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`06 to `06 Ackley
swampthing36
Member Posts: 273 ✭✭✭
I am wondering what a fair price is to have my 30-06 modified to 30-06 ackley. I've got an ackley barrel on my Encore, all the reloading gee gaws and plenty of experience. but i have this bolt rifle that I just want to fiddle with. Doe the barrel need to be yanked, reamed and set back? It has sights. Please advise.
Comments
"...it is just a matter of running the Ackley reamer in to cut the new chamber..."
Incorrect. Please read P.O. Ackley for the correct description of setting the barrel back in order to get the proper headspace.
swampthing36,
The barrel is removed from the action, indicated in on the lathe, set back at least one thread and the new chamber cut. The headspace is checked and the barrel re-installed.
Best.
Hi Swampy---I'm a big ackley fan, and have several as we speak. If your existing chamber ( including throat area) is clean, and centered in the Bbl, it is just a matter of running the Ackley reamer in to cut the new chamber, and deal with headspace. I would guess about $125 to $150. And yes the Bbl. needs to come off of the action (let your smith do that). If there is any throat wear, or issues with the existing chamber, this is a great time to set the Bbl. back a thread or two, and clean everything up. I just had a .22-250 rechambered, and set back 0.040. That was a $170 bill, but it's all new now (except Bbl. of course). Good luck
Thanks for the advice. Between the time I posed the question and your response I talked to a gunshop with a smith. He pretty much said the same thing about removing the barrel, etc. Also quoted me $150.00. thanks guys![:D]
"Sorry I don't buy your stmt."
Fortunately, it really doesn't matter what you will or won't buy. The facts of the proper method to the process is what's important and you don't know and certainly don't understand the facts of properly reaming an Ackley chamber.
From P.O. Ackley himself:
Anyone entering the experimental cartridge field, whether with an Improved or Wildcat cartridge, must have an understanding of correct headspace for the particular cartridge. Many gun shops cut incorrect chambers for Improved cartridges because they know only enough to make themselves dangerous! They often take the seemingly correct stand that since both the standard factory and the Improved cartridges can be fired in the Improved chamber, both must have the same headspace. This is totally incorrect and will result in backed out primers, blown primers, ruptured cases.or worse.
Since most cartridges today are of the rimless type, we will discuss only that configuration for headspace. Headspace is normally considered to be the distance from the face of the locked bolt to a point on the case shoulder called the datum line. This line is arbitrary to a great degree, being a point where the diameter of the case shoulder is .375" in most cases. Some use different diameters as datum points, and one in particular, the original Government .30 caliber (.30-06) does not use the datum point at all but uses the point where the shoulder joins the case body. Commercial .30-06 cases use the datum point. When we start changing things, such as forming the Ackley 40 degree Improved chamber and cases, we no longer can use this datum point for headspace, but must use the juncture point where the neck joins the shoulder. In standard chambers some part of the case shoulder, including the datum point, would contact the chamber to provide proper headspace. But when we cut out the chamber in the shoulder area, as well as some along the case body area, to change to the Improved configuration there is no longer any support for the shoulder of a standard case. Therefore, the datum point and shoulder area of the chamber no longer provides headspace. The only point of contact will be the neck-shoulder juncture. This is a very fine line. And headspace is now held between the bolt face and this neck-shoulder juncture point. The shoulder of the standard factory case is no longer supported by the chamber wall.
To assure that even the shortest standard cartridge brass will fit this Improved chamber snugly, without shoulder support, the standard headspace must be reduced by .004" from that of the factory, or SAAMI, specifications. This now causes the standard SAAMI headspace "GO" gauge to not fully enter the chamber. Thus, the standard "GO" gauge becomes the "NO-GO" gauge for use in Improved chambers! As an example, the standard .250 Savage "GO" headspace gauge in the .250 Ackley Improved chamber will not allow the bolt to close. This is required because the manufacture of pliable brass cartridge cases cannot hold the neck-shoulder juncture point exact, and we do want the standard cartridge to fit rather snugly at this point in any Improved chamber.
Best.
Your "theory" barly works on paper, and than only IF the origional chamber was cut to 0.000 HS AND the factory cases just happen to also be at 0.000 on the HS dimention. However, once you enter the real world of tolerances (0.000 to +0.006 for the chamber and -0.002 to -0.008 for the cases), it dosn't work anymore (at least not safely or reliably).
Work out the numbers for yourself, the factory chamber could well be .006 long (just under the NO-GO limit), and considering that Ackley used the GO gauge as his NO-GO, your up to .012 long in the chamber. Add in the minus .008 cartridge tolerance, and you've got as much as .020 slop
quote:Originally posted by Hawkshaw
Hi Swampy---I'm a big ackley fan, and have several as we speak. If your existing chamber ( including throat area) is clean, and centered in the Bbl, it is just a matter of running the Ackley reamer in to cut the new chamber, and deal with headspace. I would guess about $125 to $150. And yes the Bbl. needs to come off of the action (let your smith do that). If there is any throat wear, or issues with the existing chamber, this is a great time to set the Bbl. back a thread or two, and clean everything up. I just had a .22-250 rechambered, and set back 0.040. That was a $170 bill, but it's all new now (except Bbl. of course). Good luck
Thanks for the advice. Between the time I posed the question and your response I talked to a gunshop with a smith. He pretty much said the same thing about removing the barrel, etc. Also quoted me $150.00. thanks guys![:D]
For your better interest, you should take the advice of Nononsense. If that old chamber is not cleaned up properly, you stand a chance of having a false support for your headspacing when fire forming factory cases. I dislike hot gasses in my face, and am sure you would too. There is a big difference between cutting a new chamber, and modifying the old one. Being done right depends on a lot of things, and Hacksaw's advice shouldn't be one of them.
Hawkshaw,
"Sorry I don't buy your stmt."
Fortunately, it really doesn't matter what you will or won't buy. The facts of the proper method to the process is what's important and you don't know and certainly don't understand the facts of properly reaming an Ackley chamber.
From P.O. Ackley himself:
Anyone entering the experimental cartridge field, whether with an Improved or Wildcat cartridge, must have an understanding of correct headspace for the particular cartridge. Many gun shops cut incorrect chambers for Improved cartridges because they know only enough to make themselves dangerous! They often take the seemingly correct stand that since both the standard factory and the Improved cartridges can be fired in the Improved chamber, both must have the same headspace. This is totally incorrect and will result in backed out primers, blown primers, ruptured cases.or worse.
Since most cartridges today are of the rimless type, we will discuss only that configuration for headspace. Headspace is normally considered to be the distance from the face of the locked bolt to a point on the case shoulder called the datum line. This line is arbitrary to a great degree, being a point where the diameter of the case shoulder is .375" in most cases. Some use different diameters as datum points, and one in particular, the original Government .30 caliber (.30-06) does not use the datum point at all but uses the point where the shoulder joins the case body. Commercial .30-06 cases use the datum point. When we start changing things, such as forming the Ackley 40 degree Improved chamber and cases, we no longer can use this datum point for headspace, but must use the juncture point where the neck joins the shoulder. In standard chambers some part of the case shoulder, including the datum point, would contact the chamber to provide proper headspace. But when we cut out the chamber in the shoulder area, as well as some along the case body area, to change to the Improved configuration there is no longer any support for the shoulder of a standard case. Therefore, the datum point and shoulder area of the chamber no longer provides headspace. The only point of contact will be the neck-shoulder juncture. This is a very fine line. And headspace is now held between the bolt face and this neck-shoulder juncture point. The shoulder of the standard factory case is no longer supported by the chamber wall.
To assure that even the shortest standard cartridge brass will fit this Improved chamber snugly, without shoulder support, the standard headspace must be reduced by .004" from that of the factory, or SAAMI, specifications. This now causes the standard SAAMI headspace "GO" gauge to not fully enter the chamber. Thus, the standard "GO" gauge becomes the "NO-GO" gauge for use in Improved chambers! As an example, the standard .250 Savage "GO" headspace gauge in the .250 Ackley Improved chamber will not allow the bolt to close. This is required because the manufacture of pliable brass cartridge cases cannot hold the neck-shoulder juncture point exact, and we do want the standard cartridge to fit rather snugly at this point in any Improved chamber.
Best.
guys I did not intend to start a heated debate. but thank you all for answering my question. I never start a project until I have the information I deem necessary; now I do. The barrel will be coming off and brought in a full turn. Have to to index the sights. then chamber will be reamed. thank you all for your expertise.
Good for you! I'm glad you got what you needed and the project is going forward. While both the Encore and the bolt action rifle will have different needs, the basic concept is the same which might streamline your reloading some.
This isn't heated, it's just a minor disagreement with a clarification required. Virtually all of the members have ethics and manners when it comes to figuring out a solution or solving problems. There is a ton of expertise here on the Gunbroker Forums with the members going out of their way to make that expertise available to everyone that asks on or reads the forums. It's a heck of a great group of folks to be associated with any day.
Best.