.002 shoulder bump tight in chamber

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Camoman1

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I always bump my shoulders back 2 thou, but this is resulting in a bit of resistance in my chamber so I moved to bumping 4 thou, a bit more than I like. Anyone run into this issue?

-6BR FL Redding bushing dies, with Redding competition case holders, caming over every time.
-measuring with Hornady case comparators
-Lapua brass 4x fired, but has been happening since first reload.
 
Are you measuring your fired cases, then trying a .002" bump beyond that measurement? Not sure how Competition Shell Holders are working for you, as they are designed to limit bump as compared to a standard shell holder....
 
Objective is to just so size your brass to fit your chamber - does not really matter if it fits into a tool or what it actually measures - the fit into the chamber is what counts. All the rest was supposed to help you get there. If you feel resistance when chambering, and do not want that, then you were not sizing adequately - regardless of measurements.
 
eschafer said:
Are you measuring your fired cases, then trying a .002" bump beyond that measurement? Not sure how Competition Shell Holders are working for you, as they are designed to limit bump as compared to a standard shell holder....
Click to expand...

Yes I’m measuring fired cases. And yes im using the comp shell holders to limit my bump as intended.
 
Potashminer said:
Objective is to just so size your brass to fit your chamber - does not really matter if it fits into a tool or what it actually measures - the fit into the chamber is what counts. All the rest was supposed to help you get there. If you feel resistance when chambering, and do not want that, then you were not sizing adequately - regardless of measurements.
Click to expand...

Yes, I agree. Seems odd that .002 isn’t working, as it is the standard. Over bumping could cause issues down the road, especially if a guy plans on firing a case 20+ times. I figure it’s possible I’m over bumping and it’s another reason for a tight feel.
 
I am totally "winging" it, but perhaps possible that your die is pushing the case shoulder back the desired .002", but in doing so is allowing the shoulder or other part of the case to enlarge bigger than what your chamber wants to accept - hence that "resistance" that you feel? I have tracked down sizing issues by colouring a case with black jiffy marker, and then looking for where the rubbing is occurring, to try to figure out where is the issue. In the last instance that I recall, was found to be just the 1/16" inch or so ahead of the case's belt - was not the shoulder, neck, rest of the body at all.

In the process of discovering that, I found that my RCBS 338 Win Mag die would allow that case to drop right in to the belt, whereas with the RCBS 458 Win Mag die that I have, that case would stop a good 3/8" proud of the belt - both were supposed to be the same size - they are not. But both are likely within the min-to-max tolerances for those belted cases.
 
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Think about HOW a comp shellholder works... and you will have identified one possible cause of your problem.

And the solution... at least enough to give it a test.

Here is a clue... take the case and put it into EVERY shellholder in that set and compare what you see.....

Also, consider identifying WHERE the case is rubbing (potashminer, great tip)

Jerry
 
OP,
As mentioned
&
mic your Redding Comp shell holder critical dimension(s)

(You'll probably throw the POS Redding comp shell holders in the trash)
 
Sorry, but just to be clear…are you actually getting a measured difference with the comparator of 0.002” between the fired case and sized case or just relying on the competition shell holders?

I’m curious if the same 0.002” bump without the bushing in the die would provide a resistance free bolt close.
 
OP you didn't say what action you have. On actions based on a Remington 700 firing pin system, I remove the firing pin and cocking piece from the bolt. The bolt is then like a piece of pipe with a handle on it. There is no cocking or spring compressing to mask the feel. On my guns, .002" of bump would have the handle drop with a "clang!" like it was an empty chamber. I sort the sized brass by feel and size the tight cases again WITHOUT the bushing.

Another cause of tight cases is the full length die is too big at the bottom and is not reducing the diameter of the case body at the datum line. If that is happening, you will have tight cases no matter how much shoulder bump.

Harrell's makes full length bushing dies in body diameters of half thou increments. The 2.5 was causing me grief so I ordered a 3.5 and life is good. It matches the chamber cut by my reamer.
 
DANS40X said:
OP,
As mentioned
&
mic your Redding Comp shell holder critical dimension(s)

(You'll probably throw the POS Redding comp shell holders in the trash)
Click to expand...

Mine do not measure a true 0.002" difference from one to the next, kinda close lol. Still useful, sorta, but I feel they should be an accurate 0.001" step between them anyway.
 
If brass is consistent, you will get a more consistent result. If you have mixed brass, or brass that is once fired and some that was 5 times fired, there will be variation. Annealed brass will bump more than un annealed brass.
 
Potashminer said:
Objective is to just so size your brass to fit your chamber - does not really matter if it fits into a tool or what it actually measures - the fit into the chamber is what counts. All the rest was supposed to help you get there. If you feel resistance when chambering, and do not want that, then you were not sizing adequately - regardless of measurements.
Click to expand...

^^ great advice right there ^^

I came across a great youtube video years back from Eagle Eye Precision (I believe it was who made). Can't seem to find it now.

Anyhow the gist of the video is what I use now for my Rem 700 clone.

In short,
(1) take out the firing pin and ejector from the bolt.
(2) very gradually screw FL die down
(3) size a case
(4) use your comparator to see how much die sized the brass... (to see that it actually moved the datum line)
(5) throw the case into chamber and note the feel for amount of tension while you close the bolt (you get "true" feel because of step #1)

repeat steps 2 to 5... very gradually until you get the feel that you want

In my case, I size my cases just enough that the bolt closes on it own weight... which is about .0035 for my chamber.
 
It could be a reamer to die match issue. It likely not sizing enough at the .200 line at a 2 thou bump. But by the time you bump your shoulder back to 4 thou its sizing the .200 line down enough for it to go in easy.
 
Camoman1 said:
I always bump my shoulders back 2 thou, but this is resulting in a bit of resistance in my chamber so I moved to bumping 4 thou, a bit more than I like. Anyone run into this issue?

-6BR FL Redding bushing dies, with Redding competition case holders, caming over every time.
-measuring with Hornady case comparators
-Lapua brass 4x fired, but has been happening since first reload.
Click to expand...

IMO, You have a tight chamber, it's not the shoulder but the body that's tight,,,try a small base die.
 
Mystic Precision said:
Think about HOW a comp shellholder works... and you will have identified one possible cause of your problem.

And the solution... at least enough to give it a test.

Here is a clue... take the case and put it into EVERY shellholder in that set and compare what you see.....

Also, consider identifying WHERE the case is rubbing (potashminer, great tip)

Jerry
Click to expand...

Jerry explain what you mean pls

My comp case holders have all been accurate in maintaining their graduated bumps
 
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