For those who seat and crimp with seperate dies

SC_Dave said:

Regarding loading for a semi auto rifle. (AR)

Right now I seat and crimp with on die, RCBS TC. I'm thinking of separating it just like I have with 9mm. I you seat and crimp in two stations which dies do you prefer?
Thanks, David

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It is my considered opinion that neck tension alone is sufficient for most rifle applications. There are a few, such as lever actions where bullets are stacked on top of each other, bullet being pressed on the base of the cartridge on top, where crimps make sense. Elephant guns have such a recoil that bullets need to be crimped or the inertia of the bullet is such that they will seat themselves into the case. But outside of those examples, you are better off not crimping rifle bullets.

When you crimp a rifle bullet you are distorting the soft core underneath the bullet jacket. That distortion will shift the center of gravity of the bullet, irregularly and unpredictably, from the axis of rotation. Creating a source of inaccuracy.



You will probably only see this inaccuracy with good bullets. But it does not make sense to take the best bullets ever produced in human history and make them less accurate with a crimp die. If you are loading military surplus FMJ's, there is almost nothing that can be done which will improve the accuracy of the things, and conversely, they can take a lot of abuse, and still be as inaccurate as they were before the abuse!

Crimping a 223 creates more problems than it can possibly cure. You can find lots of posts where crimping bulged the case and caused jams. If you are loading for a 223 AR15, find a die that has good neck tension, a nice tight bullet to neck fit, and put the crimp die back in the box and fugget about it.

The only time I crimp a rifle round is .30-30 because it's in a tubular magazine.
I do seat and crimp pistol cartridges in separate steps. For that application, for the price and ease of use, the Lee FCD is hard to beat.

Not sure of the amount of crimp required to cause a bullet to keyhole, but,,,,,,,, wouldn't it be slick if not crimping helped with the keyholing you mentioned in another thread?

(FWIW, I do not crimp mine)

I almost never crimp a rifle bullet without a cannelure and sometimes not even then.

If I can I always prefer 2 steps because I can adjust one without effect on the other, seat depth/crimp.

I know lots of guys that say they don't crimp, even for an AR, but looking at the road the cartridge has to travel, I prefer to crimp and without detriment to the level of accuracy that I expect from my AR. I'm not shooting mosquitoes at 100 yards using a 1.5X scope anyway. I crimp with a Lee Factory Crimp collet die. I like using this die because it is insensitive to the length of the case and applies a consistent crimp. I use a medium crimp, but even a light crimp is enough to prevent the bullet from getting pushed in. If it bugs you, get bullets with a cannelure and crimp into it.

I shoot my AR aggressively. Nose to the charging handle and I really prefer that it not go boom right in my face. It's just for peace of mind.

I'm a 2-stepper, too.

For my 5.56mm and 7.62mm blasting ammo, I use a light taper crimp into the cannelure... usually. Otherwise I leave it alone. What Slam said is correct, though... you have to have good neck tension.

I will use a very light crimp for bullets with a cannelure for the rifle bullets I reload. Mostly .223 and .308. However non of the .308 I reload have a cannelure and only the plinking rounds I shoot in .223 have one. I have not noticed and loss of accuracy from the light crimp.

jmorris said:

I almost never crimp a rifle bullet without a cannelure and sometimes not even then.

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Same. And if I do crimp my AR rounds it is on my progressive presses so it's all in one stage.

I crimp and seat in 2 different stages in 460/454/and 500. Reason being, they are so long and require a crazy amount of crimp to keep the bullets in place under recoil. Sometimes (IME at least) the cases buckle before the crimp is sufficient. Ive also started doing 44 the same was since getting my light weight 44s.

I lightly roll crimp bullets with a cannelure for my semi-auto rifles. I have extra dies, seat in one press and crimp in another press.

For my semi-auto rifles, AR-15 in several different cartridges and M1 Garands, I do not crimp. Ditto for bolt rifles.

I agree with Slamfire, that crimping for rounds used in a tubular magazine rifle would be beneficial. I only have pistol cartridge lever actions rifles with tubular magazines so they get crimped anyway.

For my handgun cartridges, I crimp in a separate step. My reloading started when many semi-auto pistol cartridge seating dies came primarily with roll crimps and taper crimp seater dies were few and far between. Taper crimp dies were available but as a separate die so I got into the habit of crimping in a separate step from seating. My preference but not a necessity. Seating and crimping in the same die is a viable option as well.

Skgreen said:

Not sure of the amount of crimp required to cause a bullet to keyhole, but,,,,,,,, wouldn't it be slick if not crimping helped with the keyholing you mentioned in another thread?

(FWIW, I do not crimp mine)

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Just enough till it looks right...

I did not think of that in response to that thread because I don’t crimp rifle rounds...
If the neck won’t hold a bullet before it’s seated, it won’t hold it after.


(Oh, No! I’m a big lair. I do crimp 450Bushmaster, because they need to be expanded.)

I never seat and crimp in one step anymore. I've had too many issues with it in years past. When I do crimp it's a 2 step process and I taper crimp. Almost all of my crimping problems came from roll crimps.
I reload a 5.56 69gr round that I use a mild taper crimp and 9mm plinking and practice rounds that get crimped, but that's about these days.

The only reason I use a Lee FCD on my 308 rounds is because I flare the mouth ever so slightly with the universal neck expander before seating cast lead bullets. The slight flare prevents lead bullets, whether plain base or gas checked, from being shaved as the bullet is seated. I then use the FCD adjusted to barely kiss the mouth of the case and bring the flare back to vertical or barely inward. I don't flare or crimp when using jacketed bullets. Boat tail bullets completely eliminate the need to flare and flat base jacketed bullets self center with the seating stem if I guide the bullet up the die as I raise the press ram.

Crimping rifle rounds is typically used if the bullets are being transported and banged around and you want to prevent setback. It does no help in adding start pressure during the firing sequence. It may also help in tube fed guns but I've never seen bullet set back or bullets being pulled out by recoil in a magazine fed .308 or .223 round

Dillon rifle die sets have three dies. Decap/resize, seat, taper crimp.

I like this because I use cast bullets and use the crimp die to remove the flare required to load coated cast bullets.

That's ALL I use the crimp die for.

I like the Lee FCD and use it for both rifle and magnum pistol, I feel I can produce more consistent ammo by seating the bullet then doing a "light" crimp. I've seen bullets loaded for Garands move in the case.

I want all the bullet hold I can get when measured in pounds. I have tension gages but none of them measure tension, they all measure in pounds.

45 pounds is a good number, I have a Dillon 550B, the tool heads have 4 positions, when I load on the Dillon I use a lockout die; meaning I have to use a seat and crimp die in one position or seat and then crimp after the case is kicked out. I also have 2 RCBS Piggy Back 11 presses with a 5 hole tool head. With the extra position I can seat on one position and crimp on another. When going for 'all the bullet hold I can get I do not find it necessary to crimp.

If I could figure a way to measure neck tension I would measure neck tension, I know there is interference fit and crush fit but that does not measure tension.

F. Guffey

fguffey said:

If I could figure a way to measure neck tension I would measure neck tension.

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You don’t use a caliper?

Demi-human said:

You don’t use a caliper?

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The caliper does not measure tension.

F. Guffey

fguffey said:

I want all the bullet hold I can get when measured in pounds. I have tension gages but none of them measure tension, they all measure in pounds.
If I could figure a way to measure neck tension I would measure neck tension, I know there is interference fit and crush fit but that does not measure tension.

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Tension is force. Pounds are force. So if you can properly measure tension, you could measure the seating force or "pullout" force.
I wouldn't waste the time doing so, but if you want, you could use a bullet collet puller and if you can measure the tension on the shell holder you could measure the amount of force needed to pull the bullet out. You could also use a tension gauge and compare the force on the gauge while placing a force on your press handle. That would take into account the mechanical advantages of all the levers on the press.

You could also use a load cell to measure the seating pressure on the bullet while seating it. Use a trigger gauge to see how many ponds you are pulling on the handle. Then put the load cell between the die and the shell holder and put the same force on the handle and measure the load cell force. That will give you pounds of force. Divide by the area of the bullet and you get the initiation (start) pressure when the pullet starts moving out of the case. You'll also have to take into account the difference between test static versus dynamic friction if any.

For me, if I get 1" or so at 100 yards, it's good enough.

Most handloaders don’t have a K&M seating force press setup.
As such we transduce the measurement from another means, knowing there are more variables and forces involved than just neck size, and also knowing there is no way to correct nor account for them.

SC_Dave said:

Do you seat and crimp in two stations which dies do you prefer?

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Yes, I seat then crimp. And prefer Hornady Taper Crimp dies when I rarely do.

Got complicated after that, didn’t it?

rsrocket1 said:

Tension is force. Pounds are force. So if you can properly measure tension, you could measure the seating force or "pullout" force.
I wouldn't waste the time doing so, but if you want, you could use a bullet collet puller and if you can measure the tension on the shell holder you could measure the amount of force needed to pull the bullet out. You could also use a tension gauge and compare the force on the gauge while placing a force on your press handle. That would take into account the mechanical advantages of all the levers on the press.

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My tension gages are marked in pounds, when manufacturers started building bullet seating devises with a gage they started with the gage that was marked off in pounds, they did not use a compound gage; that would be a gage that measured tensions and pounds and I do not ever wonder why.
And they did not include a conversion for tensions to pounds.

I am the fan of bullet hold because I can measure bullet hold in pounds

F. Guffey

I guess that's why they call it a thread

It would be interesting to get statistics on the exact seating pressure on reloads. The commercial loaders can control all the properties using new brass and known projectiles. That's probably why they can deliver decent consistency. The bench rest guys try to control all the variables and can do it much better than us hacks.

fguffey said:

I am the fan of bullet hold because I can measure bullet hold in pounds

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I do not refute this observation.

I am merely a Demi-Shooter.

So, we have a cartridge with fifty pounds of seating force, and one with one hundred. How do we fix the one with too much? How would we fix one with too little?