Kevin Stenberg
Well-Known Member
I need to make some 7/08 brass. I can either squeeze down 308's, or stretch 243's. In the long run which would be better? Yes I could trade for what I need but that would add to the expense.
Resizing brass
- Thread starter Kevin Stenberg
- Start date
I used to make 25 Souper brass from 243 brass, rather than 308. Very slight necking up with no neck wall thickness or concentricity issues. One pass on new brass, trim for the sake of consistent lengths and done. Granted, it's only a .0014" (combined) bump, not .041", but it may still be the easier of the two choices.
Shoulder starts at the same distance from the base on both. Increasing the diameter of the neck seems like it would automatically account for the difference in the bases to necks. I'd take a chance of a couple 243s and see how it works out with one pass through a 7mm-08 die - if your neck expander will fit into the 243 mouth.
Shoulder starts at the same distance from the base on both. Increasing the diameter of the neck seems like it would automatically account for the difference in the bases to necks. I'd take a chance of a couple 243s and see how it works out with one pass through a 7mm-08 die - if your neck expander will fit into the 243 mouth.
Kevin Stenberg
Well-Known Member
Definitely anneal.
Spindrift
Well-Known Member
One advantage of necking down, is that you can control head-space from the first firing, by correctly adjusting your regular FL die.
If the shoulder position on some of your donor brass is a little to far back, your FL die will simply form a small "false shoulder" at the base of the neck, on which the cartridge will head-space. This ensures a healthy distribution of the brass flow at fire- forming.
I use this technique for instance for an out-of- spec, long .30-06 chamber; I expand the neck to 8mm, then down again with a carefully adjusted FL die.
If the shoulder position on some of your donor brass is a little to far back, your FL die will simply form a small "false shoulder" at the base of the neck, on which the cartridge will head-space. This ensures a healthy distribution of the brass flow at fire- forming.
I use this technique for instance for an out-of- spec, long .30-06 chamber; I expand the neck to 8mm, then down again with a carefully adjusted FL die.
Michael
Active Member. Uh/What
I would neck down for the same reasons Spindrift discusses. Additionally when a case is necked up, case length will be lost as material is pulled and stretched, that reduction in case length is not always uniform.
Necking down on the other hand will result in a longer case that will need to be trimmed and in doing so will produce cases of uniform length and the correct case length.
This based upon my own personal experience, when making 338-06 from 30-06 I end up with irregular case lengths that need trimming to a uniform length and end up quite short sometimes a good 0.050". When using 35 Whelen, form and trim, to the desired length.
If you do opt to neck up, make sure you use a tapered expander ball specifically made for case forming/neck expanding from smaller to BIGGER.
And yes anneal.
Necking down on the other hand will result in a longer case that will need to be trimmed and in doing so will produce cases of uniform length and the correct case length.
This based upon my own personal experience, when making 338-06 from 30-06 I end up with irregular case lengths that need trimming to a uniform length and end up quite short sometimes a good 0.050". When using 35 Whelen, form and trim, to the desired length.
If you do opt to neck up, make sure you use a tapered expander ball specifically made for case forming/neck expanding from smaller to BIGGER.
And yes anneal.
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CWLONGSHOT
Well-Known Member
I also would and do prefer down this way I CONTROL neck thickness instead of getting too thin.
But if you do use 243. I would anneal AFTER.
As a rule I anneal AFTER when making larger and BEFORE when making smaller. But ALWAYS ANNEAL!
CW
But if you do use 243. I would anneal AFTER.
As a rule I anneal AFTER when making larger and BEFORE when making smaller. But ALWAYS ANNEAL!
CW
Joshua
Taco Aficionado/Salish Sea Pirate/Part-Time Dragon
All my 7mm-08 brass is necked down 308. I anneal after sizing down the once fired 308. I measure to find the shortest in the batch and then trim them to length. They do end up a little short this way, but length uniformity is more important to me.
Kevin Stenberg
Well-Known Member
At this point the 7/08 rifle is new out of the box. So the chamber length is unknown.
Petrol & Powder
Well-Known Member
PM sent
This might seem idiotic these days, but my brother just fired .243 ammo in his brand new Remington 788 7-08 back in 1980- because we couldn’t find ammo.
Primers and bullets were cheap back then.
We tried necking down .308, but the thick necks caused high pressure. We did not posess neck turning tools.
The fire formed .243 cases worked just fine.
Primers and bullets were cheap back then.
We tried necking down .308, but the thick necks caused high pressure. We did not posess neck turning tools.
The fire formed .243 cases worked just fine.
RBHarter
West Central AR
Nope I'm the guy that tried 35 Rem , 243 , and settled up on 6.5 CM to form 6.5×50 SR Japanese with its .473 rim and .460ish body . So popping a 6mm up to 7mm doesn't seem odd or extravagant at all .
Yes the 250/300 Savage length does get enough taper to make the length and the CM needs about half of the head turn of the 308 clan .
Yes the 250/300 Savage length does get enough taper to make the length and the CM needs about half of the head turn of the 308 clan .
burbank.jung
Active Member
How good is your rifle and what do intend to use the ammunition for? I neck down military 30-06 than 8mm mauser brass for my T99 Arisaka so I don't accidentally chamber the round because of the headstamp. If you have a potentially accurate rifle, I'd weight separate the brass, neck up the .243 brass with a mandrel, turn the neck, anneal, and use the brass for your first set of ladder tests.