How much does crimping the middle of a case (not crimped bullet) effect setback?

[djdelirius]

Does crimping the case to prevent setback actually fully negate setback or just make it less likely to occur?

I have both crimped and non crimped .45 ammo for my Glock 30S and always use the crimped when carrying for a CCW. But I'm wondering how much effect the crimping actually has on setback for reliability. Should I still rotate through chambered ammo with the crimped ammo or is it not something I should worry about?

 

[Walkalong]

I have no idea how a cannelure in the case down below the bullet helps setback. There are more things that affect it besides that.

Neck tension is critical, so I am not sure the added cannelure would help if there was poor neck tension, but I guess that would depend on how much indentation there actually was at the cannelure, so there is another unknown.

Welcome to THR

 

[Blue68f100]

Personally I would not unload/load a round more than 3 times. I then rotate it to the shoot stack. Chambering a round is a violent action. Some say not to ride the slide, but all guns are different. I've tested with riding the slide and 1st shoot accuracy. It does not effect my guns. I have seen it impact some very tight lockup guns. I see no reason to unload a carry gun except for cleaning. I know some do it when they get home but I never do. The lower cannelure is suppose to add a small step to prevent bullet setback past that point. Just need to know the base of the bullet is at that point. Neck tension is what hold the bullet, though some Mag caliber the roll crimp actually adds neck tension. Where on a TC it does very little if any.

 

[gamestalker]

Some, actually many factory cartridges will add a canelured type crimp to the mid section of the case, as well as right at the heal of the bullet. I've seen this on both rimless, as well as rimmed handgun brass.

Trying to duplicate the factory process would be difficult at best. The best bet is to make sure your brass has adequate neck tension, this alone has never failed me. On rimless cartridges the taper crimp really does little to nothing to increase neck tension, beyond just closing up the mouth bell at least.

GS

 

[Drail]

Setback is generally only a problem if you rechamber the same round repeatedly. If you are chambering the same round over and over - ask yourself why. Figure out a way to stop doing that. Rotating rounds will not stop rounds from setting back. It will just happen later. It can be a very serious problem with some ammo in some guns. And as stated neck tension is a much better way to stop bullet movement. Crimp only does a pretty small part of that job. If you handload setback and pull can be easily eliminated - but with factory ammo it's like Russian roulette. The factories DO NOT intend for people to be rechambering rounds repeatedly. As far as they are concerned it only has to withstand ONE chambering. Cross that line and you're on your own.

 

[moxie]

Case canneluring has limited, if any, utility in preventing setback. Case neck tension is what holds a bullet in place. I just did a quick look at some of the ammo for autos around here, 9mm and .45ACP. None had case cannelures except some CorBon. The HST and Golden Sabers don't.

Rather than rotating rounds every so many chamberings to the bottom of the mag, it's better to set the chambered rounds aside until you have a chance to measure them. Replace with new rounds.

 

[9mmepiphany]

If you're really want some help from the case in preventing bullet setback, I'd recommend you look for some brass from Israeli Military Industries(IMI)...of course than you'd be limited to 9x19mm ammo.

IMI 9mm cases have a ledge/seat formed inside the case that prevents set back of loaded rounds. Whether this is located at the depth you want for your ammo is another matter.

In the big picture, you're better off not repeatedly chambering the same round of ammo from the magazine. I personally won't do it more than twice. After that, I just regulate it to a box to be shot at my next range visit

 

[djdelirius]

If you're really want some help from the case in preventing bullet setback, I'd recommend you look for some brass from Israeli Military Industries(IMI)...of course than you'd be limited to 9x19mm ammo.

IMI 9mm cases have a ledge/seat formed inside the case that prevents set back of loaded rounds. Whether this is located at the depth you want for your ammo is another matter.

In the big picture, you're better off not repeatedly chambering the same round of ammo from the magazine. I personally won't do it more than twice. After that, I just regulate it to a box to be shot at my next range visit

I've recently have thought about acquiring a Sig MK-25 for EDC which a 9. Right now I only have a USP .40 and Ruger .380 and have never even shot a 9. How are the IMIs for reliability and stopping power for an EDC? I can't really find too much info on their hollow points.

 

[Drail]

IMI makes more than 9mm.

 

[moxie]

If you want IMI 9mm, Wideners is probably the best source:

https://www.wideners.com/itemview.cfm?dir=18|829|837

Their 5.56 is first rate but I'm not aware of much in the way of testing or street results for their handgun ammo.

 

[9mmepiphany]

IMI makes more than 9mm.

With the ledge to prevent bullet setback?

 

[Mad Chemist]

I don't understand the aversion to chambering rounds of CC ammo. Just check the OAL and compare to the avg OAL of the rest of that lot of ammo. I write the avg OAL on the inside lip of the box. If it's significantly reduced, pull it and use it for components.

Or.... if our gun has an overbuilt extractor, just drop the round in the chamber, drop the slide, insert mag. No risk of setback this way, but some folks will worry about chipping their extractor.


90% of my range practice is with my primary carry gun. So I have to load and unload my carry ammo all the time. At nearly $1/rd for magic bullets, there is no way I will be burning through them as range fodder once I've function tested them.