Working on 70 pcs once fired Nosler brass in 270 WSM. I divided the brass into 2 groups according to base-ogive. 50 measured 1.716-1.717. 20 measured 1.719-1.22". Set my Forster FL die and resized down to 1.7145-1.7155. Occasionally making sure they were chambering without any problems in my gun. Now.... I don't touch my die and start to resize the 20 pieces of brass with the longer base-ogive measurements and when I recheck them, the measurements haven't changed and the brass chambers with much more difficulty than I'd like. I can only guess that my next step would be to advance the die until I get the desired base-ogive... I didn't expect to have to tighten the die with brass with a greater length.
Please explain my mistake...
- Thread starter Jody Simcox
- Start date
Yeah, boy! My mistake!! Not base to ogive, but to datum line!
First thing I do with a new gun/ barrel that I plan to reload for is establish the zero headspace number- that base to datum length that offers bolt close with resistance (usually by adding layers of tape to the casehead). I record this number in a log book and depending on the intended use of the ammo set the shoulder back 0.001" to 0.002" for match use or 0.003" for hunting loads. Many times the brass is not fully fireformed by a single firing and no shoulder setback is needed.
BoydAllen
Gold $$ Contributor
The other issue that is commonly not addressed is how much (if any) the FL die is reducing the diameter of your fired case bodies, at the shoulder and a little above the extractor groove where you can see that the sizing of the case stops. If you are not getting the bolt feel that you want, and your cases are not over length then your chamber may be too small for your particular die. The other mistake that you are making, assuming that all of your cases were fired in the same rifle is bumping back from all fired lengths. You really do need to establish your maximum datum to head measurement and always bump back from that. Cases that have not reached or come very close to the maximum do not need to have their shoulders bumped back. Generally I tell fellows who are stuck trying to set a die based on once fired cases that they should find the longest of these (shoulder to head) and set their die to produce that dimension and try it in their rifle. Generally, if they are getting any case body diameter sizing, the brass will chamber just fine. If you bump too much you are setting yourself up for incipient separations that will mean that your brass is totally ruined, and should not be reloaded. If you make that mistake and are going to throw your brass away take a hammer to the necks so that no one will make the mistake of reloading them. Finally do not set your die by feel. Doing that can lead to incipient separations if your die is not suitable for your chamber. Set it by measurement and if the proper amount of bump, from the maximum shoulder to head dimension does not give a satisfactory result...YOU NEED A DIFFERENT DIE.
Albany Mountain
Silver $$ Contributor
Being consistent with lubing the cases seems to be one of the key things I run into when I have variations with shoulder bump. When I straighten out the lube, the shoulders get more consistent.
What the OP posted about could be caused by "spring back" because the cases are different hardness and need to be annealed. This is why the idea that you can get a press like the T-7 and just leave dies "set up" wont work unless the cases are all annealed and the same hardness/softness. It is also why the idea that you can leave dies set and just flop them into place on a Co-Ax press don't work either, again, unless all cases are the same hardness. The only mistake I see is the same one we all made at one point and so many others are still making...believing that you can take a die, set it to a given length to resize and then actually have every case come out that size...believe me, it would be nice if it worked that way!!!!
Lacking cases that are all the same hard or soft level, and /or not having any way to anneal them so they are....then yes, you will have to move the die accordingly. I agree, seems like you shouldn't, and many believe you set the die once and forget it, but you are seeing that it don't work that way. Just one of the reasons it is important to understand headspace and be able to measure it. Having the tools to measure it, you are one giant leap ahead of about 95% of the "reloaders" out there!!!!
Lacking cases that are all the same hard or soft level, and /or not having any way to anneal them so they are....then yes, you will have to move the die accordingly. I agree, seems like you shouldn't, and many believe you set the die once and forget it, but you are seeing that it don't work that way. Just one of the reasons it is important to understand headspace and be able to measure it. Having the tools to measure it, you are one giant leap ahead of about 95% of the "reloaders" out there!!!!
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jepp2
Gold $$ Contributor
Lots of great advice listed above. And easy way to find out where the problem is, just apply something to the case that will "rub" off with friction. In the old days, I used to smoke the case neck with a candle to set the sizing die. Now days you can use a magic marker and chamber the round. Any rubs will show up quickly and tell you where the issue is. Bluing also works fine for this.
I am the only reloader that is not afraid of loosing his place I do not tighten the lock ring to the die, I secure the die to the press with the lock ring. And then there is that part about assuming, I do not assume the case is sized when I raise the ram, one of the first tools I reach for when reloading is a feeler gage. When I size a case and the case has more resistance to sizing than my press, lube and die can overcome I increase the ability of the press to overcome case sizing resistance by raising the case head up and off the shell holder (deck) with a shim from the feeler gage. Adding the shim has the same effect as lowering the die.
And then there are reloaders that do not know how much of the case that did not get shoved into the die. Again, I measure the gap between the bottom of the die and top of the shell holder. Bad habits: Reloaders do not keep up with the fit between the top of the shell holder and bottom of the die. If the die was adjusted down to the shell holder with an additional 1/4 turn there should not be a gap when the case is completely sized. Of the reloader must continue to screw the die down to size the case the case has more resistance to sizing than the press can overcome, it is about this time the reloader should consider annealing. The world of annealing is a mad, mad world because the advisers are hollering for attention and wanting to be chosen, something like 'pick me, pick me'.
F. Guffey
If this is directed to me, please elaborate... I don't understand how a die would size a case from 1.717" down to 1.715", then not change the measurement on a piece of brass that measured 1.720"
No, it was directed to FGUFFY I am sure. I don't know your measuring skills, but one explanation is the brass with the longer base to datum is more work hardened and springs back to it's original dimensions. What made you pick 1.714 to 1.715 as the "magic" number?
KMart
Gold $$ Contributor
This one's directed at you...seriously dude, did you not read ANY of my posts?????
I did read your post and, thanks, I appreciate your info. I originally purchased 100 pieces of what I have read to be high quality brass fo each of 3 hunting rifles. I resized 100 cases of Lapua brass in .243 Win without running into this phenomenon, and also 100 pieces of Nosler brass for 270 Win...again, without seeing this failure to resize with at least some degree of uniformity. I didn't suspect that a different hardness of metal would be an issue in brass that all came out of the same box and was only being sized for the first time since it was purchased. Thanks to you, and the rest of the knowledgeable and experienced folks on this forum, annealing my brass might be the answer- or, at least I won't be surprised in the future when all of my brass doesn't come out the same from my die- again, thanks for your input.
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