.257 Weatherby factory ammo, velocity?

[Guy Miner]

Anyone here know the real-world velocity of factory loaded 100 gr .257 Weatherby ammo?

I see it's advertised at a scorching 3600 fps... And knowing that Weatherby factory ammo is usually loaded pretty warm, I'm inclined to believe that the real world velocity is at least close to the advertised figure. But I don't know for sure.

Thanks!

Guy

 

[JD338]

Guy,

I would guess real world speed would be more like 3500 fps. Still pretty impressive.

JD338

 

[truck driver]

Weatherby ammo is shot out of a 26" barrel so it depends on if you have a Mark V or a Vanguard (24" ) new or worn barrel also. Norma loads the ammo so I would say it's close to what is advertised.

Just checked over on the Nation to see what they had to say and one fellow says he's getting 2660fps out of a tight cambered 24" barreled rifle at around 7000 ft elevation but prefers the 110 accubonds or partitions at 3350fps that he reloads. He also said that the 24" Vanguard barrels seem to post higher velocities than 26" barrels but doesn't know why. This gentleman is the go to guy over there for info so I trust his info to be right on.

 

[EOD Diver]

Guy,
That 257 WBY would make for a mean little varmint/deer rig. I know how tempting it is to pop coyotes while hunting the high country for big game. Any plans to get your 25-06 some new company?
Joe

 

[Guy Miner]

No - one fellow I hunted with over the weekend used a .257 Wby, and we've got an old one, on a Mauser action here at the house.

I just never ran any 100 gr Wby factory ammo through it. Not that I can remember anyway. Must have at some point, but likely didn't have a chronograph at the time.

Guy

 

[FOTIS]

Mine was close to 3600 fps. the 110 AccuBond was 3550 fps

26" barrel MK V

 

[truck driver]

Guy iis the one on the Mauser action a custom build or factory? Roy's original rifles were built on Mauser actions until he designed the Mark V. That one could be worth some coin.

 

[Guy Miner]

It was my grandfather's rifle, built in the late 1940's or early 1950's. Roy Weatherby's old southern California shop modified it from .257 Roberts to .257 Weatherby by opening up the bolt face and re-chambering it. Likely some more work done there as well. They did some custom stuff like that back in those days.

Grandpa made the stock, likely from one of those partially inlet stocks that could be purchased pretty inexpensively at the time.

It has shot fair, but not great. Was likely better before several generations of us fired a mess of rounds through the barrel.

I don't think it's worth much, it's just an old Mauser, sporterized, though some of the work was done by Weatherby, a long time ago.

My youngest son and I have been working on it, off and on, for several years now. I get frustrated now and again and put the project away. Lots of little things were wrong with the rifle. Have most of those solved now, but am afraid it simply needs a new barrel, and for some reason I've been reluctant to address that issue, so it's pretty much a safe queen for now.

Guy

 

[Guest]

Guy,
Not to tempt you, and you probably remember shooting it back a ways, but it is a really fun round and what it does to coyotes is amazing. :lol:
Dewey

 

[Divernhunter]

In my Vanguard I got 3487 and 3454FPS @20' with factory 100gr SP ammo.
My handloads with IMR7828SSC(73grs) and a 100gr Swift A-Frame gave me an average of 3664FPS and a group of shots all piled on each other for 5 shots.
With 73grs of RL25 I got an equally impressive group and 3368FPS. Increasing the charge to75grs gave me 3476 and still a very small group. Using a 100gr Scirocco and the 75grs gave me 3549FPS.

Using a Hornady 100gr SP I got:
IMR7828SSC--73grs--3508 & 3584 & 3493 & 3581FPS
RL22--71grs--3292FPS
IMR4381--69.7grs---3484 & 3493FPS.

Hope that helps.

 

[FOTIS]

 

[Horsethief]

1. Your not going to surpass factory velocities with handloads.
2. Feb 215 primer with max load of H-4350 will crank 3450fps with 100gn Barnes TSXs in a 24" Vanguard. It is the most accurate load in my 257 Roy.
3. The same load ought to make 3500fps in a 26" barrel.
4. 120gn Partition with H-1000 will easily do 3220fps in a Vangurd.
5. Put a hunting bullet where it will turn lungs to mush and your hunting will be over, but get your gut knife and skinning knife ready.

 

[wbyfan1]

Just looked at the chrono data from my old 257 Vanguard. Factory 100 SP's avg'd 3557 fps with 100 grain Weatherby factory SP's.