Home Forums Hunting & Shooting Gunsmithing Throat Reamer question

Looking to lengthen the throat of my 6.5-284 Win (Short action) rifle. It is built so that the max cartridge length that the action /magazine will handle is approx 2.92 inches while still being able to fit in the magazine and eject a live round. It has a Douglas 1-9" twist barrel and will currently chamber a loader round using a Swift Scirocco of approx 2.90" but when using the Hornady 129 gr interlock the longest OAL I can chamber is 2.76" due to the longer ogive. I would like to lengthen the throat approx .100 so that I can shoot the Hornady bullet at a longer more usable OAL and also possibly provide the jump that the Swift bullet may like. When renting a throat reamer will the standard reamer kit work for me with the larger diameter of the .284 shell as the sleeve provided will have the proper 30 degree angle but will be a loose fit not providing side to side support. Will the lead of the reamer in the rifling provide enough support ? Any advice appreciated or if anyone knows a gunsmith that will do this at a reasonable charge preferably in the NorthEast. This is the reamer I am thinking of renting.


https://4drentals.com/product/6-5mm-precision-throater/



Thank you
gdc

Throating reamers only cut the throat and lead. They do not work on the shoulder or rest of the chamber (if I understood your question).
In the case of the 6.5-284, you would need a 6.5 throater (as you linked) but the parent case has nothing to do with it.

An operation conducted by many savvy smiths and shooters. Key to success depends as much on accurate employment of the reamer as the design/specs of the reamer itself.

I wouldnt worry about renting a throater, there's a good chance if you pick a smiths who's been around awhile he will have one. Try Mark King in PA.

If you have never throated a barrel, and you do not have a lathe or access, suggest you give it to a smith to do.
Two best ways to screw up a barrel is to cut a crown or throat off perpendicular to the bore.

Would you mind clarifying the last comment on the throating?

If your reamer isn’t perfectly aligned with the bore it won’t cut the throat in perfect alignment with the bore. Therefore when you fire the rifle the bullet will yaw a bit causing accuracy issues. It doesn’t take much to be off. When the barrel is put into the lathe chuck it is lined up with the center of the lathe tail stock where the reamer is so this doesn’t happen. Its been a few years since I did any machining so this is a basic run down. I’m sure you can YouTube the process and it will make sense once you’ve seen it done

For one thing, your theory about the tailstock alignment is all wet you are correct to assume the throat should align with the bore, but not the tailstock, they are often not aligned correctly. The barrel should be aligned in the lathe with the bore concentric with the axis of the lathe on both ends. The pilot on the throater should be fairly close fit to bore.

All of my throaters are simple piloted reamers. There are some rudimentary skill requirements, but it is a straight forward operation (no pun intended). One potential issue is if you are trying to ream a 5R barrel (five groove) with the typical six groove reamer. The reamer will have a tendency to deflect due to uneven cutting forces. For five groove barrels, a five fluted reamer of a spiral fluted reamer will work OK. A very close fitting pilot is beneficial as well. I'm working on some instructional videos which I'll put on You Tube in the next 2 or 3 weeks (video production is harder than I thought!) and the use of a throater is one of the intended subjects.
I have seen some more complicated throater set-ups in recent years but have never tried one. I probably never will. GD

Greydog, Give us a heads up when your videos hit broadway. I've always had a fear of independent throating, so many rocks and shoals, such poor navigational aids.