Neck Thickness Variations

[bigedp51]

I'm prepping AR15 5.56 brass for non-competitive shooting and I'm running into a few cases that have over .006 to .008 side to side variances in individual case neck thickness. (you can see it with you naked eye)

What would be your maximum variation in case neck wall thickness be, before putting the brass in the scrap bucket. The majority of the brass is .002 or less, and I do not plan to neck turn.

 

[CatShooter]

I'm prepping AR15 5.56 brass for non-competitive shooting and I'm running into a few cases that have over .006 to .008 side to side variances in individual case neck thickness. (you can see it with you naked eye)

What would be your maximum variation in case neck wall thickness be, before putting the brass in the scrap bucket. The majority of the brass is .002 or less, and I do not plan to neck turn.

If you keep the 0.002" case for shooting and use the larger ones for foulers, you will be fine.

 

[Shynloco]

NOWAY I'd keep or shoot anything over .002 variance. .006 is ridiculous and a bad batch. Sidewall blowout is too risky and not worth the cost or replacement of bad brass.

 

[bigedp51]

It is once fired Remington brass fired by our local Police and SWAT teams in their AR15s. Looks like I'm going to have to check each case for case wall thickness and cull the bad cases.

I was trimming and deburring the case mouths and thought what I was seeing was a shadow. When I got the case mouth under the light you could actually see how thin the case neck was on one side.

Good call on the sidewalls, I will give these cases a good going over, I have just the gauge for the job.

 

[CatShooter]

NOWAY I'd keep or shoot anything over .002 variance. .006 is ridiculous and a bad batch. Sidewall blowout is too risky and not worth the cost or replacement of bad brass.

WHAT???

Side wall blow-out??? When did this myth get invented??

The necks on my 6mmBR are only 8 thou total thickness and they don't "blow-out"!

 

[Eddie Harren]

Uh-oh!

 

[Area Man]

Popcorn, anyone?

;D

 

[LHSmith]

SWBO (or side wall blow out) ONLY occurs with hyper-inflated re-caps ???

 

[Webster]

I love to hear the misinformation stories that get perpetuated. Maybe we can make a list of dumb things people believe in. I love the one that the powder charge uses oxygen from the atmosphere to burn.

 

[CatShooter]

I love to hear the misinformation stories that get perpetuated. Maybe we can make a list of dumb things people believe in. I love the one that the powder charge uses oxygen from the atmosphere to burn.

.. and if you make a compressed load, it won't shoot because there is no air in the case to burn the powder

 

[mysticplayer]

If the side of a case can blow out, WHERE DID THE CHAMBER GO?

My suspicion if you loaded with the best brass, then loaded the same in wonky brass from the same lot and shot them in your AR, the target would look the same.

By all means, cull brass you don't get a warm fuzzy from but remember that your system just isn't that accurate to care.

Jerry

 

[LCazador]

So I take it Shynloco is not entitled to his opinion on this? Maybe he's not introducing a new myth, maybe it's just his interpretation of what can happen when you shoot non concentric ammo. This topic of how dangerous it can be to reload range brass has come up several times over the years here. Come on guys show some respect for other peoples opinions, myths, blown out tires! Really guys?!!

 

[CatShooter]

So I take it Shynloco is not entitled to his opinion on this? Maybe he's not introducing a new myth, maybe it's just his interpretation of what can happen when you shoot non concentric ammo. This topic of how dangerous it can be to reload range brass has come up several times over the years here. Come on guys show some respect for other peoples opinions, myths, blown out tires! Really guys?!!

There are lots of things that opinions are valid - whether blonds are better than brunettes (they ain't), or whether the 30-06 is better than the 270 (it ain't)...

... but there are things that are just simple mechanical physics, and there is no room for opinions - what's your opinion on whether the sun rises in the easy or the west??? What's your opinion on which way a brick will fall if you drop it - up, or down??

It is physically impossible for the "walls to blow out" on a case with a thin neck... no matter how thin the neck is.

There was a time when cartridges were made with cases that had walls (for the whole case) that were made of copper foil - no thicker than the stuff you wrap a turkey with... and they didn't "blow out"... cuz there ain't no place to blow to.

 

[Martin52]

a few cases that have over .006 to .008 side to side variances in individual case neck thickness. (you can see it with you naked eye)

What would be your maximum variation in case neck wall thickness be, before putting the brass in the scrap bucket. The majority of the brass is .002 or less, and I do not plan to neck turn.

That is more variance than I would want to work with - are these "few" cases part of a much larger brass quantity ie they are not typical ?

Martin

 

[Phil3]

For the kind of use intended, I might consider just eyeballing them. If that kind of variation can be seen with the naked eye, that is quick and easy...and just can those.

Phil

 

[TroyMN]

This is a case from my HK630. It is not neck blow out, but it might look like blow out to some? It was from Blackhills Blue box. This gun also has a fluted chamber which might give the theory of neck blow out possible if all the stars align.

 

[CatShooter]

This is a case from my HK630. It is not neck blow out, but it might look like blow out to some? It was from Blackhills Blue box. This gun also has a fluted chamber which might give the theory of neck blow out possible if all the stars align.

Just exactly what is a "case blow out" - how does it happen? - and where have you seen real evidence of one??


What you show in your picture is a case separation which is fairly common and has nothing to do with neck thickness.

 

[kraky]

What kind of measuring is being done in the picture...is this how we're seeing .008 variation. I've never seen the tool used that way.

 

[TroyMN]

What you show in your picture is a case separation which is fairly common

That is nice to hear. This is the first time it has happened to me. My gun when it ejects it really throws them, actually bounces them off the receiver putting a big dent in the neck, some look like a half moon.

Sorry I did not mean to highjack or change the topic, I thought it could be somewhat relevant.

 

[dogdude]

hi catshooter, I've got proof of case wall blow out in my hand, if I could send pic's I would. been saving this for a couple of years. first off its head stamp is GRAF(always a good start) 7.5x55 shot out of a K-31. I know these rifles have generous everything but!! had a moving blanket on ground, when I cleaned up spent shell's found this one with a 1'' vert. split from just below shoulder to near the base. did not feel anything different during course of fire. but I still remember picking it up and thinking WTF!!! dogdude