Crimping at rounds

Never had an ar, is it necessary to crimp your reloads? All help appreciated. Thanks

Most don't. I don't.

There's not a one size fits all answer for the question.

Depending on the upper, the neck tension and even the magazine you may or may not need to. The only way to know for sure is to shoot it and then eject a live round and check the O.A.L.

When I still had an AR, the .223 upper worked fine with the neck tension at .003" under. The .204 had to be crimped no matter what the neck tension was.

I don't.

I use bushing FL dies to size everything. If my .002" neck tension did not work in an AR, I would buy a bushing the produced more neck tension. Thus far, everything has worked fine in .223 AR as well as .308 AR.

I do

I usually do but depends on the gun.

Most 5.56 chambers didn't care.
Loads for my 223 Wylde and 6.8 get a light crimp.

I crimp everything...bolt, lever, handgun.

I'll now get mail, or postings here, indicating how ridiculous that is.

I crimp my bulk 308 Win ammo, even though I have adequate neck tension on the case already. But the when loading, I flare the mouth open slightly, like when loading a straight walled pistol round. The slight crimp allows me to close up the case mouth, and control the mouth of the case better. I'm loading on a progressive press. If I load precision match rounds for my AR-10, I don't crimp them, as I have enough neck tension.

If you don't crimp and run a near max load, you run a risk of an issue. The main risk is during chambering, that the bullet catches on the mag or feed ramps and gets pushed deeper into the case. When you fire a round with the bullet seated much deeper in the case on a normally max pressure round (with the bullet seated at normal depth), you have now increased your pressures dramatically, and risk blowing the primer and having a very hot load.

The opposite, and other issue is lack of neck tension in an AR is during chambering, as the round comes to a quick stop in the chamber, the inertia of the round stopping causes the bullet to get seated further out of the case. Now you have a lower pressure round, and possibly lodging a bullet into the rifling. But lodged into the rifling can also cause a high pressure issue, depending on the chambering. To solve these issues, a consistent crimp is important.