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Bullets with a cannalure ?
- Thread starter rebs
- Start date
firewrench044
New member
Pistol bullets, NO ( they need to be crimped to
close the belling on the case )
Rifle bullets, the difference is very small
noticeable at and above 300 yards
Competition rifle ammo will not be crimped
The crimp itself adds another variable to
the ammo and therefor is avoided
(I do not crimp my hunting ammo even if the bullet
has a cannalur)( If the neck tension does not hold
the bullet, I have done something wrong )
But there are those that crimp everything (rifle)
close the belling on the case )
Rifle bullets, the difference is very small
noticeable at and above 300 yards
Competition rifle ammo will not be crimped
The crimp itself adds another variable to
the ammo and therefor is avoided
(I do not crimp my hunting ammo even if the bullet
has a cannalur)( If the neck tension does not hold
the bullet, I have done something wrong )
But there are those that crimp everything (rifle)
buck460XVR
New member
Pistol bullets, NO ( they need to be crimped to
close the belling on the case )
While this is true, there generally is no cannelure on pistol bullets, only those intended for revolvers, to help prevent bullet jump under recoil. In rifles, most of the time, the use of cannelured bullets is to prevent setback in tubular mags. In both of those situations, I doubt very much if there is any significant impact on accuracy if one is using a jacketed bullet of decent quality. The result of a bullet jumping crimp or being setback would have more of an impact.
You can ignore the cannelure on any bullet altogether. However, the cannelure itself has nothing whatever to do with accuracy. The only part of a bullet that matters is the base.
Match bullets don't have 'em because crimping is detrimental to accuracy. Has to do with overcoming the crimp and throwing the kilter off. Think least resistance.
A crimp isn't required on anything but heavy recoiling cartridges, those used in lever actions and a taper crimp only on pistol cartridges. That's not about closing bells though. It's about headspace.
Match bullets don't have 'em because crimping is detrimental to accuracy. Has to do with overcoming the crimp and throwing the kilter off. Think least resistance.
A crimp isn't required on anything but heavy recoiling cartridges, those used in lever actions and a taper crimp only on pistol cartridges. That's not about closing bells though. It's about headspace.
Not according to Sierra. They say to avoid match bullet distortion, period. It's how the whole dispute with Lee that appeared in their advertising got started after Lee came out with the collet crimp die.
Everything is about degrees. Very small errors at the base have big effects on group size. Noses tolerate a lot more error, but not an unlimited amount. Harold Vaughn show this by filing slants on noses and bullet bases. A 45° slant on a nose produced about the same error as a degree of slant on the base, IIRC. In the case of crimping a match bullet, if you move the center of gravity off center by a thousandth of an inch, you wind up with drift away from the mean POI of about a foot in 600 yards in a typical rifle. That's the sort of thing that's being avoided.
That said, both Sierra and Hornady seem to be pretty good with rolling cannelures into bullets, and number of their bullets with cannelures can shoot cloverleafs from the right rifle.
Everything is about degrees. Very small errors at the base have big effects on group size. Noses tolerate a lot more error, but not an unlimited amount. Harold Vaughn show this by filing slants on noses and bullet bases. A 45° slant on a nose produced about the same error as a degree of slant on the base, IIRC. In the case of crimping a match bullet, if you move the center of gravity off center by a thousandth of an inch, you wind up with drift away from the mean POI of about a foot in 600 yards in a typical rifle. That's the sort of thing that's being avoided.
That said, both Sierra and Hornady seem to be pretty good with rolling cannelures into bullets, and number of their bullets with cannelures can shoot cloverleafs from the right rifle.
m&p45acp10+1
New member
I will only crimp rounds that go into a tube magazine. Others are seated without crimping. If a cannulure is there I ignore it.
Stats Shooter
New member
I only have experience with a few different cannalure projectiles and all of them are from hornady. The 130 grain SST's for my .270 win, the 150 grain Spire point for my saiga.308, and the 55 grain BTFMJ for my AR.
The SST's will print same hole groups at 100 yards cold bore on a calm day. The spire points are around an Moa which is pretty good for a Red Dot sight on an AK. And the 55 grain fmj's are good in my 1:9 twist carbene length but crappy in my 1:8 twist 20" bull barrel.
And I just made a 1/2 moa load using federal fusion bullets with a cannalure.
Bottom line, if it is a factory cannalure from a good company on a tried tested and true bullet, they are likely not a problem at all. If it is a home made cannalure or a new product, I'm skeptical.
The SST's will print same hole groups at 100 yards cold bore on a calm day. The spire points are around an Moa which is pretty good for a Red Dot sight on an AK. And the 55 grain fmj's are good in my 1:9 twist carbene length but crappy in my 1:8 twist 20" bull barrel.
And I just made a 1/2 moa load using federal fusion bullets with a cannalure.
Bottom line, if it is a factory cannalure from a good company on a tried tested and true bullet, they are likely not a problem at all. If it is a home made cannalure or a new product, I'm skeptical.
I've always been under the impression that the cannelure in a rifle bullet is there to prevent or minimize any further expansion of the bullet upon impact. If you routinely seat your bullets close to the rifling often the cannelure is way ahead of the mouth of the case, depending on the length of the throat in that rifle.
In a revolver, the cannelure IS for crimping because we don't seat the bullet with respect to the distance from the rifling.
Have I been misunderstanding this all these years?
In a revolver, the cannelure IS for crimping because we don't seat the bullet with respect to the distance from the rifling.
Have I been misunderstanding this all these years?
The partition in the jacket between the base and the front portion of the decades old Nosler Partition design makes for a pretty positive expansion limit, but the amount most bullets peel back from the nose is much more dependent on terminal velocity than anything else. Nosler has lots of photos of that on their site. A number of designs have jackets that get thicker below the cannelure, and that might give the impression the cannelure is controlling expansion when it isn't. Measure cannelures and look at manufacturer tested COL's and you'll find the cannelures coincide with the case mouth at those COL's. There are even bullets with two cannelures for different chamber or case lengths they are commonly used in. Cannelure's are just a way to allow a crimp to be made that grips the bullet without distorting it.
Yes, several companies, hornady included, used to tout the cannelure as a means of mechanical core retention. I don't know when the first canellure was used, but it was obviously helpful with the heavy reconciling large bore single shots, the tube magazines, and eventually the gazillions of military rounds that were turned out and crimped for increased reliability in storage and handling. Then commercial ammunition was created with crimps for the same reason, to lock that bullet into place so that nobody could knock it loose.
I believe that most commercial bullets had them for appearance, they would have looked funny without them. Then along came Sierra, who was probably the first influential company to forego the crimp groove, and boy, what a shock it was to see it.some people got excited about them just because of the way they looked.
Honestly, I'd guess that lots of people depend on them just to set seating depth. It's probably a lot easier than using a yardstick or tape measure.
I believe that most commercial bullets had them for appearance, they would have looked funny without them. Then along came Sierra, who was probably the first influential company to forego the crimp groove, and boy, what a shock it was to see it.some people got excited about them just because of the way they looked.
Honestly, I'd guess that lots of people depend on them just to set seating depth. It's probably a lot easier than using a yardstick or tape measure.
It's funny to think a cannelure would do much to the core. Subsequently Hornady came out with the Interlock and a line of bonded core bullets, which implies the cannelure approach wasn't working.
I've got a few 173 grain M1 Ball bullets from the 1920's and 30's with cannelures. The 173 grain M1 Type bullet used in M72 National Match ammunition and in M118 Match (not the newer LR with 175 grain MatchKing bullet) is identical except that it has no cannelure. I don't know what year that omission of the cannelure was introduced or if it preceded M72 in earlier NM ammunition. I have the impression from Hatcher that they originally just tested lots of M1 Ball bullets and selected the most accurate lots for NM ammunition, but don't actually know.
I've got a few 173 grain M1 Ball bullets from the 1920's and 30's with cannelures. The 173 grain M1 Type bullet used in M72 National Match ammunition and in M118 Match (not the newer LR with 175 grain MatchKing bullet) is identical except that it has no cannelure. I don't know what year that omission of the cannelure was introduced or if it preceded M72 in earlier NM ammunition. I have the impression from Hatcher that they originally just tested lots of M1 Ball bullets and selected the most accurate lots for NM ammunition, but don't actually know.
I've always been under the impression that the cannelure in a rifle bullet is there to prevent or minimize any further expansion of the bullet upon impact.
No, sorry, that is not why it is there. It MAY do that (limit expansion), but the reason it is there is so the case can be roll crimped on the bullet, if desired.
I don't know when the first canellure was used, but it was obviously helpful with the heavy reconciling large bore single shots, the tube magazines, and eventually the gazillions of military rounds that were turned out and crimped for increased reliability in storage and handling.
A cannelure and crimp is for REPEATERS. It does NOTHING in a single shot rifle. Rifle rounds are crimped to withstand the battering that happens in magazines and during the feed cycle of semi and full auto firearms.
Tube magazines put both recoil forces and spring pressure on the bullet. Heavy recoiling magazine rifles can batter the bullet, and semi and full auto arms slam rounds into feed ramps and chambers at high speed, so a good crimp makes sense for these situations.
Also, the bigger the bullet in these cases, the more important the crimp becomes. There is a significant difference in the inertia between a 55gr .224" slug and a 500gr .458" one!
In a single shot, none of these matter. There are no rounds in the magazine to be battered during recoil, and the feed system is pretty gentle (one, by hand, slipped into the chamber) compared to repeaters.
I crimp (and crimp well) .45-70 loads for a Marlin lever gun. Loads for my Ruger no.3 and my Contender, I don't crimp at all.
Stats Shooter
New member
Question was about accuracy
The question was about the cannalure's impact on accuracy . Not the purpose of a cannalure.
Anyway, as I said the factory applied cannalure bullets I have tried seemed to shoot well. I don't crimp them despite the cannalure. I have been able to get sub moa out of bullets with cannalures that I have tried from hornady, Sierra , nosler, and federal. So if there is a difference, it is at distances beyond 1000 yards, or it is so slight I didn't notice.
Most likely, if it is a factory installed cannalure, and you have poor results, it is the crimp you tried, or that your rifle doesn't like that bullet size,shape,weight etc.
As an aside, when I first started hand loading I crimped 200 rounds for my AK, about half of them required me to force the bolt closed as I pushed the case shoulder out trying to get a good crimp ...and luckily that was on a "loose" ak chamber. On a good bolt gun or my AR-10 I would have been pulling bullets and re-sizing cases.
The question was about the cannalure's impact on accuracy . Not the purpose of a cannalure.
Anyway, as I said the factory applied cannalure bullets I have tried seemed to shoot well. I don't crimp them despite the cannalure. I have been able to get sub moa out of bullets with cannalures that I have tried from hornady, Sierra , nosler, and federal. So if there is a difference, it is at distances beyond 1000 yards, or it is so slight I didn't notice.
Most likely, if it is a factory installed cannalure, and you have poor results, it is the crimp you tried, or that your rifle doesn't like that bullet size,shape,weight etc.
As an aside, when I first started hand loading I crimped 200 rounds for my AK, about half of them required me to force the bolt closed as I pushed the case shoulder out trying to get a good crimp ...and luckily that was on a "loose" ak chamber. On a good bolt gun or my AR-10 I would have been pulling bullets and re-sizing cases.
Last edited:
buck460XVR
New member
I've always been under the impression that the cannelure in a rifle bullet is there to prevent or minimize any further expansion of the bullet upon impact
This would seem to be counter-productive since the cannelure thins the jacket, thus if it did anything to expansion, one would think it would cause the bullet to expand more or separate at the point of the cannelure. Most expansion in jacketed bullets is controlled by the thickness of the jacket. As for the cannelure holding the lead core in the gilding metal jacket, cannelures are so shallow they probably don't even distort the inside of the jacket, thus no holding/gripping properties. The cannelure is for one thing....to roll crimp into. Again, in those applications where one needs a cannelured bullet, impact on accuracy is a moot point.....because you need the cannelure. In applications where you don't need the cannelure, and you want the best accuracy possible, one still probably will have to try both in their particular firearm to see.