Do I crimp or not?

hadjii

I have 2 questions. First. Is it necessary to crimp bullets in my 350 Rem Mag to be shot in a Remington 673 Guide Rifle? Second. Can I buy a die that just crimps? My current dies (an old set of CH dies), are good dies, but the seating die has no crimping capability. Thanks

nononsense

hadjii,

I don't crimp my loads and I haven't found a need to do so. You can load the magazine with dummies if you want and load the chamber with a live cartridge and fire (somewhere safe), then measure the OAL of the dummies in the magazine. If the bullets advanced further out of the case, I would use a necking die to adjust the neck tension. Be sure to test the new loads since a tighter neck (or crimp) will raise the operating pressure curve.

Best.

bpost

Another good thing to check is the neck thickness of the brass you reload. Some brass is thicker thereby supplying additional neck tension to the bullets. Some is so thin as to barely hold the bullets. MY experience has shown that Federal and Winchester cases hold bullets very well. Remington has been a problem for me in several instances. I tend to throw Remington brass away more often due to poor neck tension. Your mileage may vary.

I have never crimped any rifle loads. Even full power .338 Winchester Magnums have not moved the bullets in the case.

PJ

To crimp or not to crimp, that is the question. I crimp some callibers, but not others. Lee makes a Factory Crimp Die (FCD) which works quite well. If your caliber is not listed on their website, the will make you one for not much money.
Pete

Sig220_Ruger77

I have a Remington 673 in the same caliber and have shot everything from 180 gr to 250 gr. bullets without cripping them. So far I haven't had any problems, but I do keep an eye on the c.o.l. and would reccomend that you do so as well. Just a note, so far the 225 gr Nosler Partitions have shot the best out of my gun, but I have yet to try the 200 gr barnes bullets which will be my next experiment. Good luck in reloading and great choice of a gun!!

B17-P51

Sometimes a crimp can be a good thing, not so much to hold the bullet for proper case length but to assure proper burning of large amounts of slow burning powder. A great example of this concept is the .44 magnum with 2400 powder. A heavy roll crimp is necessary and recommended for this reason. I dont believe a crimp of moderate nature can hurt any load, or cause problems in the load you describe and may assure proper feeding if the ramp or chamber edge is a little rough.

nononsense

The question is with regard to the .350 Rem. Mag. not pistol cartridges.

Sure die makers sell crimp dies and a couple will try to convince you that the ammunition produced in those "factory crimp" dies are more accurate than ammunition produced without the crimp. Right. If that was true, factory ammunition would be more accurate than reloading your own ammunition and we wouldn't be having this discussion.

Crimping a rifle bullet that does not have a cannelure or crimp groove distorts the bullet jacket and the lead core that has been pressed into the jacket. Any variation in the core or the jacket let alone both leads to absolute inaccuracies when you shoot the bullet. The bullet will not rotate around its center of gravity because you have created an unbalanced bullet and unbalanced bullets are not accurate.

So what's the solution?

Set your neck tension to 0.002" for most rifles and go shoot. This has been tested over and again without failure. If you happen to have a rifle that recoils more such as a .458 Win. Mag with 500 gr. bullets at maximum velocity, simply increase the neck tension to 0.003", that's all. That tension will hold virtually anything that the vast majority of the shooting population can control.

There is some terrific reading to be found on this topic albeit with a bend towards the scientific, but perfectly readable if you want to develop a better understanding of crimping.

Best.

hadjii

Thanks Everybody. I asked this question because I was loading some 158 grain handgun bullets that were .357. I could move the bullets rather easily with a pair of pliers. Anyway, my idea was to remove the expander from the size die and then run the brass back through to increase the tension on the .357 bullets. Well, it did work pretty well. I'm still playing with the rifle, figuring out what works for reloads and what don't. I'm pushing these 158 grainers at about 2800 fps, and am getting about 1.5-2.0 inch groups. I'm not going to try too hard with these bullets. Am going to try harder with heavier rifle bullets and just wanted to see what the consensus about crimping in heavier recoil rifles was.

jonk

Most seating dies will do some crimping if you screw them in to touch the brass, then 1/4 to 1/2 of a turn more, depending on how much crimp you want. If you crush the case, you went too far. [:I]

nononsense

hadjii,

If you want to work with various neck tensions, take a look at the neck bushing dies that are available from several die makers. These dies allow for interchanging different diameter bushings (.001" increments) in the top of the die so that you can customize the neck tension or release if you prefer. Using a die such as this will make loading the .357" diameter bullets much simpler. Varying the neck tension can also improve the burning of some of the powders with slower burning rates. This requires some testing and adjusting to arrive at the optimum, efficient tension.

Best.