257 weatherby

D

Doug Casner

New member
Got a mark 5 Ive had for several years. Used to shoot 1in. groups. Now I cant get it to shoot 2in. groups. Tried imr4831 , 4350, 7828. 120 nosler,117 hornady sst,115 nosler part. Havent tried 87s but its a japenese with the fast twist. The last group I shot started about 2 ins. over the bull ended up the last shot went 6ins. high with hornady ssts. Sending the scope back to Leupold. Been back once said there was nuthin wrong. I dropped the rifle one time hit on the scope. Its been back to Leupold since then though. What would make it walk higher every shot. thanks Doug







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I probably shouldn't, but.........how sure are you that it ever shot 1" groups?

IME when I go back to my "useta'coulds" they all suck MUCH worse than my remembory remembers.

And Weatherby's shooting 1" groups are about as common as Sasquatches.

al
 
Doug:

A few questions:

Is your rifle barrel chrome moly or stainless steel ?

From your records, what is fired round count of barrel ?

From your records, what was powder charge of your favorite load ?

Old Cob
 
I dont know what the barrel iis made of. Its blued so I guess its not stainless. I got it back in the 70s. Its not got that many rounds thru it only hunted with it. Do ya think its the freebore? It bothered me when the last group went 6ins. They just kept going higher. I guess it would have shot off paper high if I would have kept shootin. Sent my scope to Leupold. All reloads were about max. Maybe I should load down a little but I couldnt see much reason to run a weatherby off max. When I got the rifle I didnt keep records. If it wasnt wrote on the box I didnt know what it was. Do now. Ill keep playin with it. thanks, Doug
 
Doug,
Do your 1st 2 shots shoot fairly close together and the 3rd one opens up the group?
Best,
Dan Batko

"Where are we going and why am I in this basket?"
 
wolf gray said:
Doug,
Do your 1st 2 shots shoot fairly close together and the 3rd one opens up the group?
Best,
Dan Batko

Thats it Dan. The first 2 went about an in. apart then each shot went about an in. from the last one. Bout 5or 6 in. group. I thought it might have something to do with barrel heat but I had to go load 3 shells between shots. Im gonna put a different scope on and see what happens. That would be the easy fix but Ive got my doubts Thanks,Doug
Click to expand...
 
Doug:

From your reply, I feel we can establish your barrel is chrome moly.

Okay, if you got your rifle in say 1975 ( mid 70's ) and have fired say 40 rounds per year, your fired round count is sitting at 1400.

From Hodgdon.com published reloading data, I used 62 grains of powder being used per round based on 100 grain projectile near a maximum powder charge. I roughly estimated your .257" bore to have an area of approximately 31 square millimeter.

Using Bart Bobbitt's calulations, by dividing powder charge ( 62 grains ) by bore area ( 31 millimeter ) doing the math is 2. Squaring 2 is 4 and multiplying by 3000, barrel life expectency is 1200 fired rounds.

I have a friend who is struggling with his rifle's groups opening up also. He used "known powder charge", and Bart Bobbitt's calculation was almost dead on his "fired round count". He later had his gunsmith scope the throat to be "toast".

If you estimate your "fired round count" being below 1200, my recommendation would be to check scope bases, rings, and action screws for looseness, and go with a "known" good scope. Thoroughly clean bore using a good 1 piece cleaning rod, and solvents to remove powder, copper, and above all CARBON from bore. Eliminate any inconsistencies in reloading or shooting bench technique, and always use wind flags when shooting.

Good Luck - Hope This Helps

Old Cob
 
Thanks Cob, Man, Are you an engineer? Thats some awsome calculatin for an ole high school educated country boy like me. Ive checked my mounts,rings, and action screws. Brushed the bore with sweets. One piece rod. Run patches with butches until clean. The trigger isnt real good but it wouldnt make me shoot a 6in. group. Ive probably shot it more than I think. Took it on some deer and antelope hunts out west and several coyote hunts around here. Thanks for going to all that trouble. Its probably showin some wear. I dont know of a gunsmith around here Id take it too. Thanks again Doug
 
Doug:

In response to your question, no I am not an engineer.

I have previously read Bart Bobbitt's articles on barrel life exceptency and as mentioned have a friend struggling with group size opening up.

In addition to cleaning your rifle bore with Butch's and Sweet's as you mentioned you had, also clean for carbon. GM top engine cleaner has worked for me.

Prior to sending a bunch of money and absolutely beating yourself to death to bring your .257 Weatherby accuracy back, find a gunsmith with a bore scope and have him take a look.

If the barrel could stand to be replaced, Bart Bobbitt calulates a stainless barrel life to be three times greater than chrome moly.

At the rate it appears you shoot, a stainless should be good for the next 105 years barring a Holy War on some dog town for the next 10 years or so.

Take Care.

Old Cob
 
.257

i would clean it again. i would use usb paste . i would load some 115 bergers with H-4350 and some wlrm primers. load 3 at 2975 (approx) 3-3000, 3-3025 , 3-3050, 3-3075. take the best group of those and mess with primer . then seating depth.
 
Took my 36T off my panda yesterday put it on the 257. Brushed the bore again. Loaded some 117 interbonds with imr4350 max. Loaded I think there 110 gr. accubonds nosler with imr4831 max. The hornadys shot about 4in. I think that 257 hates 4350. The noslers shot 2in. its not good but I can live with that in my weatherby. Liked the 36x on the 257be fun to declare war on prarie dogs with it, if it shot a little better. I also took it out of the stock and took sandpaper,dont have a dremel, tried to work down the forearm a little.The reciol lug is bedded. That was a nice suprise. Wind is blowing about 50 mph here today guess no shootin today. Thanks for the ideas guys. Doug
 
Doug
Never found a better accuracy bullet in 25 caliber than the Sierra 117 Spitzer boattail and it has about the highest bc number as well.I found RE22 to shot as good or better than any of the various 4831's.
I would also follow roninflag and clean it yet again.
Lynn
 
Doug:

How feasible is it to have a high magnification target scope on a small caliber magnum hunting rifle ? How effective is a 2" rifle on a dog town ?

I realize investment in rebarreling a rifle is not only pricey but makes the rifle unavailable for a period of time. A couple of life times depending on who does the work, has been my experience.

If your rifle has previously shot well and the barrel isn't free floated, my recommendation would be to leave the "bump" in the barrel channel so that another problem is not created.

Finding a smith to scope the throat will save you time and money and start to address a possible problem - versus - treating the symtoms.

In Highest Regard.

Old Cob
 
Cob, I put the 36T on the 257 cause it was the easiest to take off and put on. Im not taking the 257 dog hunting. Maybe I shouldnt small talk so much,be more to the point. Point is ,If I can get it down to 2 ins. Ill put it back in the safe maybe take it deer hunting again sometime. I just like to have my rifles shooting to the best of their ability. Thanks for the comebacks, Doug
 
Cob, I thought I was being made fun of for putting the target scope on my mk. 5. Its not gonna stay on there it was easier to get to. Im not gonna shoot my 6ppc now anyway. Wasnt tryin to sound like a smartass but the post kinda did. Maybe I had one to many cups of coffee. Anyway no harm intended. Hope this clears it up. Thanks for takin the time to think about my problem guys. Doug
 
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