OAL for .223 (tolerance question)

[sladenotdead]

I'm sure this question is going to sound stupid to you seasoned reloaders, but this is my first batch so I am trying to be extra careful, and I trust all of you out there. The suggested OAL for the load I am doing is 2.200, I'm using 21.6 gr of H335, and SR-Mag primers. Anyway I was wondering what the tolerance is for being off of that 2.200 mark? I can't find anything in the book (hornady's newest edition) about min OAL, just max OAL. (or COL as it says in the book) I got my seating die set, and my first one came out at 2.201, and some came out at 2.200 and some at 2.199 and 2.198. How many thousands can you safely be short? If those are unacceptable I'd like to know so I can pull the bullet and start over, thanks in advance for the advice!

 

[rcmodel]

Thats pretty normal variance in OAL.
It is harmless.

It is caused by the difference in ogive profile or bullet length found in even the best of bullets.
Measure some loose bullets and you will see some variation in their length, even before you try to measure them after you seat them.

SO, it shows up as variance when you measure from case base to bullet tip or point.

The only way to find out how much variance in OAL you really have is to use a bullet comparator.
That allows you to measure off a datum line on the ogive, rather then the bullet tip.

Your seating die seats off the ogive, not the point.

rc

 

[Walkalong]

If they all come out that close you are getting a smaller than normal spread, plus what rcmodel said about the ogive.

 

[mcofboise]

The latest batch of 55 grain plinkers I bought seated to a typical OAL of 2.23... I figured it was somebody's little inside joke.
Carry on, you're doing fine.

 

[sladenotdead]

so what is a normal spread? I'm assuming then that everything is ok with my oal then?

 

[ranger335v]

"so what is a normal spread?"

Understand your concern but forget it, there is no norm nor does there need be. The book OAL is not a suggestion, as such, it's just what the reasearch team used to develop their data IN THEIR RIFLE; yours is not theirs so the OAL that will provide best accuracy for you will almost certainly be different.


"I'm assuming then that everything is ok with my oal then? "

So far as it concerns safety, YES. No rifle cares where the point of a bullet hangs in empty space, all that matters to accuracy is the jump from seated length to the lands and learning that requires some experimental shooting. Even when the 'best' seating is found it will be a window, often 10-12 thou wide, in which variations are meaningless. So it's only when we seat on the ragged edge of the good range will small differences in the wrong direction matter on target and no one can possibly tell you what that difference might be.

Bottom line is that your present tiny variations amount to some precise seating. (Not that being precisely at the wrong place can be of any value!)

 

[sladenotdead]

I think I understand it now, thanks a ton!!!

 

[Miata Mike]

The latest batch of 55 grain plinkers I bought seated to a typical OAL of 2.23... I figured it was somebody's little inside joke.

I also load my 55 grain FMJ to 2.23". What grain bullet are you using for 21.6 gr of H335 powder? Must be some heavy ones.

 

[sladenotdead]

I'm using the Hornady 55gr SPs. I'm just in the process of figuring out what loads work, so if that load (OAL 2.200, 21.6 H335, 55gr SP) seems odd, I guess I'll find out. It is a load out of the hornady book. That particular load is the one I had a question about, because it is the first one I did. What I ended up doing is loading ten rounds of several different powder charges. I am using BLC 2 and H335, and I made 3 different loads with each powder, all using the same bullet to see which load works best in my gun. I don't understand why 21.6 gr of H335 would make you think I'm shooting heavy bullets, please explain, and any other ideas are appreciated.

 

[ArchAngelCD]

I don't understand why 21.6 gr of H335 would make you think I'm shooting heavy bullets, please explain, and any other ideas are appreciated.

I'll tell you why I thought the same thing. When I load a 55gr bullet with H335 my charge is 25.0gr. When loading heavier bullets you use less powder. A charge of 21.6gr H335 would make me think you were loading a bullet ~75/77gr. That charge weight is very light for a 55gr bullet in a .223 round. Hodgdon's starting charge weight is 23.0gr and the Max is listed @25.3gr with a Speer SP 55gr bullet using the same 2.200" OAL.

Your load is going to be a low pressure load and most Ball Powders when loaded light will develop a lot of "dirt". If you're firing those rounds in an AR platform you might have to cut your range trip short because of the fouling that might build up.

BTW, I think you will find you get better results in the .223/5.56mm with H335 over BL-C(2). While both are Ball Powders and can be used in the .223, H335's burn rate is better suited for the .223 and BL-C(2) is better suited for the other NATO round, the 7.62X51. (.308 Win)

 

[sladenotdead]

Thanks for the advice. I am stocked up on both powders, h335 and blc 2. I'll see which performs better but will probably save the blc2 for my future purchase of a 7.62 x 51. as to the load I'm using, I'm strictly going off of hornadys manual, starting low and working up as I've read to do. 21.6 gr of h335 with a 55 gr sp puts it at around 2800 fps. I've also done higher powder loads, but as I said I'm starting low and working up just to see what my gun likes, and as is obvious by all my questions, I'm new so I'm figuring this all out trial and error. (and thr advice of course)

 

[Paladin38-40]

Good start

You are on the right track to slowly work up a load to find the "sweet spot" for your paticular gun. Loading data sources will vary somewhat. FWIW on 55 gr. bullets Hodgon's #22 lists a starting load of 25.0 gr. of H335 @ 36,600 cup and a max load of 27.0 gr. @ 48,200 cup. Bullet brand is not indicated.

The sweet spot for my 20" A2 is 26.0 gr H335, CCI #450 primers, Hornady 55 gr. sp, OAL ave. 2.201", crimped in the grove with a Lee Factory Crimp Die. V ave. 3175 fps.

Same load in a 16" A4 chronograph V ave. is 3017 fps.

AR's have a hardy appetite if that's what you are using, but reloading is addictive so it all works out.

 

[sladenotdead]

Yeah it's a 16 in yhm diamond build I finished last year. I went through some wolf ammo and hated it, so I'm getting into reloading to make my own gun specific ammo. Wolf is SHTF stuff in my opinion. If my lower powder loads create a lot of fouling, I'll just push a few rags through and drive on, no reason to let that cut my range time short, even though it's my backyard

 

[Miata Mike]

I don't understand why 21.6 gr of H335 would make you think I'm shooting heavy bullets, please explain, and any other ideas are appreciated.

ArchAngelCD answered as I was thinking. I have loaded 55 grain FMJ bullets with good results so far using between 24.0 and 25.0 grains of H335 powder and an OAL of 2.230.

I had checked my Modern Reloading second edition sitting on the end table, before replying and saw that a heavier bullet had a similar starting load range like what you were using. As you can see, the more information you can provide will help with answers.

 

[gdcpony]

Thats pretty normal variance in OAL.
It is harmless.

It is caused by the difference in ogive profile or bullet length found in even the best of bullets.
Measure some loose bullets and you will see some variation in their length, even before you try to measure them after you seat them.

SO, it shows up as variance when you measure from case base to bullet tip or point.

The only way to find out how much variance in OAL you really have is to use a bullet comparator.
That allows you to measure off a datum line on the ogive, rather then the bullet tip.

Your seating die seats off the ogive, not the point.

rc

This^^^^

If you have a piece of scrap metal drill a .223 hole in it and use it over the bullet to measure. Your spread will just about disappear. I use that rather than an OAL.

Here is a little oddity for you. I currently load for 3 different .223's in my family.

1- My younger daughter's Rossi likes allot of room between the bullet and the lands. I load it about .010 short of them and this puts my OAL about on the book specs. It still isn't a great shooter, but it works for her at 10yrs old.

2- My oldest's Savage Axis likes about half that much "jump" in it. So the OAL is a bit long.

3- My DPMS is truly odd. It likes zero, none, zilch jump. I load the rounds long enough that the bullets are into the lands.

As I have loaded, I have noticed a trend. In every rifle I have used the amount of jump it likes is the same for any bullet. I use a 40gr or a 55gr I seat them to jump the same and get the best groups. I have played with this allot and have yet to run wrong with it, but that may just be me. Just a thought for you.