I have acquired a 9.3x66 reamer, and would like to rechamber my husqvarna 9.3x57 to 9.3x66 sako. Same bolthead, magazine box is long enough etc.
Is it possible to accomplish this without go, no-go guages? using a factory round, eg, and a couple of sheets cigarette paper for approx 2/1000 increased clearance? Excessive head space is unlikely, since factory cartridges are if anything slightly undersized; andf I wont be using factory ammo, just reloading (neck sizing, so headspace will be controlled.
Any thoughts?

Interesting hypothesis. I just picked up a chamber reamer in 9.3 Sako as well. I am looking to go the custom route myself but I'd guess that it would clean up a 9.3x57 chamber.

As far as head-spacing goes, I would not use 9.3x57 gauges. If you can't, or aren't willing to buy some 9.3 Sako gauges, try and find some 9.3x62 gauges. The 9.3x66 was developed by running a regular 9.3x62 reamer an additional 4mm into the chamber.

I'm sure you're aware, but in case you aren't, Beretta is finally importing the Sako rifles in this chambering (they changed the designation to 370 Sako Mag.) and Federal will have factory ammo later this year. I think it's a tremendous idea - close to 375 H&H performance, no bolt-face or magazine box mods, can surpass 9.3x62 ballistics, and still get 5 down.

so the 370 Sako Magnum.......maybe I do not need the added work of the 9.3X70

Z hat is selling dies, brass, loaded ammo, and will build you a rifle! brass isnt bad at all, actally.

I understand that Sako made the 9.3x66 as long as possible to still work through the Sako T-3 action . I also understand the T-3 action the be a couple mm longer than the mauser 98 action. Is this not likely to create a situation where the longer heavier 9.3 bullets must be seated very deep and rob some of that increased case capacity. If you stay with bullets of 250 grs or lighter that may not be a problem.

Is the old Husky really safe with, what I assume, the somewhat larger pressure?
Just trying to be helpful here...

If the magazine box is factory and already long enough, it almost has to a '98 or the later Husky-designed small ring derivative so it should easily be safe for modern pressures. None of the '96 Huskies chambered for 9.3 x 57 had boxes big enough for the 9.3 x 66.

That said, I have a factory-built 9.3 x 62 on a '96 action from Stiga that I would be very leery of changing to a 9.3 x 66.

Why mess up a nice old Husqvarna in a classic cartridge just to have the latest fad?

Not to be a smartazz...but why not just take the reamer and rifle to a 'smith...the cost should be nominal...it's nothing more than a simple lathe setup and running the reamer in the additional 10 mm.

If the 'smith knows his business and has an extention handle to hold the reamer you won't even have to remove the barrel...plus he can check over the rifle at the same time if you have a question about it's safety.

You can rent gauges from several reamer rental places for 5 to 8 bucks.

I'm not very familiar with the 9.3x66 and none of my reference material has it listed so I can't comment on the pressure, but it sounds like a slightly long 9.3/30-06 to me so you should be able to use MAP pressure for any 30-06 conversion such as 338, 35 Whelen, 375/06 etc as a starting place for loads. All I found online seams to indicate the same. You could also email Sako for information on the case dimensions...they've always been very accomodating in that reguard when I needed information.

Yes, you can use a sized case as a go gauge...I've done it many times as a matter of courese, to adjust the chamber to the sizing die to reduce the amount of shoulder setback or just to get the best fit between sizer and chamber, but I always have a go gauge to check against to stay within standard specs.

I wouldn't use the thought of factory ammo having a "shorter" shoulder point as any basis to use a factory case as a go gauge...that is "wrongway" thinking. It may be true in many cases but if you are working without complete knowledge of the cartridge you could be on your way to ruining a chamber.

The factory 9.3x62 brass I bought was even shorter at the shoulder than the reworked and sized 35 Whelen cases I will use and if I had used one of those factory cases I would have had a chamber near 0.015" too short and I would have had to grind the face of the sizing die to get it to size a case for the bolt to close. Better to be slightly too long at the shoulder than too short.

I'm doing a 9.3x62 right now on a VZ24 action. The go gauge is 0.010" longer at the shoulder than a sized case so I headspaced where the bolt wouldn't drop on the go gauge and the sized case has a bit of play. Ended up where a fired case shoulder was 0.004" shorter that the go gauge...not quit splitting the difference between sized case and go gauge, but a fired case will need only 0.002-0.004" shoulder set back using Redding Competition shell holders to get the best fit and least amount of brass movement during sizing.

There is always a certain amount of tolerance range stipulated for chambers, dies, headspace and all the rest of the components...0.004" to 0.008" "nominal" for headspace, metal heats up and stretches and all the rest of the requirements of manufacturing (of any kind) which need to be taken into consideration when doing any kind of chambering.

I want my brass to last as long as possible, fit the chamber well, and have no problem with bolt closure or ejection, so I picked using the sizing die tolerance as the best compromise and try to keep headspace as near "0.000" to plus 0.005" as possible depending on the use of the weapon. Everything tightens up in a target weapon and loosens up in a hunting rifle within a range I determine for each weapon.

Maybe this information will help or maybe it will give you a headache...chambering is a simple piece of lathe work as compared to threading, but you still have to keep your head screwed on right or.....

'Njoy