as my powder but as you will all know it's bloody hard to find anything at the moment. Or if you do in the car of powder get it to you.

The Hornady Manual Edition Ten has 27.1 of Benchmark max at 2450fps in a 18"barrel the top velocity is 31.2 CFE223
This from the Hodgdons site,https://www.hodgdonreloading.com/rel...2C9694%2C10068

So I went out for a bit of a quick sight in yesterday as there was a possibility of a hunt today.
Only had a brief time during lunch so got myself zeroed

Black tape was aiming point.
Next put in 2400 as velocity and shot at 300yards.

A bit low so used applied ballistics to calculate velocity.
Came out at 2389fps.
Shot out to 400

There was a slight cross wind that I didn't allow for.
Pretty happy with the results so far.