6 Dasher brass forming (and then 115 RDF testing)

spife7980

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So I know this is basically pointless since Im only forming brass for another 120 rounds with this but still gives me my entertainment. False shoulder plus a healthy bullet jam. Even the lowest loads are giving me brass to the same blow length so Im not too concerned about that issue.

Lapua, cci 450, 105 ref, varget

Im blaming the fliers on the brass forming, I never had fliers 2 mils out with them jumping in my xc. That said there are a handful of crazy bad fliers.


It had 100 rounds on the barrel before I started and last weekend it was around 80 degrees and I got these results at 100 yards

7075867
7075872
7075879


And this weekend it was around 65 and I got these results at 500
7075873
7075866
7075880


Its interesting that the velocities dropped that much with just a few degrees.

I think Im going to go with 29.9 for the rest of my 300.
 
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Lynn Jr

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You want the false shoulder snug enough that it requires a good palming of the bolt to close it in the action.
You want to use a soft primer when fireforming and a hard primer once the brass is ready to go.
A Fed 205 primer in Lapua brass with 15 grains of red dot or unique or 700X works well.
Fill the rest of the case 100% to the top of the neck with cream of wheat or tapioca pudding mix.
Tap on the outside of the case with the spoon you used to fill the case until the breakfast cereal settles to the neck shoulder junction.
Add a piece of toilet paper or paper towel to the top of the breakfast cereal as a wadding agent.
Some guys will use a light coating of imperial sizing die wax on the brass to keep the brass from sticking to the chamber walls.
To see how affective jamming a bullet is jam one without any powder and dry fire the gun. The force of the firing pin will drive the case forward untril it is stopped by the extractor. This is what leads to early case head separations.
Try it and measure your OAL.
 

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El Cid 92

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My experience.....

Fireforming w/30gr of Varget, CCI 450, whatever .243 projectile you have, jam it 0.030 into the lands.

Practice positional shooting at 400-450yds. Simple, Effective.

Andrew
 

Milo 2.5

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@spife7980
Out of curiosity, what are your case oal's?
My first 2 dashers I bought hydro formed, the 2 newest I fireformed, way longer necks on FF cases.
I used false shoulder only, 29gr of varget with a 105 hybrid, and 29.5gr with a 110. The 110 load was really good to 1K, where the 105 load petered out quite a bit at 800 yards.
 
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El Cid 92

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After fireforming....

Headspace 1.241"
Lands 1.685", Seating to ogive 1.675"
COAL - 2.282

Current Load
32.8gr Varget
CCI 450 Primer
Berger 105gr Hybrid
2935fps
 

spife7980

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My experience.....

Fireforming w/30gr of Varget, CCI 450, whatever .243 projectile you have, jam it 0.030 into the lands.

Practice positional shooting at 400-450yds. Simple, Effective.

Andrew
Pretty much what I found as well. Only I have a good false shoulder squish as well as jamming the bullet really well. My first 100 pieces I was had the false shoulder .1 longer than needed, it was a total bitch to load but they formed really really well! I backed that down to only good pressure to chamber. I also had the bullet really really jammed, lowered that a bit as well until I could chamber a round without my hand hurting the rest of the day, not sure how much jam still but its a good healthy amount, .030 at least.

I sized the neck down more and I seated the bullet deeper and the results are still more than adequate and I could see mag feeding these instead of one at a time and having to use a glove because it was hurting my hand so bad.

So it doesnt need a crazy amount of chambering force to hold them in place solidly, just a bit of tension will do the job as required.

@spife7980
Out of curiosity, what are your case oal's?
My first 2 dashers I bought hydro formed, the 2 newest I fireformed, way longer necks on FF cases.
I used false shoulder only, 29gr of varget with a 105 hybrid, and 29.5gr with a 110. The 110 load was really good to 1K, where the 105 load petered out quite a bit at 800 yards.
Ill have to get my OALs later tonight but I do remember off the top of my head that the shoulder datums were blown forward to 1.240 with a only handful slightly less (1.238-1.239) but not grouped with any particular charge weight, just randomly among all charge weights. I had as many 1.238s with 30.9 gr as I did with 29 gr. So Im just chalking that up to brass differences and not any real differences based on charge weight.
 
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Milo 2.5

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Pretty much what I found as well.



Ill have to get my OALs later tonight but I do remember off the top of my head that the shoulder datums were blown forward to 1.240 with a only handful slightly less (1.238-1.239) but not grouped with any particular charge weight, just randomly among all charge weights. I had as many 1.238s with 30.9 gr as I did with 29 gr. So Im just chalking that up to brass differences and not any real differences based on charge weight.
I was more referring to neck length, 1.545" etc...
 

Milo 2.5

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Case length / Trim Length - 1.540"
I have my reamer diagram, plus all kinds of measuring tools, I asked a guy what OAL he was getting during his FF. My hydro formed brass I bought came to at 1.528 and has maybe grown .010" in 4 firings, where my FF brass is mostly coming out at 1.548". I'll take the longer neck any day as long as they are consistent.
 

spife7980

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Out of my check of 25 pieces I had one that was 1.553 and 2 that were 1.540. Other than that they were 1.542-1.544 with most of them being 1.544.
 
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Lynn Jr

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I have my reamer diagram, plus all kinds of measuring tools, I asked a guy what OAL he was getting during his FF. My hydro formed brass I bought came to at 1.528 and has maybe grown .010" in 4 firings, where my FF brass is mostly coming out at 1.548". I'll take the longer neck any day as long as they are consistent.
Where is that 0.020 of growth coming from?
The difference between the hydro formed brass and the fireformed brass.
 

Bravo6niner

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My hydro brass from DJ’s and Hunts is significantly shorter than my fireform.

My fireform is 1.541-1.543

Hydro from DJ’s is 1.528-1.530

Similar base to neck datum but shorter neck on the hydro
 

Milo 2.5

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No problem. Why do you think your hydro is so short? Did you trim it or it just is?
My hydro brass from DJ’s and Hunts is significantly shorter than my fireform.

My fireform is 1.541-1.543

Hydro from DJ’s is 1.528-1.530

Similar base to neck datum but shorter neck on the hydro
DITTO, my FF is slightly longer though, 1.548" avg
 

Lynn Jr

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The hydro formed brass is shorter because you are not stretching the area around the web when forming it like you do when fireforming with a bullet.
In the old days shooters would use Remington urbr brass with the small flashhole to get the neck length at any length they wanted without stretching the web.
The urbr brass also has a huge relief around the primer pockets on the inside of the case giving you more volume.
 
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Rangemaster

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I hydro form all my dasher brass a little long and then resize the shoulders back. This makes the brass appear almost fire form. I can pretty much shoot a match with this brass without any POI difference from 2 or 3 times fired brass. Here is a picture of a hydro form loaded round, take guess which one.

29FD15E6-CBB4-4A82-A66C-880862C4A462.jpeg
 
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spife7980

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How is the pressure created by the bullet that much different than the pressure created by a hammer and some bubbly?

Obviously the overall pressures but it should still exert itself just the same evenly over the entire vessel, no? Or is the gas expanding that much and that hot actually dragging the case forward with it instead of the traditional neck seal off and the case head backing up to stretch the web?

Or is it that the hydro die is tighter than the chamber? But you’re still left with the expansion upon actually firing and the rounded shoulder.
 

Sheldon N

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How is the pressure created by the bullet that much different than the pressure created by a hammer and some bubbly?
I think it's likely that the hydro die is all downward force, combined with a slower pressure spike. Everything is pushing the brass down against case head, then pressue pushes the shoulder outward and upward to fit the chamber.

Fire form has the forward pressure of firing pin, then rate of brass expansion is so fast that the case grips the chamber walls. The extra stretch and case length is pulled from the body of the brass.
 
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spife7980

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Anyone done a comparison to see if that difference makes a difference in case life? Maybe hydro will last two barrels vs only one for fire formed? I’m hoping fire formed will last two barrels worth myself.
 

Milo 2.5

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Anyone done a comparison to see if that difference makes a difference in case life? Maybe hydro will last two barrels vs only one for fire formed? I’m hoping fire formed will last two barrels worth myself.
I think the key on this case is to not hammer the shit out of it on the initial FF. I split 2 necks in FF 500 cases, but I also split 2 of 500 of hydro formed cases.
Basically, you are talking one more firing between the 2, and IMO, you have to hammer the hydro stuff harder, I still needed 2 firings on hydro formed, same as FF.
With the small quantities of brass I bought per rifle, I doubt I will transfer brass, this brass is cheaper than what I was using before.
 

El Cid 92

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Good news.... All this fireforming should go out the window when/if Alpha gets their 6 Dasher Brass in production. Supposed to be released in mid June. Fingers crossed.
 

Milo 2.5

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Good news.... All this fireforming should go out the window when/if Alpha gets their 6 Dasher Brass in production. Supposed to be released in mid June. Fingers crossed.
No shit, because all the popular brass is in stock when you want it. I'll bet you a large sum of money there will not be as many abandoning Lapua brass for any preformed brass as you think.
 
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spife7980

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No shit, because all the popular brass is in stock when you want it. I'll bet you a large sum of money there will not be as many abandoning Lapua brass for any preformed brass as you think.
If I had known that I probably would have waited two months. Granted Im new to the scene so Im not really entrenched in anything but so long as its not another norma with different specs I think it will do fine.
 

Milo 2.5

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If I had known that I probably would have waited two months. Granted Im new to the scene so Im not really entrenched in anything but so long as its not another norma with different specs I think it will do fine.
Lol, it is good to learn to FF, and 2 camps on hydro VS FF, in my circle it is wasted barrel life to FF, when half the shots they take are a waste.
These FF loads I am shooting are dang accurate, and kids can have a blast knocking them out, if they can do it in my time frame.
I just cannot see alpha pulling that much business from lapua on this, just my .02.
 

Rangemaster

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Guys, how many fire forming loads are you having to do before your case is fully form?
i was having to do 3 loads to get there, that is why I went hydro to save my barrels and save time and money.
 

Lynn Jr

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I use tapioca pudding or cream of wheat for fireforming so I am not burning up a good barrel making brass.
15 grains of powder is less harsh on a barrel than 33 grains is.
Good Luck.
 

Bradu

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How good does it form the case? I've never tried the cow method because I've always seen mixed reviews.
 

Lynn Jr

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It forms the brass good enough for bench use.
Luckily we went through 2-4 barrels a year for 10 years so we ended up with plenty of fireforming barrels.
The hydroformed brass isn't very crisp at all but at least the web area hasn't been thinned by the process.
I segregate my brass with a Juenke and it's easy to tell the good from the bad.
 
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MuleyTime

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Guys, how many fire forming loads are you having to do before your case is fully form?
i was having to do 3 loads to get there, that is why I went hydro to save my barrels and save time and money.
See POST #6 - This hits the nail right on the noggin.......engaging in this process will not only include the best practice advice but will also make FF a complete non issue. Unless of course practicing is not in your repertoire; which I have been guilty of :p....but that's how I approach it now days.
 

spife7980

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Did you just close this thread?
No lol, but I am concluding my fire forming tests/what I have to input. I guess I can throw some more numbers up once I get back to the house.
Now I just have to piss these next 100 cases away on some barricades and barrels and start actual load development.

Edit:
1558206165677.png

500 yards painted a pretty good waterline while I figure out the wind on the 66% ipsc
7079634

800 group on fill size ipsc
7079635


And then after some practice on the barricade messing the targets up for close pics it started raining in the wind so I called it quits
 
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spife7980

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Since Milos wanting more ;)...
So I have formed it all, last weekend I did a round of 105 stuff because thats what I had but then after they were loaded I found my 115s so I figured I would run a 500 yard ocw for them and abandon the 105s for now.





These 115s are some long SOBs. Base of the bullet is located about even with the body/shoulder transition, taking up more case capacity than I would like, makes me think maybe the 105s are better situated for this chambering.
.104 free bore means touching is 1.798 ogive, 2.340 oal, seated at 1.778 so ~.020 off the lands.


7088194
7088193
7088195


There was some slight wind but for the most part they were fairly consistent, does make me wonder if the stretching was due to that or just funky harmonics.
Give me some suggestions but Ill probably run this back at 100 next weekend to compare.
 
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lte82

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    Has anyone taken a marker and drawn a line up the length of the brass to see where the brass is stretching? I would think it would break the line where it stretches, if in fact is stretching near the web and not just blowing the shoulder forward.
     

    Bradu

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    Since Milos wanting more ;)...
    So I have formed it all, last weekend I did a round of 105 stuff because thats what I had but then after they were loaded I found my 115s so I figured I would run a 500 yard ocw for them and abandon the 105s for now.





    These 115s are some long SOBs. Base of the bullet is located about even with the body/shoulder transition, taking up more case capacity than I would like, makes me think maybe the 105s are better situated for this chambering.
    .104 free bore means touching is 1.798 ogive, 2.340 oal, seated at 1.778 so ~.020 off the lands.


    View attachment 7088194
    View attachment 7088193
    View attachment 7088195


    There was some slight wind but for the most part they were fairly consistent, does make me wonder if the stretching was due to that or just funky harmonics.
    Give me some suggestions but Ill probably run this back at 100 next weekend to compare.

    Pretty sure on an xc, tubb recommends a .160" freebore for the 115's. I would think this would be similar.
     

    spife7980

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    Pretty sure on an xc, tubb recommends a .160" freebore for the 115's. I would think this would be similar.
    I don’t disagree, I was thinking .040 more just off the top of my head but .160 would be good too. The xc does have a longer neck too. Everything about this bullet makes the dasher seem kind of in over its head but I’m still gonna try to make it work and see how it does.

    105 vs 115 rdf
    1.259 vs 1.345 oal
    .663 vs .777 bto via hornady comps

    Bottom of the bearing surface even
    7088340

    The hornady comparator line even
    7088342

    My wheeer touch measurements with 300 rounds on the .104 free bore barrel
    105 is 1.798 ogive, 2.395 coal
    115 is 1.793 ogive, 2.340 coal











    Edit to this just to keep the RDF measurements in one place
    I took a random sample of 10 out of the bag and got these results when seated.
    Bullet #Bullet Over All LengthBullet Base To OgiveCartridge Over All LengthCartridge Base to OgiveWeight
    11.3490.772.3681.7915115.12
    21.3460.772.3671.792115.06
    31.3470.772.3651.7915115.16
    41.3510.76952.371.791115
    51.3490.772.3691.791115.04
    61.3410.77052.361.791115
    71.3450.772.361.792115.14
    81.3470.76952.3681.791115.08
    91.3490.76952.3681.791114.96
    101.3460.782.3561.791115.2
    Average1.3470.77092.36511.7913115.076
    Max1.3510.782.371.792115.2
    Min1.3410.76952.3561.791114.96
    ES0.010.01050.0140.0010.24
    SD0.002650.003050.004500.000400.07419

    7093959
    7093960
    7093961
    7093962
    7093965
     
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    Bradu

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    I'm shooting the old dtacs in my 6 creedmoor because I had 1500 from a rifle that I sold. My freebore is way too short, they are stuffed deep in the case and I can only get 2900 fps before I got pressure. I don't know what freebore this barrel has since it came with the trg I bought but factory ammo gets seated back about .020" when chambered in the rifle. I will be glad when this barrel is shot out.
     

    FishDr

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    I'm shooting the old dtacs in my 6 creedmoor because I had 1500 from a rifle that I sold. My freebore is way too short, they are stuffed deep in the case and I can only get 2900 fps before I got pressure. I don't know what freebore this barrel has since it came with the trg I bought but factory ammo gets seated back about .020" when chambered in the rifle. I will be glad when this barrel is shot out.
    Interested in trading some of those for a new unopened 500 ct box of the new 105 RDF? I wanted to run the 105s but my FB is way too long.