6 Dasher Help

[wmcclendon]

Building a 6 Dasher and I’m a bit worried about the barrel I ended up with.

It’s a X-Caliber 1:8. I was told they used a JGS reamer. Contacted them and they say it’s a .271 neck with a .040 freebore.

Couple of questions: is this freebore going to work for me? I’m looking to shoot 87 vmax and 108 ELDs. Seems way too small from what I’ve been reading. I need to research this “donut” thing.

Will I have to turn case necks for this? Looks like I’ll be ok I think. Thinking hard about using the Norma Dasher brass. Any issues with that besides having to trim them down?

Thanks...total noob here with these wildcats. Mainly just looking for a long range prairie dog gun and target shooting.

 

[Dusty Stevens]

yea man youre way off on everything. that neck is too tight for no turn, the freebore is way short for the twist rate you have and i'd bet its for lapua brass which means its gonna be work to trim the normas to fit. that freebore is good for your lighter bullets but the twist is for the big ones. you should have a gunsmith run the correct reamer in there and set it back before you shoot it. if you want to use norma brass theyll have the reamer for that. those 2 bullets are too far apart for one freebore to work for both efficiently

 

[Phil]

I have a Dasher reamer for the 75 / 87 Vmax bullets, it is .070 freebore and set up more for the 75`s.

Like Dusty said, the 87 to 108 is a big jump in bullet length along with such a short freebore.

I know of one smith who builds Dashers with zero freebore and shoots the 55`s in an 8 twist, but that`s a really short bullet and the freebore matches it.

Talk with a good smith and he will help you get this all worked out.....

 

[avidflyer]

yea man youre way off on everything. that neck is too tight for no turn, the freebore is way short for the twist rate you have and i'd bet its for lapua brass which means its gonna be work to trim the normas to fit. that freebore is good for your lighter bullets but the twist is for the big ones. you should have a gunsmith run the correct reamer in there and set it back before you shoot it. if you want to use norma brass theyll have the reamer for that. those 2 bullets are too far apart for one freebore to work for both efficiently

Ive ran 271 neck for blue box lapua with no problems was (hate to use the word). standard for years I thought. next reamer will be 272 just for a little extra. Not a clue about Norma....

 

[johara1]

Building a 6 Dasher and I’m a bit worried about the barrel I ended up with.

It’s a X-Caliber 1:8. I was told they used a JGS reamer. Contacted them and they say it’s a .271 neck with a .040 freebore.

Couple of questions: is this freebore going to work for me? I’m looking to shoot 87 vmax and 108 ELDs. Seems way too small from what I’ve been reading. I need to research this “donut” thing.

Will I have to turn case necks for this? Looks like I’ll be ok I think. Thinking hard about using the Norma Dasher brass. Any issues with that besides having to trim them down?

Thanks...total noob here with these wildcats. Mainly just looking for a long range prairie dog gun and target shooting.

No, the free bore is too short, with the Dasher pick a bullet, you can't do both that far apart. The 108 I would be .135 to .150 FB. and the 87 won't work..... Go with a 6mm BR.IMP. and the long neck and ease of fire forming and go with a .100 FB. and both will work pretty good. I would go with the 87 and a 103 bullet I know both work very well ....... jim

 

[swd]

FB for the 87 V Max in Lapua brass would be in the .104" range. .040" is WAY too short. I have a .150" FB reamer and the 87 still has enough shank in the brass to seat it ok for occasional Varmint use.

 

[KMart]

If you are planning on using the long neck Norma brass, you need to get that done. Bullets.com is the ONLY place to get it and they are closing out all their stuff now and going out of business. It is presently showing "in stock" but don't know if their system is updating.

 

[CaptainMal]

Do some math. .271" neck diameter needs a loaded cartridge neck NO MORE than .268". That will give you .003" expansion release room.

Most Lapua brass is .013" neck thickness or less. Take that times two ( both sides) for .026" of brass. Add on the .243" bullet for an overall outside diameter, assuming you have a decent interference fit. That gives you .269" OD.. Now you have just .002" of release room. A bit tight but maybe workable.

The saving grace is neck brass is not always exact. Many will be .0125", giving you a .003" release space. If you measure the brass and it's more than .0125" then turn to that or even .012".

Now throat length is another issue. You are planing on using smaller bullets than most who do the Dasher 105 gr + target thing. You "may" be able to get a decent load with a touch into the lands. You can measure and try. That short really is for lighter and smaller bullets but again, "may" work.

Now I just hope I did not screw up my math.

 

[dmoran]

@wmcclendon
My own advise: extend the throat with a throating-reamer and skip trying to use short bullets for fire-forming (unless you leave the short throat). I personally like a "false shoulder" for fire-forming the best.
Good Luck
Donovan

 

[wmcclendon]

First off....thanks so much for all of the replies and offers to help out! Quite a great community here and I appreciate everyone's input.

Now...I don't like it, but that's just what I have I guess. JGS came back and said the reamer was based off of the original designed by Bill Franklin in 2005, for what that's worth.

So I've been looking at throat reamers. I see that 4D rents what looks to be the PTG Uni kit. Looks like something I could do by hand? I've worked in a machine shop before, so I do have some experience, but I'm no gunsmith. I hate to throw a lot more money at this barrel. Seems like I might could just get another one for the cost of what I have plus another chamber job. Of course I wouldn't need a complete chamber job.

To make matters worse, I'm in a rush of course. Got a prairie dog hunt planned in MT in late May. With that said, I think I'll focus on shooting the 87 Vmax bullets or something around that size.

For the brass, I'm thinking of going with the Norma and just trimming them to fit the current chamber length. Again, time limited. If I do end up needing a full re-chamber, then I'd probably go to the official Norma Dasher reamer specs, but it seems like just a throat change should work.

So...self throat with the 4D rental???

Thanks again everyone!

 

[DT]

If you are going with Norma Dasher brass I highly recommend going with a reamer specifically sized for that brass and not a "regular" dasher dimension reamer.

 

[Dusty Stevens]

And I’d recommend a stockpile of brass. With the demise of their only dealer grizzly may not pick it up. Lapua will be around.

 

[wmcclendon]

Is there a reason I shouldn't get the Norma brass and just trim the length down to fit my current chamber length? I've got a Giuard, so it should go easy I hope. I checked the reamer prints and the differences are minimal between the Norma and the JGS that was supposedly used. I've got .4707 vs .4708 at the .200 line.

I ordered some cerrosafe to take a mold of my chamber...any reason not to do this?

I'd plan on getting 500 of the Norma brass, and if I don't elongate the neck in the chamber, I could always switch to Lapua if needed. I'd expect the barrel to be done before I needed new brass though.

So...anyone lengthened the throat by hand with a precision throating reamer?

Thanks again!

 

[dmoran]

@wmcclendon
With a .4707" chamber, the Norma brass will work fine.
And as long as the sizing die compliment's the tight chamber, all should be good.
Good Luck
Donovan

 

[varminthunter1]

sent you a message

 

[KMart]

And I’d recommend a stockpile of brass. With the demise of their only dealer grizzly may not pick it up. Lapua will be around.

Here is Shriz statement on the future of the Dasher brass:

We ran out of the smaller packs of the Dasher brass and are converting the leftover 2000 qty cases into smaller units so it is easier for people to buy. Cannot believe how fast it is flying out! Thanks for the support guys. Oh, I had to slide a case aside for myself as I am converting my "wildcat" Dasher to a Norma Dasher which will soon be listed as a standard caliber under SAAMI. This brass will continue to flow into the USA through Norma in the future, but right now we are the only ones that have it.

 

[Gilbert Garza]

So...anyone lengthened the throat by hand with a precision throating reamer?

Thanks again!

I’ve done it, it’s not hard but it’s also slow, and very easy to oval out the bore. Just go slowly and apply even pressure downward. I did it with the barrel off and muzzle down, placed the t handle on it and started cutting. Just use oil and go slow, measure often.

 

[wmcclendon]

Ok...bit of an update. I bought 500 of the Norma Dasher Brass. Got the die for the Giraud, but haven't trimmed any yet. Also got a modified case to use with my Hornady/Stoney Point OAL gage. Checked quite a few bullets for OAL.

Rented a 6mm throating reamer from 4D reamer rental. Decided to shoot for .104ish freebore. Did a first try and took off .050 just to see how it cut. Didn't change the OAL much at all. I took a cast of the chamber and saw some change. Took another .020 off and still not much change with the OAL gage deal. Took another cast and there is definitely a change, but sort of weird. Looks like it's only cutting the leading edge of the rifling.

Cast of the throat as received. Seemed to measure .040 like the reamer print.


Cast after the second cut. Seems like it's not fully cutting the rifling. I assume this is the reason my OAL isn't really changing.


Any ideas?

 

[boltfluter]

Looks like maybe the throater was not centered correctly during the cut. Just a thought.

Paull

 

[Dusty Stevens]

once you straighten that out theres not a bullet made thatll fit that freebore length. you may as well have that rechambered with the correct reamer- id say that chamber is ruined.