Why can't I measure shoulder bump?

[M-61]

What is a good shoulder bump variation? +/- .0005 (for example 1.5425 to 1.5435)? +/- .001 (for example 1.5415 to 1.5435)?

5 ten thousandths is some serious measurement.

 

[Metal God]

My consistent results disagree with needing to touch die to shell holder.

Do you anneal every firing ? There were a few caveats in my posts it’s important people keep those in mind and understand this is not a blanket statement .

 

[Tokay444]

I anneal every firing.
None of my dies touch the shell holder and I get phenomenally consistent results from my Rockchucker Supreme.
In fact, I recently picked up a Hornady AP for loading pistol ammo in bulk. I attempted to make some rifle ammo to see if it would save me any time. My dies had to touch the shell plate to get what I needed, and low and behold, my results were far less consistent.
I picked up an Inline Fab mount and two quick change plates so I can swap between presses.

 

[Metal God]

I anneal every firing.
None of my dies touch the shell holder and I get phenomenally consistent results from my Rockchucker Supreme.

That combination along with a very good lube will get you as good a result as can be had with out firm contact IMHO . Annealing softens the shoulders resulting in the case fighting the sizing process less and reduces spring back . The Rockchucker is one of the most sturdy presses with less deflection then most , add a good lube and you're gtg in most cases . My Hornady single stage press might be one of the worst as far as flex and deflection . Before the comp shell holders I was getting +/- .003 variance head to datum . With the comp shell holders 85% of my cases come out exactly the same size as the last , the rest off by .0005 either side . I've been using them for years and it still surprises me how consistent I can size my cases without annealing .

 

[RegionRat]

At risk of confusing some newbie, the talk of die set up for sizing includes hard contact between the shell holder and the die, as well as those methods that allow for a gap.

Both methods can give good results. Sometimes, changing between one method or the other can solve a bad result. It is all okay as long as the result is good.

The fact that you see strong opinions on both methods can be confusing when you are searching here cause you have a similar question or problem. Sorry, we are not intentionally trying to argue to confuse you, but many accomplished shooters are not diplomats or poets, so forgive the appearance of static in the air...

The fact is that there are very accomplished shooters who are on both sides of the two sizing methods and even many of us who use both methods in different contexts.

There are multiple methods, tools, and hacks used to get results. It is the goal that matters, and it is okay to use either method to get to those results. If your size process has a gap, or if it has a hard cam-over contact, it is okay. If the type of dies or your press causes problems with one method or the other, it is okay to change.

What is important to learn, is that there are details in dies and shell holders, chamber dimensions, lubrication, and press stiffness and stop features, just to name a few, that can all contribute to the results when selecting a sizing method.

 

[Metal God]

Well said RegionRat , I see a lot of guys think everybody loads and or needs the same thing when reloading and use a one size fits all approach when posting advice . Example I understand annealing to dead soft necks is likely "best" for consistency and accuracy . However I find my necks have to little bullet hold for my auto loaders if I fully anneal the cases that will be used in a auto loader . Yet most guys that anneal insist there is only one way to anneal and that's to 950*+ or fully annealed . I however only look to extend case life while leaving some work hardened aspect to my necks to have a bit more bullet hold so I only anneal to 750* . Works great for my needs but would likely be total crap for a bench rest shooter .

FWIW , this is to anyone that reads my posts . I almost always write my posts in a happy , jovial manner with a smile . Sometimes the way I put my words together it does not come off that way . If anyone has taken any of my recent posts as combative they were not written with that intent and rarely are . One of the things I had to work on for my self was not to put inflection on words others have written . It's interesting how depending on how you read something , it can completely change the context . I'm a happy go lucky guy and write in the same manner , If that's not how you took my posts , please try again with a little more pep haha

 

[ronemus]

One question can the competition sh be used with other brands of dies(rcbs,Hornady) ?

Definitely - I use them with my Hornady dies. The first 0.002" step is only likely to be correct vs. a standard Redding shellholder; there is some inconsistency between brands.

 

[Tokay444]

Die float.

 

[Metal God]

I can’t tell if a press can camover just by looking at it , you’ll need to check in the way I described later in the post you took that quote from .

Can’t tell for sure what you’re measuring ( blurry pic ) but looks like you are measuring the slop in a quick release bushing . I also can’t tell if you are putting a load on the die which would be the best way to get that measurement IMO .

 

[ronemus]

I beg to differ slightly' here are pictures of three presses, in your opinion which one IF any cam over ? Walter & Lynnwood didn't send instructions and the others are kinda old. Also can you tell me what am I measuring in the last frame?

The RCBS press looks like a predecessor to the current Rock Chucker; the casting is a bit different - more sculpted.

Both presses have a toggle linkage for leverage, and can probably be set up to cam over; it doesn't appear that there is mechanical interference to prevent it. However, the only way to be certain is to do setup as described earlier. That being said, I prefer to prevent cam over by screwing down the die a bit further - hard contact.

 

[Shooter13]

No interest in what Boyd Allen says? You might want to rethink that. I have seen Boyd post for many years on various forums and he always seems factual, respectful, and helpful.

Unlike @MagnumManiac @BoydAllen has always been respectful, unlike you.

 

[Martin52]

Shoulder diameter - I mention this because I had problems with one particular FLS die and then tried a Hornady New Dimension FLS die. The Hornady reduced the (.308 lapua) fired case shoulder diameter from .4545 to .452 and set back the shoulder to measure h/s at 1.6315. The Hornady resized case fit the chamber perfectly. The other die had minimal impact on the shoulder diameter leaving it virtually unchanged, as a result, I was pushing the shoulder back too far to get the case to chamber ~ 1.628 - so the problem was not sufficiently reducing the shoulder diameter, something that does not come up in these types of discussion very often.

 

[Webster]

Years ago I used to adjust my FL dies down just enough that my brass would chamber in the rifle. I may have to go back to this...
I apologize upfront for beating the dead horse, but frankly, I am baffled at the moment.

I've been working on my 6.5 Creedmoor & 6.5x284 brass for my NRA match rifles. Both have brand new barrels installed by one of the best in the game. My brass is now all once fired from last season. So I dug out my Hornady shoulder bump set once and thought I would try and bump down a quantifiable amount, .001-.002 inches.

I started out by measuring my fired brass, and right off the bat I suspected a problem. I am measuring up to .002 variability in fired cases to the datum line. Hornady digital caliper, Hornady bump gauges, different size gauge for each cartridge of course. Same variability across the board, regardless of cartridge.

I then went thru the process of backing the FL bushing die back from the shell holder one full turn, then working down in 1/8-1/4 turn increments and trying to measure a difference. Even with my FL die all the way down on the shell holder, I can maybe [and I emphasize MAYBE] measure .001 difference from a fired case. In my investigative readings, a die screwed full down should maybe bump the shoulder .004-.007 inches, is that a fair statement?

So I have to ask, what the heck am I doing wrong?

I use Lee shell holders, and Redding Bushing Dies, I realize that's kind of like pairing a Cadillac and a Nissan. Only set of shell holders I've ever owned. I ALWAYS use the same specific shell holder for each specific cartridge. But now I am questioning the specs of the Lee shell holders?

• Maybe they are "tall" and limiting shoulder bump [limiting die adjustment too far down]? Maybe the .001 I see if right...
• Or is the Hornady aluminum shoulder gauge set junk? Maybe I just can't measure what's happening?

Either way, I can, and maybe should go back to the old way of just sizing enough so the brass chambers, but it sure would be nice to quantify that and record it. In these new times of components scarcity, its prudent to reevaluate ones process to optimize usage life.

Thanks for all the assistance. The one good thing COVID has done is give me more time to work on my shooting, rifles, reloading and dig deep back into long range shooting.

Is 0.002" enough to worry about. It's a small amount. Probably has to do with springback variation. Do you anneal the cases? Is the variability measuring error? Stacking parts up and measuring isn't an ideal situation.