Shoulder bumping technique

I'm new to reloading and would like some advice on shoulder bumping. What I'm noticing is that on the first pass through my FL sizing die the case lengthens of course, and after a couple more strokes the shoulder is back about a half of a thousandth (or not at all), and sometimes further passes will get me about 0.0015 or maybe 0.002, which is what I'm trying to obtain. Adjusting the die less than a tenth of a turn deeper gets me too far, sometimes 0.0035 or more. I can't seem to find the middle ground that gets me 1.2-2 thousandths on the first pass. First time the ram comes down (full stroke) there is a gap between the die and shell holder about the size of a sheet of paper, and second or third the die touches. With no case, the die touches. Appropriate "cam-over" at the end of the stroke. I attribute what I'm seeing to some slop in the press, not sure if I should change anything.

What would you do? Does it sound like I need to work on getting better adjustment or is this acceptable technique?

Equipment:
RCBS Summit press, bolted solidly
RCBS FL sizing dies & shellholder
Measuring shoulder with Larry Willis digital headspace gauge (confirmed my technique with them, measurements are consistent and repeatable)
Norma 6.5 Creedmoor brass, once fired, deprimed and cleaned, lubed
I have typed 3 responses and deleted them, they may have been too advanced. Let's simplify.
First, new brass once fired historically across the board grows .004-.006" in length, once fired brass coming from your chamber does not all measure the same. So getting a real consistent bump after the first firing is hard because of that fact.
So you need a baseline number in conjunction of how fired brass fits back in your chamber. Typically I "Settle" on the bump first time, then fire brass the 2nd time and now is when the setting of the die becomes more critical.
As mentioned, a consistent lube is essential to your bump. Every lube works if done right, through trial and error, you will find one you trust. I don't want to go far on lubes, but people tend to point fingers when something goes wrong. Like blaming bad behavior on whiskey if you are a beer drinker and manage to get a big belly full of whiskey and now you have to answer for it. Whiskey and one shot bad, well, NO.
On the gap between die and shellholder, most likely flex, not slop in the press. The greater the gap, the less lube on the bottom of the case that needs it the most.
On turning the die down or up, threads are a 7/8 x 14 coarse thread, a minute turn is big. A tenth of a turn is way too much. One other thing you need to figure in is thread load between the die and lock ring when adjusting it, < Bear with me, If you want to back your die off some, you loosen the die from the press, back it off some to get some room to adjust the lock ring, now you will hold the ring down while backing the die out, pinch the 2, lock the ring, you need to the same when screwing it in also, you can't relax the load. That results in large changes.
With once fired Norma brass, you are a ways from any springback scenarios that you will encounter with more firings, You will learn as you as you go, like all of us, you are not national champ first time out of the gate. If I had known 34 yrs ago what I know today there would have been many less bumps in the road.
There are a lot of shooters in CA, try find a mentor, unless you are some type of social pariah, most people are willing to help.
 
And it begins! :)

Yep, but the author did a good job explaining and warning. I do continuous process improvement (mostly in organizational/management structure) for a living and I welcome new ideas/innovation. 😇

That's why I provided the two train of thoughts for others to synthesize the information being presented. Learning is continuous, what one does with it is another story.
 
Don't feel like it has to be .002" like many say. I have heard of br guys using up to .006" since the primer pocket gives out before the case neck and shoulder from work. Point is, consistency is key (capt obvious). Set your dies close to .002", or .004". Just pick and run. If you can't anneal. .004" ish will help later since there will be more spring back thus Tighter fit. Flame suit on :)
 
Yep, but the author did a good job explaining and warning. I do continuous process improvement (mostly in organizational/management structure) for a living and I welcome new ideas/innovation. 😇

That's why I provided the two train of thoughts for others to synthesize the information being presented. Learning is continuous, what one does with it is another story.
I just had to say it :) Where is cortina shouting from the roof tops, "stop neck sizing your brass!"?
 
I prefer bump or FL resizing because I shoot out in the desert quite a bit. So sand, dust, or other debris can get in the chamber especially when going prone. So I prefer the way Sam describes to resize.
 
I'm new to reloading and would like some advice on shoulder bumping. What I'm noticing is that on the first pass through my FL sizing die the case lengthens of course, and after a couple more strokes the shoulder is back about a half of a thousandth (or not at all), and sometimes further passes will get me about 0.0015 or maybe 0.002, which is what I'm trying to obtain. Adjusting the die less than a tenth of a turn deeper gets me too far, sometimes 0.0035 or more. I can't seem to find the middle ground that gets me 1.2-2 thousandths on the first pass. First time the ram comes down (full stroke) there is a gap between the die and shell holder about the size of a sheet of paper, and second or third the die touches. With no case, the die touches. Appropriate "cam-over" at the end of the stroke. I attribute what I'm seeing to some slop in the press, not sure if I should change anything.

What would you do? Does it sound like I need to work on getting better adjustment or is this acceptable technique?

Equipment:
RCBS Summit press, bolted solidly
RCBS FL sizing dies & shellholder
Measuring shoulder with Larry Willis digital headspace gauge (confirmed my technique with them, measurements are consistent and repeatable)
Norma 6.5 Creedmoor brass, once fired, deprimed and cleaned, lubed
The easy way to consistently bump your shoulder to a repeatable -.002" ( or where your case seats fully in your rifles chamber and easily extracts) is by adding 2 items from Redding to your inventory.
You no longer will need to constantly adjust your full length resizing die.
rather set it once and forget it.
If this sounds like it's right up your alley then please read on.!
You will need two items as stated before.
1) Redding Body Die (caliber specific)
2) Redding Competition Shell Holder Set (again caliber specific )

Place your Redding Competition Shell holder marked .010" on your reloading press while lowering the handle until a firm contact has been made.
Now clear your ram while screwing in your body die another 1/16 - 1/8" to allow for a camming action, and lock in place.
Now with your trusty rifle by your side proceed as follows.
Place a lubricated cartridge case onto your press and simply lower your ram.
You are not FL Resizing but only making contact with your cases shoulder.
Note that the shell holders are designated as follows .010" - .002.
Remove case from press and place in your rifles chamber.
If it doses not feel correct whether feeding or extracting well then remove your case and add the next lower shell holder.
Repeat the procedure until your rifles action will close and open with just the right amount of pressure.
(I find that somewhere between .006" - .004"shell holders work the best for most of my rifles)
Please note that your actual shell holder will vary until you find the right one.
Once you have found the correct shell holder size you are all set.
Now any time you need to bump your shoulder after using your FL resizing die you no longer need to screw your die in or out wasting your valuable time.
It is another operation but once set up will never vary .

Simple use of a body die and shell holder set by Redding will make your reloading process much more productive.
The body die is very reasonably priced, however the competition shell holder set, because it's a set costs a little more.

I hope this helps, as I use these religiously in multiple calibers ,and rifles.
Now here are two plus factors for buying into the Redding Body Die, and Competition Shell Holder Set.

First if you shoot several rifles in the same caliber all you need to do after FL resizing is simply change shell holders while using the body die to establish the correct shoulder bump for each rifle.(document everything for further reference)
Secondly if you shoot more than one caliber with the same parent base design you do not need to buy a caliber specific shell holder set as the shell holders will work.
Example: Redding Competition Shell Set holder size#1 will fit 22 -250, 243, 6.5 C, 270, 308, & 30 -06 as well as many other wildcat calibers. (so you will be getting your moneys worth)

Belted cases unfortunately are a different story. (Caliber Specific - some will fit multiple calibers)
Just my 2 Cents worth !
 
Last edited:
What I'm noticing is that on the first pass through my FL sizing die the case lengthens of course, and after a couple more strokes the shoulder is back about a half of a thousandth (or not at all), and sometimes further passes will get me about 0.0015 or maybe 0.002, which is what I'm trying to obtain.

When the die does not make it to the shell holder the case has more resistance to sizing than the press can overcome. When I want to know the gap between the bottom of the die and top of the shell holder I use a feeler gage, the feeler gage is an excellent tool for measuring gaps.

And then there is cam over, I have at least 12 Herter presses, all of my Herter press cam over, my Herter presses are know as bump presses; because they cam over. I have 3 RCBS Rock Chucker presses, none of my Rock Chuckers cam over meaning they are not bump presses. All we have to do if find a reloader that can measure cam over.

I can increase my presse's ability to overcome the cases ability to resist sizing. The method is the same method I use for sizing cases for short chambers.

I am not sure I understand why you insist on full length sizing, I determine the length of the chamber from the shoulder of the chamber to the bolt face and then adjust the die in the press; there are times I adjust the die to avoid full length sizing. Again I have a 30/06 rifle with a field reject length chamber (from the shoulder to the bolt face). What this means the chamber is .016" longer from the shoulder of the chamber to the bolt face than a full length sized case from the shoulder of the case to the case head. If I chambered a minimum length/full length sized case in that chamber it would have .016" clearance.

F. Guffey
 
The Redding belted mag set #6 comp shell holders will fit all mags including the ultra mags and short mags. Only the 378 Weatherby based cases will not work.
 
To add to the above post. Pull your firing pin or if a shroud mounted safety ie winchester put on safe. Also remove the ejector plunger and spring for a case only feel and not that spring induced feel from the above parts.
The best video I know of explaining the above process
 
Oh I see, that makes sense, and would explain why there's some inconsistency in this measurement amongst fired cases.

Is it reasonable to just not worry about the shoulder until I can start to detect it on closing the bolt?

Thanks.
Exactly
 
Warning! This thread is more than 5 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.

Recent Posts

Top