Gunsmithing Question about Chambering/Reaming

[Danco411]

Hello Hide gunsmiths. I'm a fairly competent, self taught armorer and Cerakoter. I've been venturing into more and more home "smithing" as time and money permit. Pardon the simplicity of my question but I figured you guys would tell me if this is something I can do or would farg it up.

Is it possible and even feasible to ream a .260 Remington chamber to an AI chamber myself? I'd like to go AI and would be willing to "guinne pig" one of my barrels to try it if I have a reasonable chance of success. Can anyone tell me 1st if I should try it, 2nd what tools I would need and 3rd the basic process for doing it.

Mucho thanks!

 

[LRI]

Yes.

Take a rev or two off the tennon threads and shoulder first though. You can't "truck and trailor" an AI reamer behind the parent case. It won't headspace correctly.

Measure twice, cut once.

Good luck.

C.

 

[NXS338]

What kind of rifle is it? Is it a remington?

 

[Red_SC]

Planning to do that exact thing soon, only in .223. You'll need a barrel and action vice to take the barrel off. Chuck it in the lathe and set the shoulder for the recoil lug, the back of the tenon, and the bolt nose recess back a little. Run the reamer in to desired headspace, screw everything back together, and you're done. That's the process for a Remington, anyway. You up for it?

 

[Danco411]

No it's a Savage. I have basic tools but I guess I should have asked if it could be done without a lathe. LOL

 

[CowboyBart]

A Savage makes it easier, but you'll still need to take your barrel to a machine shop and have them "face" the breech end of the barrel. Hopefully you already have a Savage barrel nut wrench - you'll need one.
Pull your barrel off
Drop a FL resized piece of brass or a Go Gauge down the chamber
Measure how much protrudes
Go to a machine shop and have them take .060" off the breech
Rent/buy the AI reamer and reamer "T" handle
Rent Go/No Go gauges (you might be able to avoid this if you keep your FL sized piece of brass segregated/marked and are feeling lucky).
With LOTS of dark/high sulfur oil, flush the chamber with oil as you hand turn the reamer
Stop and check often - using the Go gauge or your FL sized brass - for the same amount of protrusion you had before you started.

The lucky part comes in that your sizing die has the same headspace spec as the reamer. Even though you are going to an Ackley, it still should headspace on the brass OK. I THINK the No Go standard chamber gauge is used for an Ackley Go gauge. I could be wrong on that, I have to look it up every time too.

IF you go too deep with the reamer, your headspace will be excessive. If you know how much excess it is you can go back to the machine shop and have them take off the additional length to get your protrusion back to where it should be.

If you want the Savage barrel lettering to line up where it is now, tell me if you have a small shank or large shank Savage. I'll look up the thread pitch and tell you exactly how much to take off the breech. The 060" was just a round #, but if your barrel has lettering and you want the lettering in the same spot, you'll need a more precise number.

FYI - I am not a machinist or gunsmith. I am a truck driver that dabbles with a lathe in the wee hours of the night.

When the machine shops dials in your barrel to face it, if you are standing there with the reamer and gauge(s), it would be real easy to ream the chamber then - to the correct depth. I would think that in MI, there are a lot of out of work machinists or small machine shops that are slow and will do a cash job while you wait (watch).

 

[Red_SC]

I THINK the No Go standard chamber gauge is used for an Ackley Go gauge. I could be wrong on that, I have to look it up every time too.

Nope- an AI cartridge has shorter headspace than the parent to have a crush fit on un-fireformed brass. A No Go gauge is longer.

 

[rlwilson]

Pretty sure it is The GO gauge of the standard cartridge that is the NO GO for the Ackley. The standard cartridge must have a crush fit in Ackley chamber to form.

 

[LRI]

Parent case No Go becomes the go for an AI. You are correct. Need to feel a pinch when chambering parent case brass. This gives the case the ability to FF w/o stretching the web.

c.

 

[rlwilson]

Now I am confused.

 

[JBRC]

Parent case No Go becomes the go for an AI. You are correct. Need to feel a pinch when chambering parent case brass. This gives the case the ability to FF w/o stretching the web

c.

This doesn't sound right. A No Go is +.005" longer than a Go. For a parent case to have the "pinch", the chamber would have to be
shorter not longer right. *I've set my AI's up Go 0.000" or -.002". To get the case to fit tight to limit stretch.

 

[CowboyBart]

Turns out both small shank and large shank Savages have a 20 TPI pitch. So, when you go to the machine shop and have them face the barrel breech, have them take off .050" (not .060"). This should get your lettering back in the same spot it is now.

 

[LRI]

This doesn't sound right. A No Go is +.005" longer than a Go. For a parent case to have the "pinch", the chamber would have to be
shorter not longer right. *I've set my AI's up Go 0.000" or -.002". To get the case to fit tight to limit stretch.

Ooops, your right! The parent case GO becomes the NO GO for an AI cartridge. (proof read yo' chit before posting Chad!)


Sorry bout that.

 

[wadebrown]

I have not done very many chambering jobs but I headspace so the action just closes on the parent case a go gauge and a 0.004" feeler gauge between the recoil lug and the shoulder of the barrel. I checked the closing of the action about 5 times with the feeler gauge in different spots. Then used the scotch tape method for no-go gauge.

Let me know if I am doing something wrong, also let me know a better method when using say a .308 go-gauge to headspace a .260 AI. I realize a set of gauges from the reamer manufacture for the AI is probably the best way to go, that is the way I went with my recent .280 AI.

Thanks
wade

 

[CowboyBart]

So with the gauge issue cleared up should the OP NOT take .050" off the barrel?? Should he take .048" or .046" off??
Or should he take the .050" off but add .003"-.004" to his "protrusion" number?? Basically don't go in as deep with the reamer.

 

[LRI]

The defacto practice on M700's is to peel a rev off the tennon/shoulder. That equates to .0625".

This gets you into fresh meat so that the reamer fully qualifies the new chamber. If your working with a finer pitch thread my guess would be to take at least that much. If the barrel is fluted or there's some other devices that commands a certain clock position, then adjust the amount accordingly.

One could eyeball the prints and work on some fancy math to figure out the theoretical minimum required, but rarely do numbers like this actually pan out when your on the machine doing the work. You have to factor in things like thread crush and every action is a little different in this regard.

C.

 

[CowboyBart]

All ya have to do is take the reciprocal of the TPI and come up with the thousandths that need to come off in order to keep the sights or lettering indexed. On a Savage you don't have to worry about the shoulder - there isn't one.

Mauser and other 12 TPI = .0833"

Ruger, Rem, Win.. and other 16 TPI = .0625"

Savage and Rem 760 and other 20 TPI = .050"

Springfield, '17 Enfield and other 10 TPI = .100"

OP, I would take the full .050" off the breech then go in with the Ackley reamer, but not all the way to your original protrusion number. I would leave yourself .004" proud.