223 trim length

[Magload]

Starting to get low on 223 brass so broke out a batch of Federal cases I haven't loaded before. My normal trim length is 1.750" but I use any case 1.745 to 1.755. All these cases run 1.730 to 1.740" My loads have a OAL of 2.250. If I use this length I am going to have less bullet in the case. as much as .020" less. Should I save these for my longer 67gr bullets, or am I just over thinking this. These are my plinking loads?

 

[427mach1]

I think the SAAMI spec is 1.740 - 1.760 for 223, so the most you are under is 0.010. Have you sized them yet? If not, size them then re-measure. Personally, I would load them up and shoot them even if they are still a little under, especially since they are just plinking loads. Depending on how hot you load them, they will probably stretch-to-fit after a few loadings.

 

[Magload]

I don't load hot normally just above starting loads is where I find my best groupings. I have not run these through the resizing die yet as I stuck a case in the die last night and as I have two dies with stuck cases I ordered a stuck case remover which will be here in the morning.

 

[ArchAngelCD]

If I use this length I am going to have less bullet in the case. as much as .020" less.

You do realize you are talking about 2 100th of an inch, right? That is an extremely small difference. You probably have that and more a variation when you load you ammo. I would not worry at all about 2/100" shorter brass.

 

[WmaximusD]

1.730 is the min spec for .223s

Sent from my SM-N920V using Tapatalk

 

[SMSgt]

Over thinking.

 

[moxie]

You must resize before measuring.

 

[427mach1]

1.730 is the min spec for .223s

You are correct, I had trouble finding the info on the SAAMI site and found mis-information elsewhere....

 

[DWalt]

SAAMI tolerance for the .223 case length is 1.730"-1.760" (Sized case length)
Military spec tolerance for the 5.56x45 NATO case length is 1.750"-1.760"
The Lyman reloading handbook also specifies 1.750"-1.760" for the .223

However, finding the optimum cartridge overall length (COAL) for best grouping performance in your specific rifle is more important than minor case length variations.

 

[otisrush]

I'm, by far, no expert. But when the "Can .223 cases be too short?" question comes up, in general, many folks respond with "Load 'em and shoot 'em."

I don't think I've ever read a report of a too-short case causing a problem. (Which is obviously very far from "There can't be a problem with a too-short case." I'm just reporting I've read a number of threads on this topic - and being too short has never come up as an issue.)

OR

 

[Joni_Lynn]

Since this isn't the bench rest crowd I'll go along with load 'em and shoot 'em. They'll be longer soon, perhaps as soon as the expanding ball/plug runs out of the neck the next time.

 

[Alk8944]

There are only two considerations when it comes to case length. First, if it is at maximum then it must be trimmed.As others mentioned measure after sizing the case. There can be a significant difference between as-fired and as-sized, especially with bottle-neck rifle cases.

Second, will you be crimping the case? If so then they need to be trimmed to a relatively consistent length for consistent crimp pressure.

And, yes, you are overthinking this!

 

[Magload]

I figured I was over thinking but case length effects case volume and could turn a load into a compressed load if it was pushing that point in the first place. Also if you keep the same COL then there is less bullet in the case. I am not going to worry about it I am shooting them these are not my bench rest loads.

 

[Road_Clam]

I'm ok with .740-.760 . After .760 I will do a trim. I've seen new, once fired LC brass as long as .775 !

 

[moxie]

I'm ok with .740-.760 . After .760 I will do a trim. I've seen new, once fired LC brass as long as .775 !

So? It should still be sized, measured, and trimmed.

 

[moxie]

I'm ok with .740-.760 . After .760 I will do a trim. I've seen new, once fired LC brass as long as .775 !

So? It should still be sized, measured, and trimmed if necessary. Whether it's once-fired or not, new or ancient, is irrelevant.

 

[rwsmith]

Shoot them and.....

Shoot them and they will grow a little.

 

[bigedp51]

Starting to get low on 223 brass so broke out a batch of Federal cases I haven't loaded before.

Be forewarned Federal cases are noted for having soft brass but that is not the whole story. Federal .223 cases "may" have thin flash hole webs and can have oversized primer pockets after the first firing. I buy once fired Lake City 5.56 cases because the flash hole web is thicker and military 5.56 brass is made harder in the base

I was given three five gallon buckets of .223/5.56 brass fired by our local police. And the Federal .223 brass was a pain to work with and approximately 25% ended up in my scrap brass bucket.

I bought pin gauges to check the primer pockets to find the oversized primer pockets.

And used a Lee depriming tool to check any questionable seated primers. If the primer moved with just finger pressure the case was scrapped.

If you are shooting a over gassed AR15 a tight primer pocket is required.

 

[DWalt]

Having a consistent case length is one of the two most significant factors in achieving good grouping performance. The other is finding the optimum COAL to get the optimum bullet jump distance from the case to the start of the rifling in a specific rifle. Of course, consistency of bullet weight, case weight, and powder weight helps also, but not as much as the first two factors. This is where all the labor is for bench rest shooters - optimizing all these things. Some bench rest shooters use the same few cases over and over, reloading on the shooting bench as needed with precision hand tools, pre-weighed powder charges, and pre-weighed and balanced bullets. When I was doing bench rest shooting, I never went that far, but some did.

 

[Magload]

Having a consistent case length is one of the two most significant factors in achieving good grouping performance. The other is finding the optimum COAL to get the optimum bullet jump distance from the case to the start of the rifling in a specific rifle. Of course, consistency of bullet weight, case weight, and powder weight helps also, but not as much as the first two factors.

That is why my benchrest AR has a Bob Sled in it inst of a mag. To much jump distance with a mag length bullet.