I want to have a new reamer ground and I am confused about free bore. After seeing the reamer in Precision Shooting April issue on page 49 it has just .015" free bore. Ok German Salazar's 30/06 has .086" free bore and He is shooting 200's with 20 shot strings at 1000yds what's the deal here?
Free bore or throat for 30/06 how do you figure it
- Thread starter buzzard
- Start date
buzzard: Freebore length will depend on the type of bullet you intend to use, as your first choice, and how far out of the case neck you want to seat it when the chambering is new, unfired. A serious consideration, since you would not want to start out with the bullet 3/4 of the way up the neck, and after several hundred rounds fired (depending on the cartridge) you may run out of neck length to hold the bullet. I recently spec'd a 6ppc. chambering reamer from Pacific, decided on my bullet of choice (68 Berger ), seated with the base of the bullet very close to the neck/shoulder junction, thought it would require a zero freebore, sent the dummy round to Dave Kiff for his confirmation, and sure enough, the reamer came with zero freebore. While you're at it, you may as well also specify chamber neck dia. ( I like tight, no-turn necks), and chamber overall length, ( I like .010" longer than max case length). Specifying these dimensions will give you the exact chamber dimensions you want, not what someone may have available in their shop. Custom barrel, why not a custom chamber also? 
If I were to get another .30-06 reamer, it would have a 0.338" neck diameter and 0.136" freebore (0.050" longer than the curent one). That slight extra length would be useful with the longer bullets and the .30-06 neck is long enough that it wouldn't hurt with shorter bullets. Throat erosion on a .30-06 is pretty minimal too.
I check all my bullets size and bearing surface turn necks to .013" wall my chamber neck is .335" on the end and 336 at the shoulder, My sizeing die is .001" smaler than my reamer so I do not work out side of the elasticity of my brass so, ( I have no bananas) Also use my chamber reamer to make the bullet seating die and neck sizeing die. thanks for your help You are the Man
rcw3
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buzzard said:
The reamer in the article was a 308 Winchester reamer (not a 30/06 reamer) throated specifically for the 155 gr Sierra #2156 bullets and the 155.5 Gr Berger FULLBORE bullets. That reamer needed a short throat or those 155-155.5 gr bullets would be way up in the neck of the case. The reamer shown in the P.S. article was not designed for use with bigger and heavier bullets.
Robert Whitley
Ok Robert a 155gr match bullet has and average bering surface of .533" the 308win has and .3032" case neck that gives you .2298" of bullet bearing surface sticking out of the case. If you seat the bearing surface all the way down in the case neck, do you not think with the kinda bullet run out you get with a bushing neck sizer that you will not get better accuracy with the bullet sticking up in a tight free bore as far as you can get it? Oh by the way are you a jumper or a jammer?
Buz, I saw Clark Fay this weekend and he tells me you're getting some great accuracy from your .30-06, nice going.
I shot some 155.5 Bergers at 300 yd. from the .30-06 this weekend, good accuracy (150-10X MR63 target, irons, prone). I would say about half the bearing surface was in the neck, I can check specifically later if you want. That was for a 0.010" jam.
I shot some 155.5 Bergers at 300 yd. from the .30-06 this weekend, good accuracy (150-10X MR63 target, irons, prone). I would say about half the bearing surface was in the neck, I can check specifically later if you want. That was for a 0.010" jam.
The RT-10 Clark put together for me is showing alot of promis, I was testing 155gr bullets with H4350 and getting some unusual results with the 32" barrel my buddy that was testing with me said he thought it was loading up with powder residue the fps would grow up with the same load and peak and fall as much as 6ofps. So Im going to test some in the 180gr range before I do the 210's. Clark said Trudie was on the US palma team hope things are going well for her.
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