Cannelure Affect on Accuracy

[bluetopper]

In short, does a cannelure on a bullet have an adverse effect on accuracy? I'm mostly concerned with .224" bullets. Hornady cannelured 55gr bullets seem to be very plentiful now and are the best buy going but I really want to shoot the best groups I can in my .223 and 22-250 bolt guns.

 

[243winxb]

Barrel twist rate 9-1 in 223.

Do you want a paddle wheel (cannelure) on your bullet when its spinning at 252,000 RPM. No.

[/URL][/IMG] Best for me, Nosler 55gr BT. Hornady 68gr and Sierra 69gr. Berger bullets would be great also, but i am to cheap to pay $$$.

[/URL][/IMG]

 

[rcmodel]

A cannelure is not really a 'paddle-wheel' because there is no laminar air flow in contact with the bullet behind the super-sonic shock wave coming off the bullet tip.
So, there is nothing to 'paddle'.

Besides, very little of the cannelure is left on the bullet jacket after it gets hit in the butt by 50,000 PSI, bumped up to allowable bore size, and engraved by the rifling.

If the bullet is high quality to begin with, and has the jacket opening in the nose?

I doubt you will be able to measure the difference on paper.

Witness GI match ammo, Hornady V-Max bullets w/cannelure, and the .30 & .50 cal GI ammo used by snipers at 1,500+ yards in the sandbox.

What You Really Don't Want is FMJ bullets with the jacket opening in the base.
It is impossible to make them with perfectly square bases so they don't start off wobbling from unbalanced gas pressure release as they leave the rifling crown.

Your best bet is name brand Match or Varmint type HP, or plastic tip bullets.

rc

 

[wankerjake]

I've shot some teeny groups with the Hornady 55gr SP w/ cannelure. They are accurate.

 

[ironworkerwill]

I can shoot better than 4" @ 400yards with 139 gr Horn sp .284 bullets. They have even more ridges than the .224 variety. Other folks could probably do better than that with the same setup.

I wandered the same thing about cannelures. They MIGHT have some effect but I don't think accuracy is one. I've since gone on to fuss about other things.

 

[243winxb]

The cannelure would have to be in a vacuum, a space entirely devoid of matter.

 

[ironworkerwill]

I concede that there is a variable for it on some ballistic calculators

 

[rcmodel]

Maybe so.

But I can assure you it isn't 'paddling' against anything of substance that could effect it's flight, like laminar air flow.

Rc

 

[gamestalker]

I can't discern any difference, but I don't shoot competitively either. Either way, when I'm doing my job, I can get any of my developed loads to shoot under an inch, regardless of a canelure or not. I've had groups just as good from canelured bullets, as what I get with non canelured bullets.

GS

 

[stringnut]

I have never seen any difference. For the reasons mentioned there should be no effect. Also, the bullet gets grooves swaged into it from the rifling, so, no matter what you have a bullet with grooves in it.

 

[Walkalong]

but I really want to shoot the best groups I can in my .223 and 22-250 bolt guns.

Then buy something besides 55 gr FMJ. Almost any, if not all, plastic tip, soft point, or hollow point is going to shoot better. It's all about the base.

You never see a cannelure on a match bullet, but the question is if you and your gun can shoot the difference.

 

[Eb1]

A cannelure is a must to have the bullet act as designed from certain projectiles. I haven't noticed any difference in shooting a 223 for accuracy with cannelured bullets or non-cannelured bullets. I do know that projectiles without will most likely not function as designed if they do not have a cannelure. That is why I prefer the SMK Matchking with Cannelure. Best of both IMO.

 

[steve4102]

You never see a cannelure on a match bullet, but the question is if you and your gun can shoot the difference.

Never say "never".

http://www.midwayusa.com/product/14...7-grain-hollow-point-boat-tail-with-cannelure

http://www.midwayusa.com/product/57...ail-with-cannelure-box-of-100?cm_vc=OBv573016

http://www.midwayusa.com/product/11...boat-tail-with-cannelure?cm_vc=ProductFinding

http://www.midwayusa.com/product/38...ket-boat-tail-box-of-100?cm_vc=ProductFinding

http://www.midwayusa.com/product/66...low-point-boat-tail-with-cannelure-box-of-250

 

[Walkalong]

Well then I stand corrected.

That said, I have never seen, nor will you ever see, a Benchrest shooter using a bullet with a cannelure.

The main point was if you want the best accuracy out of a .223, don't use FMJ.

 

[Steel Horse Rider]

The point of the cannelure is to make room for the casing when a bullet is crimped in the case. There is no reason to use one if you are not crimping. I was always told the purpose of the crimp was two fold One is to keep the bullet in place when shooting in an automatic or high recoil weapon and the other was to allow the pressure to build higher before the bullet leaves the casing. I think both reasons are somewhat theoretical in the real world as .223 ammunition is never going to produce a high recoil and the brass of the casing is not strong enough to hold back the pressures developed during the firing of the round. I think there are plenty of other variables that would affect accuracy far greater for hunting, recreational shooting, or other non-competitive events. Shoot away....

 

[rg1]

Only thing I would add is the consistency of the cannelure. If applied evenly all the way around I wouldn't think it would effect accuracy. IF applied evenly is the point. Not being a long distance or competitive shooter I see no difference in accuracy with cannelured 77 gr. Sierra MK bullets nor any difference in Hornady 55 SP's with and without.

 

[Eb1]

A cannelure also assists in the yawing of the bullet to help in fragmentation of the .223. I think it is a by product, but it does help.

The cannelure is to hold the bullet in place, and help with burning powder.

 

[steve4102]

I was always told the purpose of the crimp was two fold One is to keep the bullet in place when shooting in an automatic or high recoil weapon and the other was to allow the pressure to build higher before the bullet leaves the casing. I think both reasons are somewhat theoretical in the real world as .223 ammunition is never going to produce a high recoil and the brass of the casing is not strong enough to hold back the pressures developed during the firing of the round.

Here is an actual test done by Sierra.

Neck Tension

When we stop to consider the vigorous (read, downright violent) chambering cycle a loaded round endures in a Service Rifle, it becomes pretty clear it suffers abuse that would never happen in a bolt-action. This is simply the nature of the beast. It needs to be dealt with since there is no way around it.

There are two distinctly different forces that need to be considered: those that force the bullet deeper into the case, and those that pull it out of the case. When the round is stripped from the magazine and launched up the feed ramp, any resistance encountered by the bullet risks having it set back deeper into the case. Due to the abrupt stop the cartridge makes when the shoulder slams to a halt against the chamber, inertia dictates that the bullet will continue to move forward. This is exactly the same principle a kinetic bullet puller operates on, and it works within a chamber as well. Some years ago, we decided to examine this phenomenon more closely. During tests here at Sierra’s range, we chambered a variety of factory Match ammunition in an AR-15 rifle. This ammunition was from one of the most popular brands in use today, loaded with Sierra’s 69 grain MatchKing bullet. To conduct the test, we chambered individual rounds by inserting them into the magazines and manually releasing the bolt. We then repeated the tests by loading two rounds into the magazine, chambering and firing the first, and then extracting and measuring the second round. This eliminated any potential variation caused by the difference between a bolt that had been released from an open position (first round in the magazine) and those subsequent rounds that were chambered by the normal semi-automatic operation of the rifle. Measuring the rounds before chambering and then re-measuring after they were carefully extracted resulted in an average increase of three thousandths (0.003") of forward bullet movement. Some individual rounds showed up to seven thousandths (0.007") movement. Please bear in mind that these results were with factory ammunition, normally having a higher bullet pull than handloaded ammunition.

http://www.exteriorballistics.com/reloadbasics/gasgunreload.cfm

So, 223 bullets can and do move, it's just a matter of how much movement one is willing to accept.

 

[Rule3]

A lot more depends on the twist rate of your rifle(s) a heavier bullet wil give you better accuracy. I shoot a lot of the 55 gr Hornadys and they are fine for me and range blasting. But if you step up to a slightly heavier better bullet it may group better for you. Depends on all kinds of things however.

Was that vacuum in space between the shooters ears?


https://www.sierrabullets.com/store/product.cfm/sn/1380/224-dia-69-gr-HPBT-MatchKing

 

[Sunray]

You can ignore the cannelure altogether. The only part of a bullet that matters is the base.
The cannelure has nothing whatever to do with how the powder does anything. It's only there if you crimp. Crimping is only required in heavy recoiling cartridges, lever action and MG's.
"...besides 55 gr FMJ..." Depends on the bullet and the rifle. Certainly avoid milsurp FMJ's though.

 

[blueridgeMTNs]

I am glad someone brought this up. I asked this on another forum probably 2 years ago and someone said they are as accurate as non-cann bullets. I have not tried the Hornady bullets with cann but am going to after the holidays.

 

[Slamfire]

Without factory tests and test equipment this debate is basically philosophical. I am of the opinion that anything that changes the center of gravity for a bullet will cause a decrease in bullet accuracy. Deforming jackets will (back to philosophy) change the mass distribution, whether this is measurable in our firearms, I really doubt it. The Juenke machine is used by some to measure jacket thickness and concentricity and only costs $1850 for a modern version. http://www.bulletinspector.com/vern_juenke_history.htm Because the equipment is so expensive, data on just how out of balance factory bullets are has not reached the general public, and so these debates are based on concepts only.

I have not asked any of my long range National Champ buds whether any of their bullets have cannulures, because everything shows up at 1000 yards, but I am of the opinion that none do. Cannulures are fine in lever actions, elephant guns, etc, most of which still place bullets inside the shooter’s hold. I don't remember if any of my 223 Hornady match bullets have cannulures, but regardless, I have shot lots of High Master scores with the things, and I only had to hold 2 MOA to do that. If you think that is easy, come out to an XTC match sometime.

 

[Walkalong]

I am of the opinion that anything that changes the center of gravity for a bullet will cause a decrease in bullet accuracy.

I agree, and that is why they use the best jackets for match bullets. Best being defined by how uniform the thickness is.

 

[X-Rap]

I don't know what the OP's accuracy requirements are but for the difference in the Hornady bullets he mentions and a Ballistic Tip or higher quality bullet than that I think he will benefit from having more rounds to shoot than any measurable group size unless he is in an elite class of shooter with above average equipment.
I load some premium bullets but for my every gun load that shoots in pretty much everything from a 14" Contender to a 26" Savage I'll take the Hornady with a cannelure every day.

 

[Steel Horse Rider]

Steve: If the bullet in an AR cartridge moved that much just from being chambered I wonder how the .30-06 bullet is moved in a cartridge fired from a Garand? I am pretty sure the forces and mass of the M-1 in operation far exceed those in the .223 round in an AR, but then I am not a scientist, just a recreational shooter.