Shoulder bump consistency

[Dimner]

When you guys say lube properly... What is the proper lube method when only trying to bump the shoulder back?

I often lube with lanolin+alch but also have unique sizing lube. Forster instructions say lubing the entire case (neck, shoulder and body). My current method with unique lube is: lube the body with a light even coat of lube with the fingers, and put some unique lube on the mouth of the case. I'm getting +/- 0.002, but I would like to do better as that is still a gap of 0.004 between extremes.

Testing to see what works best is difficult. When you test, and it doesn't work, you now have a wide array of shoulders that make it harder to see if it works the 2nd time though.

 

[WSnyder]

When you guys say lube properly... What is the proper lube method when only trying to bump the shoulder back?

Well that's highly debated topic around here. Seriously do a couple of searches and you'll find all sorts of info and ways. I myself didn't state what I do because this is where you go to your bench and experiment to see what works for you. That's how I figured out my process and I'm sure many did the same. Not trying to be stingy but I believe that's the better way to figure it out and using my way may not work for you.

 

[sqrlgtr]

I was having same problem when I was using imperial wax ,went to a lube pad and dont lube shoulder and have a very consistent bump now. I still use imperial for when i need to move a lot of brass lol...

 

[wkdickinson]

Is buying "fired" brass really a good value? But honestly, buying used brass, shooting it in a gas gun and worrying about a consistant "shoulder bump", really?

 

[jamesk]

Good point, but that's what I'm after.

 

[K22]

I believe in full length resizing as the best means to ensure consistent functionality without any compromise in accuracy or case life.

Lots of excellent advice given here on sizing consistency which I won't repeat.

With that said, why are you bumping the shoulder back .002"? Does it need that much of a bump? Don't forget, when you full size a case you are also sizing the radial dimension of the case which is often enough to allow error free chambering with a zero to .001" bump.

In my experience, if the FL die is set so that it engages the shoulder with zero to .001" bump so the case in not extruded (lengthened), that's all that is necessary until the case hardens with repeated firing then more sizing is necessary. By monitoring the case head space with a bump gage and caliper I can optimize the sizing.

Remember, the only reason to size a case is to for the case to hold the bullet and for the case to chamber flawlessly.

 

[Dusty Stevens]

Dont lube the neck or shoulder

 

[Laguna Freak]

How consistent is your shoulder bump piece to piece? I am getting what seems to be more variation than I thought I would. Was trying to bump .002", some are that others are around .0035-.004". Just lake city brass, Hornady custom FL die. What is an acceptable spread and how would I gain more consistency?

I am also looking at the Mighty Armory sizing die. Not sure how it works exactly, can you change out the mandrels in that die to the size you want? It isn't clear to me.

I have no problem getting .002” shoulder bump with Hornady FL dies 300 WSM and 30-06. I’d look at your case lube consistency as has been suggested. I lube full length of the case very lightly. If I start seeing a little lube build up after sizing, I won’t lube the next couple cases.

 

[Tod Hendricks]

Dwell time, as others have mentioned, can help when you have brass from different chambers that are measurably different. Although, I’ve found the double cycle to be more effective and not near as boring.

You may find the double cycle works well on other operations too, at the very least between the ears.

 

[Ralph Littlefield]

I get .0005 variance at most when sizing.

No offence intended, but I read statements like this often, and I always wonder how much checking is done to verify that this is true. Given the number of variables involved, this seems like a high bar.

 

[Richard Jones]

I'll echo what others have said previously. I'll add if you're backing your die off to achieve your .002" shoulder bump you will not get a consistent and accurate bump. Use a competition shell holder set instead.

Can you elaborate on this a bit as to your reasoning? Thanks.

 

[Chubbs]

It also depends on how accurate your measuring device is. If it has an error 0.001" then you can have a 0.002" variance straight away. You have to pay a lot of cash for a 0.0005" accuracy. Most 0.0005" readings are lost in the error of 0.001'

 

[JFrank]

When I adjust my die to create headspace there’s always a couple of sample rounds while I sneak up or go past the intended, those errant rounds when shot still seem to go in the same poi. In other words ‘I can’t see the difference in .001 or .002 variations on paper so I just don’t get to axle wrapped over tiny variations in shoulder bump.

 

[jlorenzo]

Is buying "fired" brass really a good value? But honestly, buying used brass, shooting it in a gas gun and worrying about a consistant "shoulder bump", really?

Who says I'm shooting it in a gas gun? Where can I get "new" Lake City? Who says I don't have several boxes of Lapua as well?

 

[jlorenzo]

When I adjust my die to create headspace there’s always a couple of sample rounds while I sneak up or go past the intended, those errant rounds when shot still go in the same poi. In other words ‘I can’t see the difference in .001 or .002 variations on paper so I just don’t get to axle wrapped over tiny variations in shoulder bump.

This was my hope, running loads on the hot side will a case with a shoulder bumped more have higher pressure? I loaded some new Lapua without sizing it and some rounds had pressure issues while others didn't. This was with 24gr of Varget and 77gr SMK which I though was a standard load. Also loaded a lot longer than mag length (2.26) for my long throat bolt gun (around 2.50"). Had me scratching my head.

 

[jlorenzo]

I suppose I should ad my intent with these particular rounds. This will be a PRS/steel banging load with Lake City, CCI 41s, 8208 XBR and 75gr ELDs. I have had this combo shoot amazingly well out of my Bartlien. Consistently .5 moa which is plenty for me.

When I go to shoot 600y club matches I use Lapua and Bergers. I was just hoping to continue to learn and figure these things out while using the cheaper components.

 

[Rick300]

Dont lube the neck or shoulder

I keep hearing this all the time and I just don't get it. I either lightly spread Imperial all over the case or use the lanolin/alcohol mix, and if I'm using GOOD brass like Lapua or Alpha, I get extremely consistent shoulder bump. Now cheap brass is another sory but after a couple of cycles with annealing they come out pretty good too. People that use a spray are getting lube all over the case - why would properly applied Imperial be any different?

 

[okie]

The horse is dead , give him a break.

Is this a reference to Guffey???

 

[JFrank]

Spray lube is very thin and dries to the case.
Grease doesn't compress, it just builds up in the die and messes up the sizing and creates hydraulic denting in the cases shoulders.

 

[wkdickinson]

Who says I'm shooting it in a gas gun? Where can I get "new" Lake City? Who says I don't have several boxes of Lapua as well?

You have my apology, I obviously made some assumptions I shouldn't have!