Question about crimping .308 Win

Interesting thread, but does no one else here load rifle for ar15's and ar10's on a progressive? My experience doing that has led me to "M" style expansion dies, to allow bullets dropped into cases from bullet feeders, to advance stations without tipping, so they have a better chance to be seated straight.

I was taught that a taper crimp die, used carefully, can close that temporary 1/16" deep "pocket" without bullet damage. I have not seen a change in accuracy, excepting that I don't notice any loaded crooked cartridges any more, caused by tipped bullets. If anything concentricity has improved.

The rest of the neck isn't touched and has the same tension as if no crimper was used. Of course the seating stem has to fit the bullet shape, or it too reduces concentricity, and accuracy.

GW Staar said:

taper crimp die, used carefully, can close that temporary 1/16" deep "pocket" without bullet damage.

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Correctomundo ... in fact I use a [backed-way-out] sizing die to "deflare" my (cast) 350-Legend cartridge cases after seating
But I think the readers would agree...
That's not "crimping"


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GW Staar said:

Interesting thread, but does no one else here load rifle for ar15's and ar10's on a progressive? My experience doing that has led me to "M" style expansion dies, to allow bullets dropped into cases from bullet feeders, to advance stations without tipping, so they have a better chance to be seated straight.

Click to expand...

I do, using the expander in the size die (Dillon carbide ball) no additional expanders. I don’t have problems with them falling off even when loading at a fairly quick pace.

No flare on my progressive.

“Closing the flare” isn’t the same thing as the neck tension you had before flaring.

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

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I was also educated by a guy who knew more about reloading than I did and he taught me not to crimp .308, even for my M1A.

I’ve not crimped anything since.

Crimp if you feel like you need to. It won’t hurt anything…..other than accuracy

MEHavey said:

Correctomundo ... in fact I use a [backed-way-out] sizing die to "deflare" my (cast) 350-Legend cartridge cases after seating
But I think the readers would agree...
That's not "crimping"

Click to expand...

I never considered what a taper crimp die does as crimping either....closing a flare or an "M"pocket. But that's what it's named......

Varminterror said:

No flare on my progressive.

“Closing the flare” isn’t the same thing as the neck tension you had before flaring.

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No flare on mine either, no shavings either. With an "M" die....an expanded 1/16" deep pocket with straight walls, not a flare that encourages bullets to tip. Bullets hold in place vertically until you seat them and without being shaved by the case edge.(no I.S. chamfer necessary either) Below the first 1/16" "pocket" normal unflared neck tension. You can run it around the merry-go-round all day as fast as you want and never tip one like happens with a flared case. I never flare......rifle or pistol.

GW Staar said:

Interesting thread, but does no one else here load rifle for ar15's and ar10's on a progressive? My experience doing that has led me to "M" style expansion dies, to allow bullets dropped into cases from bullet feeders, to advance stations without tipping, so they have a better chance to be seated straight.

I was taught that a taper crimp die, used carefully, can close that temporary 1/16" deep "pocket" without bullet damage. I have not seen a change in accuracy, excepting that I don't notice any loaded crooked cartridges any more, caused by tipped bullets. If anything concentricity has improved.

The rest of the neck isn't touched and has the same tension as if no crimper was used. Of course the seating stem has to fit the bullet shape, or it too reduces concentricity, and accuracy.

Click to expand...

I don't flare when loading rifle on a my LNL-AP. Don't crimp either. The only ones I load are 223R 55gr general plinking ammo. I use either CFE-223 or TAC for the powder since they behave nicely and meter fairly close. All my match ammo is loaded on a SS press.

GW Staar said:

With an "M" die....an expanded 1/16" deep pocket with straight walls, not a flare

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Call it what you will, it’s an operation which perturbs the case mouth to solve a problem which shouldn’t need solving for rifle bullets. Opening the mouth just to close it again, it’s all opportunity to keep pushing more and more eccentricity into the ammunition.

Like @Nature Boy said above:

Nature Boy said:

It won’t hurt anything…..other than accuracy

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I only crimp for dangerous game rifles and semi-autos - and I'm pretty sure I don't need to crimp for semi-autos. I'm going to turn down the expander ball on my "Garand only" die to a few thousandths under bullet diameter and then forgo crimping.

On a completely unrelated note, I hope to someday get drunk on the porch with @Slamfire.

Varminterror said:

Call it what you will, it’s an operation which perturbs the case mouth to solve a problem which shouldn’t need solving for rifle bullets. Opening the mouth just to close it again, it’s all opportunity to keep pushing more and more eccentricity into the ammunition.

Like @Nature Boy said above:

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Maybe, maybe not, but it works just fine for me. I'm not into benchrest or long range varmints .... but if I was I wouldn't be using a progressive to make that ammo, anyway. For AR ammo I find it's plenty accurate....as good or better than a lot of commercial ammo. Not sure why the attack?




.

You can but I do not ever crimp this type of bullet.

I do a light taper crimp on my rifle loads. I pull a bullet now and then to be sure im not deforming it. Before a changed out my Lee rifle dies for RCBS. I hated the collot crimp die.

jmorris said:

I do, using the expander in the size die (Dillon carbide ball) no additional expanders. I don’t have problems with them falling off even when loading at a fairly quick pace.

Click to expand...

Maybe that's another answer.....the Carbide Ball. Never got to try one....I don't care for the expander ball in RCBS's.....I removed them when I got a press with enough stations to expand separately. The "M" expander worked better for me. Eccentricity? No better concentricity. My experience with expander balls was worse concentricity. Carbide would have to help. A 1050 might also help, but I have it handled just fine.

GW Staar said:

I'm not into benchrest or long range varmints .... but if I was I wouldn't be using a progressive to make that ammo

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Why not?

GW Staar said:

Maybe, maybe not, but it works just fine for me. I'm not into benchrest or long range varmints .... but if I was I wouldn't be using a progressive to make that ammo, anyway. For AR ammo I find it's plenty accurate....as good or better than a lot of commercial ammo. Not sure why the attack?




.

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They automate dillion 1050s to make national match ammo... it's a very expensive proposition but if your world class I'm sure your in someone's payroll. I know of two guys that have them but they use a lot of other expensive toys like the Amp digital seating press.... it's just money right....

Nature Boy said:

Why not?

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Which? Why not do benchrest? Too boring for my impatient nature. Why not do longe range varmints? Lost interest in killing things. Why not use a progressive for either? Well, if I was younger, I might try, in spite of people telling me I can't.

Seems I've unintentionally managed to cause both a rift and shift. Let's stop before the boss starts removing posts.

I don’t think anyone with sense is telling anyone they can’t load precision ammo on progressives. Pretty sure we just had a thread on the topic a couple of weeks ago, although it may have not been a thread specifically titled about progressives.

But the reality is pretty simple - the more times and more ways we bend our case necks, and certainly the more we deform our bullets, the more opportunity we invite for bad things to happen which negatively influence our potential for precision. So flaring or “plugging” then collapsing back down, or crimping - basically anything besides expanding and seating - is inviting potential for inconsistency. Neglecting to care whether more inconsistency occurs doesn’t mean it doesn’t occur, so the “it doesn’t matter enough to me” isn’t really a valid argument in a discussion whether the inconsistency potential exists or not. It does.

A recurring delayed propellant ignition problem can be helped with a crimp. Better to change powder type.

Increasing neck tension is better then a crimp. https://www.sierrabullets.com/reload-basics/reloading-for-semi-autos-and-service-rifles/

Single stage press vs Progressive- The progressive MAY produce more OAL variation. At maximums, .005" vs .010" Less is more normal.

I dont crimp any rifle, not even the M94. Or M16A1.

An RCBS taper crimp die would do less bullet damage If one just has to crimp. https://www.midwayusa.com/product/1012080214

Varminterror said:

I don’t think anyone with sense is telling anyone they can’t load precision ammo on progressives. Pretty sure we just had a thread on the topic a couple of weeks ago, although it may have not been a thread specifically titled about progressives.

But the reality is pretty simple - the more times and more ways we bend our case necks, and certainly the more we deform our bullets, the more opportunity we invite for bad things to happen which negatively influence our potential for precision. So flaring or “plugging” then collapsing back down, or crimping - basically anything besides expanding and seating - is inviting potential for inconsistency. Neglecting to care whether more inconsistency occurs doesn’t mean it doesn’t occur, so the “it doesn’t matter enough to me” isn’t really a valid argument in a discussion whether the inconsistency potential exists or not. It does.

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Take a look at this picture of two expanders. Pistol, but the "M" designed one on the right, and purpose is the same for rifle neck expanders. The difference between them, almost imperceptible, but IMO really worthwhile. Purpose? keeping bullets straight enough to seat straight. Concentricity is improved, therefore accuracy is improved. Daa doesn't make them for rifle....yet.



Now RCBS, Noe, and Redding, and maybe others are adding M "steps" to more die products every year......I think because it's improving accuracy not the other way around.
Below the .223 version (.308 is just like it) for their new rifle bullet feeder......again pretty imperceptible, but effective.....not really mangling the necks as you suggest.



If one decides to try one, just don't adjust it into the fillet....that WOULD flare some.....stop at the beginning of the fillet. The "step" is the shiny spot 75% up the side.

GW Staar said:

Maybe that's another answer.....the Carbide Ball. Never got to try one....I don't care for the expander ball in RCBS's.....I removed them when I got a press with enough stations to expand separately. The "M" expander worked better for me.

Click to expand...

Well, I generally stop looking for solutions when I stop having a problem and if you are happy, I wouldn’t change a single thing.

I think the key is seating a bullet straight. “M” expanders are generally brought up when someone is having problems with cast bullets. Even my cast and coated pistol bullets can get by with almost no bell/flare because they are being held straight (GSI bullet feeder) as they are being seated.



That seated bullet has yet to be crimped and the other cases have all already been expanded and belled, waiting on bullets.

My rifle cases are even better prepared to accept cast and coated bullets, as I chamfer the mouth of the case. You can think of that as a bell cut into the case mouth.

If your seater won’t hold the bullet straight as it goes in, that is another matter. The less straight it attempts to enter the case, the more bell/flare you need to get it in there or at least started.

jmorris said:

If your seater won’t hold the bullet straight as it goes in, that is another matter. The less straight it attempts to enter the case, the more bell/flare you need to get it in there or at least started.

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This is where I land in the matter. M dies are an indirect solution to a problem which shouldn’t exist to be solved. If your seater isn’t supporting the bullet, then the M dies are Advil for brain cancer - they don’t solve the problem, they just mitigate the symptom.

GW Staar said:

Now RCBS, Noe, and Redding, and maybe others are adding M "steps" to more die products every year.

Click to expand...

It would be nice if the products we buy were better defined. I have thought about casting various dies similar to the way one casts a chamber. In order to be able to measure exactly the dimensions.

A popular Internet rumor is that ALL Dillon dies are “undersize”, they claim otherwise.

“The sizing/depriming die is full-length and sized to minimum tolerances to size cases down to function in both semi and fully automatic firearms.”

That said, it’s obvious to anyone that sized brass, and measured things that brass “springs back” upon exit of any size die, so in a sense EVERY size die made is “under”.

As far as steps and such, that too has been in existence.

37 years ago, Dillon dies were like the one on the left.



I always figured it was to reduce friction but never had a problem so never measured one to see if diameters were different. There is also a step on all of the 1050 (and other “4 digit” Dillon’s, again never measured them.



It would be enlightening to “chamber cast” various size dies and see what dimensions everyone is machining their product to but that’s a lot of work and only a few people would be interested anyway.

If someone here does the work though, I will be sure and save the data.

jmorris said:

It would be nice if the products we buy were better defined. I have thought about casting various dies similar to the way one casts a chamber. In order to be able to measure exactly the dimensions.

A popular Internet rumor is that ALL Dillon dies are “undersize”, they claim otherwise.

“The sizing/depriming die is full-length and sized to minimum tolerances to size cases down to function in both semi and fully automatic firearms.”

That said, it’s obvious to anyone that sized brass, and measured things that brass “springs back” upon exit of any size die, so in a sense EVERY size die made is “under”.

As far as steps and such, that too has been in existence.

37 years ago, Dillon dies were like the one on the left.

View attachment 1083168

I always figured it was to reduce friction but never had a problem so never measured one to see if diameters were different. There is also a step on all of the 1050 (and other “4 digit” Dillon’s, again never measured them.

View attachment 1083167

It would be enlightening to “chamber cast” various size dies and see what dimensions everyone is machining their product to but that’s a lot of work and only a few people would be interested anyway.

If someone here does the work though, I will be sure and save the data.

Click to expand...

I'm curious if all die makers use the chamber spec like rcbs.... if a die maker is considered by many as undersized maybe they use the Sammi ammunition spec. The top not the bottom drawing.

AJC1 said:

I'm curious if all die makers use the chamber spec like rcbs.... if a die maker is considered by many as undersized maybe they use the Sammi ammunition spec. The top not the bottom drawing.

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Well, even RCBS makes dimensionally different dies for the exact same caliber. Like the regular/undersize, example. Not only that, in every machining blueprint, there is a tolerance defined. If, in a perfect world we want 1.00000 , in the real world we wind up with 1.0000 +/- .0001. So we could have a “pass” product that is 1.0001” or one that passes at .9999”.

I would suspect many MFG’s products would fall into this overlap but one would have to test many samples.

As for “top & bottom” drawings. One is of the chamber, the other the cartridge, tolerances are generally arranged so the largest allowable cartridge will fit the absolute minimum chamber.

Like this example where the cartridge needs to be what is on the drawing or no more than .008 Smaller.

Where the chamber needs to be on the number or .002 Larger.

Die making reamers are smaller than chambering reamers. Springback is why.