How dependable are 223 loads in Hornady's 7th edition?

[ajhardle]

I started at 20.8 gr of h335, Hornady's minimum. It states 2800 fps. Speer's manual #14 recommends 24 gr's for the same 55gr class of bullets.And the start velocity? 2805 fps. That's a huge difference. Why the huge difference?

[bigben]

Originally Posted by ajhardle

I started at 20.8 gr of h335, Hornady's minimum. It states 2800 fps. Speer's manual #14 recommends 24 gr's for the same 55gr class of bullets.And the start velocity? 2805 fps. That's a huge difference. Why the huge difference?

Different test guns different brass it could be a bunch of different things. I got a chrono this summer and it was probably one of the best things i purchased. Most of those projected fps can be off by 100 or more fps. Shoot it over a chrono and you'll know what your load is shooting

[ajhardle]

We're not talking about 100 fps here. It's a difference of 500fps. They are using different rifles,a 22" and 26", but that's not 500fps. I doubt there is that much variation in different batches of h335.I wonder if it's a misprint. Can anyone tell me what Hornady's 8th edition lists for 223 with 55 gr and h335?

[Trickymissfit]

Originally Posted by ajhardle

I started at 20.8 gr of h335, Hornady's minimum. It states 2800 fps. Speer's manual #14 recommends 24 gr's for the same 55gr class of bullets.And the start velocity? 2805 fps. That's a huge difference. Why the huge difference?

I used that same edition as you do, and I found the loads to be fairly close. But I switched over to BLC2 with a 55 grain Vmax. They used a 26" barrel in their manual, and I use a 20" barrel. I get 3270fps with 27.5 grains of powder. In a 26" barrel (same rife and barrel) I saw about 3350 fps befor I shortened the barrel. (Remington Mod. 700VS)
gary

[J E Custom]

Originally Posted by ajhardle

We're not talking about 100 fps here. It's a difference of 500fps. They are using different rifles,a 22" and 26", but that's not 500fps. I doubt there is that much variation in different batches of h335.I wonder if it's a misprint. Can anyone tell me what Hornady's 8th edition lists for 223 with 55 gr and h335?

Years ago all load data was tested in a 28'' test barrel and was fairly accurate.

Now it is calculated on computer programs and input data varies a great deal.

Most loading manuals are very conservative and if you start at minimum loads you will be safe
and can start increasing the powder charge in 1/2 grain increments until you start showing signs
of pressure.

Different chambers and barrels can effect the velocity so they stay under the max loads.

Also some manufactures enhance the data to make there product look better. A chronograph
will tell you what you highest velocity is at the max pressure. (Real world data).

J E CUSTOM

[ajhardle]

So, what I'm going to do is work up until I reach about 3100 fps. I will bet you that will be near the 25.5 to 26 gr I'm seeing in other manuals for their 55 gr bullets.

An interesting note, Hornady's max load is lower than Speer's minimum by 8/10 gr.
Hornady lists 23.2 as max.
Speer has 24 as minimum.
You can tell me different chambers, barrel lengths and components make a difference. I know, I've experienced that, but 500 fps error looks like a mistake to me.

[ajhardle]

A quick search showed others found the same. Hodgdon shows a max of 25.3. Hornady's assumption of 2800 fps with 20.8 gr of h335 it's unrealistic.