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Discussion Starter · #1 ·
i wish to by a tool to allow a couple of my 9mm's to load bullets longer. i see my options as a chamber reamer or throater. i read a couple of months ago that a chamber reamer will do the same job as a dedicated throater, while allowing cleaning up a chamber if needed.

So is this true about a chamber reamer? or just get the throater and be done with it?
 

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i wish to by a tool to allow a couple of my 9mm's to load bullets longer. i see my options as a chamber reamer or throater. i read a couple of months ago that a chamber reamer will do the same job as a dedicated throater, while allowing cleaning up a chamber if needed.

So is this true about a chamber reamer? or just get the throater and be done with it?
A finish reamer such as Manson will throat .060" from the chamber shoulder. A throater will throat as far as you may want. But first I would have to suggest the finish reamer, then if a longer throat is wanted, proceed with the throater.

LOG
 

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Reamer vs Throater

As Log stated on his 10,000th! post, one of our chamber reamers will cut a just-over-bullet-diameter cylindrical section approx. .060" long just ahead of the case mouth/headspacing shoulder. The lead angle then begins at the front end of the cylindrical section and runs down to below land diameter.

Because all cutting surfaces on a chamber reamer have a fixed relationship to each other, moving the throat forward with a chamber reamer will also move the headspacing shoulder forward, something it's good to avoid unless necessary. A throating reamer allows you to lengthen the cylindrical section ahead of the headspacing shoulder without changing headspace and is the preferred method of increasing bullet clearance when other dimensions are in-spec.

Dave Manson
 

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Discussion Starter · #4 ·
thank you for the input gentlemen. Seems like a throater will be in the gift bag this month.

Have a very merry Christmas
 

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As Log stated on his 10,000th! post, one of our chamber reamers will cut a just-over-bullet-diameter cylindrical section approx. .060" long just ahead of the case mouth/headspacing shoulder. The lead angle then begins at the front end of the cylindrical section and runs down to below land diameter.

Because all cutting surfaces on a chamber reamer have a fixed relationship to each other, moving the throat forward with a chamber reamer will also move the headspacing shoulder forward, something it's good to avoid unless necessary. A throating reamer allows you to lengthen the cylindrical section ahead of the headspacing shoulder without changing headspace and is the preferred method of increasing bullet clearance when other dimensions are in-spec.

Dave Manson
I just did the quote to further trumpet my 10,000th post!! :hrm:
So as to not be totally self serving I'll add a little more for clarity.

For those who have never used a finish reamer you should, as the results are the final touch of a barrel fitting, and a vast improvement in function.

Grasp that the finish reamer will not change the chamber depth or head space until the throat and lands are brought into conformity. For those that have used a finish reamer you can attest to the initial cutting of a finish reamer as it cuts the lands and the throat, there is a definite "feel" to this. Once the reamer has caught up to the shoulder one can instantly feel a smoothness take over. This is when the reamer is contacting all the points it is designed for. Manson reamers also sells a reamer collar that fits on the shank of the reamer to limit the cutting depth and affords the ability to pre-set/limit head space.

The reason I suggest to always first use a finish reamer is the chamber dimension as well as the freebore and leade. This assures that the chamber et'al is in conformity, before attempting to further increase the leade, which at .060" will accommodate most all cartridge lengths and bullet shapes.

Back story on barrel manufacturing is they do not use a finish reamer in the barrel manufacture. The chamber is cut with a boring bar, and the rifling starts at the chamber shoulder, no freebore and slight leade. This is why many have trouble with a factory barrel and SWC's. So, my point is always use a finish reamer first, and then if you need more than .060" leade proceed with the throater.

Dang it now 10,001! :rofl: And multiple corrections to boot!

LOG
 

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Congrats Log on the 10,000 posts.

Not just the quantity, but what really matters, the superb quality.
 
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