300 win mag reamer

[Lonewolf74]

I'm having my rifle action trued and chamber recut to design it more around the Berger 215 hybrid. By doing some research I came across an older thread where Broz gave a link to the reamer and company he would use, I'll try to post it if I can figure out how.

My questions are is this still the most desirable reamer for this application? And if anyone could tell me what effects what, what would it give me over a samii spec? Like do you want any free bore? How tight should neck clearance be to my loaded rounds? Should I get the chamber cut to the dimensions my die sizes the brass? Should I base the throat off loaded rounds with the bullet seated with base even with case shoulder to body junction, or bullet seated with ogive to boat tail junction even with case neck to shoulder junction? This would cause the bullet base to be several thousandths below shoulder to body junction but full neck to ogive contact?

Sorry for so many questions but I'm trying to figure this all out so I can get the best performance and tell my Smith exactly what to do.

 

[FURMAN]

It is the reamer I used. I would do it again.

 

[Lonewolf74]

Reamer print

 

[Lonewolf74]

That sounds good but I guess I'm kind of looking for the why part. Like what does what and are there ways I could tweak it more to me such as building it around the measurements I get from my sized brass?

 

[FURMAN]

That is the reamer I used. Why, is because it allows the correct amount of freebore for the 215 Berger to be seated at an ideal seating depth and has a good amount of neck clearance to use for a 300 Win Mag. This reamer has worked for many rifles one of which is mine. This puts the boatail junction of the 215 even with the neck shoulder junction with .040 jump if I remember correctly(I am not going to do the math because the tolerances will affect that). Many say the 300 likes .005-.007 neck clearance. I can tell you based on the accuracy of rifles cut with this reamer I see no need to deviate. I will say I have used a SAAMI with 215s with no problem but I purchased this reamer and it will be what I use from now on.

 

[Lonewolf74]

Ok so with this reamer you get .005 neck clearance? And you want it in that neighborhood not tighter like .002-.003? And it is desirable to have some free bore? .040 sounds like a lot to me but I'm still new to this and so far seat all my loads to touching lands in my rifles

 

[FURMAN]

The neck clearance will depend on brass. With WW brass it is around .006-.007 which is perfect for the 300 Win. Some cartridges have different preferences. The freebore is .202. You have to remember the length of these newer bullets.

 

[bigngreen]

I set this reamer up to be easy going, no neck turning and you won't run into issues with any brass, it's not tight anywhere and that is what makes it work well. The freebore is .187 so it gives you just a little room to seat a little of the lands and not put the pressure ring of a 215 Berger beyond the neck. It's proven a solid, easy going reamer.

 

[FURMAN]

I set this reamer up to be easy going, no neck turning and you won't run into issues with any brass, it's not tight anywhere and that is what makes it work well. The freebore is .187 so it gives you just a little room to seat a little of the lands and not put the pressure ring of a 215 Berger beyond the neck. It's proven a solid, easy going reamer.

He nailed it. This reamer is within a few thousandths of the dummy I had set up to send off when I found the reamer print. I just called and ordered it and saved a few dollars for shipping and a few days wait.

 

[bigngreen]

JGS has the reamer print as well and it's open to the public for order.

 

[Lonewolf74]

I set this reamer up to be easy going, no neck turning and you won't run into issues with any brass, it's not tight anywhere and that is what makes it work well. The freebore is .187 so it gives you just a little room to seat a little of the lands and not put the pressure ring of a 215 Berger beyond the neck. It's proven a solid, easy going reamer.

Ok I think i understand everything I just may not word it or convey what I mean properly. So with this reamer and freebore your bullets would be seated with ogive to boat tail junction even with case neck to shoulder juction and at that seating depth you would have .040 jump, or be approx .040 off the lands?

What would I gain or loose if I wanted to make the freebore. 167 and aim for .020 jump with the bullet seated the same depth?

What can you gain or loose by making the neck clearance tighter say .003-.005?

 

[FURMAN]

Analysis paralysis. This reamer works. No need to think about all the what ifs.

 

[bigngreen]

Ok I think i understand everything I just may not word it or convey what I mean properly. So with this reamer and freebore your bullets would be seated with ogive to boat tail junction even with case neck to shoulder juction and at that seating depth you would have .040 jump, or be approx .040 off the lands?

What would I gain or loose if I wanted to make the freebore. 167 and aim for .020 jump with the bullet seated the same depth?

What can you gain or loose by making the neck clearance tighter say .003-.005?

Its set up to let you seat of that far but I normally run .010-.020 of the lands, this is as short as I'd go if setting up for the 215 Berger, I was trying to keep it tight, many run .200-.220 free bore. If you make it much shorter you'll be seating the pressure ring of the Berger right on the neck shoulder junction which I don't like for accuracy.
This reamer is for a broad range of brass so normally I would not run quite that much clearance on the neck, ideally you'd take and change the neck diameter to mach the specific brass your running and go .004 over, I used to run a little tighter but things just shoot more consistent with that little bit of extra room.

 

[Lonewolf74]

I appreciate the help guy's. And I hope I'm not sounding like a pain I'm just trying to understand the why do it this way instead of that way and that sort of thing.

Basically what I'm trying to accomplish is set this up favoring the 215 hybrid but be able to use smaller lighter bullets as well. Nothing light per say but maybe some of the 185 offerings.

I have and intend to use all Norma brass. The neck diameter of my dummy rounds with the bergers is .334 however with the 195 Sierras I have it's .337.

The freebore is what I'm kind of confused on. With my brass and components the base to ogive measurement is 2.925 having the bullet seated with the ogive to boatail junction even with the case neck to shoulder junction. Now with this reamer I should be able to sear the bullet at this length and have .010-.020 jump? And ideally for the 300 win mag I don't want the jump to be less than this?