Difference between JHP and XTP?

[Marco Califo]

So, just how many angels can dance on the head of a pin?

I agree. We/me were talking about JHP's, XTP's, and expansion in water jugs. I like running rabbit trails in the weeds as much as my dog. IMO You guys refined this into nothingness. Back to the topic at hand, I previously attached photos of my Berrys Hybrid Hollow-point Expansion test, where the 0.356" bullet expanded to 0.777" here:
https://thefiringline.com/forums/sho...d.php?t=615677

[tjmga]

armoredman
I think you said it all. When changing components, start at a reduced load and work up.

[Marco Califo]

"Microsoft's "A.I." research option:
"Hornady XTP bullets and JHP (Jacketed Hollow Point) bullets are both types of handgun ammunition. The main difference between the two is that XTP bullets are designed to expand upon impact, while JHP bullets are designed to penetrate a target1."

That is the problem with AI. It is sometimes, false, out of context or non-sense.
JHP bullets are designed to expand on impact. They are NOT a penetration phenom. They are designed to limit (over) penetration.
The other big problem with AI is that if the "user" is an idiot, they can easily reach wrong conclusions, and potentially rely upon them with adverse consequences.

[Unclenick]

AI just looks at what is said on the web without really understanding it. I wouldn't be surprised if it found information on the last three decades of development of 9mm HPs that penetrate better than the Silvertip JHPs at the famous FBI Shootout in Florida did and misinterpreted that to mean expansion wasn't one of the JHP objectives. That is if it got that far. It could also just be quoting some uninformed web "authority." Keep in mind how much ignorant stuff is posted in the mountains of "information" generated by gun control groups every year, and then remember the AI looks there for answers to your questions, too.

[Sevens]

This is even more of an issue with the .454 Casull. Note that Hornady makes an XTP and an XTP-Mag. The reason is the jacket is thicker in the "Mag" for use in higher velocity handguns. Freedom Arms will suggest the use of their bullets for that reason without explaining it.

Ben Amonette, ballistician formerly of ATK explained it to me clearly when I asked for help with .460 S&W Magnum at the bench. The XTP-Mag bullet is a more robust design that will prevent a lesser-constructed bullet from going out-of-round in the high pressure violent transition from cylinder to forcing cone at potentially 65,000 PSI. The forces on the base of the bullet attempt to turn it in to an ellipse and the XTP-Mag bullet is designed with protection of the forcing cone in mind.

[armoredman]

Now that I didn't know.

[Metal god]

I always love the conversations on wording , terms and acronyms . Where's Guffey when you need him ? I'm sure he could have cleared this up in just 5 pages of post , 6 infractions and 20 post being deleted

COL and COAL "should" be two different acronyms . Just like headspace and case headspace are two different things - oh snap!

As to JHP and XTP , interestingly enough even Hornady had/has two different meanings for there XTP . To be fair the old XTP clearly has a different design then the new style so That explains why they called the old XTP a flat point (FP)

Old 38cal - 158gr FP-XTP




Compared to the newer 38cal 180gr XTP




Hornady is known to change there titles of things . Like the comparator that used to be called



Which they now call a headspace comparator removing the word cartridge .

So both the above bullets have holes in the tips and neither is formally called a HP by Hornady lol

[Unclenick]

MG,

C.O.A.L. And C.O.L. are different. You can tell because one has three letters and the other has four. The confusion stems from the fact their definitions are the same.

If anyone has old Riflemen or load books written before the Korean war, you find the four-letter version to be universal. Today the load manuals overwhelmingly use the three-letter version. It's OK, as long as you don't confuse their shared definition with that of headspace.

I think the real difference between the JHP and the XTP is the former is a physical description of bullet construction and the latter is an exercise in commercial branding.

[Metal god]

Posts: 20,846
MG,

C.O.A.L. And C.O.L. are different. You can tell because one has three letters and the other has four. The confusion stems from the fact their definitions are the same.

Oooh double snap !! Haha

Ha ….ha….haha…. He said headspace ha :-)

[Marco Califo]

Ha ….ha….haha…. He said headspace ha :-)

Headspace is room on a boat for a toilet.

[jetinteriorguy]

Originally Posted by Marco Califo

Headspace is room on a boat for a toilet.

Good one.

[cdoc42]

I have always labeled my handloads, "OAL-OG" which I interpret to me at a later date or to those looking over my shoulder, as, "OverAll Length to the Ogive.

I recognize AMP44 would argue about the use of Ogive in this instance, but I have since read about a description of seating depth of one of the shooting journals that doesn't disagree with what we apparently all understand it to imply.

[44 AMP]

I recognize AMP44 would argue about the use of Ogive in this instance,...

44AMP just enjoys a good argument!

My main issue is that using the phrase "to the ogive" is too vague, and is not clear that what you are referring to is the point on the ogive where your bullet contacts the rifling in your rifle, the way you measured it.

I think Uncle Nick did a great job of illustrating that point in his drawing. The ogive is clearly identified on the bullet (showing the entire length) and on the cartridge identified as "ogive overall seating length from bullet comparator".

I see a difference there, and I think it should be reflected in the terms used in technical discussions.

I also think Uncle Nick nailed it. JHP is a physical description of the bullet construction. XPT is a Hornady name for one of their lines of bullets.

Of course, I come from a place where Pluto is still a planet and rabbits are still in the rodent family, so, there is that....

[ballardw]

Originally Posted by cdoc42

I have always labeled my handloads, "OAL-OG" which I interpret to me at a later date or to those looking over my shoulder, as, "OverAll Length to the Ogive.

One definition that seem appropriate for ogive: (from Wikipedia)

An ogive is the roundly tapered end of a two-dimensional or three-dimensional object.

So, when I receive a round labeled "OAL-OG" , just where on the curve do I go to measure that OAL? What do I compare it to so I can tell if it is appropriate for my chamber/throat/barrel?

[stagpanther]

These two bullets are the same thing.

[Marco Califo]

No. One is a JHP the other is an Open Tip Match. One is designed to expand. The other is hell on paper.
I do not like Ogives on my pizza.

[44 AMP]

They are the same thing. Until the description moved beyond the most simple basics.

They are both bullets. SO, at that level, the same thing.
They both have jackets and hollow points. SO, again, at that level, they are the same thing.

go beyond that description, they are different things.

[Unclenick]

Yes. This created quite a fuss in the military. The AG had to issue a special opinion that match bullet HPs were non-expanding in order for the M316 mod O sniper ammo loaded with the 175-grain SMK (which Sierra developed with the military for the purpose) to be issued. Previously, the old M852 match ammo with the 168-grain SMK was labeled not-for-combat and had the not-for-combat case knurl near the base out of fear the HP would violate the Hague Accords, regardless of how it actually performed. There was an incident in the Iraq war when a commander refused to let snipers have their ammo because of the hollow point and because she was unaware of the AG's determination.

[cdoc42]

ballardw: "So, when I receive a round labeled "OAL-OG" , just where on the curve do I go to measure that OAL? What do I compare it to so I can tell if it is appropriate for my chamber/throat/barrel?

If you are using exactly the same bullet as I have labeled "OAL-OG", you need to tap it into YOUR rifle to determine where that bullet engages the rifling. Then you make a dummy round that has the bullet seated such that it engages the rifling as did the bullet alone. You measure that dummy round from the base of the case to the bullet's ogive (i.e., point on the curve where it had engaged rifling). THAT is the OAL-OG for that bullet in YOUR rifle, which most likely will differ from MY measurement in MY rifle.

Only once in 47 years of handloading did I find 2 equal rifles. One was my Browning A-Bolt in .22-250 and another Browning A-Bolt in .22.250 owned by a friend. When I worked up a load for his rifle, the OAl-OG for both, using the same bullet, was exactly the same.

[Unclenick]

Originally Posted by ballardw

just where on the curve do I go to measure that OAL?

There is no correct answer. These kinds of measurements are always comparative rather than absolute. So it can be anywhere along the ogive as long as you use it to compare seating die settings for the same bullet. The Hornady tool, the RCBS Precision Mic, the Sinclair hex tool, and others you can find all have holes that touch the ogive of a bullet at a particular diameter that their manufacturer chose. For example, both Hornady and Sinclair have their own caliper adapters that thumbscrew onto a caliper jaw for making comparative measurements. The Hornady brand caliber-specific measuring inserts are made of aluminum. The ogive contact holes in them have a bead-blasted finish to eliminate sharp edges, as aluminum would not be hard enough to maintain its diameter if it had sharp edges. But the Sinclair insert is stainless steel, and it it tougher, and the hole is drilled to imitate the angle and diameter of a chamber throat. So where the Hornady tool contacts a bullet a little further up the ogive, the Sinclair catches it where an actual chamber throat would. So does their hex tool, BTW. I prefer that approach because it lets me put bullets with different ogive profiles very close to the same distance off a gun's chamber throat, whereas an insert catching the bullet higher up will not necessarily catch a different profile the same distance up from the bullet shoulder's contact point for figuring bullet jump.

Here are measurements I made of 15 150-grain Sierra MatchKing .308" bullets using both the Hornady and Sinclair inserts. These are from the bullet bases to the ogive contact point of both comparators on the same bullets, though I had a mixup while measuring such that while they are the same 15 bullets, they are not in the same order in the columns. You will see their consistency is very close, though the Sinclair does slightly better on standard deviation, likely due to the different tooling having slightly different ogive radii and even slight shoulder variations. The Hornady tool meets the ogive at an average of 0.5240" above the base, while the Sinclair meets it at 0.3800" above the base.