55gr FMJBT load question

[Dirt_Nap]

I'm reloading a bunch of Hornady 55gr FMJBT in LC brass. I've been using Tac powder with 32.8gr powder. Unless I'm seeing it wrong, my Hornady load book puts 23.8gr at about 3000fps which is where I want to be. Trying to shoot for M193 velocity give or take. Chrono shows my loads at 2770fps +\-. What am I missing and why are my numbers so different than the book. I understand the Hornady testing is a 20" barrel and I was using a 16" barrel but still seems off.

The IMI M193 I also tested in the 16" came in pretty consistently at 3050fps

 

[Dmagna]

What cartridge? I don't think your loading that powder charge in a 223

 

[Dirt_Nap]

What cartridge? I don't think your loading that powder charge in a 223

23.8gr. My bad. Edited my post

 

[Highbrass Shooter]

You have to adjust your loads accordingly. Never in 25yrs reloading has my testing matched book loads perfectly. Different variables, barrel length, seating depth etc

 

[105Coues]

Barrel length is huge in determining velocity for 223. I have found about 50 fps per inch with that combo which would put you in the approximate range of the book. I have found approximately 400 fps differences between a 24 and 16. The difference shocked me as well. Just my experience so worth what you paid for it.

 

[436]

So you want 20" inch XM193 Ball 5.56x45mm NATO velocity 3260 fps preformacne for a 16" inch barrel with a handload, be careful you're playing with a dragon. I don't think you'er missing anything, to get that 3000 fps out of your 16" inch you'll probably need another powder, check out AA 2520 (26.8grs) vel's 3234 fps from a 24" it should give you what you want in a 16" inch barrel, you can fuge that load a little but I'd be careful and go slow. Good luck Cheers

 

[Dirt_Nap]

So you want 20" inch XM193 Ball 5.56x45mm NATO velocity 3260 fps preformacne for a 16" inch barrel with a handload, be careful you're playing with a dragon. I don't think you'er missing anything, to get that 3000 fps out of your 16" inch you'll probably need another powder, check out AA 2520 (26.8grs) vel's 3234 fps from a 24" it should give you what you want in a 16" inch barrel, you can fuge that load a little but I'd be careful and go slow. Good luck Cheers

I wasn't really shooting for 3260 fps from a 16" but was hoping to mimic the imi ammo and get around 3000 fps

 

[Critter Picker]

Have you shot any factory loads to see what you get out of them? Some barrels are just slower than others. I've seen identical rifles with 200 FPS difference shooting the same ammo.

That would be my starting point to duplicate a load.

 

[Dirt_Nap]

Have you shot any factory loads to see what you get out of them? Some barrels are just slower than others. I've seen identical rifles with 200 FPS difference shooting the same ammo.

That would be my starting point to duplicate a load.

Yes, as I mentioned the imi m193 is getting around 3050 fps out of the 16". That's all I'm trying to do

 

[Critter Picker]

You might have to try a different powder as mentioned earlier. I've gotten good velocity from CFE 223 and Accurate 2230 but at that velocity, you are walking on pretty thin ice.

 

[436]

I wasn't really shooting for 3260 fps from a 16" but was hoping to mimic the imi ammo and get around 3000 fps

I know you weren't shooting for M193 NATO velocity from your 16" inch, but... I think to get 3000 fps+ reliably in the rifle you're going to have to have a load that will produce 3260 fps in a 20" or 24" barrel. Sorry, I should have reread the post... Cheers

 

[Hydra6]

IMI M193 is 5.56 loading and your Hornady load data is 223. 556 is loaded to higher pressure than 223. TAC is fine for loading 223/556 but you need to look at 556 loading specs if you want to "clone" M193. It is more than 23.8 of TAC.

 

[436]

I wasn't really shooting for 3260 fps from a 16" but was hoping to mimic the imi ammo and get around 3000 fps

Okay, that load I sent you should do it, it does it in my 16" 5.56 barrel. Good luck Cheers