Is this a suitable crimp for use in an M1A? (pic)


May 18, 2012, 01:24 AM
I'm going to pick up my new M1A tomorrow from the FFL. I've never shot one, or ever fired a .308/7.62 Nato round. The pic below is my first reload.

I'm not new to rifle reloading, but I don't have it down like I do with pistol. I've had good luck with light crimp in my AR and M1, but I've been having a lot of trouble in my AK with the bullets coming loose during semi-auto fire.

I don't want to have the same problem with my first trip out to the range with the M1A. I'll just be zeroing the iron sights. I'm not worried about the perfect crimp for accuracy (although I'll be back here later on that very question real soon). For the weekend, I just don't want to have any problems like I did with the AK.


ETA: Better pic of the crimp, and also, I'm using RCBS taper SB taper crimp dies, seating & crimping in one step. Hopefully this helps! I don't have an FCD in 308.

If you enjoyed reading about "Is this a suitable crimp for use in an M1A? (pic)" here in archive, you'll LOVE our community. Come join today for the full version!
May 18, 2012, 01:32 AM
Looks very mild, but not a great angle for viewing crimp.

with a cannelured bullet, you can set the crimp pretty heavy if you choose to.

Some say that crimping erodes hair-splitting accuracy. If you are in that camp, it wouldn't matter if it was light, or heavy- any amount would do it.

Below is a link to what the military crimps look like ( on the left) anything between this and up would be OK :,r:7,s:0,i:89&tx=73&ty=111

May 18, 2012, 01:50 AM
In actuality crimp does not hold the bullet in place, neck tension does. If you are having problems with your AK ammo I would check your brass neck tension.

When I do crimp rifle rounds I use a Lee Factory Crimp Die. It seems to work better than most and I like the collet type of crimp it applies.

May 18, 2012, 02:10 AM
Hey Arch. I hear you on that... although (I thought) I read that in semi autos, the relaoding manuals say to crimp so that the recoil doesn't pull the bullets. I thought that's what was happening to me. I understand that nothing's going to go right without proper neck tension, but did I misread the thing about crimping for semis?

If so, why crimp a rifle round? Can/should I just skip that whole step?

May 18, 2012, 02:48 AM
In actuality crimp does not hold the bullet in place, neck tension does.

Both do. Not crimping with autoloaders often results in bullet setback. In heavy recoiling guns, it can also cause the bullet to unseat. For this reason, I only use cannelured bullets in firearms that I know will do this with smooth shank bullets. For example, in my SRH .454 with top loads, even if I don't flare the case at all, there is not enough tension to retain the bullet during firing. Likewise, my G3 will push a bullet back about 1/4" during loading if the case isn't crimped into the cannelure.

To the OP-

Crimp looks pretty light to me.

May 18, 2012, 03:11 AM
I always crimp for semi-auto rifles and when I say that I'm told I'm wasting my time. I'm always told there is no reason to crimp my M1 30-06 ammo but I do anyway. lol

BTW, that holds true for handguns doesn't always hold true for rifles, semi-auto or not.

May 18, 2012, 07:18 AM
Looks fine. Shoot a few and check the OAL on the remaining rounds to see if you have any bullet creep from recoil. Many people do not crimp their M1A ammo anyway.

May 18, 2012, 12:38 PM
I just don't want to have any problems like I did with the AK.

Off topic, but what dia bullets are you using for the AK?

May 18, 2012, 12:58 PM
Off topic, but what dia bullets are you using for the AK?

They're that "special" AK diameter... .3105" or whatever it is.

May 18, 2012, 12:59 PM
10-fo. Thought I was on to something. :)

highlander 5
May 18, 2012, 01:16 PM
There is a simple 2 step answer here. 1 measure your dies expander ball and polish it down .002" and 2 use a modest crimp. The bullet shoudn't move after that.. I have a couple of rifles in 7.62x39 and 308 win and use a carbide expander that is .306 for both and my bullets don't move when chambering.

May 18, 2012, 02:11 PM
If everything else is in spec such as the resizing die and the expander plug, neck tension should be 100% effective without the crimp. But since you are crimping your bottle neck cartridges, it is imparative to use the right bullets for the job, meaning those that have a canelure, and, don't bell the mouths as one would do with straight wall handgun cartridges.

In the event you are using the Lee Factory Crimp Die, from what I understand canelured bullets are unnecessary.

The following process is not intended to imply you are, or are not, employing these methods and process. I'm mearly relating as to how I would reload for that weapon as follows:

1. I would FL size my brass to such degree I am maintaining proper head space. And since this is an AL action, I would probably allow a little bit more head space to ensure smooth cycling. .002" should be plenty.

2. After resizing, trim all the brass to the same lengths, and at a length between the minimum and maximum case length, as determined according to SAAMI specification. Be sure to ream and chamfer after trimming to provide a smooth exterior and interior.

3. If you decide to use a canelured bullet, determining the OAL should be as simple as seating to where the canelure is positioned at the mouth. There is no real benefit in trying to seat up close and personal to the lands for AL actions, and doing so would more than likely cause cycling problems.

4. Regarding crimping, I've never crimped a bottle neck cartridge, and only because I've never encountered problems with bullet set back. If for some strange reason I were unable to keep the bullet at a constant OAL, and I have made sure the die and expander plug are in spec., then and only then would I crimp. But belling the mouths is absolutely unnecessary if the bullets being used are jacketed.

Don't be mistaken by bullets getting the nose slightly flattened from recoil impact against the magazine. If you mark the bullet with a fine tipped magic marker where it contacts the case mouth when fully seated, you'll be able to quickly know if your experiencing set back, or if the bullet tips are getting mashed slightly. In this respect, OAL measurements taken off the tip are unreliable at best, and especially so when the cartridge concerned is such that it produces significant recoil. Even a FMJ can lose .010" + due to flattening of the tip, and that number can change even more with a jacketed soft point.
Good luck and happy reloading!

May 18, 2012, 02:33 PM
I donít crimp my match bullets for my M1a and I am on the third barrel for one Super Match, and also, I got my Distinguished with the M1a before the CMP cheapened the award.

Rely on neck tension, if you have sufficient neck tension than your bullet will not pop out of the round. This might be different for chain guns, or roller bolt actions, which ram cartridges in the chamber so fast that my old military LC were crimped and had tar sealant.

Regardless of bullet type, crimping swages the bullet core. Match bullets have particularly thin sidewalls and it is easy to see the damage you do to them with Lee Factory Crimp Dies. A selection of 6.5 SMKís ruined by a LFCD is shown in this image. Even if you donít see the damage on the jacket, that soft lead core is squished.

I believe you should only crimp for lever actions with tube magazines and elephant guns where the recoil is so severe that inertia will pull the bullet out of the case neck. Maybe cast bullets and cast bullets and blackpowder. But for M1aís and Garands, they donít need it.

May 18, 2012, 03:11 PM
Thanks guys! I'll try to load some up with no crimp, and see how that works for me. These are some really great tips! Like I said, I'm no rifle reloading expert. A couple of follow up questions for those of you still reading.

@Highlander: How do you "polish" your expander plug so that it doesn't get out of round? I have a drill and some sandpaper, but I don't trust a method like that. What do you do?

@Gamestalker: Could you elaborate a bit on your first point re: "FL sizing... to maintain a proper headspace"? Forgive my ignorance, I just don't have the mental connection between sizing and headspace, or what I should be doing to achieve proper headspace on the sizing operation. Also, I was noticing the exact thing with my bullets on my first batch. Some of these are pretty old FMJs, and the tips are blunted. These particular ones are cannelured, which helps since I can just check visually to make sure they're right. But what do I do with the non-cannelured bullets (I have a box of 180gr FMJs w/o cannelure)? If the tips aren't reliable to check OAL, what do you do? Is OAL super important for accuracy? What kinds of variance is ok for seating a batch of plinkers? How about match ammo?

@Slamfire: Thanks for the tip. I'm using the RCBS taper crimp, small base die. No Lee FCD. I'm glad to hear from other M1A shooters that I should just skip crimiping. I always feel like I'm doing it wrong, and I hate doing operations to my ammo that I don't fully understand why I'm doing it. I just didn't have the confidence to do without, because I thought I "should" be doing it.

You guys are all amazing. Thank you for the help!

May 18, 2012, 06:49 PM
Forgive my ignorance, I just don't have the mental connection between sizing and headspace, or what I should be doing to achieve proper headspace on the sizing operation.

While this is a fairly long article, it is 100% on the money for the special considerations that reloading for gas guns involves. The section "Brass Preparation" explains the need for some kind of headspace gauge.

Several patterns are mentioned, and, while they do the same thing, they have different instructions for use. One "chamber type" gauge is the LE Wilson gauge -

The RCBS Precision Mic is also a good tool, if a little more expensive -

The idea is to determine the length of your fired case (as an estimate of chamber headspace) and then set up the resizing die so it creates a case which measures 0.002" to 0.004" less. This will allow unrestricted chambering (for safety) and also help extend brass life (by reducing stretch near the head).

As an attempt at humor, if you are going to ignore headspace, you should at least buy some good eye protection and a broken case extractor -


May 18, 2012, 08:06 PM
err... what article?

May 18, 2012, 08:27 PM
Forgive my ignorance, I just don't have the mental connection between sizing and headspace, or what I should be doing to achieve proper headspace on the sizing operation.

A simplistic answer is how much slop, or play, front to back, the round has when it is in the chamber.

Headspace is machined into the firearm. It has a min and a max.

Cartridges are loaded to specs, min and max, such that if they are chambered in a properly headspaced firearm, the slop, or play, front to back, will be minimal, and safe.

If we push the shoulder back to far on a bottle necked caliber such as .30-06, we can create artificial, but still dangerous, excessive headspace that could cause a case head separation.

We cannot create artificial headspace on a rimmed pistol caliber such as .38 Spl, because it headspaces on the rim.

May 18, 2012, 10:09 PM
Note to self: When including a reference to an article, it helps if you actually include it... :rolleyes:

I put the link where it was supposed to go. Please try again.

May 19, 2012, 08:28 PM
I agree with Slamfire. I never crimp for my competition ARs or M1As, and I feel it does impede accuracy. With .002" neck tension, crimping isn't necessary.

May 20, 2012, 08:50 AM
Taper crimp is worthless for avoiding either setback or setforward. If you're crimping (and I wouldn't) using a cannelured bullet, you should be roll-crimping into the cannelure. You don't taper crimp into a cannelure. That's oxymoronic. :evil:

May 21, 2012, 01:45 AM
I didn't crimp 168 grainers (Sierras, no cannalure) for the M1, but put just a real light taper crimp on the Hornady SSTs, into the cannalure. Just because.

I'd do the same for my M1A, but I don't handload for it...I still have a bunch of Aussie surplus.

If you enjoyed reading about "Is this a suitable crimp for use in an M1A? (pic)" here in archive, you'll LOVE our community. Come join today for the full version!