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Ok so I ordered a CBI barrel but their chamber has .220 freebore for longer match bullets
well I am only planning on shooting 140 gr and maybe 160gr I am also building a short action
So the.220 freebore seems like it is excessive and could give me some headaches ?
I called the next day to switch my order to a shilen barrel as they have standard reamer but not sure if my order can be changed can't get an answer. And the shop owner is away
I ordered my 284 reamer with a .225 freebore specifically for the 180 Hybrids as well as the 183 SMK. With the .225 freebore and the 180 Hybrid seated .020 off the lands, I have to nose in a loaded round to load the rifle and I have to pull the bolt out slightly to remove a loaded round.
I'm not sure what the best freebore is for the 140 class bullets, but if you are dealing with James at Northland I would bet that he would take care of you...
Yea he told me that it might be to long but I could check with shilen see how long their reamer was but only building hunting rifles I did not realize how long .220 was then I second guessed my self checked my 7-08 then called shilen then called James the next day and he is on vacQuote:
Originally Posted by cowtownup
Also want to make sure I have this right when they say .220 freebore is that .220 more then standard or is it .220 total
per Boyd Allen...
In the typical target chamber and some factory chambers, starting from the part that is designed to accommodate the case neck (For example, in the case of a .262 neck 6PPC this is a cylindrical section that is nominally .262 ID.) forward of this, the ID of the chamber funnels down (typically at a 45 degree angle) to just over bullet diameter where a new cylinder begins. This is the so called the freebore. My 6PPC reamer cuts a chamber that has a .060" long freebore that is a few ten thousandths over .243". At the front of the freebore the rifling starts. This is where the lands ramp up from zero to to full height and the groove diameter begins. In this section, sometimes referred to the as the leade, the typical taper of the rifling, referred to as the throat or leade angle, (again, for a typical target chamber) is 1 1/2 degrees. Zero freebore means that the leade begins right at next to the chamfer at the front of the neck part of the chamber. in this chamber drawing, the throat or freebore length is .105.
http://www.the-long-family.com/image...kley%20new.jpg
I can't view the picture but I got it nowQuote:
Originally Posted by cowtownup
I guess most that build the 284 use it for competition or they run heavier bullets so there are a lot of options
I am just building a hunting rifle and plan on running 140 or 160 grain Sierra HPGK so I want standard chamber to get the bullet seat depth I want I need 2.905 OAL for the 140s slightly more for 160
worse case if standard is a bit short I can hit it with a throat reamer
this build is more frustrating then my last 3 but I am learning something at same time