.223 Sub Sonic

[Treeman]

I have two new projects coming up, .223 sub sonic and .303 sub sonic
Right now, its the .223.
Does anyone have any starting points for this reload?
I am thinking of perhaps a heavier bullet, just to try one up on the .22 subsonic , it will be pointless making a .223 that is no more than a .22 subsonic.
The .22 subsonic heaviest bullet is the 60 gr, but it will usually not stabilize in most .22 barrels, the usual .22 subsonic appears to be a 40 gr bullet.

Will a 70 grain .223 type bullet stabilize at subsonic speeds in a 1-9 barrel?

[Tripodmvr]

The heavier the bullet the easier it is to get a speed below 1100fps. So a 70gr bullet should work well.

https://hodgdon.com/wp-content/uploads/2020/07/subsonic-data-final.pdf

[Treeman]

Hi Oom Drie, looked at that, but at 55 gr, I may as well just use the over counter .22 LR sub-sonic.

Was wondering along the lines of SOMCHEM as well S265 or S221 perhaps.

[Tripodmvr]

Herewith data with MP200. 3gr MP200 with 69gr Sierra Match King. Predicted speed 1130fps. You would need to fill the void with Dacron.

What length is the barrel - I used 22 inch.

[Treeman]

18 " - the one I built for Cody nearly 10 years ago. Ruger All American

[Treeman]

My Quickload has gone beserk, the screen has changed and most loads show "startup pressure too high" Huh

Start up pressure is 3626 psi

Whats changed ? Why?

Did have a power induced PC blow up and everything reinstalled ?

[Tripodmvr]

Reduce that pressure to 1500psi and the calcs are there again. I am battling to post photos from my PC. How do I do that on this forum, as I only get a URL choice.

[Tripodmvr]

Herewith image I wanted to post.

[Treeman]

Thank You, you always come through.
After much battle I came up with 1063 fps - but I was using 223 Remington SAAMI you use just 223 Remington, Why ?

[Ds J]

When I started asking about sub sonic reloading I was told repeatedly to go as heavy as possible, simply because the low speed is the limit. Heavier makes for better penetration.

Hornady makes a 90gr bullet. One should be able to seat it fairly deep in the case.

[big5ifty]

A rifle case with 3 grains of powder in it ?

Software does not predict a SEE for you.

[Ds J]

A rifle case with 3 grains of powder in it ?

Software does not predict a SEE for you.

I shoot my 308 with 5gr of MP200 for 800fps with 173gr LRN.

The reason why I took the speed so low is to stay clear of the transsonic zone. I had some trouble with that in my .22LR.

[Treeman]

I will now see if I can find some heavy .223 bullets, would like to find a lead cast bullet actually.

[Tripodmvr]

Twist rate might upset any plans of bullets heavier than 75gr in a 1 in 9 twist. Treeman should check that twist rate.

[Tripodmvr]

A rifle case with 3 grains of powder in it ?

Software does not predict a SEE for you.

Have a look at this data from Hodgon.

https://hodgdon.com/wp-content/uploads/2020/07/subsonic-data-final.pdf