help on .257 project

[B Jordan]

i have a .257 weatherby on a 700 action that i am getting ready to rebarrel and was wondering if anyone had ever played with something like a 25/7mm mag , 25/300 win mag , 257 stw or maybe even a 257/300 ultra i want to set it up for the 142,156 wildcat bullets any pros , cons ,twist recomendations i would be happy to hear thanks for your help

 

[oldfamily]

Brian you will love the stw round, I am shooting the 110 accubonds at 3700 and could get more speed if I really wanted to push things. I have used the 125 and 130 bonded wildcats had good results. I had Bill at Summersville make mine up. aka pinecrest if you know anyone from the tactical club in Houston they will know of him. You would need to go with at least a 28 in barrel would do good with a 30 no need for a break as my rifle kicks like a 22-250 with a #5 shilen 1 in 10 twist. hope this helps oldfamily

 

[B Jordan]

yea i know him pretty well i may try to call him he said he sold a bunch of his reamers a while back if he still has it i may try to buy it



does anyone make good stw brass? that was my main concern with building an stw [im getting really lazy]

do you ever shoot in that shoot at houston? i am gone most weekends so i dont get to go though i did go to one of chucks a couple months ago in pomona

 

[oldfamily]

just get 7 stw brass and resize in the 257 dies. Bill has my reamer as we speak. the only thing bad is that this is the last year that he will be working on rifles, never have been to the club at houston know Bill makes a lot a 338 lapua mags for people in the club. I found out about chucks shoot too late to go. We know the same people I bet you get items to reload with from Will's. I got load data for the stw if you need it.

 

[brianwinzor]

Brian, I also have a 257W on a Rem 700 action, but with a Krieger 26 inch 7 twist (3 contour) barrel.

I have only tested the 156 grain wildcat so far, and although it gave good accuracy, the Norma 257 brass is soft and restricts me to about 2,900 fps. This is only 70 fps more than my 25/06AI achieved with the same bullet in a 24 inch barrel.(19 grains less capacity)

Kirby and I both thought that I should be able to get 3,000 fps with the 257W case, but it won't happen with Norma brass.

Several weeks ago, I bought some 300 Winchester magnum (Remington brass)and necked them down to 257W, neck turned the cases and then annealed. The cases had a capacity of 85.2 grains compared to 87.8 for Norma new 257W brass.

Today with 300 WM brass, and using AR2218 (H50BMG in US), I worked up from 67 to 70 grains with the 156 grain bullet, and the results from a velocity view point were more encouraging. Although the necks on some cases didn't expand correctly, I achieve 2,984 fps with the 70 grain load, and probably could have gone a 1 grain higher as there were no extractor marks, primers were starting to flatten, but bolt lift was still easy.

I will re-anneal the case necks that didn't expand correctly, and retest using the 156 grain bullet at 300 yards and see what pattern emerges.

I only have about 40 left of the 142 grain ULD's at the moment, but will also test those in the coming weeks.

The 25/300WM and 257STW should produce velocities with the 156 grain ULD that are somewhere between 2,980 of the 257W and the 3,350 fps of Kirby's 257AM. Hope the above is of some help. Regards, Brian.

 

[Fiftydriver]

Brian,

Do not want to hijack the post, just a quick question, were your test loads with the 300 WIN cases the first load in those cases? If so, the flattened primers may simply be a slightly loose headspace situation and once the cases are fully formed this will go away if that is the case.

Good Shooting!!

Kirby Allen(50)

 

[James Jones]

Brian , I have a buddy that shoots a 25-300Win mag and I have to tell ya its a n awsome round it'll flat smoke the 257Wby and run realy close to the 257STW depending on the throat and barrel length.
My friend used Lapua brass and 115gr Nosler Ballistic tips and has great results on deer and hogs out to 600yds , it'll shoot alot farther but he doens't have the place to hunt that far.
My vote goes to the 25-300Winmag ,better brass , slightly shorter OAL will allow you to play with seating depth a bit more and the barrel life might be a bit longer than the STW due to it using less powder.
I'd also get it in one of the barrel makers that makes the 5R rifleing

 

[Fiftydriver]

Brian,

Well, for ease of loading the 25/7mm Rem Mag, 257 STW and 25 RUM will all be about the same as you are taking a 7mm neck down to 25 cal.

Of the three, with the heavier bullets, I would say the 257 STW will be the highest performing with the easiest to load for personality. THe 25/7mm Rem Mag will get you exactly what the 257 Wby will get so thats alot of fuss for factory performance.

The 25 RUM will be the highest performing of the three but when you get to a level of this case capacity in this bore size things really can get touchy load wise. My 257 Allen Mag has slightly more capacity then the 25 RUM but its a bit shorter.

My Allen Mag is on the 338 RUM case instead of the longer 7mm or 300. I did try a version on the longer case but I did not get any more velocity with it then I did with the shorter version so I would say the current 257 Allen Magnum and 25 RUM are about as large as is practical with the powders we have available today.

They are the most consistant with the heavy bullets so you are on the right track there. THey do shoot pretty well with the lighter weight bullets but in my experience the light bullets have never held a candle to the heavies for load consistancy and accuracy at long range.

Twist rate recommendations would be 1-8 to 1-9 for the 142 gr pill and 1-7 for the 156.

The 142 will handle the 1-7 twist but I would highly recommend getting one with a thinned land in a 5 or 6 groove. I tested these bullets in my 1-7 257 Allen Mag and at the highest velocity potential I had occasional bullet dusting but I am sure that is due to the high RPMs and wide 3 groove barrel with the J-4 jacket.

With a 6 groove I suspect you would not see that problem.

The 156 gr bullets are built on a slightly heavier jacket and I have not seen this problem with them at all with velocities up to 3300 fps which is the load I use in my 257 Allen Mag and would expect you could get very close to that with the 25 RUM.

Pros and cons, well any time you get into the class of 25 cal rounds where your dumping nearly 100 grs of powder in each case you will have a squirrelly little monster on your hands. Heavier bullets help tame the beasts but you need to realize these are EXTREME, extreme chamberings.

Kind of like a 1000 horsepower big block V-8 in a 68 camero. Can be a challange to get pointed in the right direction but once you do, watch out!!! /ubbthreads/images/graemlins/grin.gif

Good Shooting

Kirby Allen(50)

 

[brianwinzor]

Kirby, Yesterday's test was the first firing of the 300WM cases. I hope you are right about the flattened primer scenario. I hadn't thought of that possibility, but the next test firing will reveal if that is correct.

During the reloading process I did adjust the F/L die so that the bolt would only just close on the case, and during testing yesterday, I could not get the bolt to close on one of the 3 cases in the 67 grain load. On the flip side I did notice that the ease of chambering did sometimes vary a little from case to case. Regards, Brian.

 

[rotorhead]

Brian, I was wondering through Midway and they list a 25 stw brass by some company making correct stamp brass you might want to get on there and see what they have. I'm not sure of the company name or the quality of the brass but the midway site will be able to tell you.

RH

 

[257speed]

May have something of interest for you Brian, e-mail me back.

 

[B Jordan]

257speed , email sent