Used a set back die for the first time in a 7 Ultra. Chambered the round, bolt turned down with more difficulty than a fired case. Measured case and found it had grown 5/1000 at the shoulder. What gives? [img]images/icons/frown.gif[/img]
I had a similar problem with my 7mm ultra. I sent the brass and die back to Forster and they removed the .005 from the die to allow it to set the shoulder back. Don't load the brass until you get the shoulder back. I couldn't close the bolt on my gun without alot of force. The rifle was a Rem SLS and apears the reamer leaves to much head space?
when you say it grew .005 at shoulder are you talking forward or in diameter?
If you bump em back too far, you will push out edge of shoulder and make hard chambering if not impossible. Makes you think not bumping enough when actuality it is too much.
Until a fired case has grown enough to be difficult to chamber, you do not have a data line to bump back against as control point. At that time just smoke the caseneck with candle and adjust die up until touching somewhere on neck. Then resize, look at mark on neck and keep coming down until it touches shoulder. (You have to have a bump guage made from barrel stub or a set of Stoney Point tools with shoulder guages to measure datam line on shoulder) Once you come to shoulder adjust die just enough to bump shoulder .001 or .002 max. Lock die down, recheck and leave there.
You can use a set of the competition redding shellholders and use the .010 holder to just get die to touchin. When you want to bump back just change to the .008 shell holder and it bumps .002 without you adjusting die. Best bet in long run.
Bottom line is the fired case must be long enough to difficult to chamber and you should have way to measure datum line on shoulder to measure bump back. Otherwise you have no idea how far you are bumping a shoulder back and from what starting point.
Let me say first of all, the die used is a Redding Category II Body Die. Its purpose is to set the shoulder back without sizing the neck. After adjusting the die in the press and sizing a fired case, I checked a new unfired case, a neck sized only fired case and this sized case with a Stoney Point Shoulder Gauge set in a dial caliper measuring from the base of the case to the datam in the middle of the shoulder. To my suprise the resized case was .005" longer accounting for the difficulty in closing the bolt. [img]images/icons/confused.gif[/img]
Die isn't low enough to bump the shoulder back, and yes they do grow and then get bumped back AGAIN, just a little more than they started out... maybe .002" more is all you should ever need.
The comp shellholders is good cure, I guess.
That or the base of the die needs to be ground back some... and kept square. [img]images/icons/smile.gif[/img]
I assume the ram is camming over as hard as you dare on the die? My 300 Ultra FL die and body die both have to be set down tight, and camming action is quite noticable, but the shellplates on my Dillon RL550 are like .025" thicker than standard shellholders are, so...
Maybe you have the answer, I'am just bumping the shell holder according to instructions, I'll try camming over and see if that does the trick. Would this mean I have an out of specs chamber, in this factory Sendero?
Good point. I'm not sure though, I've never checked mine with one, but if a no-go gauge still will allow you to close the bolt, it would be out of spec.
I lower the die "slightly" at a time, monitor the setback closely, it can jump fast if you don't go a tad bit at a time.
I get to the point mine is camming over pretty good and I just get enough set back, any more pressure on the die and I'd have to grind some off the die.
Comp shellhoders just in case you're camming over hard and still not getting enough, or just plain feel uncomfortable with the amount of added pressure on the system it might take. There's a point were you can tell it's just idiodic to go there, mine just happened to go a little too far at that point, and I backed off and it made the difference for me... I felt comfortable with it. Obviously the setback was lessened about .003" or so, so it was still not forcing the brass into the die as far as it could where I eneded up setting it, but pressure to cam over was increasing like it was just not going any further...