Which Reamer?

[Phil3]

Can someone look at the attached reamer prints and tell me what the freebore is for each. I am not sure how to read and find this distance. These came from Pac-Nor for 6mmBR. I am trying to choose the right reamer for 70 - 90 grain bullets. I think a good freebore for these bullets might be .040" - .060", but what do I know...I am a newbie at this. Oh, I will be using New Lapua brass.



Thanks.

Phil

 

[tclaunch]

None of these are suited for your purpose. The diameter at the .200" line is to tight with exception of print 1166, also 2 of the prints are for Remington length 6BR brass at 1.530". Lapua won`t fit unless you trim first.
The first or top print is close, and is the only one thats a "no turn" but still tight at the .200" line this causes bolt click, or hard extraction on the highest point of bolt lift. It also has 0 freebore which means you would have to send in sample round with bullet seated where you want in a dummy case for them to match with separate throating.

 

[hogpatrol]

None of these are suited for your purpose. The diameter at the .200" line is to tight with exception of print 1166, also 2 of the prints are for Remington length 6BR brass at 1.530". Lapua won`t fit unless you trim first.
The first or top print is close, and is the only one thats a "no turn" but still tight at the .200" line this causes bolt click, or hard extraction on the highest point of bolt lift. It also has 0 freebore which means you would have to send in sample round with bullet seated where you want in a dummy case for them to match with separate throating.

TC, Did you check the PDF file attached? That's another print with a .2719 neck. It looks good but as you stated, freebore to be determined.

 

[rickiesrevenge]

The one in the pdf file is the one I like the best. I like the .200" line dimension, no turn neck, and the freebore is .094".

The first print has "0" freebore, second has .060", third has .060", fourth has .116"

 

[bdale]

I would go with the .040 I have a 6br setup to shoot 90 grain bullets and it puts the bullet just above the neck shoulder junction, mine is a .050 free bore

 

[tclaunch]

TC, Did you check the PDF file attached? That's another print with a .2719 neck. It looks good but as you stated, freebore to be determined.

The JGS 1262 print is my favorite no turn for the 105 class bullets. Smart money says order this with .040" freebore go out and have a ball.

 

[GrocMax]

My vote- JGS CIP spec 6BR. Cheaper too, may even be in stock. FB is in the .090's but shoots lightweights very well.

 

[billlarson]

My vote- JGS CIP spec 6BR. Cheaper too, may even be in stock. FB is in the .090's but shoots lightweights very well.

IF YUR GONNA SHOOT LONG BULLETS YOU NEED LONG FREEBORE.............

 

[Tim Singleton]

In order you posted
.000
.060
.000
.1163
.094

With the weight bullet you want to shoot I would agree .060 would be good

 

[Phil3]

None of these are suited for your purpose. The diameter at the .200" line is to tight with exception of print 1166, also 2 of the prints are for Remington length 6BR brass at 1.530". Lapua won`t fit unless you trim first.
The first or top print is close, and is the only one thats a "no turn" but still tight at the .200" line this causes bolt click, or hard extraction on the highest point of bolt lift. It also has 0 freebore which means you would have to send in sample round with bullet seated where you want in a dummy case for them to match with separate throating.

Please help me understand why a reamer would be cut that leaves the body part of the chamber too tight. On the 6mmbr.com page for the 6BR, the body runs from .4709 at its fattest point (bottom) to .4598 right before the neck. Judging from that, it does appear the chamber would be too tight at that point. That is worrisome. Understood on the Lapua brass vs Remington brass and the longer dimension of 1.570 for the Lapua brass.

I don't understand the need for sending in a dummy round. I really have no idea where I want the bullet seated in the case.

It appears I really need to settle on proper bullets. Given this barrel will be used 85% at 100 yards, I probably should be using very light bullets. From additional reading, it seems like 55 - 75 grain may be ideal, lighter than the 70 - 90 I mentioned originally. ??? If so, then maybe the zero freebore reamer (first one) is the right one, but am perplexed by the tight body dimension.

Thoughts and opinions welcome.

Phil

 

[hogpatrol]

First things first here. What EXACTLY are the bullet weights you want to shoot? Up to 105s? The lightest 55s to 65s?
Before you order a reamer, you need to determine bullet weights and buy a barrel with the proper twist. If all you're going to shoot is 100 yds., you could get by with a slow twist barrel and just shoot the lightweights. Trying to do a one size fits all in ANY barrel is going to be a set of compromises especially on 6mm/.243 caliber.

 

[Phil3]

58, 65, 68, 70, and 75 grain, judging from what I see available from Berger and Sierra and my understanding of what works best at short range (I believe I am correct). If this range is too wide, then I will narrow. The reamer question has become important because I learned that most Savage prefit barrels use ONE freebore dimension, and in the case of Criterion, it is .094". Too long it appears for the bullets below, if those bullets should be into the lands. If I get out to longer distances (move to a place with longer range), I will get another barrel suited for longer distances.

1) Sierra 70 grain HPBT MatchKing.
2) Berger 65 grain HPFB (Column).
3) Berger 68 grain HPFB.
4) Hornady 58 grain V-Max.
5) Hornady 75 grain V-Max.

There may be others in this range.

Thanks.

Phil

 

[Tim Singleton]

I think you are right most of the pre fits manufacturers will have a longer freebore that will make it hard to get to the lands with the light Bullets you list
I guess I'm a little confused now. Are you buying a prefit? Or choosing a reamer to have a barrel chambered?

 

[Phil3]

I apologize for any confusion. I wish to buy a prefit. But want to be sure the pre-fit's specs are appropriate for short bullets. From what I can gather, none do, the freebore being too long (Criterion freebore is .094" and Shilen is very close to that). That means I will have to have the barrel chambered, perhaps with my own reamer, if the barrel maker does not have a reamer suitable for the bullets I have listed. Northland Shooter Supply(Savage specialist) may be able to handle that for me, either with Criterion or Shilen barrels. If not, then I will need to contact either of those two makers directly, order a barrel chambered with a custom reamer. I have a call into Dave Kiff at Pacific Tool and Gauge to discuss best reamer specs for the bullets shown.

I am perplexed by one thing. Just how important is freebore? I ask because I am pretty sure Savage must use a very long freebore so their rifle can accomodate the longest bullet(s). And yet those rifles according to some reports do just fine with short bullets, which cannot be anywhere near the lands with the long freebore. On the other hand, I read how these short bullets shoot best when they are against the lands, a requirements necessitating a short or zero freebore.

Phil

 

[Tim Singleton]

Ok
Do you have a savage action you want to rebarrel ?

If that's where you at I think you will have a hard time having the manufacture hold up there production line to use your reamer.
You may have to plan to shoot the 80gr bullets. I have had a couple prefits in the past from McGowen if you order. 12 twist they use a reamer with a freebore in line with the weight bullet that will be used in that twist
If you order an 8 twist they chamber with a longer throat

 

[Phil3]

Thanks Tim,

Yes, I do have a unused Savage target action (right bolt, left port). I have no experience in what it means for delivery time if I want my custom reamer used. On Northland Shooter Supply website (Savage), for Criterion barrels, it says this.

"...Criterion can custom chamber barrels using customer reamers if preferred to have the barrel chambered to your exact specifications...".
http://northlandshooterssupply.com/match-grade-barrels-2/criterion-savage/

I have been told that Criterion, and perhaps others, do not change freebore based on twist. Apparently, McGowen does. Also, Pac-Nor said they do not change freebore based on twist, but they do have fiver different reamers. The prints I posted were all from Pac-Nor.

I am going to call Criterion and Shilen on what optional reamers they have, and how long will it take to get the barrel if their optional (or my) reamer is used.

Phil

 

[GrocMax]

The .094" FB CIP reamer will shoot the lights JUST FINE. In fact you'll gain velocity/lower peak pressure over a 0 FB.

Freebore is often over-analyzed.

Your bigger decision is going to be bullet choice and twist.

 

[Phil3]

This is sort of like a chicken and the egg thing. Bullet choice and twist is whatever works best for 100 - 300 yards. From what I have read, this may be the following as I listed earlier.

1) Sierra 70 grain HPBT MatchKing.
2) Berger 65 grain HPFB (Column).
3) Berger 68 grain HPFB.
4) Hornady 58 grain V-Max.
5) Hornady 75 grain V-Max.

For twist, I am thinking 1:12, maybe 1:10. I spoke with Dave Kiff at Pacific Tool and Gauge, and he suggested for Sierra and Berger bullets in the range shown, that .055" freebore would work well. They are e-mailing me a print, along with their standard reamer print. Dave said the .055" reamer would have a .271" neck for the blue box Lapua brass.

Phil

 

[Tim Singleton]

12 twist with that reamer .055 freebore would be a good match for the 68 to 80 grain bullets

 

[Deleted old_dood]

why not just trust the vendor. Send PacNor a dummy round with your bullet of choice loaded to the depth you'd like and specify if, at that length, you'd like the bullet touching. I recently got a 6BR barrel from them and that's what I did. when I placed the order I indicated I'd be sending in a dummy round. 5 weeks later I received my barrel. The freebore wasn't exactly like I specified, but it was very close. This I attribute to limitations regarding what they had on hand since I was not providing a reamer. BTW, your best bullet for short range, IMO, would be the 80gr Berger flat base since it has more bearing surface than most. At 100 yds you'll get bored with one hole groups.