How many times can Lapua 6MM Dasher brass be fired?

[40X Guy]

Boyd, thank you for the very informative insightful post! I would love to see some strain gauge results on Dasher brass. That would be interesting. I'm going to fireform another batch of brass and retire these cases after 9 firings and call it good. I probably won't back down on powder charge either as my node is perfect and thats why I like the 6 Dasher is because of the benefit of the extra speed and the superb accuracy.

Frank

 

[BoydAllen]

Frank,
This is what I was talking about. http://www.shootingsoftware.com/pressure.htm
I get your point about liking the top node. Mine was curiosity about how much velocity would have to be given up to get primer pocket life? Would 75 FPS do it? If it would, I think that a properly configured tuner could probably move the node to that velocity. Another thing that I would like to see is for someone to put a 26" Dasher barrel on a Heavy Varmint short range benchrest rifle and shoot it in a match that had tough winds to contend with. I think that it might be interesting.

 

[bozo699]

Frank,
This is what I was talking about. http://www.shootingsoftware.com/pressure.htm
I get your point about liking the top node. Mine was curiosity about how much velocity would have to be given up to get primer pocket life? Would 75 FPS do it? If it would, I think that a properly configured tuner could probably move the node to that velocity. Another thing that I would like to see is for someone to put a 26" Dasher barrel on a Heavy Varmint short range benchrest rifle and shoot it in a match that had tough winds to contend with. I think that it might be interesting.

Boyd,
Head to Deep Creek in Missoula this weekend you will see about 30 of them doing just that
Wayne.

 

[bozo699]

I can't believe anyone's still using that overbored thing, but...... my count has varied, but 20 would be about it for my guess on my stuff. Hot loads with h4895 definitely stresses some things.

Tom

Hey Mr. brdx, you have a lot of records with that old overbored thing LOL, wished I was there to watch you set a new record this weekend
Wayne.

 

[22BRGUY]

Frank...Was wondering if you are jamming or jumping with your load of 4895?
Thanks much
Dennis

 

[40X Guy]

Frank...Was wondering if you are jamming or jumping with your load of 4895?
Thanks much
Dennis

Dennis, I'm jumping the 105H Berger .010. Its the same bullet I started with in this rifle.

Frank

 

[40X Guy]

Frank,

What do your fired cases Mic down at the base out of curiosity? What receiver is your build on? Barrel length? Bore size? Velocity?

Tom

Tom, just miked about 6 of the 8 times fired cases and they mike @ .4705-.471. I checked once fired Dasher brass from my other gun and its .469-.4695 so it looks like theres some stretching going on. Its a Nesika K action, 30 inch finished Broughton with .236 bore and 3,030 fps on the nose. Dave Bruno did the smithing and used a PT&G reamer.

Frank

 

[22BRGUY]

Thanks Frank for good article and info and thanks others also

 

[BoydAllen]

I have no idea of how it works with other powders, but a while back, there was an article in Precision Shooting about the effects of drying and humidifying 133 that showed more effect than probably anyone would have guessed. It was done using the same powder charges, and, if I remember correctly, comparing the driest to the saturated, there was a difference in weight of 2% and a difference in velocity of 320 FPS, although I invite someone else to verify this. I will look through my stack of magazines to refresh my memory. My point is that if powder sits around in conditions that change its moisture content, particularly if it dries, as it might in an air conditioned or heated dwelling, a load that was worked up when the powder was fresh from the bottle, might produce more pressure per weight, which might be just enough to account for a primer pocket issue. Yes, a bit of a wild idea, but we tend to look at burn rate as a constant, when lots can vary quite a bit, and the conditions that powder is exposed to can make real differences.

 

[40X Guy]

Boyd, Tom, Wayne and everyone else who posted- many thanks as i've learned alot from the posts in this thread. We still have the BEST site on the net with the BEST people!!

I am going to load em again and get ready for the VHA shoot coming up.

Frank

 

[40X Guy]

Update, I loaded my 8 times fired Dasher brass again (no other option) for a match I shot in yesterday and rifle is still shooting very well. Brass is now 9 times fired and i am wondering if anyone has played around or tried using the Hart Case Saver tool linked here:

http://www.rwhart.com/store/proddetail.asp?prod=dhb%2Df%2Dswage%2Dsm


I am wondering if it works and how?

Frank

 

[savagedasher]

Excess pressures and loose chambers is where the problem is. I feel improper annealing can have a lot to do with it. The case is very short and hard to anneal properly. Yesterday was my 23 time loading with out annealing .Every 3 times I load I bump the shoulder .003 and only use a bushing on half the neck. Only thing I can see I do different I shoot 46.3 to 46.6 gr of H4350 which gives me 2000 psi less start pressure. According to quick with 105 hybrid my 90% of max speed is done in 18''of the barrel Varget and RL 15 4895 all reach 90% in 9 to 11 '' . Good shooting
Larry

 

[40X Guy]

Larry - 46-grains in a 6Dasher ?.?.?

Donovan, I was wondering the same thing...

Heres some measurements on my brass, virgin, .469, 9 times fired brass, .4705. Then I ran one case thru my Redding FL die, there is no change and measurement remains at .4705.

 

[savagedasher]

Sorry guys 36.3 to36.6 Good shooting Larry