How much shoulder bump?

[pirate ammo]

View attachment 1048585
I was better,, then i read Guffy's posts

anytime the word shoulder appears guffy shows up..I think he has his machine on autotrack searching for that one word...

 

[HomeSlice]

anytime the word shoulder appears guffy shows up..I think he has his machine on autotrack searching for that one word...

The problem is, It’s almost impossible for a new reloader to ask a question about case resizing here. Every single thread goes into the crapper, just like this one.

To the OP: when starting with new brass, I measure the base before firing, then again after. I push the shoulder back .002” in a bolt gun and .003” in an auto loader. This might not be perfect, but it works for me. I don’t own any neck dies. I’m not a high master (yet).

 

[ireload2]

The problem for a new reloader is he cannot easily tell the guys with 15 more minutes of experience than he has and he cannot tell the goof balls and the maliciously contrary from the folks who can really help him. The population needs some form of roundup to control the weeds and the rocks.

 

[KenOath]

The problem for a new reloader is he cannot easily tell the guys with 15 more minutes of experience than he has and he cannot tell the goof balls and the maliciously contrary from the folks who can really help him. The population needs some form of roundup to control the weeds and the rocks.

Very true... the OP will eventually do his own weeding and work out who has the right credentials to heed advice from.

 

[okie]

It’s working...

yep, LOL

 

[CharlieNC]

Actually I will agree with the Guff that the spec you need to know is the distance from the case head to the shoulder datum line (it takes a long time to decifer what he means to say). Using a comparator, how you define the spec becomes the question. To me bumping a shoulder x amount is a poor definition as the starting point after firing is not consistent and will vary based on how many times it has been fired, original length of unfired brass, etc. You need to measure the "zero" headspace length from which you want to have clearance. You can use the A Wheeler method. Or I am lazy and simply partially insert a primer and finish seating it by bolting into the chamber to measure a couple of times, which has always given me consistent results; and it has been accurate relative to indicating problems.

 

[mike a]

Typically, brass doesn't get tight, shoulder to head, on one firing. I tell people that if you can, produce a reference case by firing it, neck sized only, actually any way that you can get it to hold a bullet without touching the body, until it becomes tight. Then you can use that case as a reference for setting your die to bump. The amount you will have to bump will depend on how consistent the factory annealing of your brass is, unless you want to measure every case after sizing and go back and resize those that are harder with a different die setting. There is another issue that is typically not a problem with factory dies and chambers but which can come up when dealing with custom chambers. A die can be too big to do a proper job for a particular chamber, which is why I say NOT to rely solely on bolt feel to set a die. If case that has had its shoulder bumped back a max of .002 does not chamber easily (We are talking bolt actions here.) Then you need another die to size brass from that chamber. I have seen it happen that a fellow would use bolt feel with a mismatched die and bump his shoulders back too far to get the feel that he wanted. You cannot adjust your way out of this situation. You need a different die. For once fired brass, I recommend setting your fl die to reproduce the shoulder to head dimension of your fired cases, and check the first sized case for how it chambers. It will probably work just fine. Typically, for brass that I use in my PPC, that seems to be relatively uniform in how it sizes, I bump shoulders back a maximum of .001 from a tight case, and with that setting, the bolt closes just fine, because as long as you have even a tiny amount of clearance all the way around a case, there is nothing to interfere with the bolt closing.

This convinces me that I will get a neck die. I've often wondered if the case was getting to long or to fat. I have two 6.5 creeds, brass from one won't chamber in the other even though the headspace on the brass is shorter.

 

[BoydAllen]

Funny story about sizing: An older friend of mine, who is far from broke, but who tends to be more than a bit Scotch, and who does his own work, built a .243 AI years back. Looking at the price of a FL die he used the chamber reamer to build a bump die on his lathe that only moved the shoulder without doing anything else. The plan was to use this in combination with a collet die. At the time I told him that since he wanted to get all of the velocity that he could out of the round that his cases would be getting tight at the back, and not just at the shoulder. He blew me off. Later, what I had said came true. Knowing that it would kill him to part for the money for a proper FL die (which he could easily have afforded) and because he is a good friend who had done me some favors, I went to the next local gun show and picked up a used, non carbide 45ACP die set for $10, pulled the guts out of the sizing die and gave it to him to use as a ring die to size the backs of his cases. It worked perfectly. Of course he has a three step sizing process, but that is what happens when you squeeze a nickel until the buffalo craps.