6 mm BRX - what freebore and neck should I use?

[upandcoming]

Or to put it in other words, what is the normal way to go? I aim for using this cartridge at 600 yards and I would expect it to be mainly the 105 gr bullets (brand I guess will depend on what the barrel likes the most). So what should I chose?

Any recommendation for where to purchase a reamer would also be much appreciated.

 

[eggman]

If you are looking for a no-turn neck for the 6 BRX I would suggest .272" neck dia. If you are looking for a tight neck where you will have to turn necks .268" has been popular. As far as freebore (which is more critical to get right with the 6 BRX than the 6 BR because of the short neck ) .111 or even .099 worked for 105 Berger VLD's for years but it is taking more freebore for late production Berger 105 VLD's especially this years production. I would suggest .160" freebore which is working well for me using 105 VLD's , 107 SMK's and even 108 Berger BT's.. I suspect it would take .250" freebore to keep a 108 BIB BT above your neck shoulder junction if you choose the BIB 108.
Dave Kiff at Pacific Tool and Gauge can fix you up with a reamer once you decide on the dimensions.

Good luck,
Rodney

 

[Charles E]

The best two choices you can make are (1) what bullets do you want to use, and (2) who's going to grind your reamer.

As for (2): There are a number of reamer grinders used by competitive shooters. Pacific Tool & Gauge (AKA "Kiff"), Dave Manson, JGS, and Henriksen come to mind. For some reason, people get downright emotional about who grinds their reamers -- me too. I like Hugh Henriksen, but will allow he can be real slow. As in "Farley time."

As for (1): if you're going to vary from the 105-109 range bullets, which way? towards the 95 or the 115s? I'd suggest toward the 95s, but it's your choice.

Once you decide this one, ASK THE REAMER MAKER. He'll give you the best help; far better than us internet mouse jockies

 

[upandcoming]

As for (1): if you're going to vary from the 105-109 range bullets, which way? towards the 95 or the 115s? I'd suggest toward the 95s, but it's your choice.

Indeed I do agree with you. At 600 yards I see no use of hitting the 115s really. I guess it a mather of taste, as everything else, however if I'd need the extra balistics I guess I could pick another cartridge instead?

 

[Charles E]

if I'd need the extra balistics I guess I could pick another cartridge instead?

Not likely. Some time back, Leonard Baity set a 10 match (6-match?) aggregate recond with the 95-grain Bergers. This was at 1,000 yards. 600 yards isn't even long range. I think you're better off using a 95-grain bullet as a back-up plan; there are more of them, and you are apt to find they shoot better if the 105s let you down for some reason.

So, if you're going to have the reamer made by, say, PTG, tell Kiff what you want to do, as far as neck-turning and bullet choice goes, and he'll make you a reamer that will achieve that. Same goes for Manson or Henriksen.

To save a bit of money, you might pick a resize die first, then have the chamber reamer ground to match that. Will save you the cost of a custom die. Again, the reamer makers should be able to help you out here.

 

[bob3700]

Or to put it in other words, what is the normal way to go? I aim for using this cartridge at 600 yards and I would expect it to be mainly the 105 gr bullets (brand I guess will depend on what the barrel likes the most). So what should I chose?

Any recommendation for where to purchase a reamer would also be much appreciated.

I wanted the cartridge mainly for 600 yd NRA HP Prone and thought about trying it at 1K.

My reamer has a .272" neck with a .104" freebore.

My bbl likes the 107 SMK best with Varget. Have shot it at both distances and it is fantastic. For 1K, you need low wind conditions and its accuracy will make the scoring rings bigger.

It is not a replacement for a 6.5x284 when the wind is blowing at 1K, but in the midwest where I shoot, that is not such a huge issue.

My floating pilot reamer was done by Kiff.

RGDS

Bob

 

[rcw3]

You cannot just ask for "freebore" with a BRX

With a BRX (and a 6mm Dasher), to ask merely for a freebore length with nothing more begs an incomplete answer (as is giving the freebore of your reamer with nothing more). The BRX is a wildcat and therefore there is no set case length, and since the freebore is added onto the case length (max chamber length), just asking for the freebore gives you an incomplete answer.

Example, there are BRX reamers (and Dasher reamers too) with a 1.570" case length (max chamber length) and a .104" free bore, but then there are some BRX reamers with a 1.555" case length (max chamber length) and you would need a .119" freebore on that to equal the other reamer.

Example two, if your brass is 1.550" in overall length, and you have a 1.570" max chamber, you have a .020" gap to the end of the chamber vs a 1.555" max chamber that gives you only a .005" gap, and if the reamers both have the same freebore, the bullet comes out different on each (by .015").


To figure out what to do and what is going on you need the total picture.

Robert Whitley

 

[Lynn]

Call Pacific Tool and tell Dave or Kathleen you'll be using Lapua brass anxd want a 0.104 freebore and a 0.268 neck and your all set for 600 yards.
Waterboy

 

[rcw3]

Call Pacific Tool and tell Dave or Kathleen you'll be using Lapua brass anxd want a 0.104 freebore and a 0.268 neck and your all set for 600 yards.
Waterboy

.268" is a neck turn neck.
.272" is the popular "no neck turn" neck - a lot of shooters using this these days.

The reason I made the posting I did above is Kiff has a number of BRX reamer designs with different max chamber lengths, and saying .104" is the best freebore is of little value unless you know the max chamber length, as each is dependent upon the other to wind up with the bullet in the right place in the neck of the case.

Example, the attached reamer (which I use) has a .120" freebore, but the max chamber length is only 1.560" (vs the typical 1.570") so the net result is the same as having a .110" freebore on a chamber with a 1.570" max chamber length.

Robert Whitley

 

[Tclaunch]

upandcoming, read eggmans post very carefully before you purchase a reamer. He shoots a BRX (for many years) and has played with freebore dimensions If I were ordering a reamer I`d follow his advise.

 

[Lynn]

rcw3
Robert the original poster asked what was best not most popular and he never said he was interested in a no turn neck.
The guys shooting 0.272 necks have zero control over the clearance between the loaded rounds unless they neck turn so whats the point? If you have any old Lapua brass and any 6 year old Laopua brass to compare to the new Lapua brass in the big dark blue plastic boxes you'll quickly note one thing.The brass of old isn't the brass of today and picking a no neck turn reamer at 0.272 because you think you have plenty of clearance will quickly bite you in the chops.I know you frequent 6mmbr.com but youi may have missed all the recent posts about noted shooters ending up with zero neck clearance because they chose a 0.272 reamer in the hopes of never having to turn necks.If they are getting zero clearance now what was there clearance before when they ASSUMED it was fine?
As to the freebore as Tim Claunch and Rodney Wagner have pointed out anything from 0.090 to 0.160 works well with the bullets mentioned by the original poster so worrying over a very minute amount especially when talking directly with Kathleen or Dave as was suggested is simply wasted bandwith.
Waterboy
P.S. Have you done any work with the 105's that now need an extra 0.060 freebore as posted earlier? and if yes why is that now needed?Match Hunting Match Target thick jackets BT Match? Also please re-read your reamer drawing and take note of both approval names on it.

 

[rcw3]

Lynn

Do you actually work with the BRX or are you just passing on information from others?

The original poster never said he wanted to neck turn.

In my conversations with Kiff, the .272" no neck turn reamers for the Dasher and BRX are very popular, and with some of the well known winning competitive shooters too.

I seems to me, when one gets to reamer design, the details matter and either we are going to try to be accurate and precise or we are not (and the details are not "wasted bandwidth"). Otherwise, what's the need for the exact dimensions on the reamers down to a tenth of a thousandth (i.e. .0001").

FYI - I know well the reamer print I attached earlier, since it was made to dimensions that I specified, Dave then drew it and Kathleen checked it, then sent it to me for my final review and approval before it was made (i.e. please re-read the print, as what you said in reference to the print was not correct - I was the only one who gave "approval" to it). It is actually a third generation BRX reamer for me as I had two BRX reamers done by another reamer maker prior to having Kiff do one, so I have been around the block a few times on the design and making of BRX reamers myself, and I actually have barrels chambered up and test them out with different dimensions and reamer designs.

A .160" freebore is very long for a BRX (if the max chamber length is within normal limits). If you are shooting bullets with a very long bearing surface that would work, but the downside of that is that other 105 gr. bullets would have almost no neck holding onto them when they hit the lands.

Robert

 

[Lynn]

rcw3
Robert the specs I listed came from my reamer and not hearsay and I shoot on average 11 matches a year in actual NBRSA Benchrest Competition not Palma,F-class or highpower.
I don't know when you last spoke to Dave but as stated earlier you should read the posts on 6mmbr.com and see what is actually going on today and not from myself but fellow shooters from across all the states.As posted earlier I use a turned neck and I think the 0.272 neck shooters who think they are no turn necks are asking for trouble at some point.
I know or have heard of many shooters using the 0.272 necks that have in the past turned necks and if there clearances tighten up on them they simply turn them.Would you as a lawyer recommend to a new shooter that the 0.272 necks are no turn necks? Or would you rather read the posts on 6mmbr.com that I recommended you read earlier?
I am glad you know the reamer print and the dimensions you ordered.I am tickled you realise nothing is to print.I am suprised that after two reamers you decided to switch manufacturers.It has been my findings that when you switch manufacturers all your previous dimensions no longer mean much.
On the 0.160 freebore if you don't know how Rodney spec'ed out the reamer or the neck he chose Your statement above may be wrong based on your quote here. "The BRX is a wildcat and therefore there is no set case length, and since the freebore is added onto the case length (max chamber length), just asking for the freebore gives you an incomplete answer.
Are you an active Benchrest Competitor as I don't see you listed in the NBRSA or IBS National Match Results? I ask because we get posters who are not active benchrest competitors posting here quite often.
Waterboy

 

[rcw3]

Lynn

From your posting I see this starting to get personal and I am not going there (nor does it change the truth of what I said) so enjoy your shooting and have a nice day!

Robert

 

[Lynn]

rcw3
Robert this is a quote from Dave Kiff.
Q: How long does it take to get a 6mm BR or 6BR improved reamer? Does the customer need to send you a spec sheet or can you work off a sample round?

"When a customer calls, I ask what brass he will be using and what bullet he plans to shoot. I can usually spec the right throat length and headspace based on this information alone, but it is best if he sends a dummy round with a bullet seated exactly where he wants it--for example with the top of the boat-tail .050" above the neck-shoulder junction. I measure the dummy round off the ogive with a 100-power Deltronic comparator, inspect for concentricity and gauge the headspace. Then I prepare a print for the job right away. The completed reamer is usually ready in two to six weeks".
It isn't personal with me and it looks like Dave doesn't have any problem with it either.
Waterboy

 

[expiper]

Lynn....I have been pulling out my hair....no wonder I m goin bald..hahah....over some of these new bullets .....they shoot good ..butttt they are all over the map for Jam length.....I havent had any of the new "blue box" brass yet...I hoarded enuff aprox 5yrs ago to last the rest of my days....so Im shooting the good ole' sufff.......I would not reccomend any dims. to any one at this time!!!!either......my best advice is get lots of brass and bulllets and stik a buulet in your particular lot of brass and measure it.....seat to the optimum length and let Kiff make your reamer.....OBTW,,,Rodney Wagner also knows his $--t when it comes FB and jam and all that stufff....he has hepled and advised me several times and was "right on" ......Roger
PS...OBTW,,,,I got that 7/07 shooting the big uns' .....jumpin ....080" !!!!!......and Rx-22mmmmmmm

 

[Charles E]

In some ways, it depends on how thrifty you are. I always assume a personal reamer will last a lifetime, maybe with some resharpening. And I can guarantee you I'll change my mind about bullets somewhere along the way,

These two thoughts lead to one conclusion: The reamer should have minimal to no freebore, and a throater should be purchased. If you think you'll ever play with the cone angle, no freebore. If you're wedded to, say, 1.5-degree half-cone angle, spec the reamer for the shortest bullet you may use--like a 62-grain Fowler in 6mm.

For me, the throater should be the type you can use with a T-handle with the rifle in the stock. This type of throater can of course also be used in a lathe, but the ability to throat by only removing the bolt and some careful setup is a real plus.

For that reason, I like spiral-fluted throaters.

FWIW

 

[Lynn]

Hey Expiper
I am in total agreement with Rodneys post above.His specs and mine look identical giving we are many states apart and Dave Kiff won't have any problems sending the original poster a reamer.
For some unknown reason people want to complicate these type of things way out of proportion thinking there set-up is better than the next guys.In reality a little more or less freebore if its in the ballpark originaly means very little.Of course if your in the business of selling people Your Reamer Specs as a revenue generating tool your specs are the only ones that will work.
When you get out here this october for the nationals I will let you try some of the new brass with some of the new bullets in a 0.272 neck and you can post on how much clearance you get.Don't worry I always have a hammer on hand.LOLROFLMAO
Waterboy

 

[eggman]

Robert makes a point on how the overall case length will affect the freebore length . My reamer runs on the short side as overall case length goes but I have never had to trim until about the 10th firing and I'm usually ready to toss the brass by then anyway . Just for reference I have attached my reamer print with the .162" fb.

[/IMG]

 

[Chisolm]

Rodney,
It looks like your neck shoulder junction(1.588") is past the case mouth(1.579"). That puppy is going to be tough to grind.

James