Dasher

[wal]

Just built 6mm dasher Krieger 27" 1-8 .266 neck, long throat.
Found that this cartridge is very powder weight sensitive .2 of a grain either side can make or brake a group at 600.
Is this common with the Dasher cartridge?


Currently shooting RL15 CCI450 105 lapuas
Velocity 3059 average
ES 4 over 10 shot string
No case pressure round primers

 

[memilanuk]

+/- 0.02gr. Two *hundredths* of a grain makes or breaks your group.

Are you kidding?

 

[wal]

In no wind conditions i found that .2 grain either side shot reasonable but wasnt what i expected. But between the two consitantly halved the group size.
And was just wondering if this was common?

 

[wal]

milanuk

sorry about the typo,+/- .2 grain)

wal

 

[Woody]

Tried VV N140 again at 32.0 grains and it is a little warm so I plan to drop down a half grain or more. 300 yard group was good. 3 shots in a half inch but the 4th went low and wide which opened things up to an inch and a third. 105 Lapua's still winning out so I will use them exclusively going forward for load develpment. CCI 450 primers so far. I plan to load up 4 rounds using CCI BR primers as I have some on the shelf just to see how they perform. Getting close.

Loaded some more RL15 for the fireforming and it is still showing signs, in this new lot of powder, of pressure so I plan to back off another grain. It proves fine one day and piercing primers the next day. Ok, what is up guys? I must be missing something. That will put me 2.5 grains less than the last lot of RL15, which was fine. Could there be that much difference between lots of powder. Seems a bit much to me. Temperatures were within 5 degrees both mornings, etc., etc.

1kstr

 

[Woody]

Found out what the issue was in fireforming. Length issue. Wasn't into the lands far enough. Don't know what changed for sure but I decided to make them 15 thou longer.

Recipe shooting last night and shot a 3.5" -5 shot group at 600.
4 out of 5 were in an inch and a half. Looking good.

1kstr

 

[Woody]

For those following this post: I am going to try a different primer as I am still having occasional piercing issues during fire forming. Will report Monday on how that goes.

Thanks,


Woody

 

[AckleyImproved]

Mate

With my latest Dasher, I have two loads going. I used a ladder test at 300m.

87Vmax with 34.7 Varget seated 0.010 in from a very soft jam, and 105Amax with 32.6 varget seated the same.

The 87Vmax shot in competition a 0.801" group at 300m. I have not shot the 105's yet but they are looking even better.

As for fireforming, I used 87Vmax, but loaded them up to light which resulted in primer issues...

I I have with both my Dashers, anda range of projectiles it has taken absolutely bugger all work to get them to shoot great.

Usually between 32.5 to 33.3 grains of either RL-15 or varget with the 100+ projectiles seated 0.010 in from a very soft seat.

Cheers
AI

 

[Woody]

Well, so much for that thought. I had 1/3 of the rounds that did not go off. I tried some CCI 41 arsenal primers and they just failed to fire or my firing pin does not strike them hard enough. Back to the drawing board.

AI:
Sounds like you had some piercing issues as well. What was your fix?

Woody

 

[AckleyImproved]

Mate

Why I had primer piercing issues was because my fireforming loads were to light. The rounds were going off, but the cases were not forming 100% properly. The shoulders still very slightly rounded. This low pressure of a light load caused my primer issues,yours maybe a different issue).

I also use the false shoulder method only now. I did form up some cases by seating the projectile hard into the lands, and also using greater neck tension. Out of 50, 3 did not go off. I believe the firing pin was pushing the case forward and seating the projectile deeper, thus not having enough force hitting the primer.

If they are plain not going off, I would assume you have a head space issue when forming. If not using the false shoulder, the projectile is getting pushed into the case like above mentioned, and if you are using the false shoulder method, I would check what you are doing. For me, the flase shoulder has resulted in 100% ignition, and one lost case due to split.

Having a tight neck chambered rifle and using the false shoudler method is a pain in the @$%^, as working out how much to turn down, but it can be done. I now have two Dashers, one no turn and the other turn. Guess how I form my cases with the tight necked rifle?

Cheers
AI

 

[Woody]

AI:

I may have to goto the false shoulder method myself. I had great luck using the load and shoot method for the first 75 rounds with only one lost case and everyone going off without a hitch. Didn't change a thing then bam, been down hill ever since concerning the primers. I am going to try a few Winchester primers and see what happens. If that doesn't work I will end up going to the false shoulder method.

Thanks,

Woody