I was loading up some Hornady 68 gr OTM bullets and was comparing them to the Grafs repackaged 250 count with a cannelure that I just received.  I noticed a significant difference in the bullet length.  The non-cannelured are ~0.980" while the cannelured are ~0.924".  Did Hornady make a change or is the cannelure version shorter?  I did confirm the Grafs were 68 grains.

That short one almost looks like a 62 grain version!

We had a similar thread here not long ago... I think the round was shortened when the cannelure was added. I have some of the non-cann from about a decade ago and they are longer than new production.
Attached File

Thank you!

In March I sent an e-mail to Hornady Support asking about the OAL of their 22 Cal .224 68 gr BTHP Match™ with cannelure
Item #2278C due to many sources saying they measured 0.980" and mine were all in the 0.920" range.

This is what they said:

Robert the COL of the bullet is 0.917 +/- of 0.005. Thanks

I did not ask what the non-cannelured OAL of item# bullets #2278 or 22785 or 2278B (all 68's without cannelure)

Interesting.   I tried the longer 68 gr version in the past and it was a bad experience.  Their original length doesn't fully stabilize in a 1/9 twist,  which the whole reason I bought them - was for my 1/9 BBLs.  It took me a while to figure out why my 1 MOA 1/9 BBLS were shooting 3 MOA and my 1 MOA 1/8 BBLs ran just fine with these.  Then I ran a stability calculator, and sure enough- not stable.


But the new 68 gr short profile I bet will run just fine in a 1/9.

I e-mailed Hornady Support again yesterday and I got some more information:

Thank you for the email. The over all length of the bullets are different. The 2278B is 0.986" and the 2278C is 0.917"

So the cannelured and non-cannelured versions of the 68 grain HPBT have different OAL's.  I find that bizzare, but there it is....

So then, do they have different data for each?

No they don't.  Nor do they tell reloaders about the differences unless they ask.  A shooter with a 1-9" twist barrel will find the non-cannelured version marginally stable at best. Whereas the cannelured version will work fine and fully stable.

That is bizzare; great information though.  Thank you for the follow-up!

What would worry me is that when seated to the same OAL, you would have different case capacities, and therefore different pressure curves.

These aren't pistol cartridges, the OAL length has very little to do with pressure differences.
Alot of manuals group bullets of several grains difference in their data, so some length would not matter.
How do you know:
-they HAVE to be seated at the same OAL?
-even if you did, how do you know the capacities would be different?

Load data indicates a cartridge OAL

If there is less bullet in the case, there will more capacity or space.

Not really........ Load Data gives a recommended OAL.

We know that both bullets weigh the same: 68 grains.
What you don't know (and wouldn't unless you carefully loaded both bullets exactly the same and then measured them exactly) is how much of the bullet is actually
seated inside the case.
In other words you seem to be assuming that whatever dimensional differences there are between the two is resulting in the bullet seating deeper in the case, but you have no way of knowing that.
         
But regardless:  These aren't pistol cartridges, the OAL length has very little to do with pressure differences.
                       Alot of manuals group bullets of several grains difference in their data, so some length would not matter.


PS:  I'd be more concerned with the Stability questions others have raised and the BC changes (depending on what you use these for) between the 2.

The original 68 grain match bullets were basically Hornady's 75 grain bullet with less lead in the core. Bullet lengths, 68 v. 75, were very nearly identical.

They always shot well for me, but I use 1/7 to 1/8 twist barrels when shooting them. 24.2 grains of VihtaVuori N140 was my load when using the older style bullets seated at 2.250".

Lots of people complained they couldn't get them to group in their rifles. I suspect they were running 1/9 twist barrels.

If one bullet is longer than the other, but both are seated to the same OAL, the longer bullet will be seated deeper in the case.  I am no physics prof,  but this is obvious.

Good to know that pressure isn't an issue tho.

I never found success with the Hornady 68 gr,  the Sierra 69 gr shot great all the time.  
I shot them in 1/9 1/8 1/7 uppers.  Varget should have been magic.  

Now the 75gr would shoot decent with TAC.

You would be one of what??  Which 68 grain Hornady bullet did you try??  2278, 22785, 2278B (all without cannelure) or 2278C with cannelure.

Hornady Item# 2278C OAL is 0.917
Hornady Item#'s 2278, 22785, 2278B OAL is 0.986

And you might ask why does that matter?? It matters because of stability, and stability affects accuracy.

In a 1-9" Twist barrel a Hornady 68 grain #2278C (w/cannelure) @2700 FPS is just stable at 1.528
In a 1-9" Twist barrel a Hornady 68 grain #2278, 22785, 2278B (all wo/cannelure) @2700 is marginally stable at 1.239

Both using JBM Stability Calculator. Stability

As far a misunderstanding internal ballistics, changing the OAL only,  will affect both velocity and accuracy.

I have no idea about pressure since I have no way to measure it, and neither do you.

Well I can tell you it was the long one #2278 in 2004 because the cannelured one (2278C) did not come out until many years later.

I never crimp match ammo and refuse to buy any match bullet with a cannelure.

I haven't purchased any Hornady 68's in over ten years. I bought 10,000 the last time I bought any.

Still have a couple left....

There are alot of things that are obvious here.  
One of them being you are obviously ASSUMING that the back end of each bullet is the same.  
But you have no way of knowing that.  

Is it possible that they removed whatever air pocket there was at the meplat, resulting in a shorter bullet?  Yes, but you nor I don't know that.

But what else should be obvious is the 68grains of bullet went somewhere.  
So you nor I have no idea if, in cramming the same 68grains of bullet in the same diameter, that they changed the dimensions of the back end of the bullet.
It's possible the diameter of the very base of the bullet is wider in the cannelured bullet.
It's possible that the angle of the BT was changed.
It's possible that the shank section isn't as tapered.  
All of these possibilities mean more of the shorter (cannelured) bullet could be "inside" the case, even though the OAL is the same.

I'm not a Physics Prof either but the same 68grains of bullet has to go somewhere and maybe it went to back end.
And since they changed the OAL length pretty substantially, how do we know what else they changed?
You Don't, I don't.

Jacket thickness
Jacket material
Lead core hardness
Bearing surface

A lot of questions unanswered here. Start low, work up, look for low SD's and tight groups

BTW- the boat tail looks identical..

But is it?
Is it a 6 or 9 degree?  How about 12 degrees?

Yes alot of unknowns.  

Maybe someone here should email Hornady again and they will clarify the differences.  
In the meantime, do you want to banter back and forth about minute details that we don't know about?  :)

Well you seem to think you know everything, why don't you email Hornady and clarify the differences.

Hornady Support

I've already e-mailed them twice, and I have what I need to know about the 2 bullets.

Best of luck to you....

Did you look at the picture of both bullets, side by side, that is the gist of this thread?  You are making zero sense.

This is downright dangerous. OAL has a significant impact on pressure, even in rifle rounds.

Physics professor here:

PV = nRT

All the time, in all closed systems.  


The boat tails look identical, for all practical purposes.

The straight shank is shorter on the cannellured version.

What is really hard to just "eyeball" are the ogive shapes.  

Don't measure bullet OAL base to tip, measure base to datum on the ogive.  

Also,  check from the base to the point at which your seating stem contacts the ogive.  


Impossible to just "eyeball" is the empty space internal to the jacket and the jacket thickness differences.  


All the above is only information and of academic interest for reloaders and (IMO) is totally irrelevant if the bullets don't stabilize in your barrel.


Here's the thing I don't like.  If you work up a successful load with the short one (cannelured), then switch to the long one (plain) and they won't stabilize, you would be rightfully unhappy.  They are different and nowhere does Hornady disclose that difference in the information on their web site (I looked).  If the shapes are different, it is not simply the same bullet with/without a cannelure (2278, 2278C).  Hornady reports identical ballistic coefficients but does not report stability factors.  

Is there also a dimensional difference for the 75 gr HPBT-Match bullets (2279, 2279C)?  I was about to buy 4,000 2279C based on having used 2279.  I use 1/8" twists barrels.

These are the various versions of the Hornady 75 gr HPBT-M bullets.  T1 and T1C are almost identical.  T2 is different.

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@Husky629 - Thank you.  You had a good eye to catch this and report it.

sorry for thread hijack.

Reaction kinetics professor here:  It's not a closed system (or at least, not one of fixed volume)

V is dynamic, and a larger ratio of V compared to pistol, and a lower rxn rate generating n, compared to pistol-power as well.  Which is to say the reaction vessel is larger and the rate of gas generation slower, while the bullet itself is lighter.  An additional item is most pistol powder are fast burning chemistry and flake while most rifle powders are engineered to react slower, and are spherical or cylinders.  Meaning the supercritical fluid the rifle powder is immersed in during light off has a lower surface contact in relation to total reactant content, in comparison to pistol powder; and a lower rate of reaction in it's chemical formulation.  And so rifle has relatively less reaction boosting heat-transfer during initial light off, deep into the kernal of gunpowder.  Meaning the bootstrap/runaway behavior reaction is milder.  

Basically all meaning that in a rifle the smaller V resulting (from set-back), still has a relatively much smaller decrease in %V, and that the increase in V from primer explosion and powder burn initiation is a easier to start, with the lighter rifle bullet, allowing the density of the supercritical fluid of the combustion processes to decrease easier, which quenches the heat-transfer into the powder and rate of reaction.  All with powders that don't bootstrap themselves to runaway so readily, as a fast burning high surface area pistol powder in a tiny reaction chamber are more want to do.  FWIW, it's for this reason very fast powders designed for low-P shotgun rounds, like International Clay's are ill-advised in something like high pressure 9mm.  Emmerse that powder in a high pressure supercritical fluid of combustion gasses, and it's going to want to runaway.  Meaning the window of enough power to run, and not so much power to kaboom, is small.  So it runs just fine, until some degree of tolerance stacking is just enough to cause the very fast powder to runaway.

All resulting in the set-back issue being essentially a non-item in most rifles, as my own field activity also appears to afirm so far at least.  



PS (please note smiley faces).

Another aspect is the ogive may vary and one bullet seated off the lands may have another jammed into the lands at the same OAL.  That will definitely cause problems.

On the contrary.  You provided some useful information. And I've always pondered why Hornady has never offered their T2C as a reloading component.

They're are doing some weird stuff over in Grand Island Nebraska......

Thanks.

This is quite funny. I actually came here to post this exact same thing, but then found this thread.
I have a partial box od the hornady 68gr with cann I got from someone a few years ago. They are in a midway blue box and labeled midway repackaged, hornady 68gr with cannelure.
I also have several boxes of the hornady 68gr without the cann and for some reason I just happened to compare the two and found the very noticeable difference in their lengths.
At first, I thought one of them might have the wrong bullets in there, but they both weigh 68 grains.
The ones with can measure .917 long, and the ones without measure .987.

I just thought it was very odd as I have both nosler CC's and sierra SMK's with and without cannelures and they are identical other than the cannelure.

Hornady just isn't providing a real quality product, and hasn't for years. NO ONE competing with them is winning. Hornady always has an excuse and never a solution.

I always gave them the benefit of the doubt because their the local boys, but when they mandated vaccines BEFORE it was an official government mandate, I decided to call a spade a spade.

I competed in high power for 20 years and never did get their free bullets to shoot for shit.

I think you're being a little hard on Hornady.  As BorderPatrol pointed out, Hornady in many ways is IMHO an industry leader on many things right now.  In the past they've had some misses, and very few high-power shooters run Hornady bullets, though their 75 HPBT isn't terrible.  Their aluminium tipped bullets are supposedly doing very well in PRS.  I consider them one of the better value for your $ providers, and they've long had the repuation of the best bulk 55 FMJ bullets; which is of note here in AR15.com as a good cost-effective route to make your best quality ball ammo.  My biggest annoyances with them here today in 2022 is releasing "NEW and EXCITING" calibers, which is getting a bit insufferable in general; at a time nobody can get baseline ammo any more.  How about "NEW and EXCITING" production line expansion to control availability and pricing instead of the rounds people actually use and enjoy?

Anyway, I view Hornady as a baseline cost-effective yet good quality market leader looking toward today and tomorrow, with them embracing 6.5 Creedmoor, and 6.5 Grendel better than most any provider, and IMHO they make the best baseline brass for both.  Sort of Wendy's to Fed/Rem being McDonalds/Burger King.   Yes, I know some people find those two rounds insufferably over-represented.  The reality is, because they're actually pretty great rounds - and by over-promoting them, at least there are standardized next generation rounds everyone can focus on.  Hornady brass in those two tend to be common cost effective and abuse tolerant; though their primer-pockets on Creedmoor do tend to open up I suppose.  Historically their 68 HPBT has (IMHO) been just an awful bullet; but it looks like this new cannular version more closely resembles the 69 SMK profile (which they should have done all along).  

And you're right, the free bullets, are free for a reason. Most of them are targeted towards common-deer hunter 2 MOA is good enough for venison dinner, usage - I suppose.

As to COVID, I'm just out of passion points on some stuff.  Some other companies internal vaccination policy isn't really on my radar right now.

Reloading For The AR-15:  Hornady 75 Grain BTHP






Hornady produces three different versions of their 75 grain open-tip-match bullet in 22 caliber (0.224”). For this article, we’ll be looking at the projectile that is colloquially referred to as the “T1”.





The T1 is available as a reloading component, with a product number of #2279 for the 100 count boxes. It’s also available in 600 and 4000 count boxes.





I use the Hornady 75 grain BTHP bullet to load match-grade hand-loads for my semi-automatic AR-15s chambered in 5.56mm/223 Remington. According to Ballistic Performance of Rifle Bullets by Bryan Litz, the Hornady 75 grain BTHP has an average G1 ballistic coefficient of 0.356 and an average G7 ballistic coefficient of 0.183.

The lot of T1 projectiles used for this article have a nominal length of 0.988” and I load them to a nominal COAL of 2.245”. When fired from a Colt SOCOM barrel with a 5.56mm NATO chamber, this COAL will create a jump to the lands of 178 thousandths of an inch. When fired from a Larue Stealth barrel with a 223 Wylde chamber, this COAL will create a jump to the lands of 115 thousandths of an inch and when fired from a Krieger barrel with a 223 Remington chamber, this COAL will create a jump to the lands of 78 thousandths of an inch.

The jump to the lands figures stated above where obtained using a Sinclair bullet seating depth gauge and a Forster 223 Remington 1.4636” head-space gauge. These figures are contingent upon a variety of variables, such as the particular chamber reamer that was used for your barrel, the number of rounds that have been fired through your barrel when the measurement is obtained, the particular lot of bullets used and whether you use a virgin case, a fired case, a resized case or a head-space gauge to obtain this measurement.







WARNING!

Reloading is an inherently dangerous activity. The information provided here is for educational purposes only. It is not intended to be used for the actual loading of ammunition by the reader. No warranty, guarantee or assurance that these loads are safe is stated, suggested or implied nor should any be inferred. Usage of this information for the actual loading of ammunition may result in malfunctions, damage and destruction of property and grave injury or death to beings human in nature or otherwise. Don't even view this information in the presence of children or small animals.



For this hand-load of the Hornady 75 grain BTHP bullet, I use virgin Lake City brass that has been weight-sorted, match-prepped and neck-sized. The cases are primed with Federal GM205M primers and charged with VihtaVuori N140 powder and as mentioned above, the T1 projectile is seated to a COAL of 2.245”. This process is conducted in a semi-progressive manner on a Dillon XL-650 press using a digital electronic powder dispenser and scale to dispense a powder charge of 24.1 grains of the VihtaVuori N140.













When chronographed from a 20” Colt A2 barrel, a 10-shot string of this hand-load fired over an Oehler 35P produced a muzzle velocity of 2638 FPS with a standard deviation of 4 FPS and a coefficient of variation of 0.15%. (The muzzle velocity was calculated from the instrumental velocity using Oehler Ballistic Explorer.) A 10-shot group fired from one of my Krieger barreled AR-15s, at distance of 100 yards using my bench-rest set-up, had an extreme spread of 0.526 MOA.





No canines were harmed during the testing of this ammunition.












….

I've shot mostly Sierras & Bergers, with a smattering of Lapua & JLKs over the years. The Hornady Match and ELD bullets coming off their machines these days have been very good IMO. I've had great luck with the 80gr ELDm at the 600 yard line this summer and the 88s are looking even more promising from the limited testing I have done with them. Despite what people have said about the 75gr HPBT, they have shot just fine for the short line and I have yet to have one come apart on me.

That being said they do have a stupid number of SKUs and their product line differentation is confusing.

B

Ditto.

Regarding the 75 gr HPBT-M bullet.  Shooting from a rest, I get about 1/2 MOA with Varget and 3/4 MOA with TAC at 200 yards.  Admittedly, my bullets are from a bulk buy from years ago but they are good bullets for the money.  

I do not think they are as good as the Sierra 77 SMK but they don't cost as much as that bullet, either.

Cost is a big factor for me.  I can get Hornady 68 grain HPBT (2278C) w/cannelure for $ .17 cents a bullet right now. The best I can do on Sierrs's 69 grain MK is $ .25 cents a bullet, right now, and most are over .28 cents a pop.

Yes, Sierra is a bit more accurate, but I'm not shooting matches with either bullet.  This my primary HD bullet, and Hornady's accuracy is adequate for my uses.

Hornady is currently the best value IMO. I have always been impressed with Sierra's 69 grain MatchKing, it seems to shoot lights out from any firearm I shoot them through.

Hornady used to sell 600 bullet boxes that were cheaper than 500 from Sierra, a lot cheaper. Occasionally I would get a smoking deal on a bulk purchase in the good old days, 6000 Hornady 52 grain match for $489.00! They make a quality bullet and have kept prices reasonable. Before Nosler was sold, they too had excellent bullets at reasonable prices, not anymore.  

Under new ownership Nosler 1000 bullet boxes immediately jumped close to 33% in price. They are still great bullets, just not cheaper than Sierra's any more.

Hornady didn’t release their 68 grain BTHP bullet with a cannelure (#2278C) until more than 25 YEARS after they released their 68 grain BTHP Match bullet without a cannelure (#2278). Hornady never made any claims that the bullet with a cannelure was the same bullet as the one without a cannelure or that the only difference between the two bullets was the addition of the cannelure and a simple visual comparison of two bullets makes it painfully obvious that they are not the same bullet.

As others in this thread have noted, the bullet with the cannelure has a significantly shorter OAL than the original bullet without a cannelure. The bearing surface of the bullet with the cannelure is shorter than the bullet without a cannelure.  The ogive length of the bullet with a cannelure is shorter than the bullet without a cannelure and the radius of the ogive of the bullet with the cannelure is smaller than the bullet without a cannelure.

The historical complaints of poor accuracy with the original Hornady 68 grain BTHP were largely from people who were ignorant on the subject of gyroscopic stability and thought that they could simply substitute the 68 grain Hornady bullet for the previously released Sierra 69 grain MatchKing bullet because of the similar weight.  They didn’t understand that it was bullet length that was the predominant determinate of the rate of barrel twist needed to adequately stabilize the bullet. Many of these people thought that because the Sierra 69 grain MatchKing was adequately stabilized from their AR-15 that had a barrel with a 1:9” twist rate, that the 68 grain Hornady bullet would also be adequately stabilized from their 1:9” twist barrels, which was often not the case.

For the Sierra 69 grain MatchKing, the recommended twist rate for optimal gyroscopic stability is 1:9.5” or faster.  For the original Hornady 68 grain BTHP, the recommended twist rate for optimal gyroscopic stability is 1:8.2” or faster.  For the Hornady 68 grain BTHP with a cannelure, the recommended twist rate for optimal gyroscopic stability is 1:9.3” or faster.

Hornady’s most recent reloading manual is their 11th edition, which was published in 2021.  Neither this manual nor any of their previously published manuals have listed the 68 grain BTHP with a cannelure.  It is always the responsibility of the reloader to determine the appropriate seating depth.






As to the claims that seating the bullet deeper in rifle cartridges significantly increases peak chamber pressures, there are more factors involved in chamber pressures than just the seating depth of the bullet.  What many people seem to conveniently ignore when discussing seating depths and chamber pressures is that seating a bullet deeper in the cartridge case increases the distance of the bearing surface of the bullet to the lands of the barrel (bullet jump.)  Increasing bullet jump decreases peak chamber pressure in rifle cartridges.  Laboratory studies have shown that the two opposing factors of deeper seating depth and increased bullet jump largely tend to balance-out each other with respect to chamber pressure for small changes in bullet seating depth in rifle cartridges.

....

I believe everything you said above is correct Molon. But the big unanswered question is why?

Here are some of the why's:

Why did Hornady design a whole new 68 grain HPBT??

Why didn't they just roll a crimping grove on the original 68 grain, like they did on the 75 grain??

Why is Hornady keeping it a secret, since it is available to reloaders, and not just ammo makers??

Why not have load data just for it??

Why not have seperate BC data just for it??

And why has the fact that there are 2 totally different 68 grain Hornady HPBT bullets (totally different, and not that one just has a cannelure) for a number of years, has escaped the notice of almost everybody.... (Except you Molon, of course)

TBH, kind of agree.  A bit sloppy to have two different products the market is going to confuse like this.  Call it the 68.3gr, or whatever.  But two differing products with the same descriptor like that, in a world where everyone else' cannular/non-cannular bullets are the same bullets, is one of those "why does Hornady hate people?" moments.

They have the same SKU number as well except the cannelure bullet has a "C" identifier.


68gr HPBT______________SKU 2278 --- 100 count box

68gr HPBT______________SKU 22785 -- 500 count box

68gr HPBT______________SKU 2278B -- 4500 count box

68gr HPBT Cannelure_____SKU 2278C -- 4500 count box  

B

Excellent information as always!  It seems Hornady is a little misleading when they print this.

A true 1:9 results in an SG of about 1.3. Stable enough  for most purposes. However most button rifled barrel twists aren't true, and on the slower side in my experience.

That's interesting that their recommendation would give it such an SG. I have shot some wierd combinations that worked ok back in the day, but knowing what I know now I would never do that.

There is an interesting section in the back of the Sierra 4th edition manual that talks about twist rate and the effect on BC. They fired a bunch of 69 Sierras through various twist rate barrels and measured the BC downrange.

I think they fired them through 12, 10, 9, 8, 7 twists.

The lowest BC was with the 12 twist, but those projectiles were keyholing. 10 twist and up was stable, and as the twist rate increased so did the BC. Sierra described this as being caused by "coning motions" of the bullet tip. They were stable and flying straight through the bullets center of gravity, but nutation at the tip of the bullet caused a comprimise in the BC.

After flying down range for ~ 100 yards, these coning motions would damp out.

B

..."After flying down range for ~ 100 yards, these coning motions would damp out."...

Maybe they do, maybe they don't...

I will readily admit the SG calculations we make are not calculating stability forces or equilibrium. They are just used to parametrically fit the observed data.

It is the case that as you transition from an SG = 1 to and SG = 1.5, that you are in the gray zone where things transition from unstable to stable.

Between SG = 1 and SG = 1.5 , some of the ones with a higher SG that are unstable versus ones with a lower SG that do stabilize for a given twist, are just due to issues like their CG, BC, center of pressure, meplat defects, base or boat tail defects, muzzle crown defects, etc. etc. Even a slight increase in air density can tip the balance on a marginal bullet stability.

What I have seen with this particular bullet is that slow twist may not work out. IMO, they should keep their customers a little farther up the margin scale, but that is just in my opinion. YMMV