New to 6mm Dasher

[thatguyshm]

So over the winter I put together a Savage 6mm Dasher on a 12 FV action. 28" 7.7 twist X-Caliber 3 groove. Using new Norma brass that I had on hand, necked up to 0.264" then sized back down for a crush fit. Loading 105 Hornady HPBT for fire forming loads, I understand the limitations of the bullet. Will be switching to 107gr Sierra's with formed brass. Barrel is broken in, using SW Precision powder and Fed Match AR primers. 29.0gr gives formed brass with a 9 shot SD of 5.3 fps. I used my magnetospeed to get my velocity, which resulted in a phenomenal 200 yard group. Groups after removing the mag speed opened up to about two inches.

I don't want to go down the tuner path. I'm 0.025" off the lands, so my next step is seating depth. Other than seating, and trying some 450s, any other suggestions for tuning? Obviously it enjoyed the chrono. It's sitting in a plastic stock waiting on a laminate, so I know that's also against me, just the group had me excited. Attached is a consecutive 9 shot group.

 

[dmoran]

For 105/107 class bullets:

• Starting around 32gr with Varget, RL15, N140
• Starting around 31gr with H4895, IMR-8208XBR, IMR-4064
• Starting around 34gr with RL16, RL17, H4350

Workup up slowly with each one (like in .2-tenth increments).

 

[thatguyshm]

Thank you. Any thoughts on tightening up the fire forming load? I'm forming brass to settle the barrel. Plan was to use the formed brass to dig into load development once the stock arrives, just today's grouping got me a little excited with the chrono effectively acting like a tuner. Guess I just need to be patient and dig deeper when it's fully together.

 

[dmoran]

Equality in the cases being fire-formed, only comes from equality in the load used. The better job we can do fire-forming them and blowing them equal, will pay off in accuracy gains there after - IME.

Final case capacities reflect directly on how equal they are blown, and am willing to sacrifice fire-forming accuracy to do so. My own 6Dasher fire-forming load, typically holds 5 to 6" of vertical dispersion to 1000yds, with my pet loads typically being capable of half of that (or better).

Good luck with your endeavors !.!.!

 

[thatguyshm]

I'm can't argue the SD of 5.3, so I'm going to make minor changes but I agree totally and appreciate the advice. I just can't pass up range days like this.

 

[swd]

107 Sierra's love to be in the lands. Push them in until the engraving marks are square and work back from there.

 

[thatguyshm]

I'm basically trying to make a Gremlin drive like a Porsche. She holds about an inch and a half at 200, but I think I'm done pushing it until I get my new stock. I've formed about 100 pieces of brass, time to clean it up get it ready to load. Going to try Precision first, then RL15, then RL16 if those don't run like they should.

 

[WIB3]

Equality in the cases being fire-formed, only comes from equality in the load used. The better job we can do fire-forming them and blowing them equal, will pay off in accuracy gains there after - IME.

Final case capacities reflect directly on how equal they are blown, and am willing to sacrifice fire-forming accuracy to do so. My own 6Dasher fire-forming load, typically holds 5 to 6" of vertical dispersion to 1000yds, with my pet loads typically being capable of half of that (or better).

Good luck with your endeavors !.!.!

Well put Donovan, most don’t realize that initial case preparation and fire forming are critical for the performance of a Dasher. Loading cases for forming should not be any different than loading for a match. I don’t personally sort bullets or weigh primers, but powder charges are spot on.

 

[jobhopper66]

I believe Donovan gives some of the best advice any reloader can get. What he posts just makes sense.

 

[2moreclicks]

Equality in the cases being fire-formed, only comes from equality in the load used. The better job we can do fire-forming them and blowing them equal, will pay off in accuracy gains there after - IME.

Final case capacities reflect directly on how equal they are blown, and am willing to sacrifice fire-forming accuracy to do so. My own 6Dasher fire-forming load, typically holds 5 to 6" of vertical dispersion to 1000yds, with my pet loads typically being capable of half of that (or better).

Good luck with your endeavors !.!.!

If you don’t mine me asking what is your go to fire form load for consistency with hydro brass

 

[dmoran]

@2moreclicks .... sorry, but I don't hydro-form.

 

[2moreclicks]

@2moreclicks .... sorry, but don't hydro-form.

So am I starting out on the wrong foot with hydro formed brass?

 

[dmoran]

@2moreclicks .... it's cool, many do. I just don't.

 

[WIB3]

I have a dedicated fire forming gun. It has the exact chamber as my match guns. 30.00gr of Varget and a 107 Sierra Mk. I purchase the 107’s from those who realize that they can not make them shoot.