Home Forums Hunting & Shooting Ask The Gunwriters In need of advise on crimp dies

I've been reloading for a while now and have a question about the Lee crimp die. I've read several times that you should use a separate crimp die rather than the combination seating/ crimp die that comes with the three die Lyman, R.C.B.S. etc. setup. I don't remember if one group of cartridges performs better with the separate crimp die. Is it the revolver cartridges or the semi- auto cartridges? I know the revolver rounds .357, .41 Mag, .44 mag. etc. gets a roll crimp and the semi stuff .40, 10mm, 9mm, .45 acp, etc. gets a taper crimp. So here is my question,,, according to the Lee die page in the Midway catalog there are two choices, one is titled Taper Crimp Die, the other Carbide Factory Crimp Die. What is the difference in these two dies? I would not think that a carbide die is necessary for just turning in the tip of a shell case. And the other question,,, is it more important to use the separate crimp die with the taper crimp auto cartridges or does it improve accuracy better with the roll crimp/ revolver rounds? I don't know if it's absolutely necessary to buy a crimp die for all the cartridges I load for. I would like to hear your experiences and opinions. Thanks. RRM

I only use a Lee Crimp Dies on my strait walled cases. (450/400.,458 Win Mag and 500 Nitro.) On bottle neck cases I don't.

It is always better to crimp in a separate operation. Lee has several products called the "Factory Crimp Die", and they are all for different applications. The ones for auto loading cartridge is something like a taper crimp. The ones for revolver cartridges act more like a roll crimp. Those two are both good dies to have. There is a third type for rifle cartridges that is a collet style. I have had better accuracy by not using that die unless I have to, e. g. in tubular magazine lever action rifles. The rifle one does work better than the roll crimp, but worst than no crimp. All of them are less fussy about have all the case lengths the same. I would buy one for all the revolver cartridges you load for. I would be a good idea to get ones for your auto loaders also. I wouldn't buy them for rifle cartridges unless you had to crimp.

I like the Lee crimp dies, and have several. What I have found to be the key issue with any crimp die is case length. If you do not trim them to the same length you will get a different crimp with each round for the most part. Unless you adjust the die for every round, which to me is not practical. For straight walled pistol cases a one time trim is usually good for the life of the case, rifles not so much depending on the chambering and load.

No expert here and my advice is worth exactly what you paid for it. But I think the Lee Dies are good. To me there are two types of crimp, rolled and taper. The rolled requires a cannelure or groove to function properly. The taper can be used on bullets without a cannelure if you do this in moderation. Both can improve functioning and sometimes accuracy but must be tested in each application for each firearm. I also do not like the crimp feature on all bullet seating dies. Maybe someone smarter could avoid the issues I have had with these but the crimp feature in RCBS and other dies has accounted for the most botched loads I have produced. Yes as Smith said if your cases are not 100% equal in length you will have issues. An agree with Smith the collet style is the way to go for a taper crimp if and only if you need it.

I use Lee factory crimp dies for my .223, 30-06 M1 Garand ammo, and Rem 350 mag ammo. For handgun ammo I use the seating dies to crip.

I use an altered Lee factory crimp die in station #5 of my dedicated .223

I ground about .050 off the bottom of the collet to allow the round to get a wider crimp

I use the Lee on .223 and my Garand 30-06’s too

Thanks fellas for your comments. I normally don't crimp my rifle loads because most of my shooting is loaded one at a time, playing with target and load evaluation, unless I'm taking them hunting and the magazine will be stuffed then I give them a real small crimp. Mainly I was interested in handgun cartridges. Thanks again. RRM

I use the Lee Carbide crimp die on my hand gun straight wall cases. With that die, case length becomes less critical. The Lee carbide crimp die base will correct the over crimp bulge that prevents chambering a case with a slight bulge. The Lee die is a smart investment.

The standard Lee die is supposed to do the same, however I have only used the carbide version.

I use them a lot, maybe because I shoot a lot of big bores. But they work well on any caliber.
One trick I learned is that , even though they are made for individual cartridges, you can use them on similar calibers simply by individually sticking a round in Upside down from the top and crimping it

I've started using Lee Factory Crimp Dies on all my handgun loadings. 357 Mag, 44 Mag, 9 mm, and 45 ACP.

What I like about the dies is that it resizes the round after bullet seating. I shoot a lot of cast lead loads, and have to bell the case mouth a bit more to prevent the soft lead from getting shaved. Afterwards, without the LFCD's, I can have trouble with the rounds chambering in tight chambers. LFCD's always give a satisfying KERPLUNK.

Phil do you recommend crimping on bottle necked cases like the .375 H&H? I haven't needed to but some African hunters think it gives an extra bit of uniformity or peace of mind.

I have had excellent results using a Lee Factory Crimp Die on all my rifle cartridges. Precisely measured powder charges, cases uniformly trimmed, and bullets lightly crimped seem to produce fine accuracy for me. Perhaps something to do with equal starting pressure and powder burn? Who knows. Happy Trails

Need to look into this more as not only is the neck tension uniformed the crimp dies can straighten the bullet out and reduce run out with some load/die combos. This was with Lee dies RCBS gave me problems with buckling the neck. I think I gave up too soon before I had them adjusted properly.

I've tested otherwise identical rifle loads that were crimped with Lee Factory crimp die v. uncrimped cartridges in only two rifles that didn't need crimping to function correctly.

One of the rifles is a J. C. Higgins model 50 in .30-'06. The load was the 150 gr. Remington PCLSP/51.0 gr. IMR4064/LC69 cases/WLR primers. Twenty cartridges were crimped, and twenty were uncrimped. Half of each group was necksized with a Lee Collet die, and half were full-length resized to set the shoulder back .002" - .003" with a Lee die. This rifle shoots much better with H414/R-P cases giving 2.9" three-shot groups at 200 yds., but I was just testing sizing and crimping.

The best of the four was full lenght resized cases that were not crimped that gave an average three-shot group of 2.331" at 100 yds.
The next was the uncrimped necksized cases at 2.625".
The third was crimped necksized cases at 2.953".
Last was full length resized crimped cases at 3.829".

Crimping or not had a larger effect than the type of sizing. Both types of sizing did better without crimping. The other rifle showed the same trend.

On a separate note, this isn't the only rifle of mine that shoots better with full length resizing. Some shoot better with neck sizing, but not all.

The point is you need to try it all ways.

I have never crimped any rifle round for a bolt or semi auto. I will be on the 458 Win due to recoil setback issues though.

I roll crimp all revolver loads.

I taper crimp all semi auto loads.

No need to in an AR or Garand or such as long as the neck tension is there.

I've never seen crimps increase accuracy. YMMV.

I hope I never have to buy another Lee product the rest of my life.

I only own one separate crimp die, for a possible issue in a friends dads 270... the rest get crimped as they are seated.

You do know you can seat, and then readjust the die to crimp separately with a factory combo seat/crimp die....

Quoting rost495 "
I've never seen crimps increase accuracy

I have only seen accuracy and velocity SD improve in heavy handgun loads with major crimping.

Ten years ago I tested crimping in a Winchester 94AE in .30-30 with a 24" barrel. The rifle has a Williams FP receiver sight and had a thin patridge front sight. I loaded the 170 Speer/33.5 gr. W748/Winchester cases/CCI250 primers. I loaded 15 rounds each of uncrimped, Factory crimped, and roll crimped. I shot three five-shot groups with each at 100 yds.

Uncrimped: 2075 fps, 14.0 S. D., 4.1" avg. five-shot group.

Factory crimped: 2085 fps, 25.4 S. D., 4.1" avg. five-shot group.

roll crimped: 2081 fps, 32.6 S. D., 4.7" avg. five-shot group.

Once again thank you all for your helpful insights and experiences. Very interesting. As mentioned I was not so much interested in crimping my rifle rounds as I was with the handgun rounds. I have noticed that the bullseye handgun shooters, especially the ones shooting the .45 acp like to taper crimp to a given crimp diameter. And let's face it, these guys drop them right in there. Same can be said about the benchrest boys. They go to extremes to put them "right in there". This may be a dumb question, but here goes,,, can you both taper and roll crimp with the same Lee crimp die? Is it just a matter of how you adjust the die? Or do the semi auto cartridge crimp dies taper and the revolver cartridge crimp dies roll? Once again, thanks. RRM