Question about crimping .308 Win

My understanding is you can crimp without a cannelure, I don't crimp any of my rifle rounds however, neck tension should be plenty to hold the bullet at the proper depth.

Question: Why are you crimping this 308 ?

You can crimp them. But if you're loading for a bolt, or even a pump, action rifle, why would you need to do that? I do crimp my 308 rounds for my AR10. The Dillon die set does have a crimp die for that purpose-just another step in the process. I don't use the Dillon for and don't crimp any of my other bottleneck rifle rounds, and IMO there are very few reasons to do.

Scout21 said:

Am I able to crimp the bullet without there being a cannelure?

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Yes. Gently with a taper crimp die, or harder with a Lee FCD collet crimp die.

. . . but why would you? Crimping does exactly nothing for rifle ammo that isn't done better by carefully setting adequate neck tension. Crimping might not impact accuracy enough to notice, but ît's never an improvement unless there's something else wrong that you're bandaiding with a crimp.

Exceptions are:
- tube-fed ammo with deep cannelures in the bullets
- machine gun ammo, abused even more than tube-fed
- low pressure cast bullet ammo, for the same reason slow powders in revolvers need a heavy crimp.

I use 150g Speer HC 308 in my 30-06, my best load. I started by not crimping, but learned better. I crimp now with the Lee FC Die, just a good snug crimp, and I'm convinced better.

Just resizing the neck as snug as I could get them before, and that's fine if you pamper ammo always. But a 10 mile ride once on a 4w, rough road bouncing, just your average 4w ride. Got to my shooting range. Several of my loads, the bullet was beat down onto the powder.

Crimping or not Crimping is the same, as long as it's done right, consistent! I often get 10-20 fps spread in my loads, near 1/2" groups. I'll always crimp now!
A Cannelure is not needed, find your best seating depth, and crimp consistently, if you prefer!

I crimp with the Lee FCD. I don't crimp to the point of deforming the bullet, but I haven't seen any effect on accuracy.
The one problem I have had with crimping is the neck below the crimp can be bulged and the round will not chamber.

The key is consistency.

M65Man said:

Crimping or not Crimping is the same, as long as it's done right, consistent!

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Lee claims crimping gives the case the same bullet release resistance and thus results in consistent ignition pressure. I resemble this remark:

Archie said:

I crimp with the Lee FCD. I don't crimp to the point of deforming the bullet, but I haven't seen any effect on accuracy.

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Scout21 said:

On why I feel as though I should crimp, it's what I was taught to do by the guy who showed me how to reload. I didn't know that it was unnecessary. If it is I'd love to cut out an extra step.

Is crimping not required even on hunting ammo that can be carried all season, or even possibly a couple seasons, getting jostled around in a truck and bouncing around when slung on the back? I always figured there was a high chance of the bullet popping out, especially when constantly chambering and rechambering.

I'll be loading for my bolt rifle primarily, however a friend has asked me to work up a load for his Remington Model 7400. Wouldn't the Remington benefit from a crimp?

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A crimp is simply a mechanical lock. If your ammunition experiences a lot of impacts like off road, it may be a good solution for you. I currently only crimp lead in 308 that I expand... the military does it for the reason I stated. There is no one solution in hand loading, just what works and is safe for you.

In the past I tried both crimped and uncrimped ammo and in all calibers the uncrimped was always more accurate. You should have enough neck tension for good bullet hold with properly made sizing dies with a correctly sized expander ball and correctly sized bullets. The only rifle ammo I crimp is for use in tube fed magazines because of possible setback issues. If you insist on crimping rifle ammo then the Lee collet type FCD is the best way to go IMO.

FROGO207 said:

In the past I tried both crimped and uncrimped ammo and in all calibers the uncrimped was always more accurate. You should have enough neck tension for good bullet hold with properly made sizing dies with a correctly sized expander ball and correctly sized bullets. The only rifle ammo I crimp is for use in tube fed magazines because of possible setback issues. If you insist on crimping rifle ammo then the Lee collet type FCD is the best way to go IMO.

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This is my experience and findings also. I only crimp ammo that I will fire in a rifle with a tube magazine.

Scout21 said:

Is crimping not required even on hunting ammo that can be carried all season, or even possibly a couple seasons, getting jostled around in a truck and bouncing around when slung on the back? I always figured there was a high chance of the bullet popping out, especially when constantly chambering and rechambering.

I'll be loading for my bolt rifle primarily, however a friend has asked me to work up a load for his Remington Model 7400. Wouldn't the Remington benefit from a crimp?

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Again, as long as you have good neck tension, there is very little danger of a bullet unseating... in either direction. The key is the brass. I would use brass with as few cycles on it as possible, or... in the interests of consistency... anneal the necks.

Would the 7400 'benefit' from a crimp? That depends on the rifle and load; adding a crimp or not is simply another factor in the handload that may or may not add value... a crimp in and of itself has no value.

You can test how well the bullet hold is by using a set of bathroom scales. I put a block of wood on them, hold the round by the brass and push the nose of the bullet down onto the wood. You can compare to factory if you want but I bet you will be surprised how much you can push without bullet setback on a rifle round.

As one who was cursed with a curious mind, I've never been very good at following dogma or instructions without knowing the "why" of it. As relates to this topic, that includes loading out to the lands vs. a crimp.......or both or neither.

To me, the necessity of loading to the lands to get accuracy is blown out of the water by the impressive sub MOA accuracy guarantees of some high end gun makers. Their only guarantee caveat is it must be shot with match grade factory ammo. That isn't loaded to the lands but most certainly is crimped. So what gives?

Best explanation I've seen so far came from Richard Lee in the Lee Reloading manual. As per Mr. Lee.........what loading to the lands gets you is a consistent start (movement) pressure. As per Mr. Lee.....the Lee Factory Crimp die does the same thing. Gives you a consistent start pressure. The collet die has enough adjustment in it to grip bullets with no cannelure.

Seems like it would be pretty easy to test. Load two identical boxes.......one with crimp and one without. Five four shot groups of each. Best groups win.

Howa 9700 said:

As one who was cursed with a curious mind, I've never been very good at following dogma or instructions without knowing the "why" of it. As relates to this topic, that includes loading out to the lands vs. a crimp.......or both or neither.

To me, the necessity of loading to the lands to get accuracy is blown out of the water by the impressive sub MOA accuracy guarantees of some high end gun makers. Their only guarantee caveat is it must be shot with match grade factory ammo. That isn't loaded to the lands but most certainly is crimped. So what gives?

Best explanation I've seen so far came from Richard Lee in the Lee Reloading manual. As per Mr. Lee.........what loading to the lands gets you is a consistent start (movement) pressure. As per Mr. Lee.....the Lee Factory Crimp die does the same thing. Gives you a consistent start pressure. The collet die has enough adjustment in it to grip bullets with no cannelure.

Seems like it would be pretty easy to test. Load two identical boxes.......one with crimp and one without. Five four shot groups of each. Best groups win.

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In your senerio secant vs tangent ojive bullets would perform the same regardless of seating depth... your position is probably over simplified.

I crimp for semi rifles after I measured loaded rounds and they grew after chambering in an AR (getting closer to the lands) , I don't crimp much just enough to measure, for bolt action rifles I lightly crimp my hunting loads just for peace of mind and target loads I don't crimp but I do run them through the Lee FCD, but without the crimp, storing them in plastic ammo boxes with foam on top of the rounds so they don't rattle.
I've never tested between crimped and non crimped I'm still working on testing length, and then there is uniform primer pockets, flash holes, case capacity, different primers, neck thickness, primer seating depth, new powders, so on & so on, I need to get an electronic target set up and buy another place where I can set up longer distances.

I do NOT crimp the vast majority of my rounds. I have Lee Factory Crimp dies, but rarely use them. Only rounds that I load that will get crimped are tube fed, 44 mag and 50AE. Considering testing 44 and 50 without the crimps. I could crimp some things that may see extreme service, such as bulk packed ammo in a steel ammo can getting rattled around on an ATV... but other than that, I skip that step. 9mm, .223, deer ammo... no problem.

If you want to add neck tension, you can chock your expander ball assembly in a drill and carefully sand it down. I haven't gone there, but it's something to think about.

Lee is great about selling dies. Take your crappy factory bullet, and by squashing the thing with your new Lee Die, you make it better.





You believe that?

Today we have what are the most perfect bullets ever made by factories. I can only hope the future is even better. Great effort is made to ensure consistent weight, consistent wall thickness, and the center of gravity in the axis of rotation.

Boo boo's happen



And Lee would have you believe, doing this makes the bullets better.



When you squeeze the jacket, that soft lead core deforms, it deforms un predictably, and it moves the center of gravity randomly and unpredictably from the center of rotation. Creating inaccuracy.



Only crimp if you have to. Military bullets are crap



so if it makes you feel better, beat military bullets with a hammer, do the rain dance, cast spells, and given small sample sizes and biased testing, you will see anything you want.

Good match bullets are better





Only crimp crappy bullets, or 30-30 bullets where the crimp keeps the bullet from getting shoved in the case while cartridges are in the tube under the barrel. Otherwise, use neck tension. All my F Class friends have a bunch of neck sizing dies so they can get the perfect, and consistent neck tension. No one I ever shot with in NRA competition every crimped their bullets for accuracy, regardless of what Lee claims.

Selling the dream. Be an empowered addict.

I'd like to pick up some Speer Hot-Cor bullets for my .308 Win. Am I able to crimp the bullet without there being a cannelure?

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You can always crimp, cannelure or not. You can put the bullet in backwards if you want and crimp it, if you like.

That said you can also not crimp some and see what group shoots the best in the firearm you intend to use the ammunition in.

I must say I don’t crimp more bottle neck rifle rounds than I do crimp, cannelure or not.

Worth looking at that Speer tech bulletin above, again. If your still not sure.

Don’t crimp rifle rounds, with the exception of extreme recoil DGR rounds and tubular magazine rounds - neither of which apply to 308win.

Flat out, I’ll say the information attributed to “Mr. Lee” here both for crimp and jamming into the lands as necessary (or really even pertinent) for improving primary ignition to improve precision in rifle rounds have long been disproven. Equally, it is absolutely false to say the factory crimp die creates a proper analogy to neck tension. In principle, neck tension is “belled” by the bullet with the last work done at the BASE, with the bullet itself acting as the driver to reform the brass. Crimp, even the Lee FCD is working in the opposite direction with a steel external die working down BOTH the brass and the bullet.

Crimp is NOT equivalent to neck tension. Making up tricks and tools to achieve and test crimp is kinda like a toddler chasing pigeons around a parking lot - not terribly fruitful. You will not find folks on benchrest, F-class, or PRS firing lines relying upon crimp of any kind - we seat with no crimp - and the number of guys jamming lands in PRS is near zero, with the proportion of F-class and BR guys jamming moving farther and farther away from unity, and I’ve been told even a majority no longer jam. CERTAINLY in the context of any purpose for which anyone would use a HotCor, jamming isn’t pertinent, and is, in fact, contraindicated.

Slamfire said:

Only crimp if you have to. Military bullets are crap

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It took me a long time to figure that out. Loading generic 55grn FMJ bullets for my match AR, and not getting reasonable accuracy... and finally understanding that it wasn't me, it was the bullet. That is not to say a premium bullet will magically shoot better... my .30-30 with good SP bullets proved that to me... that is to say, it definitely preferred a specific brand of bullet over another, all else being equal. For that matter, my M1a told me that, too... even using match 168grn bullets. True story.

As stated above there is nothing wrong with crimping if it's done properly and consistently. Several of the reloading manuals have a section on crimping-like what to and not do and pictures that show what that looks like. I just received 3 new manuals-Nosler, Hornady, and Sierra. It's in one of those, but I think it's in the Sierra manual and could be in all of them. I've had ammo that I've carried, in and out of rifle, pack, etc for a long time (even year to year) without issue. I never carry loose ammo. If you're concerned about it, do it. Also, keep in mind that from one reloading session to the next, you may not be able (and probably won't) duplicate the exact crimp as the last reloading session. IMO it will affect POI and possibly accuracy. Most resizing dies have sufficient neck tension so they are not an issue as long as your COAL does not load the bullet into the lands. Competition dies like Redding have an insert to adjust the neck tension. As long as you're not using those types of dies, you should be good. Your choice.

Scout21 said:

Is crimping not required even on hunting ammo that can be carried all season, or even possibly a couple seasons, getting jostled around in a truck and bouncing around when slung on the back?

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All of those concerns ("hunting ammo carried all season, or even possibly a couple of seasons, getting jostled around in a truck and bouncing around when slung on the back") don't amount to a hill of beans when it comes to what happens to the cartridges left in the magazine of a bolt action rifle when you fire the round in the chamber. The remaining cartridges in the magazine are slammed into the front of the magazine as the rifle recoils, which could theoretically drive the bullets in those cartridges deeper into their cases.
That said, I have and do load for some pretty hard kicking hunting rifles (a couple of 30 caliber magnums and a .338 Win Mag) and I never crimp bottlenecked rifle cartridges unless they're going in a tubular magazine.
Maybe I've just been lucky, but I've always had sufficient neck tension on my bottlenecked rifle cartridges to hold the bullets in place - even with heavy recoil. Pointy, soft-tipped bullets left in the magazine when the rifles go off get their noses flattened as they slam into the front of the magazine, but they don't get pushed deeper into their cases - I've checked.

I have NEVER been able to replicate bullets being “slammed into the front of a magazine.” I index my rounds to the rear of the mag, and after firing shots, it’s easy enough to open the bolt and see that they’ve not been shifted to the front, and easy to see I’ve not experienced any setback or tip damage. In one test, I even slid a strip of carbon transfer paper into the front of my magazines to see how much contact was made - my cartridge boxes bouncing in my pack with a sheet of transfer paper in the lid caused more witness than recoil into the mag for my .30-06.

On high recoiling rifles - 416 Rigby and 458 Lott - that same quick test actually proved the opposite - I actually saw bullets PULLING from the cases. Functionally, the bullet is the more massive component in these cases, so the inertia of the case itself really isn’t enough to crowd itself onto the bullet, given proper neck tension, but the bullet is massive enough to resist recoil as the rifle pulls the case rearward.

Naturally, tubular magazines put relatively extreme compression force on the cartridges as rear cartridge hits the cartridge stop, and the rest of the stack slams into the bullet of that cartridge under spring tension - so crimp is necessary and sensible for tubular magazine rifles, but for box mag repeaters, it’s much ado about nothing for all but the highest recoil, heavy hitting cartridges - and 308win with 180 HotCor’s ain’t that.