257 weatherby reload help please


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scchokedaddy
October 8, 2011, 11:35 AM
Have an old German Weatherby chambered in 257 Weatherby Magnum, having problems with keyholing with 120 grainers. Shoots 100 grain factory ammo fine. Was told older rifles have 1in 12 twist instead of 1 in 10. trial load was 61 grains of 4350 with 120 nosler. Any suggestions will be appreciated. Am researching info for an old friend who is computer dummy, so it might take me a day to answer back as I have to call him to get answer to questions I know are coming

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rcmodel
October 8, 2011, 11:46 AM
Use a marked cleaning rod with a tight patch and measure the rifling twist.

But if it key-holes with 120's and not with 100's?

The twist is too slow for 120's.

BTW: Lyman #49 lists the .257 Weatherby as tested in a Weatherby Mk V with a 1/12 barrel.
They cut off at 115 grain Nosler #51050, and show nothing any heavier.

rc

scchokedaddy
October 8, 2011, 12:19 PM
rc thanks for fast reply. Do not have that manual,are we on right track for powder or do we need another powder? If you do not mind, whats the recommended load data in that manual? Found the bullets at Midway USA, will be ordering them soon, thanks again.

rcmodel
October 8, 2011, 12:38 PM
4350 is too fast for heavy bullet .257 W loads.

Lyman #49 says with the 115 Nosler:
IMR-4831 - 60.0 - 64.0
AA-3100 - 63.2 - 66.5.
H-4831 - 63.0 - 66.0.
RX-22 - 61.5 - 64.5.
IMR-7828 - 66.5 - 70.0. (Highest velocity starting load)
RX-25 - 67.0 - 71.0. (Potentially most accurate load)
HB870 - 72.0 - 76.0.

rc

NCsmitty
October 8, 2011, 12:49 PM
You can look at www.hodgdon.com for their up to date data for the 257 Weatherby.

You can use a slightly heavier flat based bullet compared to a boat tailed bullet because of the bullet length. Flat based bullets are easier to stabilize in the slower twist because of that.



NCsmitty

GooseGestapo
October 8, 2011, 02:05 PM
The early German Weatherby's in .257wby have a 1/12" twist.
You'll have problems with the 120's and most likely the plastic tipped 115's.

However, for an excellent load to ~250-300yds, your rifle should do well with the 117gr Hornady RN. Ballistics from this bullet aren't as bad as you might think. I load it over 70.0gr of RL25 for near 3,300fps (24"bbl).

One of the gun writers who wears "sweat stained base ball caps" is a Weatherby affectionado. However, he's stated he doesn't see the point of the 117gr RN Hornady in the Wby.
I do.
I've shot them from my 24" Vanguard and they perform brilliantly from such. (.257Robts. too!).

I think also, your IMR4350 load is a tad "slow" to stabilize the 120gr bullet from your rifle. It's probably only about 3,100fps from your 26"bbl. I've used as high as 65.0 from my gun (with 100gr bullet), but settled on 64.0 due to superlative accuracy with the 100gr bullet. But, it's a tad fast of a powder for the .257wby. H4831 and slower are better. IMR7828 has been very accurate but is ~100fps slower than RL25. FWIW; original factory loads were with H4831.....

Not all is lost with the 1/12" twist. The 100gr Nosler Partition penetrates almost as well as the heavier 115 or 120gr in the .257. This is because the rear shank portion of all three bullets are the same. It's the forward portion that has the extra weight.

Also, I've gotten excellent performance on deer with the Hornady 100gr flat-base soft-point Interloks. (original factory loaded in .257wby). It performs very closely to what you'll see from the 100gr Nosler. I shot a ~100lb doe at 90yds in '07 with my .257wby with the 100gr Hornady over 64.0gr of IMR4350 for ~3,500fps. The bullet was just under the hide and weighs 67.5gr. The same bullet from the .257Roberts (obviously not exact same bullet) at 3,000fps completely penetrated a 220lb 10pt buck at 175yds in 1984. So, at the longish ranges the .257wby is intended for, the Hornady Interloks work superbly.....slowing it down inproves penetration...

My favorite powder for my .257wby is RL25. I'm getting ~3,600fps from a max load of 74.0gr and moa or better accuracy (3-shots, don't want to shoot my barrel out....). It's my "go-to" rifle for hunting over powerlines and airports doing "population control.
When typical hunting, however, where "close" shots are possible or hunting an area with large deer, I use the heavier bullets, though they aren't really needed.

For a heavier than 100gr bullet and other than the 117gr RN Hornady, I suggest you try the 115gr Nosler Partition or 117gr Sierra Flat-base. Load these over 66.0-70.0gr of RL25. These are the ones that stand a better chance of stabilizing from the 1/12" bbl. But, the 100gr Nosler or 100gr Swift (longer base section) should do anything you will want the .257wby to do. I would not hesitate to use the .257wby on an elk even with the 100gr bullets, so long as it was a Nosler or Swift A-frame, preferably the A-frame... though if after elk on purpose, I'd carry a bigger gun....

Edit to add: But, for "blasting little deer", I use a full case of WC860 (aka H870) in re-formed R-P 7mmMag brass, and Hornady 100gr "blems". It gets ~3,450fps and costs next to nothing to shoot. And, is decently accurate.....

scchokedaddy
October 11, 2011, 12:28 PM
Hey guys sorry I haven't been back to say thank you for your help. Will be seeing the old man one morning this week, will take load data with me. If you come up with more info please add. Do not get on everyday as I drive a truck at nite thanks again

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