6mm Dasher Case Prep

[Robby T]

I'm finallly jumping off the old 6.5x284 bandwagon and joining that rebellious group of 6mm Dasher shooters. I have a few questions about case prep and primer selection if any one cares to lend a hand.

1. Is it necessary to uniform the primer pocket? Good, bad, ugly?

2. Is the pen vise the way to go to clean up the flake in the flash hole?

3. I have an abundance of Remington SR benchrest primers and BR4. With 30 something grains of RL 15, what seems to be the hot primer these days?


Robby

 

[TheBlueEyedBear]

You're gonna love this 'thang'!! ;D I see all these right-ups about the 6BRX vs 6DASHER and people favoring the BRX: But, have you noticed how many records have been set with the DASHER. Here in Montana this cartridge is as familiar as the state bird!
Question 1) YES
Question 2) I like the Sinclair tool
Question 3) forgot what it was :-[ Oh yeah,,, primers. I really like the Wolf SRM, especially for fire-forming.

Remember, you only have to fire-form ONCE. It is a pain in the butt, but well worth the effort. And, if you're gonna do all that work fire-forming, be sure to take a little more time to turn the necks. It will pay off.

 

[Robby T]

Thanks for the info. I used to regularly clean up with my 6.5-284, but that little squatty 6mm thing showed up one day and has kicked my butt match after match. Plus, I'm ready to get more than 500 rounds down a barrel without having to go through the re-barreling process.

 

[TheBlueEyedBear]

Shaaa-zaaam!!!
You made a great choice!!

 

[skeetlee]

If a guy had a .272 6 dasher chamber could he still turn the necks .001 just to clean them up and be ok? Or is that a bad idea with a standard neck chamber?

 

[TheBlueEyedBear]

Definately TURN them. My DASHER has a .271 neck and I turn .001 (approx). I find the lowest spot on the neck and then turn to 'clean it up'. I truly believe that the closer you get to perfection in your case prep, the closer you will come to the perfect round of ammunition. Of course, if you're like me and still can't shoot,,,, it wouldn't make much difference..
It's fun to try though!!!

Barry

 

[Robby T]

As far as the fire forming goes, I read a lot about the false shoulder method, but I have seen some people "load and shoot". My buddy does this (load and shoot) with his 308 Baer, 22-250 Ackely, and 223 Ackely. I saw some comments on another post where people had neck splits either way, so does it really matter? He hasnt split any necks that I know of.

I know the thing with the dasher is that we are actually shortening the neck some from the standard br case vs. just blowing the shoulder out.

 

[canderson]

You will have to use a false shoulder to get the br brass to headspace correctly. I have used varget or H4895 to fireform. Find an accurate load and go kick some tail. Velocity should be somewhere in the upper 2800.

 

[alf]

Ackleys headspace on the parent cases' shoulder for fireforming.

Dashers, like the Gibbs line, move the shoulder forward, so a secondary false shoulder needs to be formed to hold the case properly for fireforming.

Here's a pic showing the 22 Dasher steps. For the 6 Dasher, I expand to 25 cal first, and then back down to 6 to form the new shoulder. I use my custom die that's set to bump the fired brass a thousandths or so, but put a .010" shim under it to leave a good crush fit for fireforming, plus seat the bullets HARD in the lands.

 

[Robby T]

Alf, Lynn,

Thank you for the detailed answers and the picture certainly helps. I've been competing in 600 yrds now for about 5 years with a 6.5 and did well until the 6 br family showed up. Needless to say, I'm still a newbe with reloading and learning the hard way most of the time(safely) . Your advice helps tremendously.

I have a Krieger 1:8 finished at 28" on the way, so I've been getting cases prepped in the mean time. I've had some really great success with 6.5 and 30 with Krieger, so I have a high expectation of my 6mm on the way. Any of you guys thinking of going to IBS Nationals this year?

 

[RDavies]

Something you might find, against all common sense, is that fireforming rounds can be super accurate as well.

 

[Robby T]

cr500,

I've read where a lot of guys are using Varget to fire form. Would another powder with the same burn rate work fine too? I have plenty of benchmark, 4064, and RE 10x.

As far as having accuracy results on fireforming, are you doing that with a fire forming charge, or are you doing it with the same charge and powder that you intend to compete with?

Robby

 

[queen_stick]

Robby,

You can use a standard 6Br load to fireform, for example, 30.0gr of Varget. Basically, shoot the Dasher as if it's a 6BR to fireform. I only shot at 100yds with mine when fireforming, and it shot really well - 30.0gr Varget, 105 Amax jammed. I'm sure other popular 6Br powders/loads would work the same. Some people load down to fireform, but I think more people are starting to use full loads, because they're accurate enough to compete with. You can fireform in a match, so the rounds fired aren't considered "pointless."

Walt