Safari Gunsmithing?
- Thread starter Boomer454
- Start date
Turkeyslayer 1300
CGN Ultra frequent flyer
- Location
- Russell, Ontario
Why would you rechamber it? .257 Ackley is the .257 Roberts improved and is only 1-250 fps slower than the 06.It would be cheaper to buy dies if you don't have em or extra brass.
It'd be easier and less expensive to just re-barrel if you opt to go that route. Mind you, it'd be a backwards step. The AI gives better velocities and has longer case life. .257 AI brass can be made by fire forming regular factory .257 Roberts ammo. Said ammo isn't as difficult to find as it used to be. Federal, Remington, Winchester(supposedly +P though) and Hornady all load it.
Going to a .25-06 would require a long action just for the mag length. Same length as a .30-06. The .257 is under 2.780" OAL. The .25-06 is 3.25" OAL. Both with the bullet. Nearly half an inch difference.
For a plain old .257 Roberts you'd need another barrel or, like rgv says, have the barrel machined. The shoulder of the AI is 29 thou bigger in diameter and the shoulder angle is bigger. You can't add steel.
Going to a .25-06 would require a long action just for the mag length. Same length as a .30-06. The .257 is under 2.780" OAL. The .25-06 is 3.25" OAL. Both with the bullet. Nearly half an inch difference.
For a plain old .257 Roberts you'd need another barrel or, like rgv says, have the barrel machined. The shoulder of the AI is 29 thou bigger in diameter and the shoulder angle is bigger. You can't add steel.
I understand that the AI is a better performer. That is not the problem.
The problem is that I have a serious head space issue. I kind of had stars in my eyes when I bought this one. The guy who sold it to me kept saying that he was .257 Weatherby velocities out of it, and had his own load data and chronograph read outs to prove it.
What I should have heard is "I way over loaded it and am dumping it on you because it is broken..."
Case head separations on the first firing after fire forming. I tried all the brass manufactures, a variety of load manuals advice. But the fact remains... This chamber needs some work...
Oh well, live and learn. I was young and not really experienced when I did that deal.
The problem is that I have a serious head space issue. I kind of had stars in my eyes when I bought this one. The guy who sold it to me kept saying that he was .257 Weatherby velocities out of it, and had his own load data and chronograph read outs to prove it.
What I should have heard is "I way over loaded it and am dumping it on you because it is broken..."
Case head separations on the first firing after fire forming. I tried all the brass manufactures, a variety of load manuals advice. But the fact remains... This chamber needs some work...
Oh well, live and learn. I was young and not really experienced when I did that deal.
"...kind of had stars in my eyes..." Some rifles will just do that. Mine was a BAR LMG when it was still no big deal. Had the money, but had just been laid off. I didn't buy it, despite my youth and inexperience. Needed gas money more. Been kicking myself ever since.
"....257 Weatherby velocities out of it..." Maybe with 75 grain bullets, but not the regular 117.
Do or have a chamber cast done. That'll tell you the exact cartridge it's chambered in and the dimensions of the chamber. It could well be that it was re-chambered to AI incorrectly by a monkey with a reamer. Or some putz changed the bolt without using headspace guages.
Fixing the headspace will require machining the barrel. Maybe a bunch. Maybe just a bit.
"....257 Weatherby velocities out of it..." Maybe with 75 grain bullets, but not the regular 117.
Do or have a chamber cast done. That'll tell you the exact cartridge it's chambered in and the dimensions of the chamber. It could well be that it was re-chambered to AI incorrectly by a monkey with a reamer. Or some putz changed the bolt without using headspace guages.
Fixing the headspace will require machining the barrel. Maybe a bunch. Maybe just a bit.
buy some 7x57 brass (or once fired 270/30-06 if you don;t mind trimming and are a cheap-ass like me)
neck them down in your 257 AI die with the bottom of the die 1/8" from the shell holder
screw the die in a bit at a time until the bolt will close on teh case with some effort (meaning the palm of your hand on the bolt knob, no mallets). you will create a false shoulder for the initial firing
check OAL, load a fireforming load and go to town.
from then on, keep a close eye on your die setting so you do not push the shoulder back.
enjoy your rifle.
betcha the guy that did the original re-chamber did not set the barrel back, as is necessary for correct headspacing on a AI
It is not a re-chambered original barrel. It is a Shilen barrel that is stamped .257 Ackley Improved.
I believe it was built at Premier in Calgary.
I bought it from the second owner...
I have a good supply of .270 and .30-06 brass. I will give that a try.
Here are a few pics of a fired formed and a factory round for comparison.
The fired round was a factory round that was fire formed only, never reloaded.
I believe it was built at Premier in Calgary.
I bought it from the second owner...
I have a good supply of .270 and .30-06 brass. I will give that a try.
Here are a few pics of a fired formed and a factory round for comparison.
The fired round was a factory round that was fire formed only, never reloaded.
Is set back of the lugs something that is easy to see? If that is part of the problem does that mean the bolt needs to be replaced? Or can it be fixed?
Here are some pics of the bolt and action.
Is there anything that jumps right out at any of the more experienced members here?
Is lug setback "obvious" or something you can only "see" with a set of calipers or a dial indicator of some sort?
Thing is - you could be dealing with undersized brass, which would display the same symptom as excessive chamber headspace. RGV addresses that in a previous post - its an easy fix, and should be checked first. Even if the chamber is slightly long, you can compensate with your dies.
Lug setback can occur on the contact faces of either the receiver or the bolt, whichever is softer. If the bolt lugs are worn, you should see indications of wear on the rear side of the lugs. If the receiver lugs are worn sufficiently, the bolt becomes sticky upon extraction after firing, as it must clear the lip caused by wear.
Hard to tell in your pics, but the rear face of the bolt lugs look OK - the original machining appears intact?
Lug setback can occur on the contact faces of either the receiver or the bolt, whichever is softer. If the bolt lugs are worn, you should see indications of wear on the rear side of the lugs. If the receiver lugs are worn sufficiently, the bolt becomes sticky upon extraction after firing, as it must clear the lip caused by wear.
Hard to tell in your pics, but the rear face of the bolt lugs look OK - the original machining appears intact?
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Bearing in mind that I am NOT a gunsmith - nor have I stayed at a Holiday Inn lately - you need to exanime the rear of the lugs , very carefully to see if there is any damage in this area.
As I understand it, the lugs can be damaged due to excessive pressure caused bt excessive headspace.. Remember it is the rear of the lugs that takes the pressure, not the front!
As I understand it, the lugs can be damaged due to excessive pressure caused bt excessive headspace.. Remember it is the rear of the lugs that takes the pressure, not the front!
