[atblis]

I am sure this has been covered somewhere but can't find it searching.

Do you need to crimp 223 when loading for an AR15? I have M193 projectiles which have a cannelure.

Thanks,
Andrew

[average_shooter]

I crimp. I recall reading that setback could occur due to rounds in the magazine getting knocked around during recoil (not so sure about that one, but anything can happen) and/or setback could happen when the round is chambered.

[rcmodel]

It is not necessary if your AR-15 & your magazines are feeding without mashing the bullets back in the cases.

If it is, you need to address that rather then crimping to mask the true problem.

On the other hand, you can crimp if it makes you feel all warm & fuzzy.
The down side is, your cases won't last as long before case-mouth cracks develop.

A .223 doesn't have enough recoil to set back bullets in the magazine.
That's more for elephant rifles & lever-actions with a stiff tube mag spring & stack of cartridges pounding on every round.

rc

[Historian]

A big +1 for RC's point. Been loading .223 for my Bushmaster for about two years now. At first I applied a tapper crimp to my loads then I tried a few without the extra step. They work just fine. Haven't had a jam, a bullet pushed back in the case or failure to feed yet. I think that crimping for an AR is really not necessay and just takes up more time.

Historian

"Democracy requires wisdom."

[cougar1717]

I'm kind of surprised the seach tool couldn't find an AR crimp thread. It feels like this same question is asked about every other week. My experience with reloading .223 Remington for an AR this is that there was no discernable difference between crimped and uncrimped ammo in terms of reliability to feed and accuracy.

[atblis]

Tried again and found a couple threads. Was searching for 223 and crimp. Needed to search for AR15 and crimp. Duh.

http://www.thehighroad.org/showthread.php?t=355335&highlight=ar15+crimp

[taliv]

definitely crimp for military style projectiles. (e.g. m193, m855)
definitely do not crimp for OTM style projectiles. (e.g. SMK 69g, 80g)

[freakshow10mm]

I agree with Taliv. I crimp for FMJ but not for match ammo. FMJ is to be fed from the magazine (and has a violent path to the chamber) whereas the OTM is to be single loaded by hand and bobsled.

[steve4102]

Here is what the experts at Sierra have to say about neck tension and crimping for a service rifle.


When we stop to consider the vigorous (read, downright violent) chambering cycle a loaded round endures in a Service Rifle, it becomes pretty clear it suffers abuse that would never happen in a bolt-action. This is simply the nature of the beast. It needs to be dealt with since there is no way around it.

There are two distinctly different forces that need to be considered: those that force the bullet deeper into the case, and those that pull it out of the case. When the round is stripped from the magazine and launched up the feed ramp, any resistance encountered by the bullet risks having it set back deeper into the case. Due to the abrupt stop the cartridge makes when the shoulder slams to a halt against the chamber, inertia dictates that the bullet will continue to move forward. This is exactly the same principle a kinetic bullet puller operates on, and it works within a chamber as well.
To counteract this tendency, the semi-auto shooter is left with basically two options: applying a crimp or increasing neck tension.


I load for several auto-loaders and I use the Lee Factory Crimp Die in all of them. I use it with cannelure bullets and non-cannelure bullets. It not only holds the bullet in place it can and does improve accuracy. IMO, if you want your bullets to stay put, take the advice from the experts at Sierra and increase neck tension or apply a crimp.

[edelbrock]

definitely crimp for military style projectiles. (e.g. m193, m855)
definitely do not crimp for OTM style projectiles. (e.g. SMK 69g, 80g)
+1
If the bullet has a cannelure then I crimp. If it doesn't then I don't.
That being said I usually buy bullets without a cannelure because I don't want to crimp.

[Walkalong]

I am with Taliv on this one as well.

I crimp all my ammo loaded for serious business because I want it to positively work. The military crimps for the same reason. It may get banged against the ramp on the way in and we want the bullet to stay put and not cause any function problems.

As far as ammo loaded for accuracy I do not crimp but rely on neck tension.

[Coltdriver]

Probably one of the top reasons for blowing up your AR is setting back a round on chambering.

The .223 rounds in an AR have a rough life. Tempting fate by not crimping may or may not catch up with you. But if it does you will never forget it.

Take a look on youtube under blow up ar. They do go off big and it pretty much trashes the rifle.

My advice, crimp.

[NoAlibi]

I use Lee's factory crimp die in several of my semi-auto rifles and I find an improvement in accuracy over reloaded rounds without using the die.

Lee states that it makes the start pressure more uniform which results in better accuracy. I can see some problems with this statement if all the cases aren't trimmed exactly the same as well as if some of the other case variables aren't dealt with.

What I think is happening is that the pressure rises in the case and before the bullet leaves the case, the case obturates filling the chamber. As a result the longitudinal axis of the bullet becomes concentric with the logitudinal centerline of the bore. Thus, when the bullet enters the lands there is less deformation to it and accuracy is enhanced.

Any thoughts on this. :confused:

[Maj Dad]

Using a progressive (I use a Dillon 550B) the crimping is accomplished with each pull of the lever. No extra step required; I use a roll crimp to crimp into the cannelure but a taper crimp would probably be as good. Autos slam things around and a good, tight crimp keeps things from coming loose, in my experience. You can learn on your own, or apply the experience of others; suit yourself. There's no harm in some lessons, problems with others. This is one that's probably not harmful... ;)

[jim147]

I haven't been able to find much accuracy change between crimped or not crimped in .223.
So I crimp it. It makes me all warm and fuzzy inside.
I haven't seen much change in .222 with or without a crimp.
So I don't crimp it. It also makes me warm and fuzzy inside.
The moral of the story. Do what you feel works best.
The other moral. Whiskey makes me feel warm and fuzzy inside.

jim

I'm feeling pretty warm and fuzzy tonight.