[Lambo]

.223/5.56mm, Bullet:.224 69gr BTHP Barrel Length: 20in Barrel Twist 1 in 8
Note:
IMR/Hodgdon shows 2.235
http://data.hodgdon.com/cartridge_load.asp
Winchester shows 2.120
http://data.hodgdon.com/cartridge_load.asp

Lyman 48th Page 145 shows, 2.260
:confused: Anyone know for sure?:banghead:

[Coltdriver]

For most AR type rifles the COL consideration is what will fit and feed from the mag.

You will also find that if you have a rifle chambered for 5.56 that you will not be able to load the bullet far enough out to get even remotely close to the lands, and even if you could it would not feed through the mag.

If you have a 223 chamber then you are still constrained by what will feed through the mag.

So, go with the standard cartridge length for your chambering. It would not hurt for you to measure the col with the bullet touching the lands just because that is good practice and essential to know when you reload.

Beyond that you might fool with the col a bit to see if a particular length works better for a particular load that you worked up.

What rifle are you shooting?

[Lambo]

What rifle are you shooting?
http://i32.photobucket.com/albums/d9/RWLambo/Gun%20Photos/RockRiverArmsNM.jpg

[ranger335v]

COL and seating depths are controlled by YOUR rifle and YOUR bullet, it's not some magic formula developed by the book publishers and engraved in stone.

If your COL is really short the load isn't likely to shoot well. If it's much too long it won't work through your magazine and the rifle becomes a single shot. Between those extremes it's up to you.

[Ol` Joe]

Hodgdon likely used a Sierra bullet in their data and Winchester used one of their own. Which are you useing?

[Coltdriver]

Nice looking rifles. I shoot a Bushmaster shorty.

From the description you have the 223 Wylde chamber. I am not familiar with the dimensions, however, its probably got a shorter throat and you may actually be able to get the bullet closer to the lands.

So, measure your chamber. You can do a search on how to do this on THR because it has been described at length here several times.

Once you have this very critical measurement you can determine what COL you can use that will fit in your mag and what distance that COL will give you for a particular bullet to the lands. Keep in mind that different weight bullets will have a different ogive and thus the max COL length you can use will vary with the bullet type. I have discovered the hard way that in reloading, knowing your actual chamber dimensions is extremely important! They vary from rifle to rifle.

Let us know what that Wylde chamber is all about and what combo you come up with!