.223/5.56 crimping


April 7, 2013, 08:06 AM
Im new to reloading and was wondering how much crimp for .223/5.56 for the ar,I have a Lee Factory Crimp Die followed instructions for a light crimp seems to work great,can any of you guys tell me the amount of crimp needed,they look and feel good although I have yet to fire any of my reloads.Im using TAC in this batch,any help would be appreciated thanks,mmkkpro.

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April 7, 2013, 08:15 AM
Honestly, I've never had to crimp a bottle neck cartridge. But I would imagine if the bullet doesn't have a canelure, you would only want to apply a light taper crimp, so as to not deform the bullet shank, or buckle the shoulder of the case. And if it has a canelure, I would probably use a light crimp into the center of the canelure.
And if your asking specifically about the FCD, I have not ever owned, or used one.
I doubt I provided you with any useful information, sorry about that.


April 7, 2013, 08:32 AM
The reason for a crimp is for neck tension. As the case wears out, the more crimp you are going to want. Not knowing information you didn't provide. In an AR, you want to crimp because the mag and loaded rounds are moving pretty fast, and you want that bullet to stay there on the way up through the mag. In a bolt action rifle, or break open, you don't need to crimp, because the action is working slower and cartridge isn't being thrown around.

Me personally, I very lightly crimp for the AR, and for the bolt action and my break, I do not.

April 7, 2013, 08:50 AM
I have read alot about crimping for the AR. I decided not to crimp. If you are crimping, taper or roll?

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April 7, 2013, 08:58 AM
I'm with gamestalker. I never crimp for my ARs (several different cartridges), bolt rifles or M1 Garands.

A crimp will not make up for poor neck tension in 223 Remington.

April 7, 2013, 09:02 AM
I have never used a crimp on my AR loads and have had no issues.

April 7, 2013, 09:02 AM
I've been led to believe that to much crimp will also ruin acuracy too but I'm no expert in reloading.

April 7, 2013, 09:09 AM
I've been led to believe that to much crimp will also ruin acuracy too but I'm no expert in reloading.

Lots of discussion and disagreement around this subject of crimping and accuracy.

April 7, 2013, 09:18 AM
Yep, nothing is set in stone about that, there are so many other variables at work.

April 7, 2013, 10:45 AM
Please look carefully at the attached photo of an eight round clip of .30 cal match cartridges arsenal loaded for the M1 Garand. (LC-62)You will noticed that the cartridges are NOT crimped. Whereas service ammo for the Garand was crimped, it was well known that crimping also degrades accuracy. Which is why ammo loaded for top accuracy was not crimped.

April 7, 2013, 10:49 AM
I have tried it both ways loading 223/5.56 ammo. My best accuracy is without a crimp. Try it both ways yourself--stick with what works the best for you.:)

April 8, 2013, 12:46 AM
I used a small crimp when I had my Ruger Mini 14 Ranch Rifle, no longer have that weapon. However, I still use a slight crimp on each and every round I reload using my Remington 788 .223, cannalured bullets or no. Totally up to you, I don't/haven't noticed any accuracy difference.

April 8, 2013, 11:41 AM
I have decided not to crimp for .223/5.56. Neck tension seems to be sufficient without the crimp.

April 8, 2013, 12:30 PM
Keep in mind, much of the ammo I used in the army was not only not crimped, it was horribly belled, and I have never had one misfire or cause a malfunction. Some of the bullets were easily jiggling in the case.

April 8, 2013, 01:56 PM
I crimp all my semi-auto ammo with the Lee factory crimp die. I use what I call a Med-Light crimp. This helps secure the bullet during the violent cycling of the action and also improves accuracy in my rifles. To much crimp will degrade accuracy, not enough will not secure the bullet, you will have to test for yourself how much if any crimp to use.

Here is what Sierra has to say about neck tension and crimping for semi-autos.

Neck Tension

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. Some years ago, we decided to examine this phenomenon more closely. During tests here at Sierra’s range, we chambered a variety of factory Match ammunition in an AR-15 rifle. This ammunition was from one of the most popular brands in use today, loaded with Sierra’s 69 grain MatchKing bullet. To conduct the test, we chambered individual rounds by inserting them into the magazines and manually releasing the bolt. We then repeated the tests by loading two rounds into the magazine, chambering and firing the first, and then extracting and measuring the second round. This eliminated any potential variation caused by the difference between a bolt that had been released from an open position (first round in the magazine) and those subsequent rounds that were chambered by the normal semi-automatic operation of the rifle. Measuring the rounds before chambering and then re-measuring after they were carefully extracted resulted in an average increase of three thousandths (0.003") of forward bullet movement. Some individual rounds showed up to seven thousandths (0.007") movement. Please bear in mind that these results were with factory ammunition, normally having a higher bullet pull than handloaded ammunition.

To counteract this tendency, the semi-auto shooter is left with basically two options: applying a crimp or increasing neck tension. The first option, crimping, brings up some other issues that can be troublesome. In general, crimping degrades accuracy. Most match bullets are not cannelured (which also seriously damages accuracy potential), a requirement for correct application of most crimps. Still, there are taper crimp dies available from most of the major manufacturers. Lee offers their “Factory Crimp” die as an alternative, which seems to be one of the better options for those bullets without a cannelure. That having been said, crimping is still, at best, an occasionally necessary evil.

If you are going to crimp, the Lee Factory Crimp die is the way to go.

Here is an accuracy test done using non-cannelured bullets and some pretty high dollar rifles. Note that the LFCD improved accuracy in all three rifles in all three cartridges.


35 Whelen
April 8, 2013, 02:29 PM
I've been shooting High Power off and on for several years now and not one of the guys I shoot with crimps their ammunition. I load for a Mini-14,an AR, an SKS, a Saiga and a Garand and I never crimp the bullets, cannelured or not. Never had a single misfeed or problem.
With regards to accuracy, one only need look to those who seek the ultimate in accuracy; the benchrest and long-range shooters. I'd bet you won't any of those guys that crimp.

April 8, 2013, 03:01 PM
I crimp if there is a crimp groove for my AR. I don't crimp 45ACP and always crimp for my 444 Marlin. Oh, I crimp fairly stout but not so much that it leaves any marks. For bulk fmj it seems to help accuracy and I guess that it helps with uniform neck tension with mixed head stamp brass. My VMAX isn't crimped and does just as good as any factory ammo.

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April 8, 2013, 03:37 PM
Last summer, I experimented with a crimp on my plinking rounds made with Hornady 55-gr FMJBT/WC bullets. In accuracy testing, the groups got larger by about 3/4 of an inch at 100 yards.

I used a "medium" crimp, which I estimated by crimping to about half the crimp I observed on new LC ammo. The crimp was clearly in the canelure, so I am sure that I was not deforming the jackets.

April 8, 2013, 06:09 PM
With regards to accuracy, one only need look to those who seek the ultimate in accuracy; the benchrest and long-range shooters. I'd bet you won't any of those guys that crimp.

Probably not, but you won't find these guys shooting $800-$1000 off the shelf AR's in competition either. Does that mean that we non-benchresters should not use or even own a rifle that would not fit the needs or requirements of a BR shooter? After all, If the BR gang don't do it or use it it cannot be good and must be dismissed.

On the other hand, I would not consider using BR loading techniques for my off the shelf sporting rifles either. Things like, Indexing every round, Pig Jamming the bullet into the lands, Chamber necks so tight that sizing is not needed, Loading the chamber single shot, etc.etc.etc.

The BR comparison is Apples to Oranges at best.

In stead of using Apple-to-Oranges comparisons and theories take a look at actual tested data in the Link above.

April 8, 2013, 06:14 PM
Colt AR 15
10 Rounds each target.
Midsouth 55gr HP bullets. No Cannelure
100 yards.
2 groups of 5 at each target.
Crimped with the Lee Factory Crimp die.


April 8, 2013, 06:27 PM
For the past year or so, I have been (light) crimping all bullets in my AR loads.


April 8, 2013, 06:39 PM
dont know if this is light medium or heavy but this is ammo I crimped with the lee die. I have done 1000s of rounds this way and never had an issue. I have not shot groups with this setup but at 25-200 meters the round goes where the red dot is.
.these are the standard hornady 55 grain FMJBT

cajun executioner
April 8, 2013, 06:39 PM
I'm new to reloading but I loaded rounds for my AR with 55gr canelured bullets without a crimp and had sub MOA results with no issues.

April 8, 2013, 06:48 PM
I have the die (since it came with my kit) but I don't crimp my .223.

Cranky CJ
April 8, 2013, 09:51 PM
without a crimp they don't feed smoothly. with a crimp the gun eats them like tic tacs and its awesome. every one I load gets enough of a crimp to feed smoothly. couldn't tell you if its medium or light. its just right for my gun.

April 9, 2013, 11:54 AM
So, are you guys roll crimping with cannelure or tapering with either
cannelure or without cannelure?

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April 9, 2013, 05:58 PM
So, are you guys roll crimping with cannelure or tapering with either
cannelure or without cannelure?

Collet crimping with the Lee Factory Crimp die, both cannelured and non-cannelured bullets.

Matt Dillon
April 9, 2013, 06:00 PM
Collet crimping with Lee FCD on cannelured bullets.

April 9, 2013, 09:11 PM
Same as the last two posters...

April 10, 2013, 11:47 AM
^^^^ Same for me^^^^

April 10, 2013, 01:22 PM
Last year I too was new to reloading for the AR. I had been working up loads with various bullets, you know Soft point, FMJ/BT, TSX using once fired brass. Because I was new to loading shouldered brass I came here and asked questions and loaded without a crimp. Things went well until I loaded up some CFE 223 and worked my way up from min. charge weight at about 25 grns I started to get flattened primers and quit shooting. I couldn't figure what was going on. I switched powders and started again, about my third shot something did not seem right as the round loaded. I dropped my mag and opened the breech I am sure glad i was paying attention. The bullet had come out of the case and powder was everywhere. It took several minutes for my heart to settle down enough where I could think. I checked the rounds in the mag. The first round on top showed signs of set back ( this was probably the cause of my previous flattened primers) Now I only use bullets with a cannelure and a medium crimp in the AR. I have went on to load with CFE 223 again with max loads and never the first sign of pressure and no more loose bullets in the breech. I was lucky, be damned careful.

April 10, 2013, 01:37 PM
If your bullets fall out, or set-back??

You do not have a correct amount of case neck tension.

Most often caused by an over-size expander button.
Your expander plug should measure no more then .2225" for proper neck tension.

It should take 50+ pounds of pressure to move an un-crimped .223 bullet in the case if your case neck tension is what it should be.


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