Why 44 xtp 300gr has two canulars???

They don't anymore!

At least not the last box I bought. Bums me out a bit as I was loading the at the longer OAL, taking advantage of the added powder space. Some revolver cylinders allow this, some dont. My Ruger Redhawk certainly does

I assume that reducing the jump to the forcing cone would be of some accuracy advantage as well. I have no real evidence of such a thing though.

I did some searching after discovering that my latest box of bullets only had one cannelure. Sounds like that might be the new norm based off internet hearsay.

44 Remington Magnum and 444 Marlin.

Keyfer 55 said:

Never saw any load data ? w296/h110 ???
Would it cause unsafe pressure? For 44 rem.

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Check out the Hodgdon website and go to their Reloading Data Center page and select your Caliber(44 Rem Magnum) bullet weigh(300gr) and then select the powders you are interested in( W296/H110).

http://www.hodgdonreloading.com/data/pistol

mcb said:

44 Remington Magnum and 444 Marlin.

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This is a widely passed rumor, but I’ve never found it to be true. Hornady will tell you this, directly, but when you ask - then why do the COAL and Case length in your manual correspond to seating in the SHORT cannelure? - they don’t have an answer.

What I do find coincidental, however, if the second cannelure is meant for the 444marlin, why does it JUST HAPPEN to place the front of the bullet right at the front of a Ruger Super Blackhawk cylinder? The second cannelure doesn’t seem to correspond to anything other than the Ruger cylinder length...

So I load my 300 XTP’s to the second cannelure and stoke an over-book load of H110/W296 under them, which results in about 100-150fps more than the book-max load, and does so with lower pressure.

I have a C-H cannelure tool and place the cannelure where I want on several bullets. As Varminterror states, it reduces pressure in hot loads.

Varminterror said:

This is a widely passed rumor, but I’ve never found it to be true. Hornady will tell you this, directly, but when you ask - then why do the COAL and Case length in your manual correspond to seating in the SHORT cannelure? - they don’t have an answer.

What I do find coincidental, however, if the second cannelure is meant for the 444marlin, why does it JUST HAPPEN to place the front of the bullet right at the front of a Ruger Super Blackhawk cylinder? The second cannelure doesn’t seem to correspond to anything other than the Ruger cylinder length...

So I load my 300 XTP’s to the second cannelure and stoke an over-book load of H110/W296 under them, which results in about 100-150fps more than the book-max load, and does so with lower pressure.

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Sometimes a company will do things an never admit they do it. The long cannelure is no doubt for loading 44 Mag longer than SAAMI OAL but they can't admit that without opening up liability issues. This might be why they have removed that long cannelure that someone up thread indicated.

mcb said:

Sometimes a company will do things an never admit they do it. The long cannelure is no doubt for loading 44 Mag longer than SAAMI OAL but they can't admit that without opening up liability issues. This might be why they have removed that long cannelure that someone up thread indicated.

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Which is also a very popular rumor...

How many products does Hornady produce for handloaders? How many made for wildcatters?

I can’t think of the last firearms owners manual I read which did not call against use of handloads. The Hornady manuals call out the same absolution of liability for use of their products and data...

I have shot them in my 444 marlin seated in the 2nd canelure. Gives a bit of extra case capacity. I do the same thing with my 357 maximum with the 180 XTP which also has two cannelurs. In fact when I had the barrel made I requested the throat length specifically so I could do that.

Years ago someone asked Hornady why they had the two cannelures and were told it was to facilitate production....whatever that means. If you look at them the lower cannelure is the same distance from the base as the 240, which would allow it to be run on the same machinery and also provide a good reference point should someone want to load to the same internal case volume. Of course the 300 is longer so they then added a second cannelure which is the same distance from the nose so you can load them to the same OAL as the 240 if whatever you're shooting is length sensitive.

I think there might also have been some thought to the impact behavior and adding a second cannelure would help to prevent core separation so that might be another factor. But as others have mentioned....there's a LOT of conjecture and wonderment as to exactly WHY they have/had them. I kind of like the option of loading to the same internal volume or length which can be very useful for the experienced handloader.

I swear that somewhere in my memory banks I stashed away that the lower cannelure was for use in long cylinder revolvers such as the Super Redhawk, and Freedom Arms .44 Mags...

Crimping in the lower cannelure facilitated more powder, and/or less pressure depending on charge...

There are also cast molds with two crimp grooves for this same use...

Interesting thing to note, the lower crimp groove is in the right location to use .44 Spl brass, seated to .44 Mag length.

Same is true for 180/.357 bullets in .38 Spl brass.

GarrettJ said:

Interesting thing to note, the lower crimp groove is in the right location to use .44 Spl brass, seated to .44 Mag length.

Same is true for 180/.357 bullets in .38 Spl brass.

View attachment 785245

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Interesting, wonder if the same is true of the 45 cal 300gr XTP/MAG between 45 Colt and 454 Casull? It also has two cannelures

The old Barnes #42921 200-grain XPB bullet is intended for use in the .44 S&W Special cartridge. The cannelure position and design of the X-cavity on the #42921 bullet are tuned specifically for the .44 S&W Special, while the #42920 bullet is intended for use in the .44 Remington Magnum cartridge.

mcb said:

Interesting, wonder if the same is true of the 45 cal 300gr XTP/MAG between 45 Colt and 454 Casull? It also has two cannelures

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When did that start? I’ve loaded thousands of the 300grn XTP mag 45cal’s and none have a second cannelure.

Varminterror said:

When did that start? I’ve loaded thousands of the 300grn XTP mag 45cal’s and none have a second cannelure.

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The 45 cal 300 gr XTP/MAG version has just one cannelures, while 45 cal HP/XTP has two. I use the XTP/MAG version in my 450 Bushmaster and the HP/XTP in my 58 cal muzzle loader with sabots.

Varminterror said:

When did that start? I’ve loaded thousands of the 300grn XTP mag 45cal’s and none have a second cannelure.

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I don't know. I do know XTPs had two cannelures in the mid-90s when I started loading .45 Colt for my Blackhawk. I got away from loading heavy 300s for a long time. But these 300s I bought last fall also have two crimp grooves. I could not say if Hornady dropped the second one in the mean time.

mcb said:

The 45 cal 300 gr XTP/MAG version has just one cannelures, while 45 cal HP/XTP has two.

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And there you go. I never even thought to check how many versions they make.

What’s the gap between the cannelures? That would tell you if it were meant to load 45colt at 454c length or not. Or maybe 45schofield cases at 45colt length.

Varminterror said:

What’s the gap between the cannelures? That would tell you if it were meant to load 45colt at 454c length or not. Or maybe 45schofield cases at 45colt length.

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The two cannelures are .082" apart on the .45 XTPs.
Spacing is .145" on the .44 XTPs.

Like I mentioned earlier, my last box only has one cannelure.

The box on the left is a year or more old. The ones on the right I got at a LGS a few weeks ago.