I have only fireformed 57 pieces of Lapua 6BR brass into 6mm Dasher cases, and I used 30 grs of RL15, loaded the 105 Amax long and all 57 cases, the best I know and can tell, formed perfectly. If I had used the false shoulder technique, what might have been better about the cases? Is there more consistent length or what when you go to the extra effort of the false shoulder?
Dasher Fireforming
- Thread starter gmorganal
- Start date
gmorganal: Some prefer the false shoulder, but I'm with you in preferring the straight loading & firing method. Although in my example a 6 BRX not the dasher. Using 30 grs. of Varget with any flat base 85 gr. or heavier bullet, tighter than normal neck & a .010" jam. Have not lost a single case & they have all fully formed with the first firing. Why mess with what works ( for you?).
bozo699
Gold $$ Contributor
gmorganal,
I agree with Frank and use the exact same method as he does except I jam about .030 innstead of .010, some guns won't fire with the method that we use so they use a false shoulder as to not drive the bullet back into the case and not fire, and some use the cow method, I have tried all three and agree with Frank whole heartedly that I have the least problems with the jam and shoot method, and out of several hundred cases I have only lost 3 cases and two of them had creases in the shoulder before I fireformed them. Using the same components you are using and .030 jam I am shooting 1/2" or so at 100 yards fireforming the brass.
Wayne.
I agree with Frank and use the exact same method as he does except I jam about .030 innstead of .010, some guns won't fire with the method that we use so they use a false shoulder as to not drive the bullet back into the case and not fire, and some use the cow method, I have tried all three and agree with Frank whole heartedly that I have the least problems with the jam and shoot method, and out of several hundred cases I have only lost 3 cases and two of them had creases in the shoulder before I fireformed them. Using the same components you are using and .030 jam I am shooting 1/2" or so at 100 yards fireforming the brass.
Wayne.
gmorganal
When you fireform without the false shoulder the firing pin strike forces the case forward into the chamber.You need to remember the shoulder is 0.100 farther forward on a Dasher than it is on the straight 6BR.
What happens then is you stretch the area right in front of the cases web thus thinning it out.
To check for this you can simply measure the distance from the casehead to the front shoulder.I use the little brass colored Harrels tool that comes with there die sets and my match brass measures 1.689 inches long when it is at maximum length and 1.688 when I am going to a big match.This measurement includes the tools length.
Without the false shoulder your first time fireformed brass will be all over the place but as long as seperations don't occur itwill work.I think Richard Schatz told me he fireforms without the false shoulder and he is known as Mr Dasher.
Lynn
When you fireform without the false shoulder the firing pin strike forces the case forward into the chamber.You need to remember the shoulder is 0.100 farther forward on a Dasher than it is on the straight 6BR.
What happens then is you stretch the area right in front of the cases web thus thinning it out.
To check for this you can simply measure the distance from the casehead to the front shoulder.I use the little brass colored Harrels tool that comes with there die sets and my match brass measures 1.689 inches long when it is at maximum length and 1.688 when I am going to a big match.This measurement includes the tools length.
Without the false shoulder your first time fireformed brass will be all over the place but as long as seperations don't occur itwill work.I think Richard Schatz told me he fireforms without the false shoulder and he is known as Mr Dasher.
Lynn
THanks for your responses, men. I guess I'll just keep doing as I have been. The brass I have fireformed, the 57 pieces, now have 7 firings on them, and the only problem I have at all is there is a difference in case to case as far as force required to seat a primer. I have been loading between 33.3 and 33.5 grs of RL15.
gmorganal: I cannot speak about the dasher, as I have no experience with it, but the 6 BRX is very close ( same case capacity, but 30 degree shoulder), so they are at least similar. Have a box of 20 that have been loaded 24 times now & all is normal. Bolt lift & primer pockets still tight as new. Initially tried the cow method with recommended loads of fast burning pistol powder, false shoulder, cotton wad, etc. and cases were far from being fully formed with the first firing. Headspace approx. .025" shorter than chamber, rounded off corners, etc. Try different methods & use whatever works best for you. My standard load for the BRX is 33 grs. of Varget with the 107 SMK seated to touch, chronographed at an average of 2930 fps.
rcw3
Site $$ Sponsor
Here's the deal with the "in the lands" vs the false shoulder method - there is no method that works 100% in all situations and applications without some issues.
The main issue is whether you can go through the fire forming process and not drive the 6BR brass case forward in the Dasher chamber (during the fire forming process) by way of closing the bolt or having it hit with the firing pin.
If you have a no neck turn chamber and you are using new 6BR brass (not neck turned) and have good neck tension and the bullet has good adherence (i.e. not using moly or a bullet or other lubricant) and load the bullet in the lands well, the "in the lands" technique will normally work perfectly. If your cases come out well formed and the variance of the brass OAL is within the normal range of the "out of the box" brass, you're fine with this technique.
Now some shooters turn the necks so the brass is thinner or use a mandrel up front on the brass, etc. (and when they do so they typically use lubricant such that there is some residue left on the inside of the case) and go through a whole lot of up front brass preparation so they do not have good neck tension and/or good bullet adherence. In this situation, they may not be able to use the "in the lands" technique because upon closing the bolt the extractor and/or ejector (like a plunger ejector if they have one) may have enough force to push the 6BR case into the Dasher chamber, or when the firing pin hits the primer it can do the same thing. In this situation, the false shoulder method may be what is needed.
I do not like the falser shoulder method because I feel it overworks the neck metal and that you really should re-anneal the neck if you are going to use that method (which is also more work and a pain).
If your fire formed cases are coming out with a reasonable consistent OAL - that typically is an indication the method you are using works fine. When you get wide variations in brass OAL after fire forming, it typically means your brass is not being held back against the bolt face when you are fire forming, and the false shoulder method may be needed to do so.
There's some info here on this:
http://www.6mmar.com/6mm_Dasher.php
Robert Whitley
The main issue is whether you can go through the fire forming process and not drive the 6BR brass case forward in the Dasher chamber (during the fire forming process) by way of closing the bolt or having it hit with the firing pin.
If you have a no neck turn chamber and you are using new 6BR brass (not neck turned) and have good neck tension and the bullet has good adherence (i.e. not using moly or a bullet or other lubricant) and load the bullet in the lands well, the "in the lands" technique will normally work perfectly. If your cases come out well formed and the variance of the brass OAL is within the normal range of the "out of the box" brass, you're fine with this technique.
Now some shooters turn the necks so the brass is thinner or use a mandrel up front on the brass, etc. (and when they do so they typically use lubricant such that there is some residue left on the inside of the case) and go through a whole lot of up front brass preparation so they do not have good neck tension and/or good bullet adherence. In this situation, they may not be able to use the "in the lands" technique because upon closing the bolt the extractor and/or ejector (like a plunger ejector if they have one) may have enough force to push the 6BR case into the Dasher chamber, or when the firing pin hits the primer it can do the same thing. In this situation, the false shoulder method may be what is needed.
I do not like the falser shoulder method because I feel it overworks the neck metal and that you really should re-anneal the neck if you are going to use that method (which is also more work and a pain).
If your fire formed cases are coming out with a reasonable consistent OAL - that typically is an indication the method you are using works fine. When you get wide variations in brass OAL after fire forming, it typically means your brass is not being held back against the bolt face when you are fire forming, and the false shoulder method may be needed to do so.
There's some info here on this:
http://www.6mmar.com/6mm_Dasher.php
Robert Whitley
falconpilot
Gold $$ Contributor
I agree with Donovan. I've formed over a thousand rounds of Dasher brass using the false neck method. I'll lose on average 1-3 cases per hundred..bare in mind that I'm shooting a .269 neck, so I'm turning my neck to .0115-.012...I also fire form at 32.5grs, pretty close to my formed load. I've found that my cases all measure very close to the same after the first firing. I've got some brass that has 15 firing on them..granted, they have been annealed a time or two..
Not suprisingly I don't agree with Robert Whitley's opinion.
I don't turn my necks or lube them prior to fireforming and without the false shoulder they never stay put on the boltsface by neck tension alone.This is with Remington,Stiller,Borden and BAT actions.
I am assuming Robert is using a shellholder type action?
If your using the C.O.W. method and getting rounded short shoulders your not using the proper amount of powder or your not using the proper amount of C.O.W. or both are wrong.
I am using 15-16 grains of Red Dot.I completely fill the entire case with C.O.W. including the entire neck.I then vibrate the cases or tap on them with the spoon used to fill them until the C.O.W. has settled to the neck/shoulder junction.If it goes lower you need to add more C.O.W.
I then use about a 1/4 sheet of toilet paper as the wadding to fill the entire neck.
I use a small amount of Imperial Sizing Die Wax on the outside of the brass and fire away.
If your getting more than 0.004 variation something is wrong.
I have done it wihout the false shoulder but the round to round variations were too large.
Lynn
I don't turn my necks or lube them prior to fireforming and without the false shoulder they never stay put on the boltsface by neck tension alone.This is with Remington,Stiller,Borden and BAT actions.
I am assuming Robert is using a shellholder type action?
If your using the C.O.W. method and getting rounded short shoulders your not using the proper amount of powder or your not using the proper amount of C.O.W. or both are wrong.
I am using 15-16 grains of Red Dot.I completely fill the entire case with C.O.W. including the entire neck.I then vibrate the cases or tap on them with the spoon used to fill them until the C.O.W. has settled to the neck/shoulder junction.If it goes lower you need to add more C.O.W.
I then use about a 1/4 sheet of toilet paper as the wadding to fill the entire neck.
I use a small amount of Imperial Sizing Die Wax on the outside of the brass and fire away.
If your getting more than 0.004 variation something is wrong.
I have done it wihout the false shoulder but the round to round variations were too large.
Lynn
Lynn: A can appreciate your method as working fine for you, but I get the same results by just loading a "standard" 6BR case with 30 grs. of varget, 85 gr. or heavier flat base bullet, tighter than normal neck diameter and .010" jam. Fire it and be done. And groups are sometimes a pleasant surprise. 
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