cast bullets, to crimp or not to crimp?

[Guest kj4gxu]

I have a case of Magnus 125gr 9mm (no 402) http://www.magnusbullets.com/images/bullet%20photos/image402.jpg which I'll be picking up from Midsouth Shooters supply this afternoon.  This will be my first foray into lead/cast bullets and was wondering if crimping is necessary.  

I'll be using them with my Ruger P95.

 

If crimping is necessary will the crimp feature included in the seating die in my Lee 3 die set be sufficient or will this require a separate factory crimp die?

 

all my previous reloading has been jacked or plated bullets.

Edited November 5, 2013 by kj4gxu

[musicman]

I don't really put a crimp on my 9mm. I pretty much just have the seat/crimp die turned enough to remove the flare for bullet seating. However, I run everything through a Lee FCD at the end, which I feel puts a good squeeze on the case/bullet to avoid setback issues.

Caveat: I have not used that exact bullet profile. I just run regular plated rn or lrn.

[stumpy]

There used to be only taper and roll crimp dies available, now we have the Lee factory crimp die.  No, I don't have one of these and have never seen a case that has been passed through one but have to expect it would give results very similar to a taper crimp die.  Musicman said it right, all you need to do is remove the flare from the mouth of the case.  Die adjustment can be a bit of a challenge for this without an accurate measuring tool like a micrometer or dial caliper.  Your bullet diameter should be .356", and the case walls about .010" at the mouth of the case.  Final crimped diameter for the case mouth should be right at.376" (remember, you are measuring 2 case wall sections - on both sides of a single bullet).  If the loaded case measures larger than that you may have feed issues.  Feed is also affected by the overall loaded length of your ammo, and again by the profile of the bullet nose.  Taper crimp dies are available as a single item, are not all that expensive, and Midsouth should have them in stock.  I have bought several Lee taper crimp dies over the years and find them excellent at giving perfect results when correctly adjusted.

 

Stumpy

[Caster]

No crimp. Just close the bell. Also, stay away from the Lee Factory Cimp die with cast unless you're willing to go an extra mile or two. They WILL size the bullet down and cause fits of inaccuracy and leading. I use one but I have found a particular brand of brass (FC) and I also pull loaded rounds periodically and check the diameter.
I've also used some diamond lapping compound to open up the carbide sizer ring another one and a half thousandths. This puts me right where I want to be for MY gun. Your mileage will undoubtedly vary.

Crimps are WAY over used. There are VERY few reasons to crimp. Tube magazines and bottle neck cartridge auto loaders typically need a bit of crimp. Magnum revolver cartridges too for both boolit movement and helping ignition.
I don't crimp anything for my .308 bolt gun for the most part. I don't crimp any of my 9mm loads. I only use the FCD to close the expanded case mouth and iron out the lower part of the case.

[Dolomite_supafly]

You can get more bullet tension by reducing the sizing mandrel by a few thousandths with jacketed bullets. For cast bullets you actually should use a larger mandrel to keep the case neck from sizing the cast bullets down. If it is a pistol caliber you do like Caster said and open up the carbine ring a few thousandths when shooting exclusively cast.

 

I never crimp cast bullets, only remove the bell like others have recommended. That is for rifle and pistol calibers. As a matter of fact I do not crimp jacketed bullets either in any of my loads because I use a reduced mandrel size with jacketed bullets.

[chances R]

Well since I have started using the Lee FCD my feeding problems have virtually disappeared.  This is especially true with cast bullets.  I use it in 45 and 9 s.   My bullet seating die (Reddings Pro) come no where near eliminating all of the bell for my cast bullets.  The FCD finishes off the case at .468 for me. 

Edited November 10, 2013 by chances R

[DWARREN123]

Remove flare to point that the cartridge falls into the chamber and falls out on its own. No crimp is really needed except for higher powered revolver ammo.

My opinion.  

[frankmako]

over the past several years i started using the lee factory crimp and/or taper crimp for 9mm, 45 acp, and 40 s&w.  before then i did not crimp, just closed the bell. the reason i got them was i want to try them to see how well they work.  i don't know if the factory crimping has any effect on the round. i know on my reloads they don't.   i don't fully set the factory crimp to get the full effect.  i use it to sung the case to the bullet.  i do crimp my 44 mag and 357 mag rounds. 

[Guest kj4gxu]

thanks for the info all.  Hoping to get the chance this week to sit down and actually put some of it to good use.