Nosler Partitionin a 243

Colonel Plink

One of my manuals has big ol' letters warning against using boat tail data for the partition. But only in 243. Similar loads in the 257 Roberts (+P) have no such warning. Why is that?

gunnut505

Which manual, and what year?

62fuelie

Probably the longer bearing surface of the partition bullet may be enough to raise pressures higher than desired.

perry shooter

Federal Loads that exact bullet in one variation of ammo I have been using it for over 30 years in Valmet Model and 115 grain in 25-06 Both have never failed me.

Colonel Plink

quote:Originally posted by gunnut505
Which manual, and what year?


It's an older (mebbe 10 years) Speer #13.

quote:Originally posted by 62fuelie
Probably the longer bearing surface of the partition bullet may be enough to raise pressures higher than desired.
That makes sense. I also wondered if the jacket not covering the base of the bullet might cause it to open up slightly like the old style soft lead bullets. I know, long shot, but it had occurred to me.

navc130

What they are probably saying, is that caliber reload, with that bullet caused excessive pressure in their labratory testing. Reason unknown or not reported.

Mobuck

I would agree that the possibility of the longer bearing surface plus the open base causing increased pressure is real. At the time the manual was published, the .243 100 grain partition was the smallest caliber produced. It's quite possible that softer jacket material had to be used to allow proper extrusion/swaging of the jacket. In addition, the 243 Win with a 100 grain bullet has a lot of bullet inside the case. If pressure caused the base of the bullet to swell while still inside the case, things could get ugly very quick.

243winxb

Two cores separated by a bulkhead (partition). The bulkhead being thicker/harder than lead will raise pressure when compaired to a conventionallead core. This should apply to all cartridges, not just the 243 win.

Colonel Plink

Thanks for all the replies. There's a world of knowledge running around this place[:)]

laylandad

What page are you on? I have looked and am not seeing this warning. I load both the 100gr Speer BTSP and Nosler Partition's. Just wondering if I should alter my loading procedures.


It's an older (mebbe 10 years) Speer #13.

quote:Originally posted by 62fuelie
Probably the longer bearing surface of the partition bullet may be enough to raise pressures higher than desired.
That makes sense. I also wondered if the jacket not covering the base of the bullet might cause it to open up slightly like the old style soft lead bullets. I know, long shot, but it had occurred to me.
[/quote]

Colonel Plink

quote:Originally posted by laylandad
What page are you on? I have looked and am not seeing this warning. I load both the 100gr Speer BTSP and Nosler Partition's. Just wondering if I should alter my loading procedures.



page 174. I just looked at it again and it actually says to NOT use Boattails with the Partition data. Now I'm wondering if I just read it wrong... dunno. I don't have any such warning in the Lee book I have.

RCrosby

Are we dealing with the earlier Noslers that had "relief groove" turned adjacent to the internal partition? Just wondering if that might be a factor???