6br a study of the zero freebore

[urbanrifleman]

Here are several bullets touching using my JGS zero freebore 6br reamer.

 

[urbanrifleman]

In conclusion I have decided that I will order a zero fb in 6bra as I see no reason to lengthen the fb for short range and the zero freebore appears to me to absolutely ideal for the bullets under 70 grain including the FB. Any bullet other than the Berger 80 fb will work fine. If I try the 80 grain bullets I am going to start shooting the Bart Dominator BT. I cannot see messing with anything that splits the dimension between 0 and 104.

The conclusion being that if you plan to shoot the 80 fb you might as well go to the standard 104 freebore.

 

[urbanrifleman]

So to that end I will have the zero and the 104 for 6bra

 

[gunsandgunsmithing]

So to that end I will have the zero and the 104 for 6bra

I think you're correct IF you wish to lean more toward the 55 gr or other ultra lite 6mm bullets. You could use a bit more freebore and not be able to use the 55s but would then be able to use the 80s without being into the donut area. About .090 is what I consider to be the most generic, meaning it will work with the widest range of bullets available. That being most 60 grain bullets up to the 105 class. In the accuracy world, it's about optimization more than anything else. The long neck on a br case makes it very forgiving though, allowing a wide range of bullet lengths that will work without splitting freebore hairs.

 

[urbanrifleman]

Bart uses the same 104 for short line and long range. After doing this study I can see why.

As long as you stick to boat tail bullets I bet you might even be able to go to 90 grain. But I was going yo use the zero for 12 twist and slower. And the 104 for everything else. Of course a person could request the 104 for the 12 twist.

The thing that I learned after doing my freebore study is that 15 thou you can't even see... A lot of these discussions over freebore are so small on a long neck I don't see it making any significant difference (that is my opinion). My first zero freebore shoots amazing with light bullets and if you look at the 68 Avenger picture you can see it is just about perfect where it sits in the neck.

 

[gunsandgunsmithing]

Bart uses the same 104 for short line and long range. After doing this study I can see why.

As long as you stick to boat tail bullets I bet you might even be able to go to 90 grain. But I was going yo use the zero for 12 twist and slower. And the 104 for everything else. Of course a person could request the 104 for the 12 twist.

The thing that I learned after doing my freebore study is that 15 thou you can't even see... A lot of these discussions over freebore are so small on a long neck I don't see it making any significant difference (that is my opinion). My first zero freebore shoots amazing with light bullets and if you look at the 68 Avenger picture you can see it is just about perfect where it sits in the neck.

I'm not disagreeing with you. I just think that the zero freebore is gearing to the light bullets where a little more will move away from the 55s and more toward the 80s

 

[urbanrifleman]

I'm not disagreeing with you. I just think that the zero freebore is gearing to the light bullets where a little more will move away from the 55s and more toward the 80s

Im only seeing that the only bullet that would be a problem would be a 80 flatback. I looked around and it seems the guys shooting the 80s in short range are shooting boat tails. So, except for that one bullet all should be good.

And yes I think the 55 in 6br and especially BRA should be the new varmint king. I am shooting the 55s nearly 4000 in my standard 6br. The bra should be well over 4000. With 32 grains of powder.

I am enjoying the discussion

 

[gunsandgunsmithing]

Im only seeing that the only bullet that would be a problem would be a 80 flatback. I looked around and it seems the guys shooting the 80s in short range are shooting boat tails. So, except for that one bullet all should be good.

And yes I think the 55 in 6br and especially BRA should be the new varmint king. I am shooting the 55s nearly 4000 in my standard 6br. The bra should be well over 4000. With 32 grains of powder.

I am enjoying the discussion

Ok...That explains your rationale for gearing toward the 55s. I wouldn't say that most people in sr br that are shooting 80s are shooting boat tails, though. You can't trust match reports. I'd say there is a good, pretty even mix of fb vs bt. But, if you're gearing toward the varmint crowd, it's a different ball of wax anyway. I can assure you that there won't be many, if any br shooters using the 55s and you're giving up case volume to be able to use that bullet. Nothing wrong with your plan if you want to be able to shoot the 55s. I'd just prefer a better freebore for the 80s. If you compare the bearing surfaces of a Berger 80fb to a berger 105bt, they are very close. So, what works for the 80 can work with the heavies, too. Maybe not ideal, but .090 will shoot 60fb to 105bt's.

If you want the most flexibility, about .090-.100 is it but it won't work with the 55s.

 

[urbanrifleman]

If you want the most flexibility, about .090-.100 is it but it won't work with the 55s.

I don't think I am going to have a lot of serious high level BR shooters ordering Remington barrels, but I can hope!!!.

I will have the 104 reamer which is what Bart uses with 80s and he does pretty good with it. And from the pictures you can see why, I cannot image a few thou making any difference. 90 to 104 is essentially the thickness of three sheets of notebook paper, less than 1/64".

I guess in the end, as I do on many matters I hear bantered about in shooting, I find the discussion of freebore, under practical study, to be more about discussion than actual difference, at least in this case of the 6BR. Everyone has their pet numbers, but most of the numbers are too fine to have any practical effect on the bullet. Zero to 104 is a good jump. Splitting it just has little practical improvement. In my observation.

If I were going to order reamers for top Benchrest shooters I would order one specifically for that market.

 

[gunsandgunsmithing]

I don't think I am going to have a lot of serious high level BR shooters ordering Remington barrels, but I can hope!!!.

I will have the 104 reamer which is what Bart uses with 80s and he does pretty good with it. And from the pictures you can see why, I cannot image a few thou making any difference. 90 to 104 is essentially the thickness of three sheets of notebook paper, less than 1/64".

I guess in the end, as I do on many matters I hear bantered about in shooting, I find the discussion of freebore, under practical study, to be more about discussion than actual difference, at least in this case of the 6BR. Everyone has their pet numbers, but most of the numbers are too fine to have any practical effect on the bullet. Zero to 104 is a good jump. Splitting it just has little practical improvement. In my observation.

If I were going to order reamers for top Benchrest shooters I would order one specifically for that market.

You'll have your bases pretty well covered with those two reamers. When I said .090-.104, it was a range that will work well with a wide variety of bullets, not a specific number. I agree with you. Nothing magic happens within that range unless it gets you off of the donut.

I also agree with something else that I saw you post in the last few days. That being about tight necks and donuts. An example I use a lot is being confined to a given magazine length. If the bullet is to be seated at or below the donut, I like more neck clearance...enough to allow it to form on the outside of the case. Then, just don't size that far down the neck and the donut never interferes with the bullet. I've read and heard speculation about a "turbulence point", yada, yada..but I've never been convinced that it matters as long as the donut can't interfere with the bullet. I think you're on the right track.

 

[urbanrifleman]

You'll have your bases pretty well covered with those two reamers. When I said .090-.104, it was a range that will work well with a wide variety of bullets, not a specific number. I agree with you. Nothing magic happens within that range unless it gets you off of the donut.

I also agree with something else that I saw you post in the last few days. That being about tight necks and donuts. An example I use a lot is being confined to a given magazine length. If the bullet is to be seated at or below the donut, I like more neck clearance...enough to allow it to form on the outside of the case. Then, just don't size that far down the neck and the donut never interferes with the bullet. I've read and heard speculation about a "turbulence point", yada, yada..but I've never been convinced that it matters as long as the donut can't interfere with the bullet. I think you're on the right track.

David Tubb also agreed with me the other night on the phone. He told me that the 6XC shoots best at 277 neck, and I mean by "best" I mean most accurately. He is an advocate that you NEED looser necks for accuracy. Tubb does pretty good, he pretty much dominates any competition he enters, but strangely few listen to him.

I really, really want to make my new 6BRA reamers 276 neck, but I am going to use them to make barrels for others, and I know that people will FREAK OUT and say that is will ruin their brass, or won't shoot, etc etc and I do not feel like messing with all the convincing and arguing.

I am going to get these and then order my own personal reamers in 275-276 neck.

Oh, and Tubb is going to be shooting my benchrest design in F class... Oh, it is going to be yummy...

 

[gunsandgunsmithing]

David Tubb also agreed with me the other night on the phone. He told me that the 6XC shoots best at 277 neck, and I mean by "best" I mean most accurately. He is an advocate that you NEED looser necks for accuracy. Tubb does pretty good, he pretty much dominates any competition he enters, but strangely few listen to him.

I really, really want to make my new 6BRA reamers 276 neck, but I am going to use them to make barrels for others, and I know that people will FREAK OUT and say that is will ruin their brass, or won't shoot, etc etc and I do not feel like messing with all the convincing and arguing.

I am going to get these and then order my own personal reamers in 275-276 neck.

Oh, and Tubb is going to be shooting my benchrest design in F class... Oh, it is going to be yummy...

You could open the neck in a separate op, but I'd do it from the same setup after chambering the barrel. You can buy necking reamers or if your setup is good, you can just use an inexpensive chucking reamer of your preferred size to make the neck bigger. Not difficult at all. Just don't go too deep. There are also neck/throating reamers that can open the neck and lengthen the freebore in one step. You could also just buy a zero freebore reamer and a separate throater, setting freebore wherever you want it.

 

[NorCalMikie]

You go with a looong freebore and the lighter bullets (50s & 55s) can't get anywhere the lands.
You freebore WILL wear over time.
Probably sooner than you were thinking.
Go short and do heavier bullets as the throat wears. That way, you can still reach the lands.

 

[urbanrifleman]

You go with a looong freebore and the lighter bullets (50s & 55s) can't get anywhere the lands.
You freebore WILL wear over time.
Probably sooner than you were thinking.
Go short and do heavier bullets as the throat wears. That way, you can still reach the lands.

That is my plan. I have been looking at some of these other guys posting ppc targets I'm not sure my 6br doesn't shoot pretty good.

 

[Alex Wheeler]

My no turn 6BRA 0fb with a 55 blitz king. Varmint vaporizer. I have zeros in 6br, BRA, and Dasher because the 55s work so well on the varmints, and I have not had a lot of luck jumping those little bullets. A 60 grain sierra varminter will work in a .090 and would be my first pick for a varmint bullet in a mid-long freebore.

 

[urbanrifleman]

My no turn 6BRA 0fb with a 55 blitz king. Varmint vaporizer. I have zeros in 6br, BRA, and Dasher because the 55s work so well on the varmints, and I have not had a lot of luck jumping those little bullets. A 60 grain sierra varminter will work in a .090 and would be my first pick for a varmint bullet in a mid-long freebore.View attachment 1095514

EWWWWW..... THATS KEEEWWL.

That appears to be identical to the 55 Nosler Varmedgeddon.

 

[Alex Wheeler]

The 55 blitz is the most explosive I have found so far.

 

[Mark W]

My no turn 6BRA 0fb with a 55 blitz king. Varmint vaporizer. I have zeros in 6br, BRA, and Dasher because the 55s work so well on the varmints, and I have not had a lot of luck jumping those little bullets. A 60 grain sierra varminter will work in a .090 and would be my first pick for a varmint bullet in a mid-long freebore.

Would you mind sharing which powder that you’re liking with 70 grain and under bullets in the BRA?

 

[Alex Wheeler]

H322

 

[Murray Brook]

You go with a looong freebore and the lighter bullets (50s & 55s) can't get anywhere the lands.
You freebore WILL wear over time.
Probably sooner than you were thinking.
Go short and do heavier bullets as the throat wears. That way, you can still reach the lands.

What twist are you using with your zero freebore 6br TKS