.223 col

[Hardtarget]

I've been loading some .223 for the AR. My load book shows max length as 2.260 so I've been loading just short enough to fit the mag. However, I see many loads listed with a shorter COL.

I'm trying to figure what is best. and how do you figure the best COL for a given load.

So far I've not had any problems show up...but, if I should be loading shorter (for safety or accuracy) I'm ready to make that change.

If this is just a matter of "try different to see if it works better" then I'm ready for that. I'll take a load that shoots well and try shorter...if it improves...great!

Have I answered my own question in this? Give me a hint about how you arrived at your pet loads so I can push my thinking in the right direction. I'm having a great time looking for the combination my rifle likes so THANKS in advance for your time and input on this.

Mark

 

[gojuice101]

A lot of it is trial and error, and depends on the rifle and bullet. Some rifles shoot better with the bullet seated out farther, and some are the other way around.

Also, different bullets are different lengths so that affects the COL. Just remember when seating a bullet deeper, you lower the internal volume of the case and can raise pressures, so you have to work safely with that.

Some of my loads come in at 2.26". I also have other loads that are as short as 2.17". Varies with bullet, load, etc. I've done a bunch of testing to arrive at my various loads, and they are shot in multiple guns.

 

[steve4102]

Just remember when seating a bullet deeper, you lower the internal volume of the case and can raise pressures, so you have to work safely with that.

Although this is true in a straight walled pistol round, seating deeper in a bottle necked rifle round like the 223 will decrease pressure, not increase it.

 

[edfardos]

Bullet manufacturers suggest lengths in their data. Hornoady 55grain bullets were seated at 1.200" during their tests for example.

 

[ironworkerwill]

1.200"

2.100''?

 

[Trailduster79]

I have been loading 55grn FMJ's at 2.200. Works well for me.

 

[moxie]

What bullet?

 

[higgite]

Bullet manufacturers suggest lengths in their data. Hornoady 55grain bullets were seated at 1.200" during their tests for example.

2.100''?

I think he meant 2.2". At least, I hope he meant 2.2".

 

[Trailduster79]

Moxie - That is with a Hornady 55grn FMJ BT.

Also using that COL with Xtreme bullets 55 grn FMJ.

Both are over 26grn of CFE223

 

[climbnjump]

Just remember when seating a bullet deeper, you lower the internal volume of the case and can raise pressures, so you have to work safely with that.

Although this is true in a straight walled pistol round, seating deeper in a bottle necked rifle round like the 223 will decrease pressure, not increase it.

Well, if you have a load - bottle necked case - where the bullet is seated into or just on the lands, then seating the bullet slightly deeper can reduce max pressure.

But beyond that, seating a bullet deeper in a bottle necked case will reduce volume just as it will in a straight walled case so max pressure will go up. It is true that the effect will be less pronounced because the percentage volume decrease will be less, but pressures will still go up.

 

[moxie]

With the Hornady 55FMJBT I use an OAL of 2.250". That centers the edge of the case mouth on the cannelure (nominally). Works well for me.

 

[matrem]

Depending on how your seater die touches bullet, I've seen metplats within a certain lot/ box on some hollow points vary enough to cause feeding problems in ARs if pushing the 2.26 limit unless you're checking every single one.

I've not noticed that in polymer tip or fmjs though.
Even at that, my go to polymer tips are loaded no longer than 2.257.

 

[rg1]

For Hornady 55 FMJ's I seat from 2.200-2.230" maximum. In 2 different brand AR's distance to touch the lands with the Hornady 55 FMJ is 2.370" to 2.390" so no matter what oal it still has a long jump to engage the rifling. Hornady's 55 FMJ has a blunt nose and oal for it is shorter than some other military style bullets with a longer sharper pointed tip. For these 2.250" is better. Best advice for most bullets is to seat to the bullet company manual recommended length. For 77 Sierra Matchkings recommended oal is often 2.260" but even though they fit in my magazines they don't feed reliably and they get seated to 2.250" and total reliability. Even these long 77 gr. match bullets would have to be seated to 2.316" to get to the lands in my one National Match rifle. Main point is the AR's have long throats and I've not seen any accuracy gains seating my bullets longer than manual recommended lengths. I have gotten better reliability seating slightly shorter than maximum magazine length. Even long military 62 gr FMJ's do better at 2.250" than out to maximum magazine length at 2.260" in my rifles. BUT, in my one .223 Rem bolt action rifle the Hornady 55 FMJ bullet can only be seated out to 2.246" before it touches the rifling. So take into account that bolt action rifles have shorter throats than AR's. I agree with the previous post by "matrem" that bullet tips vary enough to cause feeding problems when seating to maximum mag length.You set your seater with one bullet at 2.260" and some longer tipped bullets may be longer by .005" or more. Make sure the longest length is less than 2.260"

 

[notaglockfanboy]

It is true with any pressure vessel. When you reduce case capacity, you raise pressure. It is physics.

 

[Hardtarget]

To all that have responded to my question...thank you very much!

From the measurements you've shared I see my reloads are very much in line with the rounds you produce. I don't have much "one-on-one" contact with other reloaders in my circle of friends. However, I know who to turn to with questions! You guys are great!

Thanks again. Off to reload!

Mark