I don’t know much about chamber reamers, or chamber reaming. Can hand reamers be used to ACCURATELY modify factory rifle chambers in conversion like, let’s say, 222 rem to 223AI, 250 savage to 257 Rob AI, or 223 to 224 Ruger etc.? Must the barrel be removed from the action when using hand reamers? Thanks!

You're trying to cut too much with the chambers you mention. Hand reaming is best done to headspace a short chambered barrel. Short chambered by .025".

DO NOT try this at home!!!
Not saying someone has not done it, but there are easier, more accurate ways. Like removing the barrel and setting it up in a lathe.
Trying it with the barrel installed will be a chore; think about it; an extension has to be used, and how will you keep it centered?

quote:

Originally posted by dpcd:
DO NOT try this at home!!!
Not saying someone has not done it, but there are easier, more accurate ways. Like removing the barrel and setting it up in a lathe.
Trying it with the barrel installed will be a chore; think about it; an extension has to be used, and how will you keep it centered?

That’s kind of what I was thinking. Thanks!

How about extending throats?

That's different; you can extend throats but by hand it is hard to tell how deep you are cutting; just go slow and be careful.

quote:

Originally posted by dpcd:
That's different; you can extend throats but by hand it is hard to tell how deep you are cutting; just go slow and be careful.

Ok thanks.

I've also thought about this. The problem as I see it is (as DPCD noted) is trying to keep the reamer centered on the bore. So you would want the pilot to be in the bore before the reamer starts cutting. Most reamers I've seen don't have long enough pilots for this to occur.

They will self center until the pilot engages, but when you are hand reaming you might (will) place side pressure on it and make the chamber whopper jawed. Which is a bad thing.

The only way that hand reaming has any hope of not making an off center chamber is to have the barrel removed, and clamp the barrel securely in a vertical position, where the reamer can be operated from above. This places the operator in a natural position to not pull the reamer off-center as easily, and to see what they are doing more clearly.

Having the breech end exposed to clearly observe what is happening is essential to doing this well. Working through the receive is a recipe for problems.

I suppose a tight fitting receiver guide bushing could be utilized, but that would certainly add an element of complexity to the operation.

Just found this video. Is it a hand reaming method?

https://m.youtube.com/watch?v=2cKZo5B2uoQ

Yes, he is lengthening the throat.

quote:

Originally posted by dpcd:
Yes, he is lengthening the throat.

Cool! Thanks!

PTG uni-throated:

https://pacifictoolandgauge.co...ni-throater-kit.html

“The Uni-Throater/Necker concept was developed by Dave Kiff to enable gunsmiths to perform precise, repeatable operations quickly with a simple hand tool. The tool features a removable pilot which guides a 6-flute HSS (high-speed steel) cutter. What sets the Uni-Throater/Necker apart from ordinary reamers is its unique method of controlling depth of cut.

The straight portion of the cutter passes through a sliding bushing with a tapered shoulder at the front end. The bushing is precisely honed so that the cutter can rotate or move axially with ease, but lateral movement is virtually zero. Behind the bushing, the cutter shank is threaded with micrometer threads (40 TPI). A brass adjustment nut, backed by a knurled lock nut, controls precisely how far into the throat the cutter can reach. The adjustment nut features five equidistant grooves around its circumference each groove corresponds to .005" (.13mm) of axial adjustment. Adjustments as small as .001" (.025mm) can be made with confidence.

To set up the Uni-Throater/Necker, gently insert the cutter into a "control" chamber (or a dummy chamber cut to the correct dimensions), turning in the "backward" (non-cutting) direction, until the cutter contacts the rifling lands in the barrel. Zero the adjustment nut against the sliding bushing for a rough adjustment, then tighten a little more (forcing the cutter slightly back out of the chamber) and lock the nuts. Now cut a throat/neck in a new chamber and measure the result. To increase the depth of cut, carefully back off the adjustment nut, lock in place, and cut again. Repeat this process until you achieve the required throat/neck dimensions. You now have a tool set up to cut the exact same throat/neck every time!

The Uni-Throater/Necker can be used conventionally, in a lathe. It also is threaded for attachment on our Uni-Throater T-Handle. With the T-Handle, you can perform throating operations in barrels while they are assembled to the action/stock. There is also a threaded Shank Extension available, which converts the Uni-Throater/Necker to a 3/8" (.375" / 9.5mm) square drive. This drive is compatible with our Chamber Reamer T-Handle and common square-drive implements. If you require either a Uni-Throater T-Handle or Shank Extension, consider purchasing our Premium Uni-Throater/Necker Kit, which includes these accessories at a discount from their individual prices.

The standard shoulder angle for the Sliding Bushing is 30 degrees. In the chamber, this shoulder will contact HIGH on lesser shoulder angles (e.g. the .270 Winchester family of cartridges), and contact LOW on greater shoulder angles (e.g. 40-Degree Ackley Improved cartridges). Usually, this limited contact is adequate to control depth of cut while maintaining concentricity, but a little more care must be taken in the setup to avoid overcutting the chamber. Pacific Tool and Gauge sells replacement Sliding Bushings, and for an extra charge we will manufacture your Sliding Bushing with a custom shoulder angle. Refer to the Sliding Bushing product page for more information.

Uni-Throater/Neckers are available for most SAAMI cartridge specifications. The exceptions are shoulderless cartridges (e.g. .30 Carbine or .44 Remington Magnum).


NOTE: All PTG Reamers and Cutting Tools are designed to work with petroleum-based lubricant. Water-based lubricant can give acceptable results, however the life of the tool will be reduced. For best results use petroleum-based lubricant.”

Ive seen many 22 hornets, 218 bees, and a few others cut out to IMP chambers, heck you could almost do that with a fingernail file. I wouldn't want to go much beyond that, but I know many that did back in the day, and they cut good chambers by golly...Id say skill and experience is the key..