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Reamer Free Bore

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Gary Manteit
Gary Manteit's picture
Reamer Free Bore

What free bore for a 6PPC are you using? I have a Manson reamer with 50th free bore which works well with flat base projectiles but is too long for a lot of boattail projectiles. They only just enter the case mouth when seated out near the lands. Manson will re-grind the free bore of the reamer and I was thinking of reducing it to 20th. What are peoples experience with free bore length?

Thanks
Gary

proquip
Free Bore

You also need to consider the case length - this can vary from 1.505 to 1.522 depending on the reamer spec. My std is 1.518 case length with a 040 free bore unless the customer requests otherwise - this suits projectiles like the 65BT just touching the lands. 020 FB would be fine providing the case length is not also on the short side.

Cheers

David

Michael Huebner
Michael Huebner's picture
Reamer Free Bore

As per David you need to also consider the case length of the reamer.

If you are going to use bullets made on 0.790 jackets case length of around (1.510) to 1.515 and free bore of (0.030) to 0.025. Some are using 0.00 free bore with 790 jacketed bullets, with case length of 1.515

My reamer is 0.030FB with 1.510 using 790 jacketed 7-9ogive bullets with 0.075" boat tail and it could be shortened to 0.020" no problem at all. This can also use Berger 65BT which from memory have a BT of 0.125"

I am assuming you have a case length of 1.520 + 0.050FB which is fine for 820 or 825 jacketed bullets. So nothing wrong with that reamer just use bullets made from the longer jackets around 67-68gns or use FB only from 790 jacketed bullets.

The question is what bullets are you using? Or what bullets do you want to use?

Cheers

Michael

Gary Manteit
Gary Manteit's picture
Reamer Free Bore

Thanks David and Michael your input is appreciated. Checking the reamer spec sheet the reamer cuts a 1.525" chamber. I have been using the cases from the old barrel which I replaced and were trimmed to 1.490' for a 1.500" chamber. I will make up some new Lapua cases trimmed to 1.515" to see how they go. An extra .025th may be enough to hold some of the boat tails. Manson will re-grind the Free Bore to .020th for $50.00 so with that extra .030th I should be able to handle all projectiles.

Gary

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