Bullet test medium?

[Oldbloke]

I'm only comparing the characteristics that are likely to determine terminal performance.

[JohnV]

I'm only comparing the characteristics that are likely to determine terminal performance.

You have lost me . A Nosler Partition is in no way comparable to a cup and core as far as terminal ballistics go .
The Speer bullet I quoted is close to what you are making .

[Oldbloke]

"I don't think you can really compare an Interlock or Partition bullet with a cup and core flat base or with a boatail bullet"

John, im not comparing them with nosler petitions overall perfomance. The idea was very simply get an idea if the jacket and core (of bullet 1) are physically similar to most hunting bullets.
Since the jacket and core does more or less fit a hunting bullet it gives me confidence that it should work ok on game.
Not in the slightest interested BC or flight ballistics.

[JohnV]

Well as I said before the cores plural in a Nosler partition and its H mantel jacket are not anything like what you or I make so the terminal ballistics will have no real comparison . You are on the wrong track to understand the bullet you are making .
Your bullets and some of mine are very close to the Speer 130 grain HP flat base in construction ( cup and loose core ) flat base with a generous meplat and a fairly moderate ogive curve . I can't see your bullet properly to judge the ogive shape or whether it is tangent or more secant . Only a heat solder core bonded bullet can be compared to a Nosler Partition in terminal performance because of the way the bonding works and the fact the core expands forward to fill the ogive during point forming and is not bonded , so it acts on impact like a Nosler partition . The front expands but the rear stays intact . Chemical bonded bullets are far more unpredictable as to how exactly they are made . Some have the whole core boned some may not .
I have shot stacks of game over the decades with standard cup and core bullets our average soft skinned game does not require anything more fancy . I only ever fired bonded bullets at a real big pigs or something bigger again .
I have taken Fallow deer with an 80 grain 243 cup and core bullet and it dropped like a stone .

[bladeracer]

"I don't think you can really compare an Interlock or Partition bullet with a cup and core flat base or with a boatail bullet"

John, im not comparing them with nosler petitions overall perfomance. The idea was very simply get an idea if the jacket and core (of bullet 1) are physically similar to most hunting bullets.
Since the jacket and core does more or less fit a hunting bullet it gives me confidence that it should work ok on game.
Not in the slightest interested BC or flight ballistics.

Does the hardness of the copper alloy of the jacket play a significant role in deformation? The Partition designs try to separate the front and rear of the bullet, the front being left "soft" to allow it to deform and increase in diameter, the rear being "hard" so it stays together, including remaining attached to the deformed front part of the bullet, to maintain mass and punch deeper into the medium being struck. Some of the copper or brass designs deliberately break the front part up so it separates into shards that spread through the flesh doing extra damage, but leaving the main part of the bullet reduced in mass restricting its penetration ability - but copper/brass bullets already have significantly less mass than lead of similar size. I do feel that an engineered copper/brass bullet is likely to perform more consistently than a bullet built around swaging a lead slug into a drawn copper cup.

I personally don't want to be reliant on a bullet performing perfectly upon hitting and travelling through very different mediums, I think that is too much to ask of it. I prefer to rely on accuracy and placing the bullet where it will do the job regardless of how much deformation it might experience.

Don't ignore BC entirely, it dictates how quickly velocity is lost from the bullet, and velocity dictates how the bullet performs upon impact. Under perhaps 50m it's probably insignificant, but at longer ranges it might matter.
For example, a 150gn Hornady RN (BC.186) versus a 150gn SST (BC.415), both launched at 2800fps.
At 50m they're down to 2538fps and 2679fps, probably insignificant for how the bullet behaves upon impact.
At 100m they're down to 2287fps and 2563fps - nearly 300fps difference is starting to matter I think, especially if you aren't launching them as hard as 2800fps.
At 150m they're making 2050fps and 2448fps, 20% more velocity. If you launch them at a more moderate velocity you're getting close to where the manufacturer might state that it's hitting its expansion threshold. The wind drift is not that significant unless you're shooting foxes - 125mm and 55mm in a 10mph crosswind but it could play a role in how well you can place your bullet on the target. Having higher BC is rarely a bad thing.

On the other hand though, a big blunt meplat may well be a very significant advantage in bullet performance regardless of the reduced velocity, especially when making holes larger than .30-cal.

[JohnV]

Jacket hardness does play a part in a bullets terminal ballistics and also bullet swaging . That is why heat solder bonded bullets are better because they are not only bonded below the ogive they are also well annealed . A soft jacket it tougher than a hard brittle jacket that could just split . The drawback is slightly increased copper fouling but most people would not use many and I just moly coat them and that fixes that . I am not interested in monolithic bullets so I don't know much about their in field performance .