Dasher Split Necks (Please Help)

[Subsilent22]

Well I just got back from a 600 yard F-class match yesterday in which I shot my new 6 Dasher in. I have been playing with some fire forming loads here at the house using the false shoulder method, after adjusting the load I was consistently getting decent blow lengths and pretty good accuracy. Also every piece of brass came out well formed without any splits on the shoulders or necks. The brass I used here at home I annealed on my bench-source after creating my false shoulder. I have been waiting for this match to come up so that I could fire-form and compete at the same time thus giving me my new match brass. Well I loaded everything the same as before except I decided not to anneal the 70 rounds that went to the match with me. The ammo shot as good as I could have asked for: 594-24X with a brand new setup: from front rest to gun to rear bag, all first time out at a match. So I am happy with the results for now but when I got home I started to inspect my brass as usual and out of 69 pieces of new brass 50 have very very faint hairline cracks in the shoulder. The cracks are so small I had to pull out a magnifying glass to look at them and determine weather they were cracks or just scratches. After inspecting them I do believe they are cracks however I can not feel them on the inside with a dental pick nor can I get my fingernail or dental pick to catch on all of them on the outside. I wonder if they are just stress cracks that don't follow all the way threw to the inside? What are the chances if I annealed these and then fired them that they would seal up the crack? That may be a crazy question but dang Im pretty upset that it appears that I have wasted 50 brand new pieces of brass!! FYI I have spent more money and time trying to figure out the Dasher than I ever thought possible, Hence the name of the gun thats printed across my mirage shield (DAMN DASHER)

Thanks for all help in advance!

 

[Yellow11]

Try inserting a light source into you brass, whilst in a darkened area. If you have cracks the light will pick them out...

 

[Webster]

You cannot repair or a seal cracked case. Even if the crack does not penetrate the full thickness of the case it's dangerous. The crack should grow with future sizing and shooting. Cut the worst looking case up so you get a small piece with the defect in the middle. Polish the carbon off of the case inside and look for internal cracks. A scratch won't be on both sides of the shoulder wall. Bend the small section and see if if breaks at the suspected crack. If it fails in the suspected area it has to be a crack. If you know someone thats a welder or you could go to a welder supply store nd buy penetrating dye thats used to reveal cracks. Probably cost close to $50 for the set of 3 components in spray cans. I am surprized they cracked after annealing. Are all of the cracked cases similar in appearance as to size and location on the shoulder?

Cracks can be tight so that light won't go through. It wouldn't hurt to try it. If light goes through it's a pretty nasty crack.

After saying all of this I would trash the cases if I thought there was any possibility of cracks. Your health and safety are more important than the cost of the cases. I hope that shooters that fire form Dashers might add their experience.

 

[Raythemanroe]

I just got done reading about a Dasher splitting necks with Lapua brass.. The shooter stated he annealed his new brass from the get go after that..


Ray

 

[Subsilent22]

Webster, thanks for the ideas and I will cut one up and see what I find. All cases that have marks appear similar but not the exact same as far as location. Some start about a 1/16 above the shoulder body junction and run to the junction and stop, some run past it to the body about 1/16 down, some have 2 cracks that just are in the middle of the shoulder, between the neck shoulder junction and the body shoulder junction. None of these cracks/lines run from or up to the neck shoulder junction (only shoulder body) All of these appear as if a eyelash fell on the shoulder and you spotted it but a lot smaller in thickness than an eyelash. They are so small I can't get them to show up on a picture that I wanted to post for y'all. Some will barley catch your fingernail and some won't. The ones that will catch you have to run your nail over it a few times and at the right angle to get it to catch. I have tried blowing air through the case plugging the flash hole and can't seem to get air to pass through, although I know pressures are a lot higher when fired.

 

[eww1350]

I have seen surface fractures that dont go all the way thru the brass...looks like stretch marks...I recommend loading up ten and firing them and see if you get any powder burn bleed thru..if not then anneal them and don't worry about them anymore...but this should be a lesson...always aneal before fireforming even with new brass...it is not annealed consistantly from the factory escpecially the 6BR Blue Box stuff is the worst...if you could afford to buy some old Gold Box Lapua brass do it... it is that much better...IMO


Eddie in Texas

 

[22BRGUY]

Any possibility of a chamber burr that would be causing it either upon seating or extraction. If you can fire one once more and check for the same type marks only in a slightly different place, it might indicate a burr

 

[Lapua40X]

Back when I was working in QA for an electronics company we often made adapters to test certain devices produced on military contract. I developed an adapter for testing ULMS controls using air injection. If you have the time and a few common tools you can make something like that for testing your cases and far exceed the level of analysis that you might achieve using dental picks and light sources.

 

[dcali]

I'm not convinced from your description that they're actually cracks. But no, you cannot fix a crack.

 

[Webster]

I don't know if you can properly determine if it's a crack with what we have at home. Where I worked we would have made a cross section through the suspected crack. Then we would mold it in epoxy, polish it and examine on a microscope. Anything less than that you are guessing unless it's blatently obvious. The recommendations that you fire some cartridges with various powder charges is scary. I think all of use have fired a cartridge that split the neck without any apparent safety issues. I don't know what happens if you get a large failure in the shoulder. Tight cracks, partial penetration and carbon buildup would prevent using light or gas pressure drop methods. If you cut a piece out with a Dremel tool and bend it, the crack would open up to some degree only if it had some depth to it. If you can afford to shoot a custom rifle in competition I don't think you should worry about the cost of throwing the cases out.

 

[dkhunt14]

Back in about 2003 or 2004 Phil Bower went to the IBS Nationals in Virginia and had cases with about 40 firings on them. The necks were cracked so bad you could see light through them. he fired a new IBS Group record at 1000 yards with them cases. Matt

 

[Raythemanroe]

Back in about 2003 or 2004 Phil Bower went to the IBS Nationals in Virginia and had cases with about 40 firings on them. The necks were cracked so bad you could see light through them. he fired a new IBS Group record at 1000 yards with them cases. Matt

Of course your not recommending that?



Ray

 

[MarkS]

subsilent22,
Sounds like your cases are split, that is where they split. you will need to trash them. Your FF load may be too hot or your shoulder is not holding things tight. I have used about every type of FF there is. I have the best results with jamming the bullet hard and putting enough grip on them, so they don't move.


Mark Schronce

 

[LRPV]

Is it possible that you could've had a bristle from a brush come off in your chamber?

 

[Subsilent22]

Well Gents, I think we have it figured out. I took all the brass that I suspected had cracks to Alton Britt (owner of Dixie Precision) who I would consider a professional, after examining the brass a conclusion was reached. It appears that there are either chatter marks in my chamber from being reamed or like someone mentioned a bristle had been left in there from a brush. To verify that they are not cracks I took the worst 6 cases and full length sized them multiple times, intentionally over sizing them to see if the cracks opened up, they did not change. I also cut one up from a suggestion I received on here and put the piece in a vice, indicating the crack in the middle, screwed the vice together to crush the brass and see if the crack opened up or the brass folded in that spot, it did not. So it appears I'm in the clear. I just want to say thank you to all that replied and gave advice, I took all advice and used parts of everyone thoughts to reach the conclusion that I have reached. Thanks again and keep me in the X ring!

 

[Erik Cortina]

Somewhat strange question (not doubting you). I have never seen a case neck with a crack that didn't just be a complete CRACK. I really don't have an answer for you!

So, if it was me, and I was really in the dark as to what it was, even after examining with higher power optics.
I would reload 1 cartridge with a 10 to 20 percent powder load , and fire it with my shooting glasses on and see how it looked after that, if OK I would load up 5 more cases stepping up the load a little at a time to the original level, thoroughly examining each case after firing under magnification, document any changes you might see.

If you get through that with no visual or apparent problems , shoot 1 hot load, If still no problems , clean everything up spotless and get back to shooting.

Safety is FIRST, never forget that!

That would be more dangerous than anything else! A very low powder charge is just as bad or worse than an overcharge!

 

[Raythemanroe]

I have had someone argue that low charging can cause excessive pressures. I have seen it twice and the gun makes a hole different sound, more of a pop (not good).. Brass had to be knocked out, brass was definitely junk and gas blowing back..


Ray

 

[moajoe]

I have had someone argue that low charging can cause excessive pressures. I have seen it twice and the gun makes a hole different sound, more of a pop (not good).. Brass had to be knocked out, brass was definitely junk and gas blowing back..


Ray

I believe they call it a flashover. Not enough power in the case will cause excessive pressure because most of the powder is ignited at once instead of a burn from back to front. Saw this happen at a match with the shooter next to me. I herd him say "smoke out the back of the bolt hit me in the face". then they spent 5 minutes trying to open the bolt. Tapping it with a rubber mallet finally got it released. The case was blown and the head had a huge nipple were it flowed into the ejector. Couldn't believe my eyes when I saw that.
Anyway he was discussing his loading technique and the powder he was using and determined that it could not have been an overcharge since the charged used filled the case.

 

[AAA]

What action are you using for your new dasher?

 

[upSLIDEdown]

For the guys saying to anneal before fireforming...

Im getting ready to start my dasher adventures. I plan on doing false shoulder fireforming. When are you guys annealing? Before expanding? After expanding but before sizing the shoulder into it? Or after everything but before loading?