5.56/223 case length - whats too short?

[shoen1200]

I had thought to speed my case resizing efforts by putting the Lee Case Length Gage and Cutter in a drill press chuck rather than use the Case Locking Stud in a cordless drill.

I discovered that the tip/end of Lee Case Length Gage was intended to contact the base of the Locking Stud that retains the case.

If the Lee Trimmer setup is used as intended the trim length is a pretty consistent across all case brands at 1.7580.

By using only the Case Length Gage and Cutter in the drill press the cases are pretty short.

Depending on case brand they came out as 1.7450 or 1.7340.

Reloading Manuals give a max length of 1.7600. I have not seen a minimum length.

Can these short necks be counted on for proper tension to retain a 55gr bullet?

They would be used in a bolt and semi-auto.

Would accuracy be worse compared to normal length cases?

Please let me know what you think.

Thanks.

 

[Gonzofam]

Sami for 223 is 1.760- .020 . You are very close to no go. Hopefully someone will chime in with a definitive answer for yah . I have been tossing to the scrap pile any less than 1.746.

 

[Gonzofam]

Here you go.This helped me.

 

[243winxb]

RCBS X Die instruction say to trim to 1.740" Or .020" under maximum. Brass that is trimmed under 1.740", use in your bolt action. Measurement taken after FL sizing, as always.

 

[rcmodel]

I discovered that the tip/end of Lee Case Length Gage was intended to contact the base of the Locking Stud that retains the case.

Use the drill press table as the depth stop.
Just hand-hold the case flat on the iron table and run the cutter down until it stops.

The depth stop stud is screwed in the rod, and you can take it out, apply a drop of lock-Tight, and then adjust it exactly for use with the drill press table.

Mine kept cutting shorter and shorter as the threads wore until I used the lock-tight on it.

Since then, I have done probably 1,000 more and it has not changed again.

rc

 

[shoen1200]

Thank you guys for your information.
It was good news for me.
About 80% of the 1500 cases I had cleaned deprimed and resized are at the 1.7450 length.
I would have hated to lose all that time and effort not to mention the brass.
Thank you for your help.

 

[Slamfire]

Case neck length is a safety consideration if it is too long. Then it will pinch the bullet in the throat and pressures will rise.

I don't crimp rifle bullets so trim length is not critical for me. As long as it is not too long, I will not have pressure problems. Too short?: I don't know how "they" define too short. I know I have trimmed 30-06 brass far below the "recommended" minimum and the stuff all went bang.

I believe it is too short if it does not hold the bullet anymore. At that point you obviously have an issue.

Cases act as gas seals. If you ignore the part about keeping the powder and bullet together for handling purposes (which is a huge part of things) the brass case is simply a gas seal. As long as it contains the pressures of combustion and keeps the gas from going in the action it is doing its job.

So don't fret about "how short". Just keep the length below max. That is what you should be worrying about.

 

[rcmodel]

Brass of the proper length helps protect the chamber against throat erosion.

If you notice a shot-out barrel, the erosion starts right in front of the chamber in the barrel throat.

Were it not for proper length brass, it would start in the front of the chamber.
Then you couldn't get a fired case to come out of the chamber because the mouth would be expanded into the erosion damaged portion of the chamber.

rc

 

[Slamfire]

If you notice a shot-out barrel, the erosion starts right in front of the chamber in the barrel throat.

I have noticed "throat" erosion on the barrels I have replaced. These are either 30 caliber or .223. This throat erosion is metal removal infront of the chamber. The lands noticeably wear down but I have never seen pitts , pitted material, or a ring that cannot be identified as something left by a reamer profile. After a good cleaning the surface is quite mirror like.

When my target barrels erode about three points on the gage, which with a 308 is around 4000-5000 rounds, it gets replaced. The last Douglas barrel I replaced, it throated a one at the muzzle. This is not well known in the shooting community, but the muzzle wears out as you shoot.

I have never noticed any erosion in the front of the chamber where the case neck resides. When the barrel is off I can get my eye very close, but I have not submitted my barrel for surface finish gaging, as the barrel has zero value and it would not make economic sense to spend money on this rather esoteric point.

I also have a 586 that was sold to me after having been fired close to 100,000 rounds of 38 Spl. I can't remember the round count, might have been 40K, 50K, or 60K. The gentleman who shot it set a PPC record and he only fired 148 LSWC with 2.7 grains Bullseye. If erosion was an issue you would expect to see something in the cylinder, but it is mirror finish from breech to throat.

Maybe someone shooting an extreme high pressure round might see something, maybe someone shooting barrels well past their accuracy life, but I have not seen it and am not worried about it.