Powder Recommendations For 257 Weatherby Mag?

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  • Deep Creek Rock

    .._. .._ _._. _._ .._
    I got recommended by my brother to do some handloads for a friend of his that he deer hunts with. He asked if Id develop, and do some handloads for his 257 Weatherby Mag. I agreed to, Id like to see if I can get that thing turned into a tack driver with handloads. He has saved all his factory brass (which is made by Norma) - good thing that stuff is pricey!! He is going to supply me with the dies, and everything else needed. I think it will be intresting to reload that case with its ogee/radiused shoulder.

    Anyways, I believe the rifle is a Mark V, but not 100% sure yet. I asked him to leave me the rifle for a bit to make sure everything chambers, and feeds fine.

    Im not 100% sure what bullet he would prefer to shoot out of it. The owner, and his kids use it for deer. I believe they are firing a 110 grainer using factory overpriced Weatherby ammo.

    Has anyone loaded for one of these, and are there any particular powder that seems to perform the best? Im more intrested to get the rifle to print small groups -the owner to save some cash, since it is pricey to shoot.

    I do know the Weatherby's are freebored, so realistically, I will stick to the COL listed in the load data, to make sure it fits the mag & feeds properly.
     

    Mason-Dixon

    Member
    Nov 26, 2011
    20
    A good friend uses either IMR 4831 or H4831 with all bullet weights. He says he's tried IMR 7828 as well but got better grouping results with both 4831's. He tends to shoot the heavier bullets for this caliber, 100gr plus at high loading densities near or at maximum charges. Has not had any brass life problems. After the case has blown out to chamber dimensions he only sizes enough for reliable chambering. I guess he's (at least partially?) using the neck to head-space on rather than the belt. He say's he got that tip from one of the 1000 yd Williamsport shooters a long time ago that he hunted with. He double checks all his rounds for chambering before he hunts with them. He also uses Federal LR Magnum primers and checks case OAL after each firing. If he finds a case(s) that stretches more than the others that case(s) gets retired immediately.
    Said that with factory Weatherby cases that will happen occasionally. Good Luck
     

    engineerbrian

    JMB fan club
    Sep 3, 2010
    10,148
    Fredneck
    I cant answer your question, seeing how i dont re load yet. However, I have 40 rounds of .257 Weatherby Mag that someone gave me about 10 years ago to get rid of for them. I figured it wasnt cheap so i've kept it layinng around until i could find someone to give it to. IDK if its factory ammo or re loaded, but worst case you could pull the bullets and salvage the brass.

    Let me if you want it and i'll bring it by in my western Md travels.
     

    gotguns

    Ultimate Member
    Industry Partner
    I don't reload for this one...however. Weatherby uses federal match primers and norma powders. One of my customers I know buys an alliant powder for his 257 mag. (which one I don't remember) Sorry so vague...but what I know. Typically 117 grain bullet for .25 calibers on deer. I use siera game king 117 in my 25/06, never lost one yet.
     

    Deep Creek Rock

    .._. .._ _._. _._ .._
    For bullet type - I am thinking that Hornady's Interlock 117 SPBT, would be ideal for the guy shooting it. They hunt both thick hardwoods, and wide open fields. So the distance are both close and far (I dont subscribe to the brush gun theory one bit!)

    Noslers load data, claims the BT is too destructive on meat at close range for that caliber, but is great at long ranges. The Partition is really too pricey, for whitetails.

    Ive had great luck with Hornadys Interlock FMJ, for my 06 target rounds-they group just as good as Ballistic Tips, but you get twice as many for the cost. The Hornady 117 grains SPBT is an expanding bullet (unlike the the FMJ's) and has a boat tail to boot, so that may be some advantage on the longshots.

    As far as neck sizing, Im kinda up in the air on that. Alot of load manuals recommend full length sizing for Magnum bottlenecks. Since he is buying the die set, Ill just start off with a full length sizer set. I want to make sure these things chamber when he is out in the fields. without issues.

    I do see IMR 4831 as an accuracy powder in the 257 Weatherby Mag load for data, for certain weights -mostly the lighter bullets.

    Once I have the rifle in my hands, and determine the twist rate, Ill get a better idea of what should work.

    Most belted mags headspace on the shoulder - not the belt. The belt is just for asthetics, to denote it as a Magnum round. However there are a few that do headspace on the belt (300 H&H) Most of the English Magnums. I think the 257WM is based on the 300 H&H case, but it is not stated in the manuals as headspacing on the belt.
     
    Last edited:

    mossy33oak

    Active Member
    Nov 29, 2011
    116
    Curl Cowty
    Have you given the Accubond a thought? 110 gr Accubond in that cartridge should be an awesome round. I would try RL-22 with a max grain of 63, min of 59. As far as once fired brass for that gun, there is an alternative between FL and neck resizing. You can take a fireformed case and Partial Full Length resize it. By turning your Die up one turn instead of down, you can resize the neck and shoulders. I do this with all of my once fired brass IF i'm using it in the same gun. I have never had a feeding issue for any of the guns I reload for, even the 300 RUM which is known for feeding issues.
     

    Deep Creek Rock

    .._. .._ _._. _._ .._
    I cant answer your question, seeing how i dont re load yet. However, I have 40 rounds of .257 Weatherby Mag that someone gave me about 10 years ago to get rid of for them. I figured it wasnt cheap so i've kept it layinng around until i could find someone to give it to. IDK if its factory ammo or re loaded, but worst case you could pull the bullets and salvage the brass.

    Let me if you want it and i'll bring it by in my western Md travels.

    If it was factory loaded - I would take them off your hands. But if your not sure if there reloads, It would be hard to tell how many times they were loaded etc. I dont want to run into any troubles since this is going to be loaded for someone else. The gun owner does have a bunch of once fired brass - he has saved all that he has fired from that rifle.

    Then Id I have to go out and buy a Kinetic Hammer. I can honestly say, I never had to pull any of my handloads apart.
     

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