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.......with the Wehlen brass that I have been re-loading.
http://i51.photobucket.com/albums/f3...-space-web.jpg
As can be seen the primers are proud of the base after firing. This does not happen to the RWS 8x60s Cases, only to the Wehlen ones. There does not appear to be any marking at the base of the case though. Is it a headspace problem with these cases?
I am shooting it in a Mauser K98k in calibre 8x60s
looks as though you donot get enough case set back to re seat your primers.
your load may be a bit low on pressure.
Most likely you reformed your 35's shoulders too low. Compare them with the RWS ones.
kg
duncan,Quote:
Originally Posted by duncaninfrance
Fireforming 35 Whelen brass to 8X60s???? hmmmm????
Seems like there would need to be an in-between sizing step somewhere.
That may exaggerate the headspace control problem if the shoulder is set back in reducing the neck diameter????
The only experience I have with that is confined to the 35 Whelen cartridge and rifles chambered for it.
Folks that own and love Whelens usually don't like the second possible explanation.
First, a couple of possible explanations in this instance would be..... excess headspace in the gun or shoulder or datum ring set-back during re-sizing/re-forming in a die. I doubt a problem with the gun because the 8X60 brass doesn't show the symptons.
The second possibility is..... The Whelen brass carries the 17.5 degree shoulder of the parent 30-06. The amount of headspace control is limited to a datum ring defined by the fairly small amount of area between the forward body/shoulder diameter and the neck diameter coupled with the shallow angle of the 17.5 degree shoulder. In low pressure loads the primer fires and the impulse pushes both directions.... one direction < the case is pushed forward..... the opposite direction > the primer is pushed rearward. Next the powder charge ignites and expands the case walls against the chamber holding the case forward. After the round fires the pressure goes back to ambient. The primer stays in its backed-out position. The SYMPTON is the backed-out primer. The CAUSE is as explained above. This is usually revealed with lower pressure loads.
In higher pressure loads the primer ignites, the case is pushed forward, the primer is pushed reawward, the forward case wall clings to the chamber as pressure builds, even higher pressure stretches the case body rearward and re-seats the primer and hides the problem.... the problem is not corrected just hidden. Even if the rifle does not have excess headspace this case stretching is inherent in the design of the Whelen case.
It cannot be cured. It can be helped by fireforming with normal pressure loads, then only sizing partially and not touching the junction of the neck and shoulder to help maintain the headspace control datum ring on the shoulder. I say helped not cured because that first firing does stretch the rear portion of the case body..... the area that can show the first signs of case failure or head separation at sometime in the future..... in other words a reduction in case life goes with the territory with the design. A short chamber to begin with can help where the shoulder is contacted when the bolt is closed on the very first firing of the spec headspace length brass. The Whelen AI version with its slightly blown out shoulder and sharper shoulder angle is the only cure for the problem in the 35 Whelen.
This relates to what you described and is similar, not exact but may shed some light on what is going on with your loads using the Whelen cases :coffee:
Thanks.
Here is a pic of the 2 loaded types side by side.
http://i51.photobucket.com/albums/f3...WEHLEN-WEB.jpg
The load is 49.2 grains (3 grams) of SNPE Vectan Tubal 5000. Bullet is PRVI Partisan HPBT 175 grain seated 8.25mm. Primers are CCI 200 Large Rifle. I use ther samer for both cases but as I said, only the Wehlen have this problem.
duncan,
I can only guess... but the one on the left looks like the Whelen??
Looking at the popped out primers on first post, it seems like somewhere between the new 35 Whelen brass and the finished round the headspacing control of the brass case itself has been compromised.
My first instinct would be to take a single, new 35 Whelen case and trim, chamfer, and lightly lube. Set an 8mm sizing die so that only about 3/4 of the neck is sized down to 8mm. That will create a false shoulder about 3/4 of the way along the neck and also stays away from the shoulder itself. Do not prime or add powder. Seat a bullet to normal depth. The false shoulder should add increased headspace control and lightly force the cartridge back against the bolt face when the bolt is closed. You should be able to feel this resistance. You may have to try different amounts of this type sizing to get the best result. If light resistance is felt when closing bolt, load a couple of rounds with the same charge that showed the backed-out pirmers. The resistance may be enough to keep the cartridge against the bolt face when the firing pin hits the primer and when the primer fires. If it does then the case will be correctly fireformed for the chamber and you should have no further headspace problems from cases done that way. There will be no hidden stretching and the cases should have a more normal life expectancy. Both the 30-06 and the 338-06 do not show that tendancy for headspace problem but the 35 Whelen can. The 8mm should be fine ONCE it is correctly sized and fireformed.
Another way to fireform for correct headspace uses jammed cast bullets. But that is another step if this doesn't work.
Hope that helps and you can resolve the problem.
If not then maybe just stick to the 8x60 RWS brass.
I just compared the 2 case dims. Is there anything there that points a finger?
http://i51.photobucket.com/albums/f3...S-DIMS-WEB.jpg
duncan,
Short answer No, or very, very difficult to measure precisely. The only way to do that comparison is to know the location and angle of the datum ring on the RWS case shoulder that gives the correct headspace control in the rifle chamber. Then theoretically that measurement set could be compared to the problem Whelen case. Kind of a reverse headspace gauge for the cartridge case. But even that would have to be calibrated or indexed to the RWS case or better.... both the RWS case and the chamber itself. Yikes!!! The LE Wilson case length and headspace gauge is just such a gauge based on standard chamber specs for the common cartridges but the 8x60 is not one of them :(.
Having said that.... the closest you can come to a practical single useful measurement comparing the two would be to measure from the base of the case to the junction of the case and shoulder. If that measurement is shorter for the Whelen case than the RWS case then it possibly indicates where the problem is. It may indicate greater headspace in the Whelen case and could account for the symptoms of the backed out primers.
The datum ring on a rimless case shoulder can be described as a slice of a truncated cone- the area of critical contact that keeps the case from moving forward during firing pin fall and primer ignition (detonation)
The surface area of that datum ring plus the cone angle of the datum ring both determine how effective the individual case will be in controlling headspace. All other things being equal that is why an "Improved" case shoulder will have better headspace control than a "regular" shoulder.
Excellent schematics by the way! You might try a photo showing the measurements as I described in the second paragraph above beginning with, "having said that.....". Then we'll know we're talking about the same specs.
if you fired the whelen with a fairly low pressure load it was driven forward by the
firing pin, the case was caught on the rim, which appears to be .008 thinner
the case expanded forward and outward gripping the walls, being where it was the primer was able to back out of the case that extra .008.
i see this with light loads when forming my ackley cases so i form with full loads.
The data here is a bit old, as the powders names will tell, and 12,70g is about 196gr; but your load seem definitely light (the primers said that much too :)).
http://i191.photobucket.com/albums/z...cBrt_trieb.gif
http://i191.photobucket.com/albums/z...E-p38_8x60.jpg
You could either try a stouter load or use the same with the bullet engaging the rifling, in order to get that brass up to a proper fit; in other words fireform it (clarification added). . I'd rather have Versifier give his opinion here.
Here is some more inspiration (sorry for the low res.):
http://www.nobelsport.fr/nobelsport/...paule_2006.pdf
http://i191.photobucket.com/albums/z...Watersdata.jpg
kg
duncan,
kg42 has provided some excellent drawings for the cartridge. First, if you increase the pressure to get rid of the backed-out primers all you are doing is hiding a symptom of a problem. It would be best to try to solve the problem.
In the "cartouche maxi" drawing it is the 50.90 length that could help if trying to compare the problem Whelen case to the RWS case that works. Again, in taking those measrements it is not easy to be as precise as might be required to be valid. But, if there are gross differences between the Whelen case and the RWS case then it suggests where the problem may be.
Thanks for that. Am now looking at the problem from all angles and will report back on the solution - if I find one!!
duncan,
Please do! Either success or more problems.
In your second photo it shows two measurements that could be added to get the one I was talking about. I don't know your units but assume metric.
If I read the numbers right and added right the measurements would be:
Whelen case- 46.83 from base to neck junction
RWS case - 47.53 from base to neck junction
That is .7 mm shorter which MAY show the problem... Are those the correct numbers? If so then the .7 mm transates to about .027" which are the units Im used to. I think even using the expedient base to neck junction length... the .027" is too much.
You might try re-measuring using just the end points of base to neck junction. That may give a little more precision.
Since we're dealing with up to 50-60 Thou PSI with this stuff I am trying to be cautious here. Even the RWS 8x60 base to neck junction measurement seems a little short at 47.53. The spec drawing that kg42 posted shows that measurement should be between about 50.85 and 50.90. Some of that discrepency may have to do with mesurement error and your rifle's particular chamber- hard to say for sure.
One final thought. Sometimes the simplest explanation can be the correct one. When you have new, unfired brass and run it into your sizing die be sure to keep the die away from the shoulder. If you run it in too far the die may set the shoulder back causing this type of problem. To check for that simply mark the shoulder with a felt tip marker. If the die is contacting the shoulder it will show.
Anyway good luck, and proceed with care.
First thing, 3 grams x 15.43 give me 46.29 grains, or 49.2 grains x 0.0648 = 3.19 grams. I don't know your set up but please look into that :).
Then I should have asked earlier if you re-formed the 35's yourself and if the RWS was virgin or had been fired before with a factory load (in an other gun?).
The correct procedure to re-form the 35's would be to size them progressively until they chamber. Theoretically the Whelen's shoulder shouldn't fit, but it is close enough that you might find a "second shoulder" on their necks at the end of the process, if your chamber is on the roomy side and/or your brass on the small side.
A way to find about oversized chambers is to stick adhesive paper on a factory brass/ctrge's head and to gently try to chamber it (I don't remember how much is too much by the industry's standards).
And to clarify my last post, I meant that your lot of converted 35 cases could be fireformed to match your gun's chamber (and identified in case some brass weakness developped).
Then neck sizing only would indeed be very good idea with such an action.
kg
KG. My load is ALWAYS in grams because the scales are in grams so the actual charge is 3 grams. Must have been malfunction of digit on calculator keyboard!
I am certainly going to look at things and will get back to this thread in due course but I have got to put a new ceiling into my mothers lounge starting Tuesday so I am going to be a bit busy for a while!!
http://i51.photobucket.com/albums/f3...7-x-64-web.jpg
Having tried the above today there was no problem with primers partly coming out so it would appear that the load was TOO mild and the cases formed from Whelen were just not capable of re-forming to 8 x 60s which the SAKO have.