416 Rigby (Big Bore) - To Crimp or Not to Crimp

[BryceM]

I've always crimped my .416 Rigby loads. 400 gr TSX and BBS. It hasn't seemed to hurt accuracy in my CZ550 - right around 1" at 100 yards. YMMV.

 

[Rare Breed]

I am looking for some wisdom on crimping of Big Bore Calibers. I just returned from South Africa where I had the opportunity to speak with several PHs about reloading. The consensus was that they do not crimp .416 Rigby. In fact I was able to inspect several of their reloaded rounds, and they were all uncrimped.

My previous practice has been to crimp, because of the, perhaps only perceived, potential for recoil to move the bullets in the magazine. The PHs said that they had never seen this to be a problem.

I am going back for Buffalo in 2 months, and need to get to work on reloading 416 Rigby. Please let me know your thoughts / experiences. Thank you.

Any big bore in a bolt action I am always going to crimp. For my DRs which has drawn criticism on our forum I do not crimp and have had zero problems

 

[Lone Star Bluegrass]

Light-medium crimp.

 

[Frederik Badenhorst]

Here is a cautionary tale for the non crimpers. I hunted my first elephant recently in the Caprivi. I was using my VC double in 450 NE. Shooting 480 gr CEB’ at 2150 fps. I crimped them using a Lee Factory Crimp die, but also never had issues with non crimped ammo in the past , so the crimp was only applied out of an abundance of caution .
I however crimped the bullets on the driving bands and not in the grooves of the canulure, because I didn’t think it would be a problem. I shot hundreds of rounds during practice without any problems.
On the day of the hunt I shot the bull with a perfect side brain shot from my right barrel. It went down and I put in an immediate insurance shot into the shoulder with my left barrel. I reloaded and the ph said hit it again in the shoulder as it was toppling down, I did so.
I then broke open my double reloaded the right barrel only and ran to the front to put another bullet in the chest of the elephant from between the legs. I broke open the gun again, reloaded the right barrel again and ran to the back of the elephant,which was now laying on its side and at the PH’s behest gave it another one through the top of the head with the right barrel.
When the dust settled I broke open the gun but was hard pressed to remove the left sided cartridge. It was stuck. I pried it out of the breech with a pocket knife and ended up with an action full of gunpowder. The bullet was firmly lodged in the left barrel. Nobody at camp had a cleaning rod and I had to wait to get back home before I could drive it out with a dowel and a rubber mallet.
It was never an issue during practice because I always fired a right and then a left, never being alarmed at the effect of recoil on a bullet in an unfired chamber after multiple shots.

 

[uplander01]

Frederik Badenhorst,......you just gave the best example ever of why you crimp.

 

[KDF]

This is actually a math problem, not a "crimp vs non crimp"
@Shootist43 had it right up above, the issue is neck tension.

It is neck tension, and the depth of seating of the bullet that holds the bullet in place during recoil (It's also the nature of the surface of the inside of the case neck) or when it is bouncing around. When you are crimping, what you are doing is artificially raising the neck tension on the bullet. BUT, it can comes at a slight/large cost of accuracy.

Proper neck tension has a huge impact on accuracy, which is why all the dudes shooting precision competition are buying the new dies with bushing in them, so they can dial in the neck tension. The reason you need to change this is because different brass have different thicknesses and different dies are cut ever so slightly different. Meaning one brass in one die can have a lot of neck tension and a different brass in a different die may be able to be pulled out by hand, due to a lack of neck tension.

So... How the hell does this help you decide? Well, you just need to measure the neck tension of your setup.

1. Take a brass, full length size it, measure the outside of the brass at the neck with your calipers to see its overall diameter, that is X.
2. Now load a bullet into it and measure again that is Y. Y-X is how much neck tension you have on the brass.

-For competition shooting, you want around .002" neck tension. Enough to hold it in place with light recoil, but not so much to interfere with the bullet leaving.
-For DG I would want .006" or greater. This ensures the bullet can survive the recoil.

So the best thing to do is to get bushing dies and then buy bushings to set your neck tension between .006 and .008. This will give the grip you need to hold it in place, and be the most repeatable (which equates to accurate). I have never even looked for bushing dies in big bores however, so I am not sure if you would have to custom order them.

OR, just measure what you have. If your neck tension is over .006, and you are not seating your projectiles way out, you wont have a problem. BUT, if you measure your neck tension and it is like .003 or something below .006, then I would use that crimp. Because in this game reliability means a lot more than pin point accuracy.

Great info. I think that approach is spot on. I actually use neck bushing dies for 243 and 300WM. Never occurred to me that just measure the necks on the 416s. I am going give that a try and report back. Simple solutions are the best!

 

[Luvthunt]

Using the Lee CD I crimp all from 375 up. For reasons that I normally use mica on the inside neck sizing. I believe the mica with the wax stops necks being pushed into shoulders, particularly the 416 Rigby.
Have run tests on the range and do not find movement in OAL.

 

[Just a dude in BC]

Using the Lee CD I crimp all from 375 up. For reasons that I normally use mica on the inside neck sizing. I believe the mica with the wax stops necks being pushed into shoulders, particularly the 416 Rigby.
Have run tests on the range and do not find movement in OAL.

I use imperial sizing wax, and yea it is SLICK. I put a little on the inside of bottle neck cases and it makes it way nicer to size. What I do now is tumble the cases twice.
-Tumble to clean
-Size and de-prime
-Tumble again to clean off the wax inside and out.