Home Forums Hunting & Shooting Gunsmithing Reamer modification on 6mm

The chamber on an improved 6mm I have has 150 thou freebore which is way too long for the new pointy 90 grain Sierra TGK. It's ok for the less pointy projectiles that have a much lower bc. I run out of magazine length 3.04" and also neck length because of the aggressive boat-tail when trying to seat near the lands. Accuracy is poor because of this. I'm wanting to set the Model 70 barrel back 2 threads (total 0.125") and recut the chamber. I'm assuming I probably need to get a new reamer with around a 0.020 to 0.040" freebore. Would if be really difficult to modify my existing reamer either so it has a reduced throat or no throat at all so it just cuts the chamber without the throat? If it didn't cut the throat then the barrel set back of 2 threads would be just right. Thank you.

You may want to consider having the reamer done with no throat and then throat separately for your specific application.

With the exception of some specialized BR chambers, most all my barrels have been done this way.

Good shootin' -Al

Yes, but I wouldn't have to do the throat as I could use the old throat which would be shortened by 0.125". So my question is, can my reamer be reground to be able to do this, as it will save me a lot of money on a new reamer.

Rifle,
You can do the conversion you want. Load a dummy round with the freebore and COL you want and send it to Manson reamers. He will reduce the throat by the amount you want. He can even totally grind the existing throat off your reamer and then you throat as you desire.
Bill

Thank you.

Oh, I savvy what you're trying to do.

My suggestion is to have your 'smith back it up enough to cut a complete new throat after the reamer has been modified.

Good shootin' -Al

I spoke to him. He can grind the throat off the reamer (he's done that before) and use a separate throat reamer. Thanks.