Crimping .223 rounds for an AR


February 13, 2008, 01:36 PM
I am in the process of getting into reloading for my Bushmaster Varminter and have been reading quite a bit about crimping the brass on any rounds to be used in an AR. The Sierra website on reloading .223s doesn't mention it for any of their bullets. What's the opinon of you guys who have been doing this for a while. I plan on loading light loads for target shooting at 100 yds. Right now I am planning on using once reloaded Lake City brass manufacted no earlier than '04 and 52g HPBTs.


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February 13, 2008, 02:48 PM
I taper crimp all my .223 ammo loaded for semi autos. Some folks don't.

February 13, 2008, 03:10 PM
+1 on taper crimping.

February 13, 2008, 03:31 PM
Can you tell me how to "taper crimp"? Is it built into the seating die?

February 13, 2008, 03:41 PM
Most .223 seaters are set up to roll crimp. I purchased a seperate taper crimp die from Redding (

February 13, 2008, 03:51 PM
Just what I needed to know. Thanks guys.


February 13, 2008, 04:05 PM
What kind of crimp does a Lee factory crimp die put on?

And, would anyone here consider relying soley on neck tension to hold the bullet in place, and not crimp, even for say an AR15?

I started reloading 223 a month or two ago and always crimp with the Lee FCD. An "ol' timer" at the range told me he never crimps his 223 (he shoots one of those new Sig 556 rifles) to extend the brass life. I don't quite feel comfortable with that so I still crimp. I've had 357 rounds get stuck due to recoil knocking the bullets out by the last round in the cylinder; I know an AR15 doesn't experience nearly the recoil forces of a 357 snubbie but I'm still concerned that it could happen somewhat. Anyone got an opinion?

February 13, 2008, 04:35 PM
A revolver pulls bullets due to the force of the recoil jerking the revolver backward suddenly while the bullets want to stay where they were.

Nothing like that happens in an AR, or any other repeating rifle.

What happens with a repeating rifle (as opposed to a double rifle used for elephant hunting) is one of three things.
1. Strong recoil drives the bullets deeper into the case from the pounding they take in the box magazine.
2. Moderate recoil drives the bullets deeper in the cases in a tube magazine lever-action.
3. The bullets get driven deeper into the case from hitting the feed ramp on their way into the chamber.

The .223 doesn't recoil enough for #1 to be a factor.
And it doesn't have a tube magazine like a lever-gun.

SO, that leaves #3 as a possibility.
If you have sufficient case neck tension,
and your mags feed properly,
and your AR feed ramps are cut correctly,
the bullets probably will not move from feed ramp impact.

If in doubt, it's probably wise to crimp for semi-autos.
Thats what the military does.

February 14, 2008, 12:22 PM
I acutally have 100 uncrimped .223's right now to give a try through my ar15. If i do have problems then I'll be crimping.. My plan is to shoot a couple, check the bullets OAL then shoot some more, and check OAL again.. See if it changes or not..

HOWEVER I am concerned about this if something goes wrong.. yikes. I would say just crimp it if you feel unsure about it, what, it's only another 30 minutes to crimp..

February 14, 2008, 01:48 PM
It doesn't need it. The vast majority of highpower shooters (guys shooting the AR) don't crimp. It's a sin to squeeze a good match bullet.

February 14, 2008, 01:49 PM
You have to check the one in the chamber, not the others in the magazine.

If you do get any setback, it will be during feeding.

February 14, 2008, 02:00 PM
What kind of crimp does a Lee factory crimp die put on?

And, would anyone here consider relying soley on neck tension to hold the bullet in place, and not crimp, even for say an AR15?

I have yet to crimp ANY of my .223 loads for my Bushmaster AR. They've also been shot in several other AR's my buddy has, no problems.

Now I'll qualify that last remark by saying I never have taken measurements before and after a round has been chambered in actual firing. That means measure a round for OAL, load it in a mag under another round, shoot that round from a magazine, let the round cycle into the chamber. Then remove the round and measure it again. If the bullet has moved to a shorter OAL, then you need to do one of two things. Crimp, or increase bullet pull. Increasing bullet pull means making sure the expander ball does not leave the neck too big to hold a bullet tightly. There are bushing dies that allow you to control the amount of neck tension you end up with.

A lee FCD puts a crimp on the mouth of the case by means of a collet that pushes in from the side, or at 90 degrees to the shell length. To properly taper crimp, you need to have all the brass at the same length. A FCD will crimp shells of differing length. Also a FCD will form a crimp on the sides of a NON cannelured bullet. Some say it will deform bullets in doing that. It WILL form a slight indentation in the bearing surface of a bullet when the case mouth is forced into it.

February 14, 2008, 03:54 PM
Set back may or may not happen without crimping. I put a very light crimp on mine.

February 14, 2008, 06:28 PM
If I'm single loading, no crimp. Loading from a mag, light crimp with Lee FCD.

February 15, 2008, 10:22 AM
If there is a canellure, I crimp. If not, and especially on thin jacketed varmit bullets, I don't crimp. In ad hoc testing, it seemed to me that using Hornady 55 gr. FMJ bullets, those I crimped with the FCD shot tighter groups with less velocity spreads than those without the crimp, but seated to the same depth.

The crimp sometimes helps out with the initial resistance upon firing, much like one might obtain seating bullets a bit long, and just short of the leade.

February 15, 2008, 11:43 AM
I reload 223 for my AK yes a 223 AK never have crimped, never had any issues.

February 15, 2008, 06:55 PM
Haven't reloaded a ton for my AR.. but no crimp here either. The only semis that get a crimp is when I need to bell to insert the bullet and then it's only to remove the bell. I'm not convinced that additional crimp does anything to hold a bullet... unless it has a canellure.

February 15, 2008, 07:03 PM
I use a Lee FCD on my AR's ammo on all 100 rounds that I've loaded so far.

Which reminds me that I need to check FedEx's website for the whereabouts of my next 500 bullets.

Hoosier Reloader
February 15, 2008, 08:52 PM
I've reloaded several thousand rounds of .223 for my AR's over the years and never had a problem, crimp or not.
If I do crimp, I use a Lee FCD because I like a crimp that is straight into the side of the neck instead of pushing down on the case neck.
If you're shooting a lot of rapid fire you may want to crimp your rounds.

February 15, 2008, 09:20 PM
CRIMP a 22 cal bullet:what:

Nope, I don't crimp .223 for the ARs or the 22-250 for the M700 and I use RCBS X-Dies to resize. I don't believe in working the neck of the cartridge anymore then necessary. Now the 30-06 is a different story, every round gets crimped. I might also note that I only get about 7-10 reloads out of my 30-06 brass before the necks start splitting compared to my 22 cal brass where some of it has been loaded 10-15 or more times and still hasn't split.

February 15, 2008, 10:28 PM
Crimping for an AR should not be necessary. If it is, you have another problem that needs addressing, either with the neck tension or with the gun.

It adds another variable, and the whole purpose of reloading is to closely control all variables.

February 15, 2008, 10:34 PM
If you wait until you notice that something is wrong, it might be too late. I found that it is best to apply a crimp on ANY round that feeds through a semiautomatic rifle. If you don't, you risk the bullet being driven backward into the case. When that happens, your pressure WILL skyrocket.

In my case, the least that happened were blown primers. I also experienced stuck cases where the bottom of the case swaged outward and looked like a small belted magnum.

This went away with a crimp applied.

I heartily recommend--and use--the Lee Factory Crimp die. You don't need to drive the case into the bullet--a light crimp is all that is needed.

February 15, 2008, 11:43 PM
LFCD here too.

Bolt actions no, auto fed yes -regardless of caliber / recoil

February 16, 2008, 02:12 AM
.223 probably doesn't need crimping. But if you want to crimp then either taper crimp on non-canellure bullets or buy cheap canellured bullets for roll crimping. it is counter-productive to do a roll crimp on a precision non-canellured bullet. If you roll crimp into a precision bullet then are you distorting that finely controlled jacket.

February 16, 2008, 05:12 PM
I've run thousands of my reloads through three ARs and a Galil. No crimp. No problems.

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