Necking up 6.5mm to 7mm via fireforming- dumb idea?

[rimfiremac]

I have a pile of 6.5-284 cases I need to neck up to straight 284. That's a 0.5mm or 20 thou (inch) diameter increase, and likewise a 60 thou increase in circumferential length. I know that an option is to send away to Sinclair for an expander, twiddle thumbs for a few weeks, pay customs duties, postage, tax, and then finally for the price of more than half a box of Lapua brass, I'll have an expander that may or may not yield doughnuts.

If I were to alternatively fireform the brass with my 'in stock' shotgun powder/ tissue per established practice, are there any benefits/ risks/ criticalities to that choice? Would immediate annealing be recommended after forming? Note that I do not have fireforming experience at this time. Trying to chart the waters safely.

 

[elkhuntr]

I have up sized 243 win to 260, and visa versa, 308 to 243. So no real issue unless your brass is well used and the potential for cracking has increased. I would anneal the brass prior to sizing to help with the process if it were well used brass. Worst thing is you'll try one case and find out if it works or not. If you create donuts....drink coffee. But seriously, just size and outside neck turn into the shoulder a little bit then those pesky donuts will be history.

Sizing up will not allow you to create a false shoulder and that is why I try to neck down where possible. Necking down appears to eliminate donut creation as well. Just FL size and go for it. My two cents. Elky.

 

[jfarrell]

I just upsized from 6.5 X284 Lapua to straight 284. I used a K&M mandrel window riser with the press adapter and the complete 277 mandrel first then the 284 with Imperial lube. You can get all the supplies from RRRRPPPPSSS international in BC

 

[358Rooster]

Before my .284 Redding dies arrived from Sinclair, I bought a Hornady 7mm neck die from our local shop and expanded the necks on all my Lapua 6.5-284 brass. Worked like a charm. Hornady's long, tapered expander button makes it so it's barely noticeable going through the press. Imperial sizing wax is your friend.

Rooster

 

[NormB]

I have a pile of 6.5-284 cases I need to neck up to straight 284. That's a 0.5mm or 20 thou (inch) diameter increase, and likewise a 60 thou increase in circumferential length. I know that an option is to send away to Sinclair for an expander, twiddle thumbs for a few weeks, pay customs duties, postage, tax, and then finally for the price of more than half a box of Lapua brass, I'll have an expander that may or may not yield doughnuts.

If I were to alternatively fireform the brass with my 'in stock' shotgun powder/ tissue per established practice, are there any benefits/ risks/ criticalities to that choice? Would immediate annealing be recommended after forming? Note that I do not have fireforming experience at this time. Trying to chart the waters safely.

If you have a collet bullet puller die, Tightly hold a long 7mm bullet with its base in a 7mm collet. Screw die/bullet combo in press. Lube inside the necks with lanolin, Run the cases up over the 7mm bullet and presto .284 brass.

NormB

 

[rimfiremac]

Before my .284 Redding dies arrived from Sinclair, I bought a Hornady 7mm neck die from our local shop and expanded the necks on all my Lapua 6.5-284 brass. Worked like a charm. Hornady's long, tapered expander button makes it so it's barely noticeable going through the press. Imperial sizing wax is your friend.

Rooster

Bingo, this is a piece of equipment I have! The thought of doing just that crossed my mind, but I hadn't been convinced that it would work correctly. Thanks for the suggestions all

 

[nanuk]

I just fireformed a factory 270win, in a 35Whelen chamber

one pull and presto, 35whelen brass.

using bullseye, and COW works very well too

as to annealing, I've heard it both ways... yea and nay

if you have a way to anneal, it can't hurt. I'd anneal before fireforming.

 

[358Rooster]

Bingo, this is a piece of equipment I have! The thought of doing just that crossed my mind, but I hadn't been convinced that it would work correctly. Thanks for the suggestions all

Yup, just debur the inside of the necks (the Lapua stuff is usually pretty good to begin with but I like to put a small chamfer on it anyway), spin a Q-tip lightly in the sizing wax and just 'wet' the inside of the case mouth and give 'er! Probably the easiest operation you'll perform in handloading.

Rooster