Gunsmithing Making a 6BRA With a Dasher Reamer?

[ThePretzel]

I haven't had much experience with the specific process of chambering a rifle, but would it be possible to chamber a rifle in 6BRA using a 6 Dasher reamer?

I ask because the 6 Dasher is the same thing as the 6 BRA, but with the shoulder moved out by 0.080", and you can just trim 0.080" off a Dasher sizing die to create a 6BRA sizing die. Wouldn't that mean you could chamber in 6BRA by essentially chambering a Dasher with 0.080" too little of headspace by just not running the reamer in as far? Or would doing this create a throat that is too short?

If this wouldn't work I'm curious to learn why that would be.

 

[bohem]

You will need a necking reamer and throating reamer to fix the front end of the chamber.
Remember that the BRA and Dasher both come at the same trim length as a 6BR. You're trading neck length for body length. Holding the reamer short will net you a Dasher length neck (as opposed to the BRA length neck) and a body that's 0.080 too short.

 

[ThePretzel]

You will need a necking reamer and throating reamer to fix the front end of the chamber.
Remember that the BRA and Dasher both come at the same trim length as a 6BR. You're trading neck length for body length. Holding the reamer short will net you a Dasher length neck (as opposed to the BRA length neck) and a body that's 0.080 too short.

That makes sense then. I kind of forgot about the cutting that goes into the neck.

 

[Steelnecktie]

I chambered mine with a 6BR reamer and a 6Dasher reamer. 6BR reamer goes in to about .004” short of my go gauge (headspace on my lot of brass) then followed that with a 6 Dasher reamer .084” short. The Dasher reamer was a tight neck, so it didn’t touch the neck that the 6BR reamer cut.
Cutting .080” off a hardened die is going to be the toughest part, I’d just get a die that’s for 6 BRA.
I’ve shot factory loaded 6BR ammo in mine and it works perfectly, fireforming loads in this rifle are also super accurate.

 

[ThePretzel]

I chambered mine with a 6BR reamer and a 6Dasher reamer. 6BR reamer goes in to about .004” short of my go gauge (headspace on my lot of brass) then followed that with a 6 Dasher reamer .084” short. The Dasher reamer was a tight neck, so it didn’t touch the neck that the 6BR reamer cut.
Cutting .080” off a hardened die is going to be the toughest part, I’d just get a die that’s for 6 BRA.
I’ve shot factory loaded 6BR ammo in mine and it works perfectly, fireforming loads in this rifle are also super accurate.

That's actually an interesting way of cutting it. I was asking if it could be done with a 6 Dasher reamer because I'm looking to purchase a pre-fit barrel this summer from NSS and I was wondering if it would be possible to get a 6BRA chambering using only the reamers they had on hand. They do have 6BR and 6 Dasher though, and the headspacing is adjusted with a barrel nut so they'd just need the 80 thousandths offset between their Dasher and BR reamers to theoretically make this work (though who knows if their reamer for Dasher is tight neck, I somehow doubt it is).

After doing more looking around this afternoon and evening at my different options, I think I'll instead stick with something like 6XC. I wanted to shoot 115's at a faster velocity than 6BR (was hoping for 3000+ fps), but was also hoping for a 2,000 round barrel life and the option of using small rifle primers to make brass last longer.

I had been reading stuff on people using 6XC for benchrest matches and switching barrel at 1,000-1,500 rounds which concerned me, but once I looked at more PRS-oriented sources (to match my intended use case) people were using barrels for between 2,000-2,500 rounds without issues. I also found out that Alpha Munitions makes 6XC brass with small rifle primer pockets, and from what I've read their brass seems to be of high enough quality (though it looked like they could benefit from some trimming). Not having to worry about fireforming the cases, even if you're only really changing the shoulder angle, is admittedly a plus since it let's me rest easier when doing load development on virgin brass (I know that in most cases fired brass will behave close enough to virgin for my purposes, where I'm pretty happy if the rifle shoots near 1/2 MOA consistently).

 

[Steelnecktie]

You can not do it with just Dasher reamer, Dasher doesn’t have a long enough neck, that’s why you need the BR reamer. Or you could just get a 6BRA reamer. The 6XC or 6 Creedmoor will give better muzzle velocity, but just to ease your mind, I’m running accuracy node with 30.6gr. H4895 and 107SMK at 2960fps. Was able to run 105 Berger at 3100fps. with Varget, compressed load. This was out of a 29” barrel.

 

[bohem]

That's actually an interesting way of cutting it. I was asking if it could be done with a 6 Dasher reamer because I'm looking to purchase a pre-fit barrel this summer from NSS and I was wondering if it would be possible to get a 6BRA chambering using only the reamers they had on hand. They do have 6BR and 6 Dasher though, and the headspacing is adjusted with a barrel nut so they'd just need the 80 thousandths offset between their Dasher and BR reamers to theoretically make this work (though who knows if their reamer for Dasher is tight neck, I somehow doubt it is).

After doing more looking around this afternoon and evening at my different options, I think I'll instead stick with something like 6XC. I wanted to shoot 115's at a faster velocity than 6BR (was hoping for 3000+ fps), but was also hoping for a 2,000 round barrel life and the option of using small rifle primers to make brass last longer.

I had been reading stuff on people using 6XC for benchrest matches and switching barrel at 1,000-1,500 rounds which concerned me, but once I looked at more PRS-oriented sources (to match my intended use case) people were using barrels for between 2,000-2,500 rounds without issues. I also found out that Alpha Munitions makes 6XC brass with small rifle primer pockets, and from what I've read their brass seems to be of high enough quality (though it looked like they could benefit from some trimming). Not having to worry about fireforming the cases, even if you're only really changing the shoulder angle, is admittedly a plus since it let's me rest easier when doing load development on virgin brass (I know that in most cases fired brass will behave close enough to virgin for my purposes, where I'm pretty happy if the rifle shoots near 1/2 MOA consistently).

An alternate solution would be that we have a 6BRA reamer that's setup identically to the Dasher and BR chambers (freebore, neck dia, lead, etc) and we'll make you a Savage/Remage/Bighorn/etc prefit that you can use with or without a barrel nut, with or without the BarLoc, etc.

Then you can breathe easy knowing that the chamber was cut with 1 reamer the way it was supposed to be cut instead of worrying that the additional machining processes (which I am pretty sure would nullify any warranty NSS might offer) were successful and didn't cause any damage.

 

[Sheldon N]

The other problem with trying to use a Dasher reamer run in short (besides what's already mentioned above) is that you're going to end up with a smaller base diameter by roughly 0.001" due to the body taper. That would make it more difficult for your sizing die to adequately size the base of the case.

 

[Steelnecktie]

The other problem with trying to use a Dasher reamer run in short (besides what's already mentioned above) is that you're going to end up with a smaller base diameter by roughly 0.001" due to the body taper. That would make it more difficult for your sizing die to adequately size the base of the case.

Actually it works perfectly fine, because your cutting .080” off bottom of die. Or just order a die for 6BRA. Never had a problem.

 

[Sheldon N]

Actually it works perfectly fine, because your cutting .080” off bottom of die. Or just order a die for 6BRA. Never had a problem.

Depends on how long you run the brass, how small your die is, and how big your Dasher reamer was to start out.

I've got a Dasher that eventually a Forster die was barely sizing the base of the case at all, only maybe 0.0002 at best, and that would result in sticky bolt lift (clickers) from even normal loads. Had to buy a Harrells D4 small base die to continue running the brass after 8 or 9 firings.

My BRA has an even larger base diameter reamer than my Dasher chamber, I'm using the same model Forster Dasher die shortened, and now 5 firings in on the brass the case is only getting sized a bit under half a thou at the base. If my chamber was based on that smaller diameter Dasher reamer, run in short so another 0.001 smaller, I'd likely be running into the same problems I had with my original Dasher.

 

[Steelnecktie]

I’m easily over 10 firings on my 6BRA brass, I have no issues. I use Widden dies with mine. My BRA is not oversized at base like yours, I chamber my own barrels though. I think that little cartridge is great.
Sheldon N
If you have problems and know what they are, why not try to fix them? I can’t argue your bad chamber or dies that dont work or whatever measurements are off.
I’m just offering OP my experience with my BRA. He asked how to chamber one with Dasher reamer and I gave him an excact answer to how do it.

 

[Sheldon N]

I’m just offering OP my experience with my BRA. He asked how to chamber one with Dasher reamer and I gave him an excact answer to how do it.

To be clear, I'm not saying your suggested method is bad. By running in a 6BR reamer at the base, you get 6BR sized chamber at the base of your 6BRA.

What I'm saying is that if you just ran a Dasher reamer in alone, then throated out the neck and freebore, you'd be left with a BRA that was about 0.001 smaller than the base of whatever size your Dasher reamer was. And that's not a good thing.

My BRA chamber is not oversized, it's the same dimensions as pretty much all the BRA reamers out there right now. Based on the same reamer print that all the world record BR guns are running.

As far as solving the problem of brass to chamber fit, there's only two things you can do... pay attention to reamer dimensions when you get a rifle chambered, or buy smaller dies. I did the latter before I ever even had problems - sold a Whidden die and bought Forster because of the smaller base spec but it still wasn't enough. I ended up dealing with stuff like trying to shoot a spinner stage but the gun not cycling quickly or staying on target when I would run the bolt due to heavy bolt lift, even with a moderate/conservative load.

For anyone else still reading our rabbit trail on this thread, here's a good video on how this issue plays out. The video is by the same guy who is partially behind the resurgence of the BRA and who chambered a bunch of the record setting rifles.

 

[Steelnecktie]

For anyone else still reading our rabbit trail on this thread, here's a good video on how this issue plays out. The video is by the same guy who is partially behind the resurgence of the BRA and who chambered a bunch of the record setting rifles.

Yep, and before Alex ordered a dedicated 6BRA reamer, he was clambering them record winning guns with 2 reamers, that’s how he told me to chamber mine and to cut .080” off Dasher die. I’ve had ZERO problems out of mine with this method.
Good running the rabbit trail with you.

 

[ThePretzel]

@Steelnecktie , are you using your 6BR go gauge then for headspacing? If so, do you headspace it before running the Dasher reamer into the chamber and then just run the Dasher reamer in accordingly? I'm planning to go with a pre-fit barrel since I would like to save on gunsmithing costs, but I'm just trying to figure out how to properly headspace it before I ask around and potentially place any orders.

I know the shoulder angle is different than on the 6BR, which is why I wasn't sure if a 6BR go gauge would really work with it. I suppose I could take a Dasher go gauge and turn 0.080" off of it on a lathe to create my own custom go gauge, but then I just get to deal with poking it out with a cleaning rod since I'd probably be turning it down too far for an extractor to grab it. I could also potentially create a go-gauge from scratch, but that's more work than I want to do if I can just trim a Dasher gauge instead.

I have access to a machine shop (and know how to use it to boot), but it's on a college campus so I can't exactly bring a rifle barrel into the shop to chamber it myself or else I'd just order/borrow a Dasher and BR reamer to make it myself with a shouldered barrel.

 

[dimar1492]

Like other Ackley style chambers, the go gauge can be the pre-Ackley length minus .004"

If using a barrel nut setup you might even consider headspacing to your virgin BR brass. Then you can dictate a perfect snug fit for your fire forming.

 

[Sheldon N]

are you using your 6BR go gauge then for headspacing? If so, do you headspace it before running the Dasher reamer into the chamber and then just run the Dasher reamer in accordingly? I'm planning to go with a pre-fit barrel since I would like to save on gunsmithing costs, but I'm just trying to figure out how to properly headspace it before I ask around and potentially place any orders.

The preferred method seems to be chambering 0.003-0.004 short on a 6BR go gauge, which should give a nice light crush fit on virgin 6BR brass. That's what my gunsmith did. I presume with the two reamer process you would do that based on the Dasher reamer which sets the neck/shoulder junction.

I think it would be tough to have a savage/remage prefit in 6BRA, without making a custom 6BRA go gauge. You wouldn't have an easy way to measure where to tighten the barrel to with a standard 6BR go gauge.

If you're going to do a BRA, I'd suggest a shouldered barrel.

 

[ThePretzel]

The preferred method seems to be chambering 0.003-0.004 short on a 6BR go gauge, which should give a nice light crush fit on virgin 6BR brass. That's what my gunsmith did. I presume with the two reamer process you would do that based on the Dasher reamer which sets the neck/shoulder junction.

I think it would be tough to have a savage/remage prefit in 6BRA, without making a custom 6BRA go gauge. You wouldn't have an easy way to measure where to tighten the barrel to with a standard 6BR go gauge.

If you're going to do a BRA, I'd suggest a shouldered barrel.

If the method is to headspace 3-4 thousandths short on a 6BR go gauge, I can easily trim that off the base of the 6BR gauge without having issues extracting the gauge. Just touch up against the base with a finish cutter to set your zero, move it in 3 thousandths, and cut it smooth again. Then, of course, clearly mark the go gauge as being for BRA use only.

 

[Steelnecktie]

Why would you cut a go gauge? Just headspace the barrel off of a factory piece of BR brass. I used a BR go gauge and a Dasher go gauge both to measure what I was cutting. This was not on a pre fit.

 

[ThePretzel]

Why would you cut a go gauge? Just headspace the barrel off of a factory piece of BR brass. I used a BR go gauge and a Dasher go gauge both to measure what I was cutting. This was not on a pre fit.

I feel kinda stupid now. I forgot that I had something, like a piece of brass, already that would work...

Ha ha, thanks for showing me the forest when I was focused on the trees there.

 

[jsthntn247]

I haven't had much experience with the specific process of chambering a rifle, but would it be possible to chamber a rifle in 6BRA using a 6 Dasher reamer?

I ask because the 6 Dasher is the same thing as the 6 BRA, but with the shoulder moved out by 0.080", and you can just trim 0.080" off a Dasher sizing die to create a 6BRA sizing die. Wouldn't that mean you could chamber in 6BRA by essentially chambering a Dasher with 0.080" too little of headspace by just not running the reamer in as far? Or would doing this create a throat that is too short?

If this wouldn't work I'm curious to learn why that would be.

This will work if you use a Norma Dasher reamer.