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I see there are a few different styles of chamber reamers available. What are the differences in use and functionality? Will any type of chamber reamer allow you to throat your chamber to lengths suitable for a particular bullet, or is one type required over another for this task? Thanks in advance for any replies. I've got a pretty good idea how this stuff works, but I'm a little in the dark on this issue.

Thanks,

Steven
 

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I'm not a gunsmith by any stretch, but based on what my gunsmith has told me, most reamers set the throat as they ream the chamber. I was thinking of rechambering a short action rifle to .257 Roberts, and he said the reamer he had would make the throat too long. He can lengthen a throat with the lathe, but apparently you need a different type of reamer to make custom throats. Sorry I can't be of any more precise help. Hopefully someone will chime in, here.

IDShooter
 

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Hi, Steven:
Some time ago Mr. Gates suggested using a throater on short throated Marlins in .35 Remington. I never did mine, but he said it's simple operation. Dave Manson lists throaters and neckers for $30, about half way down this page. I suppose a necker is used to ream out a tight benchrest neck to standard dimensions.
http://www.mansonreamers.com/Pricelist.htm

Clymer has throaters too. This is a messed up site, as the links don't work and the catalogue is a PDF file.
http://www.clymertool.com/catalogue/index.html

Bye
Jack
 

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I have used a reamer to rechamber revolver cylinders, and have used a throating reamer on several 45/70's. The throaters are available from Brownells. I did not find it hard to do at all. The firearms in question are a single shot, and two leveractions that had short throats from the factory. I wanted to use bullets from a mould that I like and had to cut the throat deeper. If you go slow with lots of liube it is fairly easy to do. All three shoot accurately with the cast bullets.
 

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I buy Manson reamers from Brownell's and Manson.

The technical explanations on the phone are excellent at both sources.

I use the reamer design feature of the Clymer website to get the dimensions of some chambers.

I have made my own reamers, and modified reamers, and used a boring bar, and used drills and chucking reamers etc. That kind of effort usually comes out poorly for a complicated tapered cartridge. I will change the throat that way, but a real throater sure is better.
 

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The Hog Whisperer (Administrator)
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OK, there are several kinds of reamers that are commonly used in cutting chambers. Basically any reamer is the same at heart, they all cut some metal to make a hole larger (or a different shape) by being turned in an existing hole.

As you are no doubt aware, they resemble a drill bit more than any other kind of cutting tool. There might be straight flutes, spiral flutes, adjustable cutters, different kinds of pilots, and basically there is no limit to the exact shape you can make one.

For gunsmiting work, you will find two basic types. The first is an 'all in one' reamer where the chamber is cut along with the throat, to make a standard chamber. If you push this type of reamer further into the chamber to lengthen the throat, it will change your headspace!

To lengthen a throat or increase the diameter, a smaller throating reamer is used. It does not (should not!) change the headspace.

To further specialize, a throating reamer may be either straight or tapered. For a revolver throat, normally a straight reamer would be used. For a rifle throat, they commonly have a slight amount of taper and this should be accounted for in the shape of the reamer. Plus you have the transition to the rifling so an angle on the front of the reamer is added so that you don't have a square shoulder on the end of the land.

Also reamers can have solid or replaceable pilots, or no pilot at all. The pilot keeps the reamer in line with the bore. So that's a desireable feature, assuming the pilot is the correct size.

A common over-the-counter straight reamer (sometimes referred to as a 'decimal reamer' because you just buy them according to the size in thousandths of an inch) would be cheap for extending throats but probably not the best choice for serious gunsmithing.

As noted, it is possible to cut chambers with boring bars, etc., but the reamer makes the job much easier.
 
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