.223 Load velocity question.

[mecam]

If a certain load (55gr .223) is rated at 3100fps with a 24" barrel, what would the velocity be with a 16" barrel?

[StukaJr]

The "Rule of thumb" is that you will lose 30fps per every 1" in 3000-3500 fps velocity range and 20fps loss per every 1" at velocity of 2500-3000fps... You can guesstimate a velocity loss of 200 fps or so, but you won't know for sure until you chrono it...

High Speed, high pressure rounds lose velocity a lot quicker in short barrels than the heavy/slower rounds, so my gut feeling would have to say that your actual velocity should be in 2700-2750 fps range... The numbers above are primarily derived from larger bore calibers...

[mecam]

Thanks. I was guessing around 2700fps. I'll just get me the F1 chrono from Walmart.

[gose]

Thanks. I was guessing around 2700fps. I'll just get me the F1 chrono from Walmart.

I have a chrono you can borrow. I'll bring it on Sunday, if you want.

[mecam]

I have a chrono you can borrow. I'll bring it on Sunday, if you want.

Thanks gose but I don't think I will make it on Sunday though. My left elbow is still messed up. I can't even pull a mag out of a mag pouch or raise the rifle from the hand guard. I mentioned Walmart cause they have the F1 for $69 and I have a $50 gift certificate.

[gose]

Thanks gose but I don't think I will make it on Sunday though. My left elbow is still messed up. I can't even pull a mag out of a mag pouch or raise the rifle from the hand guard. I mentioned Walmart cause they have the F1 for $69 and I have a $50 gift certificate.

Ahh, sorry to hear that. Lets hope for a full recovery to the May match then.

Let me know if you change your mind on the Chrono. I'll be at Chabot both Sat and Sun and could meet you on the way home either day.

[mecam]

Ahh, sorry to hear that. Lets hope for a full recovery to the May match then.

Let me know if you change your mind on the Chrono. I'll be at Chabot both Sat and Sun and could meet you on the way home either day.

thanks man.

[ar15barrels]

3100 seems aweful low for a 55gr bullet from a 223 in a 24" barrel.
Are you sure of that velocity?
I ran some quickload sims and it would be WAY low pressure to only be going that fast.

Here is a graph of velocity vs barrel length on a standard pressure load.

[mecam]

I got the data from Hodgdon's chart. Varget powder at minimum load for 55gr shows 3174fps for 24". Basically I want to accomplish 2900+ out of 16" barrel if possible.