I am new to reloading, and am doing 7mm Rem mag. I am confused about crimping, do I need to crimp? If a bullet has a cennelure is it required to be crimped?
Thanks for any help.

Don't worry about it.

I don,t kknow how much rading you have done on reloading,but some people whom load bullets with cannalures like to roll crimp them,and other bullets just taper crimp them.If you want a roll crimp,the instructions to set up your dies comes in the box with them,if your using RCBS dies. A roll crimp is suggested for those whom are loading for semi-automatic rifles to insure that the bullets will not move due to the operatiion of the gun. This is why military rounds are crimped.van

If shooting a bolt action don't bother crimping. After sizing you have plenty of neck tension.

No crimp needed on any rifle except those with a tubuler magazine. If you find the perfect seating depth, the case mouth will not be at the cannelure anyway.

IMHO, crimping is optional in 99% of the cases.

I use a compressed load in my 375 H&H so I bought the Lee factory crimp die (FCD) for it and loaded my first rounds using it. It shot scary well from the start so I've continued to use it.

In my 22.250 I did a controlled experiment with identical components with and without the Lee FCD. My chronograph showed a distinct improvement in extreme spread and standard deviation on the order of about 15% or so and a small improvement in group size averages (I'll have to dig up the test sheet for exact numbers) so I continue to use it in that gun also.

The only crimp die I use is a Lee Factory Crimp and I own one in every caliber. I have set up side-by-side loaded-at-the-same-time tests between identical loads and in each case the crimped cases yielded a little more velocity and a little better groups. Not very much and it can only be seen in averages from groups of 10 shots or more.

Anyway, if it improves velocity, accuracy and you don't have to worry about bullet movement, why not?

Once again, Lee Factory Crimp only!

lee factory crimp die

The're easy to use and fool proof, at $8.00, what's the problem?

Thanks for all the help, looks like no crimping will have me shooting my own loads sooner. May experiment later, just to see if I can do it.

My experience with the Lee Factory Crimp Die agrees with woods'. I use it on everything, bolt or not. May not make a big difference, but it's there.

I agree with the other Lee Factory Crimp die users and now use Lee's on all my rifle rounds.

Here's a good read for ya.

http://www.accuratereloading.com/crimping.html