No-turn neck size for 6BR

[rstreich]

I had a wonderful surprise arrive today: my brand-spankin'-new BAT SV. Got two barrels ready to go, now I just need a reamer. Having turned about 1000 necks in the last few months with with about 1200 to go for other projects, I'm definitely ready for a no-turn neck. The question is: What neck size do I want?

I've seen both .271 and .272 neck sizes referred to as "no-turn" necks. I also read a little bit about the latest Lapua being a little thicker, didn't I? For you guys who have seen several lots of 6BR, have the necks been pretty consistent? Or should I just buy my brass and base it off of that particular lot?

I'd rather err on the small side. Worst case, I skim a thousandth or two. After 1000 of them, I think I'm finally getting proficient at it.

thanks for the help,

robert

 

[jb1000br]

.272 won't hurt ya...

.271 is too tight IMO...

JB

 

[Hipshot]

I went with a .272 and it's perfect. There is enough room for the brass to let go of the bullet by about .002 with Lapua brass. My S die bushing is set to give .242 ID for a .002 hold on the bullets,naked).

 

[steveyrock]

I am always worried that even the Lapua brass down the road will loose it's quality so I went with a 264 chamber,I still think a 272 neck is risk as far as relying on brass quality over the long haul and if I am going to bother to skim them in a neck turner I might as well go all the way and cut them down.

There is nothing wrong with a no turn neck but I myself have some concerns that others may not worrie about.Bench rest shooters still turn necks.

 

[jb1000br]

Bench rest shooters still turn necks.

"Most" do...

JB

 

[Forum Boss]

Steve makes some valid points. However a .267 neck,or even a .268) will normally give full clean-up. PPC shooters such as Jackie Schmidt have demonstrated that a .266 or .267 can be just as accurate as the old standard of .262-.263.

If I wanted to shoot factory loaded 6BR ammo, I would go with a .272, as it tends to have a bit of a flare in the mouth where they seat the bullet.

Otherwise, a .271 or a .272 tapering to .271 should work fine with nearly all the bullets we shoot.

 

[jb1000br]

Jackie is shooting a .269...

 

[rstreich]

I was talking to my gunsmith about it today. Since this is going to be a varmint rifle, .272 would be a better choice. I think just for once, I'm going to stick to my original idea and go with the .272 based on what you guys have said.

Now, any thoughts on freebore? I've got two barrels: a Krieger 1-10 and a Broughton 1-8. I want to set the throat up so I can shoot little bullets in the Krieger--figure a max size of 87 gr. V-Max or BIB 95s.

I'll have the gunsmith extend the throat for the Broughton. That barrel will be for the longer stuff--105s, 107s, and the like.

Thanks for all the replies,

robert

 

[rstreich]

Hmm, can the BIB 95s stand an 8-twist with a 6BR pushing them?

You're right about Dave, he is really helpful. I was just trying to get some preliminary info and opinions here before I called him so I wouldn't take up so much of his time.

robert

 

[JamesnTN]

you will need from .090-.100 freebore to be sufficient for the 95-107 bullets .100-.115 for the 108 FB BIB

This is based off a Dasher reamer so you may be able to get away with say .110 for 87-108 grn bullets with the longer necked BR case.

 

[dreever]

For the BIB 95's I'd go with a .082 freebore, that gets the base about .030 above the neck shoulder junction. Talk to Dave Kiff about the reamer he did for me with the BIB 95's in mind.
I differ from a lot of guys when it comes to VLD's like the Berger 95 and 105's. That is to say I wouldn't go with a freebore any longer than .060. That will allow you to chase the lands for a longer period of time. The 95 VLD's especially have a very short bearing surface so with freebores of .085 and above you won't have much bullet in the neck from the very start.
I'm currently shooting the 105 VLD's with a .060 freebore and they are doing rather well.
As to the BIB 95's in an eight twist, at 6BR velocities no problem. If your going more than 3200fps in anything else they'll blow up according to Randy.

Danny

 

[Forum Boss]

Danny,

There's a guy at my club with a 6BR done up by Jim Borden. For reasons unknown, Jim chambered it with a hellacious .150 freebore. My friend shoots it with Berger 105s hanging WAY out there. Believe it or not, it shoots great. Vertical just over an inch at 600 yards. So who knows....

I think Jason's Freebore is about .113. That obviously works too.

,All measurements Kiff method. For a Henriksen reamer add about .040)

 

[NorCalMikie]

While were on the subject of "freebore", how do you measure it? Got a Shilen barrel that 55s won't come close to a jam but the accuracy is "outstanding"! Anything bigger than that will jam real easy. Never was sure how to get that measurement. Mike

 

[Aussie_bob]

Just getting back to reamers and neck sizing wouldn`t you be better off scimming all your necks as then they would have all the same neck thickness and when useing a bushing die they would then have all the same neck tension. If you cleaned up all the neck say .012 neck wall thickness you would end up with a finished load at .267 so anywhere from .269-.270 reamer and a .265 neck bushing would give you more consistancy.

 

[jb1000br]

You would think...but I can't argue with the consistenct I'm getting with my no-turn, bushing sized BR...

JB

 

[rstreich]

Just getting back to reamers and neck sizing wouldn`t you be better off scimming all your necks as then they would have all the same neck thickness and when useing a bushing die they would then have all the same neck tension. If you cleaned up all the neck say .012 neck wall thickness you would end up with a finished load at .267 so anywhere from .269-.270 reamer and a .265 neck bushing would give you more consistancy.

I'm sure it would be better, Bob, but every other rifle I own,other than a few production rifles) is a turned neck. My .223 was supposed to be a no-turn, but then Lapua changed the brass up. For just one rifle, I want to be lazy for a while.

Besides, if it doesn't shoot like I hope, I can always blame JB for leading me astray right?

robert

 

[tenring]

Funny thing; my 6BR Kreiger has a no turn .271 neck. I skimmed the Lapua necks slightly and the groups opened up. The ultimate answer is: go with whatever works best for you.