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Hand reaming Ackley in new barrel

RonnieMilsurp

RonnieMilsurp

Gold $$ Contributor
I know this is a topic of other threads here. I did read this one that is pretty pertinent:

Ackley Improved reamer

Is it possible to run an Ackley Improved reamer, by hand, through your action and ream your chamber without removing the barrel from the action? Then, fireform your brass... Thanks in advance! Steve
forum.accurateshooter.com

But my situation is different in that my barrel is new and is a "pre-fit" barrel from Lothar-Walther that is short chambered (by how much, I don't know yet). My understanding is to go fully finger tight and then go 1/8" past that with the action wrench in the vise (per Larry Potterfield, at least!). Then finish reaming out a few thou at a time checking often with gauges and a bolt without the firing pin assembly.

I know that Ackley chambers are 4 thou shorter at the neck/shoulder junction and I figure the existing chamber has to be quite a bit shorter than that at the moment, so I should be good. Also, given that the Ackley dimensions are wider and shoulders farther forward, I really don't anticipate a scenario in which the reamer I use is smaller. I plan to rent a reamer from 4D.

What I'm asking:

-Does anyone see an error in my thinking?
-Any tips on hand reaming? I have a t-handle extension and cutting oil. Am planning on doing it with the barreled action vertically oriented in the vise.

Thanks!
 
Rechambering a barrel to a larger diameter case with a reamer is always a crapshoot, even in a lathe. With the larger Ackley shoulder, the reamer starts cutting long before the pilot can center it in the rifling. The best that can happen is that it follows the existing chamber. Hand reaming (unlike the tailstock in a lathe) can never push the reamer straight into the bore without some sideways pressure, which produces a larger chamber and more than likely off center from the rifling by the time the pilot arrives there. I would spend a few more bucks and get someone to do it in a lathe. A lot more can go wrong by hand reaming nearly all the chamber, as opposed to reaming just a few thousandths in a normal short chambered barrel.
 
SBS, thanks for that info. I had wondered about that exact thing. I don't suppose they make a reamer with an extra long pilot, do they? Would a pull-through reamer do the trick? If so, can one be rented? Seems pretty specialized considering it's AI. PTG doesn't list one in AI but I wonder if they can make it.

Ggmac, it's on a Mauser clone Zastava.
 
RonnieMilsurp said:
Thanks. PTG lists quite a few pull throughs. What's that about?

Pull-Through Chamber Reamers - Pacific Tool and Gauge

Pull-Through Chamber Reamers at Pacific Tool and Gauge
pacifictoolandgauge.com pacifictoolandgauge.com
Click to expand...
They use them on mass production. They almost chamber complete, install and finish the barreled action, then crank the pull thru til the bolt closes. They usually do this on cheaper guns. Ptg makes OEM reamers so thats why they are there
 
Click on one of the pull-through reamers and read the info. just under the reamer. "made to ream the last few thousandths of short chambered barrel". Normally used for semi-autos where is not convenient to remove the bolt and the barrel for the several "tries" that are encountered on firearms that are not made to such tight tolerances that simply reaming to a specified dimension will work. Plus semi-auto gas guns have ports that have to be centered on the hole in the gas cylinder, so if you can't chance chambering too deeply and then turn the barrel in some more to fix it -- which you can commonly do in bolt guns. Also noticed all I looked at featured solid pilots, which means they have to be undersized so they will fit all barrels of that nominal bore size. That doesn't help in centering the reamer either.
 
Gotcha, thanks Dusty and SBS. Makes sense.

Regarding the standard chamber reamer pilot not reaching the bore before the wider shoulder starts to cut, is this 100% certain? I ask because I just took some measurements on the 30-06 AI reamer I have and (if I'm measuring correctly) there seems to be enough length that the pilot is just starting to engage the bore dimension at the moment the shoulders start to cut. I know that "just starting" is not the same as fully engaged. I also know that it may not be the same on a 6.5x55 reamer.
 
RonnieMilsurp said:
Gotcha, thanks Dusty and SBS. Makes sense.

Regarding the standard chamber reamer pilot not reaching the bore before the wider shoulder starts to cut, is this 100% certain? I ask because I just took some measurements on the 30-06 AI reamer I have and (if I'm measuring correctly) there seems to be enough length that the pilot is just starting to engage the bore dimension at the moment the shoulders start to cut. I know that "just starting" is not the same as fully engaged. I also know that it may not be the same on a 6.5x55 reamer.
Click to expand...
You can have the nose ground longer
 
Thank you, Dusty. I just put in an email to PTG to see if they will do this.

Paul, thanks, I totally get the logic there. My problem is that I have this urge to always push myself to try new things. Being a classic car mechanic/small shop owner, I have been conditioned to not be afraid to do big things, sometimes at my own peril!

Then there's the whole thing of waiting several months to get the job done...
 
RonnieMilsurp said:
Thank you, Dusty. I just put in an email to PTG to see if they will do this.

Paul, thanks, I totally get the logic there. My problem is that I have this urge to always push myself to try new things. Being a classic car mechanic/small shop owner, I have been conditioned to not be afraid to do big things, sometimes at my own peril!

Then there's the whole thing of waiting several months to get the job done...
Click to expand...
What it is they will set the reamer back but since they cant drill and tap the end it just gets longer. So if you change neck dia or freebore the bushing is still in the same spot but everything else is farther back. Just got one back from jgs thats at least 1/4” longer on the front end
 
you can measure your cartridge case that’s sticking out of the barrel and determine how much exactly needs to come off .
Insert complete bolt with the trigger assembly and minus extractor , with a depth mic , read the distance to the bolt face and the inner collar , you should have aprx .110 IF I REMEMBER CORRECTLY, subtract the cartridge protrusion ( base of cartridge to barrel face ) from what you have on the receiver . Of course youll have to push the shoulder back on a dummy cartridge or two ( to get your short chambered spec )
Hope this makes sense .
I usually use the lathe to get within.003-.005 then hand ream .
 
Tommie, did you do them from contoured blanks or were they short-chambered?

Jackie, thanks for that info. Are you referring to their "LW50"? I got a chrome moly barrel.

Ggmac, thank you.
 
RonnieMilsurp said:
Tommie, did you do them from contoured blanks or were they short-chambered?

Jackie, thanks for that info. Are you referring to their "LW50"? I got a chrome moly barrel.

Ggmac, thank you.
Click to expand...
Yes. They call it a proprietary Stainless alloy, but it is a type of Precipitating Hardenning Stainless similar to 17-4.

I would assume their chrome moly barrels machine like any other unless they are tempering the material to a higher RC hardness.
 
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