6 Dasher build guidance

[earthquake]

Greetings! I'm working towards my first 6mm build and via the encouragement of distant friends, I've decided on the 6mmDasher. I am collecting pieces/parts for this and will be forming my own brass from Lapua 6BR brass.

A good friend/gunsmith of mine is going to chamber it for me. I have a 8-twist Bartlein Sendero barral and will mate it up with a Bighorn TL3 repeater when it comes in June. I am looking at reamers now and bullets.com has one listed for just under $150 which seems like a deal to me. My question is that I've been told/recommended a 0.104 freebore for this cartridge. The page on bullets dot com shows 0.060 freebore length, but when you click on the "Additional specs .PDF" file, the fb dimension, dimension 'a' looks to be 0.104 if I'm reading it right?

Also, is says bore is 0.236 and my barrel blank is 0.237....will this reamer work for me?

http://bullets.com/products/6mm-Dasher-Chambering-Finish-Reamer/T23209

I've got everything so far but the brass and the action. I had planned on fire-forming my own with the false shoulder method, but I'm a bit leery about doing it. I am probably going to pay someone to hydro-form the brass for me. Either pay him $180 to do 300 pcs. or spend about that amount on bullets/powder/primers and barrel wear to do the same thing and risk a blown-up gun if I do something wrong! What say the experts? I really appreciate your time and guidance!

 

[dkhunt14]

I shoot a .155 freebore. Most 1000 Yard shooters are using a .135. I wouldn't build with anything less. Matt

 

[ShootDots]

I shoot a .155 freebore. Most 1000 Yard shooters are using a .135. I wouldn't build with anything less. Matt

I also shoot a .155 freebore. It works for everything from 105VLD's thru the 105 Hybrids... GREAT freebore length.. I also use a .271 neck, which if you turn the brass to 12K neck wall thickness will give you 4K chamber neck clearance.

I would call DJ's brass service and have him: 1.) turn the necks to 12K; 2.) chamfer the case necks (mouths); 3.) Hydroform and finally 4.) anneal that brass..It is just about the same cost (if you consider barrel wear) as fireforming the brass yourself..

 

[tclaunch]

I am not thrilled by the reamer drawing, letterbox E & F on the freebore diameter is tight, and the box that says the chamber length is 1.555" and 6BR brass is longer than this. I`d hate to see you have to trim brass before it would chamber fireform rounds. Hydroforming is easy, if you have $150.00 they can be had and then the die is yours and will pay for itself.

 

[earthquake]

Ok, thanks for the advice so far. Some stuff to think about here. Forgot to mention I will be shooting Berger 105 hybrids at least first...I have 1k of them.

 

[earthquake]

I also shoot a .155 freebore. It works for everything from 105VLD's thru the 105 Hybrids... GREAT freebore length.. I also use a .271 neck, which if you turn the brass to 12K neck wall thickness will give you 4K chamber neck clearance.

I would call DJ's brass service and have him: 1.) turn the necks to 12K; 2.) chamfer the case necks (mouths); 3.) Hydroform and finally 4.) anneal that brass..It is just about the same cost (if you consider barrel wear) as fireforming the brass yourself..

I had contacted DJ about doing the hydroforming for me. As for turning, not sure what 12k means (sorry, new to turning necks), and I could chamfer myself on my Giraud trimmer. As for annealing, would that be necessary on brand-new brass? I planned on having the order shipped directly to him. Thanks again for all the help!

 

[ShootDots]

I had contacted DJ about doing the hydroforming for me. As for turning, not sure what 12k means (sorry, new to turning necks), and I could chamfer myself on my Giraud trimmer. As for annealing, would that be necessary on brand-new brass? I planned on having the order shipped directly to him. Thanks again for all the help!

Turning your necks to 12K is simply MY way of shortening down 12 thousandths.. You can do decimal points too, for ease of writing >>>BUT I get the decimal points "messed up" from time to time writing. So 12K is easy for me. I am not a BIG fan of "factory anneal" jobs... When I was fireforming myself, If I annealed first, I lost very few cases. If I did not anneal first, I lost upwards of 3+ cases per 100 fired.. It is literally pennies for the service of chamfering. That's why I have him do it..

 

[savagedasher]

My next reamer will be .2705 with 140 FB
7.5 or 7.25 twist . Larry

 

[earthquake]

Turning your necks to 12K is simply MY way of shortening down 12 thousandths.. You can do decimal points too, for ease of writing >>>BUT I get the decimal points "messed up" from time to time writing. So 12K is easy for me. I am not a BIG fan of "factory anneal" jobs... When I was fireforming myself, If I annealed first, I lost very few cases. If I did not anneal first, I lost upwards of 3+ cases per 100 fired.. It is literally pennies for the service of chamfering. That's why I have him do it..

Got it. Thank you for the explanation.

 

[bsumoba]

.155 freebore, .271 neck.

I turn neck to 0.012", which ended up being a 95% cleanup on my necks.

I fireform with 105 VLD jammed 20-30K and 29.5gr Varget. Scary accurate at 100 yards and will be great for local mid-range matches. I have had zero misfires. I used to do a false shoulder, but found that jamming 30K in with 0.004" of neck tension does that job just as well.

works well for 108BT, 105 hybrids and 105 VLDs. You stay well above the neck/shoulder junction as well.

work around 32.6-33.5 gr with Varget and 32.2-32.8gr for RE-15. Started maybe jammed 10K in and then try jumping out to maybe 20-25K. I am jumping 5K.

 

[Mulligan]

I also will be chambering a dasher very soon. The one I have is a 1:8 twist, 104 free bore, no turn .271 neck.
I bought this rifle used, it is my first dasher.
Why the .155 FB? I am asking only to educate myself before I order. I just started shooting F-open. Looking for tips for a new F-class shooter please.

I was amazed at the accuracy I received when fire forming.... Not sure if that is normal however I (rookie) would shoot these in competition.
CW

 

[ShootDots]

I also will be chambering a dasher very soon. The one I have is a 1:8 twist, 104 free bore, no turn .271 neck.
I bought this rifle used, it is my first dasher.
Why the .155 FB? I am asking only to educate myself before I order. I just started shooting F-open. Looking for tips for a new F-class shooter please.

I was amazed at the accuracy I received when fire forming.... Not sure if that is normal however I (rookie) would shoot these in competition.
CW

I like the .155 because it is VERY "flexible" as far as bullets go. You can shoot a 105 VLD (generally a short bearing surface) to the 105 Hybrids and 108 Berger B/Tail>>>both with long bearing surfaces. With the latter bullets you need a MINIMUM of .135-140 to keep the bearing surface ABOVE the neck / shoulder junction. Additionally, if you shoot the 105 VLD's, you can get a bit more powder in there because of the longer freebore>>>it essentially increases case capacity.. I hope this helps to some degree..

 

[22DASHER]

.125" fb was a little too short in my Dasher shooting the 108 Bergers. Where it shoots the best, the bearing surface is at or just below the neck shoulder junction.

 

[Mulligan]

Are you jumping or jamming?

 

[22DASHER]

Are you jumping or jamming?

I was jumping .010"

 

[dkhunt14]

When you lengthen the freebore it gives you a little more capacity. It usually helps you get the velocity without over pressuring the cases. It also keeps the pressure ring of the bullet out of the donut area. I also don't like when the pressure ring of a bullet gets pushed through the sized part of a neck into the unsized part. About .135 is minimum of what you want. .155 works about right for the 105 class bullets. Matt

 

[Mulligan]

Wow, good info.
I have been shooting the 108s, because of supply I am now using the 107s. Are the 105s the fav? Is anyone shooting the 115s and if so is the FB the same?

 

[dkhunt14]

The 107 shoots good also. The new pointed ones have been pretty good. I prefer the 105 VLD and the 108 BT over the Hybrid. I believe if you don't have a 7 or 7.5 twist you will not get the 115 to shoot good at distance. I know a few that tried them and didn't have much luck. Now this is 1000 yard BR. Matt

 

[Kebee]

Greetings! I'm working towards my first 6mm build and via the encouragement of distant friends, I've decided on the 6mmDasher. I am collecting pieces/parts for this and will be forming my own brass from Lapua 6BR brass.

A good friend/gunsmith of mine is going to chamber it for me. I have a 8-twist Bartlein Sendero barral and will mate it up with a Bighorn TL3 repeater when it comes in June. I am looking at reamers now and bullets.com has one listed for just under $150 which seems like a deal to me. My question is that I've been told/recommended a 0.104 freebore for this cartridge. The page on bullets dot com shows 0.060 freebore length, but when you click on the "Additional specs .PDF" file, the fb dimension, dimension 'a' looks to be 0.104 if I'm reading it right?

Also, is says bore is 0.236 and my barrel blank is 0.237....will this reamer work for me?

http://bullets.com/products/6mm-Dasher-Chambering-Finish-Reamer/T23209

I've got everything so far but the brass and the action. I had planned on fire-forming my own with the false shoulder method, but I'm a bit leery about doing it. I am probably going to pay someone to hydro-form the brass for me. Either pay him $180 to do 300 pcs. or spend about that amount on bullets/powder/primers and barrel wear to do the same thing and risk a blown-up gun if I do something wrong! What say the experts? I really appreciate your time and guidance!

Call pacific tool and they wil email you the print for bullets reamer. The freebore is 104. The .060 is a misprint. 104 is ok for Berger 105s into the LANs, but if you want to shoot amax 105 or 107s or 108s the freebore may be short. My preference is 125 to 135 freebore. It gives more bullet choices.

 

[earthquake]

Resurrecting this thread. I got the PT&G reamer and it is .104 FB. I have every last piece for this build but the action. That won't be available until June. Gonna send the 6BR brass to DJ for forming I've decided. Thanks for all the help!

Manners T6A carbon fiber stock
Bartlein Sendero SS 5R barrel, 1:8 twist, 26"
Timney Calvin Elite trigger
APA Little Bastard Gen II brake
Berger 105 hybrid
Varget
CCI 450 primer
Lapua 6BR brass
Redding FL sizing bushing die
Forster Ultra micro seater die

Bighorn TL3 short action (June)