What does "zero" freebore mean

Jackie,
I can see that most all like the Lapua brass better because it is better, and Remington 7BR brass may be junk, but that's what I have and what I will be working with till I can find some Lapua.

I am NOT building a 30 BR to shoot "tin cans", I have much better ways to waste my time and money. And my goal is NOT to become a famous benchrest shooter, or to even be in the top 100. In fact I'm not building a benchrest rifle as you guys know them, it will be used mostly for BR but also for a bit of offhand. Need something with low recoil, with better accuracy than a factory rifle, about half of the shooting with this rifle will be with breech seated lead bullets, it's going to be one of those one gun do everything rifles, probably wont do much of anything real good, but it will be a way for me to get into a lot of different shooting events by conforming to all the different rules without building 5 different rifles.

Being retired, somewhat disabled, and on a limited fixed income I cant afford what some of you guys can. I've been a target shooter going on 50 years now but never had to set down to shoot and never built this type of rifle so am very green at it. Anyway I want to give it a try and wanted to stay with a low recoil accurate 30 caliber.

Thanks for letting me know that it will be ok to trim to 1.500. My gunsmith is not an extreme accuracy guy but knows a lot about general gunsmithing and has done more than his share of re-barreling, been doing it for about 30 years.
S S
 
S/S said:
Remington ... that's what I have and what I will be working with till I can find some Lapua.
Click to expand...

Lapua can be found many places. Here are two of my favorite sources with good prices: http://www.brunoshooters.com/Merchant2/merchant.mv?Screen=SFNT&Store_Code=BSS and http://www.powdervalleyinc.com/.

I use the Lapua 6mmBR Norma brass and then neck it up to .308 with the K&M 6mm-.30 Special Expand Mandrel and Expand Iron Tool available here: http://www.kmshooting.com/index.php. :)
 
abintx,
Thanks for the links, I'll check them out and do what I can with my next SS check.

And a big THANKS to sdean for the PM, I sent a PM back to you.
Thanks again
S S
 
S/S said:
abintx,
Thanks for the links, I'll check them out and do what I can with my next SS check.
Click to expand...

Note: With Bruno's you can order Lapua by the piece. 48, 56, 108, etc. Don't have to order in boxes of 100 each. :)
 
S/S said:
Jackie,
I can see that most all like the Lapua brass better because it is better, and Remington 7BR brass may be junk, but that's what I have and what I will be working with till I can find some Lapua.

I am NOT building a 30 BR to shoot "tin cans", I have much better ways to waste my time and money. And my goal is NOT to become a famous benchrest shooter, or to even be in the top 100. In fact I'm not building a benchrest rifle as you guys know them, it will be used mostly for BR but also for a bit of offhand. Need something with low recoil, with better accuracy than a factory rifle, about half of the shooting with this rifle will be with breech seated lead bullets, it's going to be one of those one gun do everything rifles, probably wont do much of anything real good, but it will be a way for me to get into a lot of different shooting events by conforming to all the different rules without building 5 different rifles.

Being retired, somewhat disabled, and on a limited fixed income I cant afford what some of you guys can. I've been a target shooter going on 50 years now but never had to set down to shoot and never built this type of rifle so am very green at it. Anyway I want to give it a try and wanted to stay with a low recoil accurate 30 caliber.

Thanks for letting me know that it will be ok to trim to 1.500. My gunsmith is not an extreme accuracy guy but knows a lot about general gunsmithing and has done more than his share of re-barreling, been doing it for about 30 years.
S S
Click to expand...

Again, the the potential 'problem' with trimming your 30 BR brass to a 1.500" OAL: the reamer used to cut your chamber could have been ground to the original SAAMI/JGS 6MM BR length (1.570" long) - in this case, you need MUCH longer brass! :eek: IF this is the case, and you trim to 1.500", you have created 0.070" of empty neck, which is equivalent to having 0.070" of free-bore, but at the WHOPPING neck diameter!:eek: Now, if the reamer in question has ANY (REAL) free-bore (un-rifled section of the barrel, at or, slighter larger than GROOVE diameter), THAT length is added to the empty neck length . . . and you have a real wreck.

With a truly ZERO free-bore chambering, assuming that the case neck-length is trimmed to an OAL which is no more that between 0.015" and 0.010" short of the chamber length, when a typical, 7-8 caliber ogive, 125 Gr., thirty caliber bullet (based upon the 1.00" long jacket, ), is seated to just touch the lands, the bullet-base should rest about 3/4 of the way down the neck - or, from the case shoulder/neck junction, 1/4th up the neck, toward the case mouth. With bullets based upon the .925" long jacket, the bullet base will rest at just about mid-neck. (Note: a reamer/brass combination which will not accommodate trimming the case necks, thus, OAL, to 'fill' all but 0.010-0.015" of the chamber neck is of little use. This is the reason my original reamer -the [so called] Robinett reamer - features a MAXIMUM OAL of 1.510", and ZERO free-bore . . . and I trim to 1.500" - there WAS/IS a reason to the maddness: using my archaic tooling/methods, necked-up LAPUA brass measure 1.515" or less - usually 1.512" to 1.513". Really, so long as it can be filled with brass, chamber neck-length is of little consequence . . . but, too long a chamber neck, combined with short barss, and any free-bore, adds up to misery. The virgin brass/reamer/case forming combination must be well thought out - using the SAAMI 6BR neck/OAL lengths is a recipe for grief. Some case forming methods produce longer necks, thus, a longer chamber neck length is not undesirable - but still, the 'fit' must be kept in mind.)

So, if you are unable to seat a bullet to 'contact the lands', there is something amiss with the reamer - maybe two, or, more somethings . . . :eek:RG

P.S. I have 'gobs' of the old 7mm BR (Remington) brass it works well enough for a few firings, but even at the relatively modest 30 BR pressures, as compared to the 6PPC model, the primer pockets loosen too quickly to suit my desire. This is because the unfired Remington brass, just above the extractor-groove, measures 0.463-0.464" in diameter, while most of the reamers in common use cut a corresponding 0.471+ diameter. The LAPUA brass (6BR NORMA head-stamp), while seemingly 'tougher' to begin with, also measures 0.469 at the web. The virgin 7mm BR Rem. brass is also short - dictating a shortish chamber neck/OAL - on the order of 1.510", or, the length of the [so called] Robinett reamer.
 
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Well guys,
I got a copy of the reamer print, guess what, it's a R. G. Robinett reamer, it's a real honor to be able to talk with the designer of from what I've been told is "the" one and only reamer to use for a 30 BR. My next step is to do what Boyd suggested, do a casting of the chamber, will have to wait till Tue to do that. I have enough length to be able to trim to 1.500 with out any problems.

A big Thanks to you R. G. Robinett for taking the time to type all that info out. It's very much appreciated.
S S
 
Randy.....

There is a lot of good info in your post here,
In your opinion, which is the best method of expanding new brass. Some folks use a press with a expander and other use Bullseye with a paper patch to form to the chamber. Could you please give us the in and outs of which way you would recommend and why. In order to best fit the case to the chamber.
 
Oal

To get OAL. Place a bullet in the chamber and hold this in place with a piece of dowel. Next place a cleaning rod in the barrel from the muzzle end and mark the location where the rod contacts the bullet.
Now remove the bullet an place the bolt in the action and lock it in place.
Move the cleaning rod so that it contacts the bolt and mark that location on the cleaning rod.
Pull the cleaning rod out and using a dial caliper, measure the distance between the 2 marks. this will be your OAL without any bullet jump, which you may or may not want.
 
I think we found the problem, it turned out to be a "long neck" reamer. Dave Kiff is taking care of it and I think things will work out ok. My thanks to all that helped and especially to Steve D.
S S
 
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