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

[KDF]

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.

 

[mdwest]

I know a lot of folks believe in crimping.

Me personally, I don’t crimp any of my heavier kickers, past or present… multiple 300 magnums, 45-70, 458 socom, 375 H&H, 416 Taylor, etc…

Have shot hundreds upon hundreds of rounds out of each of them… and never experienced a problem from any of them..

 

[deewayne2003]

I’ve been crimping for the last 25 years and see no reason to stop.

FYI - you will also listen to PH’s and others talk about (insert random “logic”) is the reason you pull the back trigger on a double first - which is incorrect.

 

[Joker12]

Of course you should crimp. I speak from personal experience that bullets in uncrimped ammo can move both from recoil or just from being bounced around in the vehicle. Why take that chance when its so easy to prevent?

 

[Mark A Ouellette]

Crimp or not to crimp ... ?

1. I listen to my PH about hunting. I do what they tell me. That is why I am paying them! But do they know anything about reloading?

2. PH's witness clients successes and problems, some of which may concern crimped cartridges. But, for all the hunters who load their own ammo and don't have problems, would the PH remember them? Would a PH conduct surveys of clients asking if the loaded their ammo and do they crimp and record the data in a spreadsheet? Most PH's witness a new client shoot at a 50 or 100 yard/meter target to learn if Joe Hunter can hit the broad side of a barn. If Joe made a cloverleaf of three bullet holes touching each other ar 100 meters, would a PH care? Who a PH start asking about Joe's ammo and who loaded it? If Joe was the loader, would the PH write down Joe's load data? Probably not.

3. As for a PH giving advice on loading ammo, how much loading experience do 99% of the PH's have? Those PH's probably do not have access to loading components like we do in western countries. Do they understand the importance of neck thickness and tension? Add to that case length... If not, then not crimping is a good rule.

4. Consistency is the key to accurate loaded ammo, be it factory or personal. Variances in neck tension can cause variances in pressure. Variances in overall case length will cause pressure variances when crimped in a standard neck crimp die. That may cause differences in muzzle velocity. Too much crimp pressure against a bullet could cause overpressure resulting in difficult case extraction. Maybe even case head seperation. Boy, that would really screw up a client hunter's day!

5. During practice I load up the magazine and shoot all but the last cartridge. Then I measure the overall length and compare against the OAL that I measured during final inspection of my loading process. If their is a difference three times, I know I should crimp. Once may be a random occurrence, twice may be coincidence, but three times is a pattern.

6. I prefer Lee Factory Crimp Dies. They produce much more consistent crimps than neck crimps by crimping along (longitudinally) the length of the case neck, rather than just at the very end of the neck.

Consistency is the key!

 

[Green Chile]

I crimp and it works for me but not just on heavy calibers. It certainly hasn't hurt me to crimp and it's extra insurance and consistency as Mark said.

 

[Shootist43]

I crimp, but I think Mark's testing regimen is the optimal way to go. IMHO neck tension is the "Elephant" in this room.

 

[PHOENIX PHIL]

I've measured rounds down in the magazine prior to and after firing another obviously in the chamber. I haven't done this on every rifle, but a couple. Without question the rounds became shorter. Will this be the case in all rifle/caliber combinations? I wouldn't be surprised if not. But after this experience I always crimp. I also prefer the Lee FCD.

With the Lee FCD, once set and I get started, I'd guess about 5 minutes or so to crimp an entire box of 50. Maybe 10 minutes total. So why not crimp? I think that's the question that should be asked.

The only time I see not crimping is for the long range shooters. If they're loading one at a time, I can see that. But for hunting situations I don't.

 

[Ontario Hunter]

I recently "accidentally" purchased online a box of old Barnes 400 gr "X" bullets for my 404J. No canalure or grooves on them so I reset my dies to not crimp. Figured I would use them at the range to work up loads. I found these cartridges were MUCH easier to pound out bullets to change powder loads. Some bullets were in fact WAY too easy to pound out - as in just a whack or two with the hammer. My ten pound 404 may be "relatively" light for thumper gun recoil but it still shakes me up significantly and will kiss my eyebrow if I don't hang on tight (even with +4" eye relief!). No way am I going after dangerous game with bullets that slippery stuffed in its magazine. I suspect with a full box and maximum follower spring tension, the potention for bullet movement in cases during firing might be less. But with one or two rounds only in the gun I would be especially concerned. Also, my reloaded rounds are inside hard plastic boxes. There's a very real possibility of bullet movement in uncrimped cartridges during flights to Africa. I have seen the rough treatment baggage apes can dish out to luggage!

 

[Inline6]

I do not crimp. I do my best to get 100% fill on powder. If that is achieved, the bullet has no where to go. JMHO

 

[Green Chile]

I've measured rounds down in the magazine prior to and after firing another obviously in the chamber. I haven't done this on every rifle, but a couple. Without question the rounds became shorter. Will this be the case in all rifle/caliber combinations? I wouldn't be surprised if not. But after this experience I always crimp. I also prefer the Lee FCD.

With the Lee FCD, once set and I get started, I'd guess about 5 minutes or so to crimp an entire box of 50. Maybe 10 minutes total. So why not crimp? I think that's the question that should be asked.

The only time I see not crimping is for the long range shooters. If they're loading one at a time, I can see that. But for hunting situations I don't.

This is my thinking as well. I don't crimp for my Sharps rifles, etc. I also like the Lee FCD and use them a lot. Very easy and quick to run a box through it.

 

[Ontario Hunter]

I do not crimp. I do my best to get 100% fill on powder. If that is achieved, the bullet has no where to go. JMHO

So you're thinking gunpowder cannot be compressed? I'd like to see some proof. Seems I recall reading exactly the opposite.

 

[Skshyk]

I usually never crimp, but my last trip to Africa I had 1 round in my ammo belt which the bullet and been pressed into the cartridge. It was a nosler solid in 375. I will be crimping from now on especially hunting rounds.

 

[Inline6]

So you're thinking gunpowder cannot be compressed? I'd like to see some proof. Seems I recall reading exactly the opposite.

No that is not what I'm saying, gunpowder can be compressed that's why you can fill above 100% and still seat a bullet. Have you reloaded a compressed charge?

What I'm saying is I have not had problems with bullets moving. Add to that a 100%+ case fill with powder. The bullet moving under recoil would be unlikely.

 

[KDF]

Crimp or not to crimp ... ?

1. I listen to my PH about hunting. I do what they tell me. That is why I am paying them! But do they know anything about reloading?

2. PH's witness clients successes and problems, some of which may concern crimped cartridges. But, for all the hunters who load their own ammo and don't have problems, would the PH remember them? Would a PH conduct surveys of clients asking if the loaded their ammo and do they crimp and record the data in a spreadsheet? Most PH's witness a new client shoot at a 50 or 100 yard/meter target to learn if Joe Hunter can hit the broad side of a barn. If Joe made a cloverleaf of three bullet holes touching each other ar 100 meters, would a PH care? Who a PH start asking about Joe's ammo and who loaded it? If Joe was the loader, would the PH write down Joe's load data? Probably not.

3. As for a PH giving advice on loading ammo, how much loading experience do 99% of the PH's have? Those PH's probably do not have access to loading components like we do in western countries. Do they understand the importance of neck thickness and tension? Add to that case length... If not, then not crimping is a good rule.

4. Consistency is the key to accurate loaded ammo, be it factory or personal. Variances in neck tension can cause variances in pressure. Variances in overall case length will cause pressure variances when crimped in a standard neck crimp die. That may cause differences in muzzle velocity. Too much crimp pressure against a bullet could cause overpressure resulting in difficult case extraction. Maybe even case head seperation. Boy, that would really screw up a client hunter's day!

5. During practice I load up the magazine and shoot all but the last cartridge. Then I measure the overall length and compare against the OAL that I measured during final inspection of my loading process. If their is a difference three times, I know I should crimp. Once may be a random occurrence, twice may be coincidence, but three times is a pattern.

6. I prefer Lee Factory Crimp Dies. They produce much more consistent crimps than neck crimps by crimping along (longitudinally) the length of the case neck, rather than just at the very end of the neck.

Consistency is the key!

Mark,

I think that the testing/measuring process you describe is the way to go. I will report back with my results. Thanks.

 

[Just a dude in BC]

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.

 

[Green Chile]

Love your comments/data, particularly around reliability. That's far more important than a little bit of accuracy. A lot of people are looking for a level of accuracy that CANNOT be held in field conditions.

 

[Ontario Hunter]

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.

Interesting. Good info. I'll try your method for checking neck tension. I'm not a competitive bench or long range shooter so pinpoint accuracy has never been a huge concern. Your closing statement bears some consideration. We are talking about dangerous game at typically fifty yards or less. How much is accuracy/reliability at that range affected by a bit of bullet movement in the case? Asking because I don't know. Perhaps I should experiment and purposely alter OAL on same powder loads to see what happens?

I generally check OAL of every cartridge I reload. Curiously, I found some of these old Barnes X bullets seat differently when nothing has changed with the dies. I've had to reset the die to obtain uniform length. I do know that jump to lands can make a difference with Barnes bullets so I'm careful to ensure all cartridges are same length. Thinking I should probably put those bullets on the scale and check for uniformity. However, they do group very well at fifty yards with holes touching.

 

[uplander01]

338 WM and up, crimp every single time if there is a cannelure. LEE factory crimp dies are magic.

 

[Just a dude in BC]

@Green Chile Thanks I appreciate the feedback

@Ontario Hunter
I have done a more than a reasonable amount of competitive shooting, so I can answer some of these questions... Kind of... The kind of, is because it varies a lot from rifle to rifle, mostly depending on how your chambers were cut... When I built up my precision rig, I custom ordered the reamer, and had it cut with that, knowing it was to my specs, and that it was the first chamber cut with that reamer.

So... To answer your questions:
1: "How much is accuracy/reliability at that range affected by a bit of bullet movement in the case?" Ans - This depends again on your rifle, but here is how you can check it, and specifically, here is how you check it in a comparative sense. Prep up 40ish brass at the same time, so they are all as consistent as you can. Take the first 20, and put them into 4 groups of 5 rounds each. What you want to do is make 5 rounds that sit about 25 thou back from the lands (if using solid copper rounds, they need runup if lead, make them just kiss the lands). Then group 2 will be 20-25 thou shorter, group 3 45-55thou shorter, group 4 70-75 thou shorter. When you shoot those groups one of two things will happen. Either almost nothing, OR you will find your groups trending toward or away from tightness. If you do this enough, you will find the optimal length for accuracy in your gun. BUT what you will also do is determine exactly how much accuracy variation occurs from a different COL. In my experience a few thou can make a measurable difference, but it takes like 50 thou or more to start getting unacceptable results.
Then take the other 20 brass and load them up to the length of the most accurate group from the first test. Crimp 10 of them, leave the other 10 un crimped. Now shoot those and compare. Your crimp might make a big difference, it might make almost no difference. BUT, I have never seen a crimp make the groups better, the best case scenario is that they are not much worse.

2: "Curiously, I found some of these old Barnes X bullets seat differently when nothing has changed with the dies."
Ans - Nothing wrong with that, provided that it is only a few thou, say +-5 or so. The reason for this is based on how the measurement is made. When you measure COL with your calipers, you are measuring base of the case, to tip of the bullet. BUT, modern dies DO NOT seat based on the tip. They seat based on the ogive, so that they do not deform the tip. So that few thou variation you are seeing is the difference in the actual bullet tips themselves. How do you check this? Well, take 10 bullets, measure their lengths (just the projectile), and you will see that they are different lengths. Now load them in cases that you have measured that are the same length. You should see that the variation in overall lengths now roughly corresponds to the bullet overall lengths. Though there will still be some differences, because the ogives will be slightly different. Guys that shoot F class matches and stuff will actually buy bullets in massive quantities, so they can sort bullets by their bearing surface length and ogive characteristic and stuff to make lots of bullets that are more similar. I don't not recommend this for DG rifles at all. Because it is a super waste of time. Honestly we are aiming for 4" groups off sticks at 100. Not sub MOA, which is an expectation I have had to temper in myself.

Here is an example of a test for the 143gr ELD-X bullet in my 6.5x55
Kissing the lands - .58" 5 shot group
5 thou behind lands - .51" 5 shot group
10 thou behind lands - .32" group with a called flyer
15 thou behind lands - .18" group with another called flyer - I am human
20 thou behind lands - .67"
25 thou behind- 48" and a suspected flyer.

The point is that you can see it get tighter, hit an optimal length, then open up again. Small changes in length can affect accuracy. But in all these examples, that max variation is still only around .5" over 25 thou of seating depth. So I would wager unless your bullets are shifting A LOT, its not affecting accuracy that much.