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For bolt-action rifles, do I have to crimp a case at the bullet's cannelure? If I want to adjust the depth of the bullet's seating into the chamber (e.g., 10-20 thousandths from the lands or touching the lands), can I crimp the bullet with the cannelure extending outside the mouth of the case? If there is no cannelure, Is there any guideline on how much (percent?) of the bullet has to be inside the case?
 

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The answer is yes but I would recommend a collet style crimp die (such as the Lee Factory Crimp Die) when doing this as opposed to the 'roll' crimp on many seating dies.

I often seat bullets farther out than the cannelure and use a collet crimping die.

Is there any guideline on how much (percent?) of the bullet has to be inside the case?
Not really - but enough to where the bullet seats square in the case mouth and it is held snugly and doesn't get moved or knocked out!
 

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NO, the cannelure is only there for crimping, something I never do on rifle ammo.
 

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The Hog Whisperer (Administrator)
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There's rarely any reason to crimp bolt gun ammo at all. If you want to play with it, go ahead.
 

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Is there any guideline on how much (percent?) of the bullet has to be inside the case?
No guideline but the start of the rifling and magazine length determines Overall length. You can't 'jamb' a bullet past the start of the rifling but you can stick a bullet in the throat, so back-off a few thou so you don't dump powder all in your rifle. I've never done that, of course. :cool:
 

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Great answers above!! I'll just add a bit,... Lee Factory Crimp Die is my go to die if a roll crimp is not needed. No cannelure required, both jacketed and lead. But, you have to be careful not to ask for TOO MUCH CRIMP from this die.

I prefer a little crimp on my bolt gun loads, just for a little more tension consistency, because I don't get too deep in the weeds concerning neck dimensions that effect neck tension, which I believe is a good practice for UN-CRIMPED cartridges.

As for SEATING DEPTH,... I learned a very long time ago, so long ago I forget which reload book it was,... that, seating as close to the diameter of the caliber was recommended highly!
So, for ought6 / 308 caliber, seating close to the ball park of .308" inches is what I try to keep in mind when trying to adjust my seating depth for a chamber I want to try something different with. Trying different Seating depths has helped me get better long distance groups with a couple of rifles, I have had to deal with. Doing such was not my more enjoyable loading experiences, your tolerance for such, may be different.:cool:
 

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.......... Is there any guideline on how much (percent?) of the bullet has to be inside the case?
As Shooter444 said, the bullet generally needs to be as deep (or more) inside the case as the diameter of the bullet. You can play with that some. Imagine seating a .308 bullet only .2 deep. I wouldn;t do that.
 
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Great answers above!! I'll just add a bit,... Lee Factory Crimp Die is my go to die if a roll crimp is not needed. No cannelure required, both jacketed and lead. But, you have to be careful not to ask for TOO MUCH CRIMP from this die.

I prefer a little crimp on my bolt gun loads, just for a little more tension consistency, because I don't get too deep in the weeds concerning neck dimensions that effect neck tension, which I believe is a good practice for UN-CRIMPED cartridges.

As for SEATING DEPTH,... I learned a very long time ago, so long ago I forget which reload book it was,... that, seating as close to the diameter of the caliber was recommended highly!
So, for ought6 / 308 caliber, seating close to the ball park of .308" inches is what I try to keep in mind when trying to adjust my seating depth for a chamber I want to try something different with. Trying different Seating depths has helped me get better long distance groups with a couple of rifles, I have had to deal with. Doing such was not my more enjoyable loading experiences, your tolerance for such, may be different.:cool:
I think that you either misread or your recollection of what you think you read is slightly in error.

The old rule was to avoid seating a bullet to a depth that was less than the diameter of the bullet, not to seat it to a depth equal to the diameter. The idea being that if a bullet was seated too short you wouldn't have enough neck tension.
 

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No "guide line" either really. With light for caliber bullets (LCB) I seat them where they shoot the best, which in the case of the 58 grain Vmax in my .243 varmint rifle is just over 1/2 caliber using the "naked eye" method of measuring.

A certain 788 in .223 shot 55 grain bulk Winchester bullets (with cannelure) very well with the cannelure well out of the case, say "two widths" of the cannelure roughly.

Most crimping is done to prevent bullet movement during rough handling say for a semi or full auto or for a revolver.

My 2¢

RJ
 

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As for SEATING DEPTH,... I learned a very long time ago, so long ago I forget which reload book it was,... that, seating as close to the diameter of the caliber was recommended highly!
So, for ought6 / 308 caliber, seating close to the ball park of .308" inches is what I try to keep in mind when trying to adjust my seating depth for a chamber I want to try something different with. Trying different Seating depths has helped me get better long distance groups with a couple of rifles, I have had to deal with. Doing such was not my more enjoyable loading experiences, your tolerance for such, may be different.:cool:
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Maybe what I wrote above in bold, wasn't clear enough. So, allow me,... seating as close to caliber diameter, as possible,... either deeper, or, a little less.
 

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The Hog Whisperer (Administrator)
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Seat the bullet where it 'want's to be seated. Generally, I suspect that seating as long as the throat/magazine will allow, minus a bit, will normally yield the best results.... but your gun will tell you if it matters at all. Listen to the gun, not the gun rags ;)
 

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For bolt-action rifles, do I have to crimp a case at the bullet's cannelure? If I want to adjust the depth of the bullet's seating into the chamber (e.g., 10-20 thousandths from the lands or touching the lands), can I crimp the bullet with the cannelure extending outside the mouth of the case? If there is no cannelure, Is there any guideline on how much (percent?) of the bullet has to be inside the case?
No, you do not have to crimp the bullet in a bolt action rifle. It is recommended that you leave enough bullet in the neck to equal the diameter of the bullet, but I have seated bullets out a bit further than that with no adverse results in some cartridges. I prefer inside neck diameter to be around .0015 to .002 under bullet diameter for most rifle cartridges and that should be plenty to keep a bullet from moving in the case. In my opinion, any more than .002 under bullet diameter and the bullet is just going to act as an expander anyway, and I think bullets make poor neck expanders possibly causing other problems. YMMV
 

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Hello all New here Old everywhere else ; February will mark 54 years reloading and still retain all extremities (y)

It's generally considered unsafe to load a projectile in a brass case , less than 0.050" under the projectiles diameter .

Most certainly Never do so in a semi or full auto . IMO
 

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NO, the cannelure is only there for crimping, something I never do on rifle ammo.
Have to agree with JBelk. If you want to apply a crimp, regardless of style, that's what the cannelure is for. Applying any kind of crimp onto a bullet with smooth sides is only going to distort the bullet and be detrimental to accuracy. There have been tons of tests over the last 40 years on crimping and how it affects accuracy, and from what I've seen crimping does NOT improve accuracy in any way, but will ruin it quite readily. I can't tell you how many guys I've seen spend a lot of time working up a good accurate load, then destroy all their work by crimping the damn bullet.
 

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Keep in mind that rules of thumb are just starting points. The old Cal 30 M1 Ball bullet (has a cannelure) and National Match M1 Type (same bullet but without cannelure) has a bearing surface (the full-diameter cylindrical part) that is less than a caliber long (about 0.27"), and the M1 Ball cannelure is just 0.2" forward of the heel of its boattail, so seating it a caliber deep would be meaningless. M2 Ball bullets have the middle of their cannelure 0.25" forward of the base, so the same applies to them. They just barely make the caliber-0.05 rule by seating until the front of the cannelure is level with the neck, but, it is worth noting bother the 0.20" and 0.25" seating depths on the first two and last bullet type, respectively, allow it to run through machineguns and BARs and other fully automatic weapons without a hitch. For bolt gun magazine feed, unless you are working the bolt really fast, you are unlikely to stress it that hard. So, if you single-load your bolt gun, there are essentially no requirements beyond what shoots.

Middleton Tompkins told a class I took that he uses soft seating. This is in single-loading guns; mainly Palma match rifles. Soft seating starts with the case neck so lightly sized that you can push the bullet deeper with your fingers. The bullet is loaded sticking out further than will meet the throat, and when the bolt is closed it completes seating against the throat. He said he loaded that way for himself and his whole family, and between himself and his wife, Nancy Gallagher-Tompkins and her two daughters, they probably have more international Palma and related match gold medals than any other family on the planet. Mid said the one drawback to this method is that if a ceasefire is called on the line and you have to unload a round, you need need to point the muzzle up and extract slowly to catch the case before powder spills into the action because the bullet is usually lightly jammed into the throat. You also need a cleaning rod or a short length of brass dowel to drop into the muzzle to knock the bullet loose.

Anyway, the bottom line is you do what works for the kind of shooting you are doing. Seating a bullet about a caliber into a case mouth or to its cannelure, which is where the manufacturer will have tested it, is often a good starting point from which to begin experimentation. The one caveat to that is that if you are going to experiment with bullets touching the lands, keep in mind that practice raises peak pressure, so you want to find your baseline load doing that to avoid a pressure surprise from starting further back and working forward. In that case, Berger's procedure makes sense to follow. But where you will land for best accuracy, nobody knows ahead.
 

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For bolt-action rifles, do I have to crimp a case at the bullet's cannelure? If I want to adjust the depth of the bullet's seating into the chamber (e.g., 10-20 thousandths from the lands or touching the lands), can I crimp the bullet with the cannelure extending outside the mouth of the case? If there is no cannelure, Is there any guideline on how much (percent?) of the bullet has to be inside the case?
The simple answer is NO, but it may depend on what cartridge/bullet combination you are shooting and other factors. If you consider shooting very light weight bullets (say, 110 gr. in a 30-06), you are not going to have as much bearing surface with the case neck as you would with a 150 or 180 gr. bullet. This might require crimping, but you'd just have to experiment to see whether this combination works satisfactorily in your rifle without crimping. As some have noted already, crimps do not do anything to improve accuracy and will actually degrade accuracy. Further, case life is shortened by crimping since you are doing extra work on the mouth of the case. Crimps are generally thought necessary to prevent bullets from being pushed into the case (think tubular magazine rifles), or from working out of the case due to recoil (think revolvers). But, these are NOT absolute certain rules. I have conducted experiments and tests with my 94 Winchester in 30 W.C.F. (a/k/a 30-30) and have determined that I do not need to crimp the bullets for my rifle. I wrote about this in the following forum thread:


However, I did not follow what would be considered the 'standard' loading procedure. I did not expand the entire neck using the expanding button found on most sizing die decapping rods, but used a separate neck expanding die and only expanded as much of the neck as needed for the bullet based on the depth I wanted to seat it. This left an internal ridge in the case neck right where the base of the bullet was, and this ridge prevented any possibility of the tubular magazine spring and rifle recoil from causing the bullet to be collapsed into the case. You will just have to test for yourself and may have to get creative in your loading process.
 

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An interesting experiment. Thank you. I suspect the physics of this has some unique-to-system elements. If you have a heavy recoiling tubular magazine gun (some of M.L. McPherson's experiments with hot 45-70 loads, for example) and especially if you are down to the last couple of rounds in the magazine, inertia will cause the magazine spring to compress against those rounds during recoil, and it then will slam them back against the bottom of the carrier channel as it expands again. Everything hinges on how hard that slam is as compared to seating force. An extended magazine, with its longer spring may make that worse. But trying it out, as you did, is the way to determine that for your gun and loads.

As to crimps worsening accuracy, that is a can of worms. In the '90s, when Lee came out with their Factory Crimp Dies they got into a running argument with Sierra that played out in the two companies' advertising, about whether it could improve accuracy, as Lee claimed, or would worsen it by distorting the bullets, as Sierra claimed. The latter idea is based on long standing experience with how difficult it is to roll a cannelure into a bullet without unbalancing it at least a little, which is why match bullets typically don't have one. But some folks did and still do report accuracy improvements using the LFCD.

In the end, Lee started putting into their ads that their LFCD could improve accuracy with everyone's bullets except that it wasn't recommended for Sierra's bullets, in particular. Just everyone else's. The whole thing was pretty childish and wasn't resolved by test examples. It was all about claims.

So, what's a person to believe. You do see some folks, with some guns, post reports of accuracy improvement when crimping with the LFCD. In the end, it is going to come down to what the dominant limitations are on accuracy in your shooting system. The added start pressure could certainly make some powder charges shoot more consistently and perhaps tune them a bit as to barrel time in a direction that would randomly be better in some guns and worse in others. The bullet deformation would be a bad thing in a short bearing surface bullet because of the potential to upset the base, but, if uniformly crimped and not overly deep in a longer bearing surface bullet where the crimp is kept well clear of distorting the base, the distortion could be insignificant to some kinds of guns and shooting. It will reduce the bullet BC a little and not perfectly uniformly so I would be pretty hesitant to even waste ammo testing it at long ranges. But when you are talking about 100 to 200-yard eastern woods hunting ranges and 2 moa guns, it may well provide a net improvement as the imbalance effect on groups could then be on the order of only a couple of hundredths of an inch, and more consistent ignition could improve a 2 moa gun by more than that. So there is no fixed answer, alas. It's just something else that has to be tested at your intended range, with your particular weapon, just like so much else.
 
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I am not an educated ballistician, but, I find it hard to believe that an evenly applied crimp indentation has any more negative effect on bullet flight, than a factory cannelure,... and, I find it even harder to believe, a crimp indentation has more negative effect than the deep and wide, multiple lube grooves, on cast boolits.

But, like I said,... I am no ballistician.
 
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