Proper Sized Case Dimensions?

[07Kingpin]

Looking for a proper inner neck dimension after sizing.

Virgin Starline cases measure .448 inner diameter.

Fired cases measure .458 and sized cases are .443.

I understand I will be expanding the neck at charging but this seems like a lot of neck tension.

Using a Lee FLS die.

Sorry if this has been covered I'm used to loading bottleneck cartridges.

[Texas Sheepdawg]

Specs are in the Hornady loading manual. I don’t have mine on hand at the moment.

[Hoot]

Simply put, this caliber craves neck tension like no bottleneck I've ever loaded for. IMHO, forget physical dimensions (within reason). The narrower, the merrier. This particularly important with smooth sided bullets like the 250 FTX. If it didn't headspace off the case mouth, you could crank down on the crimp, but it does. Over the past 10 years, members have struggled to get adequate neck tension, stopping just short of gluing the bullets in.

Take whatever inherent tension that you can get, as long as the bullets start when you go to seat them. That's one of the reasons that Hornady dies reign supreme. Their seating die aligns the bullet so that it starts easily even though it doesn't perch inside the mouth. No need for the expansion die as long as you chamfer the inside of the mouth.

In over 2500 reloads, IIRC, I've crunched one case. Even then, it was during my experiment with the Tight Neck Tension project chronicled within this sub-forum. That's where we tried pre-loading the case tension using a 45 LC sizing die to impart an even narrower section down the case as far as the bullet went inside. Now those were some narrow mouths! We got away with it thanks to the Hornady seating die alignment feature. Forster and a couple other premium die sets use a similar bullet alignment system. IMHO, Lee made a mistake cutting that corner to keep their cost down.

Hoot

[Al in Mi]

IIRC, a year or so ago didn't Lee have a issue with not sizing down enough to get enough bullet tension ?? Sounds like they fixed it, maybe a hair too much, but you might be able to get away with partial rezizing.

I just measured one of my fresh fired cases from the 16" Bushey, fired ID is .456, resized .448. That was with a Hornady sizer. I'm also blessed with a Hornady expander that doesn't expand the ID at all, just use it to add a touch of flare.

[Texas Sheepdawg]

Simply put, this caliber craves neck tension like no bottleneck I've ever loaded for. IMHO, forget physical dimensions (within reason). The narrower, the merrier. This particularly important with smooth sided bullets like the 250 FTX. If it didn't headspace off the case mouth, you could crank down on the crimp, but it does. Over the past 10 years, members have struggled to get adequate neck tension, stopping just short of gluing the bullets in.

Take whatever inherent tension that you can get, as long as the bullets start when you go to seat them. That's one of the reasons that Hornady dies reign supreme. Their seating die aligns the bullet so that it starts easily even though it doesn't perch inside the mouth. No need for the expansion die as long as you chamfer the inside of the mouth.

In over 2500 reloads, IIRC, I've crunched one case. Even then, it was during my experiment with the Tight Neck Tension project chronicled within this sub-forum. That's where we tried pre-loading the case tension using a 45 LC sizing die to impart an even narrower section down the case as far as the bullet went inside. Now those were some narrow mouths! We got away with it thanks to the Hornady seating die alignment feature. Forster and a couple other premium die sets use a similar bullet alignment system. IMHO, Lee made a mistake cutting that corner to keep their cost down.

Hoot

I wished this were true of my seating die. I must always use just a hair of expander die on my cases. I’ve dwarped a few cases just trying to seat without first expanding. It Never fails. So I just add a tiny little touch of expander die on all my brass.

[07Kingpin]

Thanks for the replies and the good info.

I'm going to try a few loads using jacketed bullets before I start experimenting with cast lead- will update with results.

[Hoot]

Thanks for the replies and the good info.

I'm going to try a few loads using jacketed bullets before I start experimenting with cast lead- will update with results.

Given the wealth of experience available here using jacketed bullets, that's a wise choice. There will be plenty of time for experimentation.

Hoot