Marco Califo
New member
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.
I do not like Ogives on my pizza.
Difference between JHP and XTP?
- Thread starter Prof Young
- Start date
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.
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.
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.
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.
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.
ballardw said:
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.