Poll: oversized bullet...

[Bobbygun]

Well, I believe with regard to COAL SAAAMI has established maximum OAL lengths (such as 1.169 I see for 9mm) - but no minimum.

For example I just miked a factory Blazer round of 9mm and it measures 1.143. I don't know the bullet weight but its probably either 115 - 124 as its an aluminum cased round I found last time out shooting.

I guess my point is I suspect most factory ammo will vary in OAL.

Maybe a few can measure some factory 9mm and post the OAL they see.

This diagram shows the SAAMI OAL minimum to be 1.000.

https://i0.wp.com/www.theballisticassistant.com/wp-content/uploads/2021/01/9mm-Luger.jpg

 

[Koda]

My guess is SAAMI specs a minimum to assure proper feeding on ball ammo (FMJ).

 

[wombatz]

I suspect that the minimum is mostly there for autoloaders. A revolver can safely and dependably use flush mount wadcutters that are below SAAMI minimum.

Since 9mm is mostly used in autoloaders it is wise to have a minimum to help gun designers have some idea of what they might need to build for.

Edit: I was informed that there was another post before mine. I should have checked it first. But, yup I think you are correct.

 

[bpyycpyy]

You did a much better job of saying what I said, plus bonus points for the attachment.

To be fair, I wouldn't have posted mine had I seen yours (no need to be redundant). Your post wasn't there when I started mine and posted only a moment after yours (page updated as soon as I posted).

I'm with others indicating that the COAL values are to establish a criteria for manufacturer to follow for consistency. If chambers have an established measurement and bullets do to, then there can be a guarantee of compatibility. These minimum/maximum values can be exceeded IF you are aware of the potential consequences and know how to compensate (adjusting powder charge for example). I've seen postings of several people loading past maximum COAL but they generally have custom made guns, generous chambers in factory rifles and magazines that allow for longer length cartridges.

 

[Defense Minister]

They should not exceed .2245. That said, we're talking thousandths of an inch here, so are you able to confirm the accuracy of your measuring instrument?

 

[Koda]

They should not exceed .2245. That said, we're talking thousandths of an inch here, so are you able to confirm the accuracy of your measuring instrument?

Thats an excellent question. My Mic is virtually brand new, but a cheap brand. However I took a bullet sample to work and it micd the same, and those are (supposed) "calibrated" approved by the company.
I should buy a gauge pin to regularly check my mic and Mitutoyo calipers.

 

[Koda]

Closure.
I heard back. Turns out they were on vacation.
Upon return they reviewed my emails and validated my measurements, and are shipping me a replacement order.

Excellent customer service and they stand behind their product.

 

[Local Loader]

That's good, have to say I'm still curious who it was.

 

[Bobbygun]

They should not exceed .2245. That said, we're talking thousandths of an inch here, so are you able to confirm the accuracy of your measuring instrument?

That really is an excellent question. My caliper shows -.003 when it is closed, so I mentally add that much to the reading. Should have bought a better one, but I've made do with this one for quite a while.

 

[osprey]

That really is an excellent question. My caliper shows -.003 when it is closed, so I mentally add that much to the reading. Should have bought a better one, but I've made do with this one for quite a while.

Dial calipers have a bezel nut you can loosen and rotate dial until pointer reads -0- with jaws shut. Tighten bezel nut up and you are gtg.

 

[Bobbygun]

That really is an excellent question. My caliper shows -.003 when it is closed, so I mentally add that much to the reading. Should have bought a better one, but I've made do with this one for quite a while.

Dial calipers have a bezel nut you can loosen and rotate dial until pointer reads -0- with jaws shut. Tighten bezel nut up and you are gtg.

Thanks, I'll look into that.

But, where you been the last 15 years???

Okay. I didn't see a bezel nut on my Lyman branded caliper made in Switzerland. However, buried underneath were some instructions for calibrating (imagine that)! Basically I just pressed down on the watch face (bezel?) and turned it to zero. Now it's calibrated and now I REALLY feel stupid for putting up with that .003 off for so long when it took about five seconds to fix it.

So, thanks @osprey for setting me on the path to enlightenment.