Do you need to crimp your 470NE loads for a Double Rifle?

I reloaded some without and some with a slight roll crimp to compare how they shoot/chronograph.

Thanks

yes

+1 YES

Lee Precision will make you a crimp die. I sent in a case and bullet to them for my 450 NE and they are creating the die at this time. I tried to crimp with my dies but for some reason caused problems. I have read where the crimp given by the Lee crimper is prefered over the normal roll crimp.

Yes, if used in a double rifle, no, if used in a single shot!

For sure.

When I owned one I use to crimp, however I never had any movement when I used Bullets without.
Why is it necessary?

Don't take any chances. Crimp them I have a lee crimp die they are inexpensive and totally worth the wait.

Crimping a loaded round should be second nature in any rifle other than a single shot. Along with the proper sized expander plug and a tight enough neck will always help burn the powder and get the necessary velocities needed. As always, there'll always some who never crimp their rounds and they seem to have no problems. Basically, it's your choice.

quote:

Originally posted by ozhunter:
When I owned one I use to crimp, however I never had any movement when I used Bullets without.
Why is it necessary?

ozhunter.
It is important for several reasons. It can influence velocity. But I seriously doubt that the animal will notice the difference. The main reason for a crimp is this. If you only fire one barrel, the recoil can cause the bullet in the other chamber to ride forward and engage the rifling. When you open the rifle the extractor will pull the case out of the chamber leaving the bullet still engaged in the rifling. This leaves you with a chamber full of powder. This is not a good situation on the range and potentially life threating while hunting. This may or may not happen depending on the amount of recoil, and the bullet's shape.

Thanks for the reply.
I did quite a few test and found that there was no movement of the Bullet in the case at all with my 470.
A good friend of mine shoots a double a few times a week and with the particular double he shoots now, I would imagine he has shot a few thousand rounds with it, he does not crimp and has not had any movement.
Might be luck?

From the recoil of the rifle, the bullet would tend to stay in place (whichever of Newton's Laws is about stationary objects tend to stay that way).

In bolt actions, it is why the front of the magazine gets beat up from the bullets dinging the box. Which is a reason to crimp them so the bullet doesn't get pushed back into the case. Right?

In a double, the opposite will occur in that the bullets would tend to come out as the case goes with the rifle. Of course, the bullet will only come out, if it did, until it hits the rifling. I'm sure some would freak out about a change in COL or the possibility of a round getting stuck in the chamber if the bullet got jammed against the rifling, especially if one round is in one barrel after repeated shots only in the other barrel.

It may never happen but crimping is so easy to do with any RCBS die, why not?

ozhunter, does your friend have a chrono? Would be interesting to see if his velocities are up with the rounds uncrimped vs crimped ones. I've found that crimped rounds burn the charge cleaner and give me the velocities that I want.

quote:

Originally posted by Will:
From the recoil of the rifle, the bullet would tend to stay in place (whichever of Newton's Laws is about stationary objects tend to stay that way).

In bolt actions, it is why the front of the magazine gets beat up from the bullets dinging the box. Which is a reason to crimp them so the bullet doesn't get pushed back into the case. Right?

In a double, the opposite will occur in that the bullets would tend to come out as the case goes with the rifle. Of course, the bullet will only come out, if it did, until it hits the rifling. I'm sure some would freak out about a change in COL or the possibility of a round getting stuck in the chamber if the bullet got jammed against the rifling, especially if one round is in one barrel after repeated shots only in the other barrel.

It may never happen but crimping is so easy to do with any RCBS die, why not?

Will,

How do you crimp with any RCBS die. I have a full length resize and seating die for my 470 NE but I am not clear on how to crimp with "any rcbs die". I would like to start crimping my rounds.

Crl

quote:

Originally posted by crl:

quote:

Originally posted by Will:
From the recoil of the rifle, the bullet would tend to stay in place (whichever of Newton's Laws is about stationary objects tend to stay that way).

In bolt actions, it is why the front of the magazine gets beat up from the bullets dinging the box. Which is a reason to crimp them so the bullet doesn't get pushed back into the case. Right?

In a double, the opposite will occur in that the bullets would tend to come out as the case goes with the rifle. Of course, the bullet will only come out, if it did, until it hits the rifling. I'm sure some would freak out about a change in COL or the possibility of a round getting stuck in the chamber if the bullet got jammed against the rifling, especially if one round is in one barrel after repeated shots only in the other barrel.

It may never happen but crimping is so easy to do with any RCBS die, why not?

Will,

How do you crimp with any RCBS die. I have a full length resize and seating die for my 470 NE but I am not clear on how to crimp with "any rcbs die". I would like to start crimping my rounds.

Crl

There are folks probably better quualified to explain this, but ...

After you seat the bullet, you back out the seating "thing" (plug or whatever it's called on the top of the die) essentially all the way. Then very carefully run the round up into the die until the round just touches the die at the neck. Once you get the knack of it, you can feel the die crimping the case on the bullet.

Just go slow as it only takes a feather touch. If you over do it it will crush the case. Then you have gone too far!

Thanks. That is what I was thinking but wanted to make sure.

Clark

crl

As I posted above. Send in a case with a bullet seated and have Lee make you up a crimp die. A roll crimp for a double rifle is the least prefered crimp from everything I have read. Also I change bullets which means setting up the RCBS dies each time too crimp. With a Lee crimp just run the case up and crimp, so simple.

quote:

Originally posted by 475Guy1:
ozhunter, does your friend have a chrono? Would be interesting to see if his velocities are up with the rounds uncrimped vs crimped ones. I've found that crimped rounds burn the charge cleaner and give me the velocities that I want.

We both use chronographs and find more even velocity's without a crimp.
I find that if every case is not the exact length the crimp can vary slightly.
Can this be a problem?
PS; After every shot fired with about six rounds total I would check with calipers one round that I had in the unfired barrel which showed no movement.
We did this test on a few occasions.

Well, you seem to have a very good handle on things. Differing case lengths basically come into play when crimping. Since you guys have no problems, knock on wood, as you know what you're doing.

quote:

Originally posted by ozhunter:

quote:

Originally posted by 475Guy1:
ozhunter, does your friend have a chrono? Would be interesting to see if his velocities are up with the rounds uncrimped vs crimped ones. I've found that crimped rounds burn the charge cleaner and give me the velocities that I want.

We both use chronographs and find more even velocity's without a crimp.
I find that if every case is not the exact length the crimp can vary slightly.
Can this be a problem?

I am curious as to what you consider more uniform. On any given day my loads (POWDER MEASURED BY HAND EVERY TIME) can vary by 50 fps or more and even more than on the previous day. Sometimes they are close and sometimes they are not. I crimp them all. Not sure that powders or cases, disregarding length, are uniform enough to provide consistently "uniform" velocities. And that ignores all the variations due to ambient temperatrure.

Personally, I'm not worried about it, just curious. If they all hover around a certain desired velocity, that is good enough for me.

quote:

Originally posted by driftwood:
crl

As I posted above. Send in a case with a bullet seated and have Lee make you up a crimp die. A roll crimp for a double rifle is the least prefered crimp from everything I have read. Also I change bullets which means setting up the RCBS dies each time too crimp. With a Lee crimp just run the case up and crimp, so simple.

I called them and there is a six month lead time. I will probably do this but in the short run, I will try the other method.

crl

Ozhunter,
If you do not crimp, on ocassion a bullet will jump and stick in the lands. This occurs when you have shot one barrel a bit and not the other and the unfired bullets moves forward a tad with each shot..When you open the gun the bulles hangs and the case comes out leaving a mess in the chamber..

I had this happen one time on a buffalo hunt, fortunatly I had used a filler and the powder did not come out, so I quickly stuck the case back in and shot both barrels at the bull, it worked that time.

I like to fill a case with powder, I usually like a filler, and I like a crimp..

There is no down side to crimping in my experience so why take a chance?

465H&H

The process I use is to trim all the cases to the same length before loading. This does a couple of things. You have all your cases the same length so you get a uniform crimp and the case mouths are square which may help accuracy. Always be sure your expander is small enough to give a good tight fit when you seat the bullet. I think this is more important than the crimp for constant velocity. I haven’t seen but have been told of cases where crimping (on bullets without a canuller) would not stop the bullets from moving under recoil when there is not enough neck tension. You should chamfer the inside of the case mouth to make it easier to seat the bullet. I also ream the flash hole and remove the burr on the inside of the flash hole.
Bill

quote:

Originally posted by MHC_TX:
Do you need to crimp your 470NE loads for a Double Rifle?

No, never. Crimping in double rifles is a mindless holdover from bolt rifles, and is a waste of time.

I shoot double rifles pretty much exclusively, never crimp, and have never had a bullet move under recoil in shooting what is now thousands of rounds loaded that way.

What IS important is that your expander ball is not too large. Personally, I prefer to simply discard the expander/decap assembly and decap with a hand punch, but the expander can be used as long as it isn't too large - and most large bore flanged nitro dies come with an expander that is way too big. I'd suggest nothing larger than .005" under bullet diameter.

I find crimping DR ammo a needless aggravation, and it does have another downside. In his book "Big Bore Cartridge Load Data Collection", Pierre van der Walt writes:

"Crimping has always been a problem for me on doubles and I see that Graeme Wright, who can be rated amongst the top double rifle cartridge reloaders in the world, is also not a crimping fan for double cartridges. An incorrectly applied crimp can prevent a double from fully chambering the cartridge and closing. Remember they do not have the camming power of bolt action rifles."

Further, in his discussion of the .500 Nitro Express, he states:

"A-Square recommends a roll crimp, but I have not experienced the need. Full length resizing the case leaves the mouth area marginally undersize. After belling and subsequent bullet seating the bullet cannot set back in to the case as the bullet will expand the mouth area more than the case body diameter immediately behind the seated bullet. The only possibility then is that the bullet can pull out of the case under recoil. Neither Neels Ferreira, BASA's .500 Nitro Express expert, nor I have experienced that problem."

Also, the flanged nitros don't have the length limitations of magazine rifle cartridges, so they're long necked, with more contact area to hold the bullet. Barring an oversize expander ball, crimping simply isn't needed.

If you're concerned about it, load some rounds after sizing the cases without the expander ball, seat without crimping, and test it. Mark the head of one round. Alternating rights and lefts, rotate the marked round into the off barrel for each shot, until you've fired 10 rounds with the marked round in the barrel next door, then check for bullet movement. I've done that test many times, most recently I did so on two occasions with a .500/.465. I've never once had a bullet move under recoil.

I agree with ozhunter. I've found extreme velocity spreads consistently lower without crimp.
---------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."

Sometimes I wonder if we all live on the same planet.

quote:

(whichever of Newton's Laws is about stationary objects tend to stay that way).

Actually, it's objects that are in motion stay in motion, not objects at rest etc.

Just given you a hard time Will.

I thought everything was in motion; stationary just means in the same motion as another object. Before anyone starts complaining about continental drift whiplash, be assured that some things "appear" to be stationary.

No crimping for doubles. I'm on the same planet as 400 Nitro.

Never needed to crimp my 500/450. But, the original expander ball for my .350 No. 2 left the neck too big and the bullet fit too loose so I had RCBS make up a new die.

Key seems to be to get as close to a quarter inch of bullet head into the case neck as possible. I had tried to seat my .350 No. 2 out to maximum OAL (3.69 inches), but the head looked and felt too shallowly seated. A look at some original Rigby ammo showed OAL well under maximum length, seemingly with the object of putting .25 inch of the head into the case neck. So I now seat about a tenth of an inch or even a little more under the maximum cartridge OAL.

Regards

When I started loading for a double I read the Graeme Wright book Shooting The British Double. His opinion seemed to be Crimping came about in the old days when people used to shot a lot from just one Barrel and leaving the same round in the other Barrel. This would cause it to move. As far as he was concerned you could take it or leave it with the crimp. IF you where working a load decide whether you wanted a crimp or not and keep it that way.

He explains crimping with the seater die pretty good.

I worked up my load with a crimp, but did try shooting 10 rounds through the right with an un crimped round in the left Barrel. After shooting it was the same length as loaded.

I was reading Graeme Wright's Shooting the British Double Rifle last night (which should be more descriptively called Reloading for the British ...).

It is the 2nd edition, where he has changed his mind about crimping, as now he thinks it is a good idea.

Ha!



I know whereof I speak.

Will,
I used to think the same thing, but this thread has clarified that for me, apparantly we do not all live on the same planet.

I turn my expander balls down .004 to .005, I use a case full of powder and a dacron wad if needed, I trim my cases in a file trim die, and I had a bullet jump and stick in my .470 on a buffalo at 20 yards, and near got me in trouble, but I had a filler in the case that held everything in place, and stuck the case back in the chamber with another round and fired both barrels..It was a truly eventful experience...guess I will continue to crimp the living crap out of those cases.

All of the rounds used to regulate the new rifles being built today are crimped.

To avoid any regulation and or reliability problems you should definitely crimp. To my way of thinking, better safe than sorry.

I use a Lee factory crimping die. It does a great job.