7mm Rem Mag to 257 Wby

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JasonYuke

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Never played with the 257 just got my componants wby brass it way too $$ at 54.00 per 20 with a box Or I can get a bag of 50 for $75 , BUT it looks like you can push the 300 WM or 7mm rem into a 257 wby, anyone ever do this?

If so do they require reduced load Fireforming?

Regards
 
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JasonYuke said:
Never played with the 257 just got my componants wby brass it way too $$ at 54.00 per 20 with a box Or I can get a bag of 50 for $75 , BUT it looks like you can push the 300 WM or 7mm rem into a 257 wby, anyone ever do this?

If so do they require reduced load Fireforming?

Regards
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Use 7 rem mag or 264 win if you can find it.Lube it up and 1 pass through the 257 weatherby dies and they come out looking like the real thing.Check the length and neck thickness and your away. One thing though ,weatherby brass weighs about 10 gr or so lighter than win or rem (weigh some to be sure) So it is important to load accordingly.

Rich
 
you will have to fire form the brass, I just had this conversation with my gunsmith today and to me it is not worth farting around with I'm just going to spend the extra money and buy the 257 weatherby brass.
If you do continue to try and use it watch your headspacing.

Kelly
 
RR said:
BULLLs**t
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Double bull####.:D The 7mm Rem Mags that I neck down to .257 come out with perfectly formed shoulders, and less run-out than factory Weatherby out of the box. Regarding headspace, the first firing will be headspaced by the belt.
Unfired cases are a bit softer and form easily. The cases are a bit shorter than Weatherby cases. Imperial sizing die wax on the case makes the job easy.
 
I sized 200 Herters (Norma) 264's to 257WBY about 20 yr. ago. Still running strong. I neck size only now as we keep the brass separate between rifles. prob. 10 firings, maybe more. I also sized some 270 Wby down to 257 and they work well also. Since these headspace off the belt, for the first firing, new brass would have more chance of excess headspace than resized brass. Mark
 
Newbie reloading question

In Lyman's 49th and in the ABC's of reloading danger is often mentioned. How dangerous is reloading if one follows directions? Is it possible for exaple for a case to fail and the gun to explode or to throwback fless, blinding, searing gas?
 
I sure don't know why WBY thinks their brass is so good.I looked over a friends (once shot) $86/box of 20 WBY 300 mag brass and was very disappointed to see that all had factory pits in the drawing of the brass (some nasty) and two never made it to be reloaded once because of cracked necks.I hope these guys are able to find a cheaper alternative but they had best be prepared to shell out a few bucks for a neck reamer or cutter because resizing down from .284 to .257 is going to thicken those necks and raise pressures for sure.I know because I resized a bunch of freebie 300 Win mag cases to .284 for my 7mm Rem mag.The necks got too thick to safely shoot jacketed bullets but work well shooting at lead bullet pressures so that's what I use them for because I'm too cheap to get a neck reamer for 60 free cases.
 
Watch your neck thickness when necking down 7mmrem brass.It worked fine in my factory barrel,but in the tighter chamber of my replacement barrel it didn't provide enough clearance without neck turning.On the other hand the factory 257brass worked fine in both barrels.
 
Madrod said:
I sure don't know why WBY thinks their brass is so good.I looked over a friends (once shot) $86/box of 20 WBY 300 mag brass and was very disappointed to see that all had factory pits in the drawing of the brass (some nasty) and two never made it to be reloaded once because of cracked necks.I hope these guys are able to find a cheaper alternative but they had best be prepared to shell out a few bucks for a neck reamer or cutter because resizing down from .284 to .257 is going to thicken those necks and raise pressures for sure.I know because I resized a bunch of freebie 300 Win mag cases to .284 for my 7mm Rem mag.The necks got too thick to safely shoot jacketed bullets but work well shooting at lead bullet pressures so that's what I use them for because I'm too cheap to get a neck reamer for 60 free cases.
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Madrod,

The reason you have necks that are too thick when using 300 Win brass is because you ended up with part of the neck of the 7 mag case being formed out of the shoulder of the longer 300 Win case! BTDT several times. Same thing happens with some brass when necking 30-06 up to 35 Whelen or 9.3X62.

Necking 7mm Rem mag brass to 257 Wby is no problem at all in this regard. Done several hundred over the years, and never had to ream case necks. Fired cases that are formed out of 7 mm, allow 257 bullets to slip right through without any resistance.

Ted
 
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I resized 7mm Rem mag brass to 257 Weatherby for my Vanguard never had a problem, shorter necks was it.

Can someone tell me how you turn 300 Win mag brass to 7mm Rem Mag, I thought they would be little long :rolleyes:
 
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