A question about bumping the shoulder?

[Orange Dust]

This does get your attention when you are paying between 2 and 3 dollars per piece of brass for sure!!!

 

[WildBillG]

I am out nothing if I try this shoulder bump method am I. As of right now I have to FL size my friends 300WM brass any way. The way I have thedie setright now is just touching the shell holder and brass is easy to reload. From what I have read I will find a tool around the house and start bumping the shoulder back.
I will have to worry about neck tension and precise seating and alingment later on. We have had some good and bad groups but have been playing with powder and bullet seating depth thus far. Thank you all for the help. It was my hope when I started this thread that shoulder bumping would mean I could turn the die out more. The important thing is that I learned some thing.

 

[MAD10]

I think you are misunderstanding a little. This may get a little long winded, but I'll try and clear up all your concerns, as best I can. The short answer, is you don't need special dies, and there is no "best of both worlds".

1) Blindly following die instructions "touch the shell holder, then add 1/8 turn" or whatever, will almost certainly bump the shoulder a bunch more than necessary. My OEM Savage barrel had ~0.01" more headspace than my current Shilen barrel, and more than any other rifle I have measured. I'm pretty sure it was out of SAAMI spec. Before I really understood that, I was following die instructions, and probably bumping the shoulder at least 0.015" every reload. Case head separations occurred at 3-4 firings...

2) As above, bumping the shoulder 0.002" from fired, in no way means the brass will now chamber in every gun. My OEM Savage would eat neck sized only brass from any gun, as it's chamber was incredibly long (I proved this with 2 friends' guns once fired brass). If I'd known back then to FL size and bump the shoulder 0.002", my ammo CERTAINLY still wouldn't fit in most guns (even my buddies identical Savage LRH had 0.005" less clearance).

3) From rifle to rifle, shoulder position variation has far less affect than throat length, when it comes to "touching the lands". My buddy's identical rifle had a 0.02" difference in throat, but only 0.005" in shoulder. I've measured 3 different 30-06 rifles, and they had a whopping 0.13" extreme spread in base-to-ogive for the same projectiles. It is unlikely you'll run into "jammed bullets" simply due to headspace. For example, the two 30-06 mentioned above, I could have run the bullets 0.1" off the lands in the Rem700, and it would have jammed the bullet in the Win M70 anyway. The difference in headspace (base to shoulder) between the two rifles is about 0.002". If I wanted to run brass for both of them, I'd bump them to the shortest of the two, but I'd still have to deal with huge difference in bullet jump.

4) "Best of both worlds" doesn't really exist (see 30-06 examples above). If you want reliable ammo that will feed in any gun, build it right at max SAAMI specs (like factory ammo is), for both shoulder position (headspace), and base to bullet ogive. If you do that, it will almost assuredly reduce brass life, due to excessive chamber clearance, allowing the brass to expand far more than necessary, and then be resized back down more than necessary. It will also be loose in almost all chambers, with highly variable bullet jump, and therefore not provide the best precision possible.

5) Any die, machined to proper specifications, will allow you to do the minimum necessary sizing for a chamber machined to proper specifications. Measure your fired brass, seat the die deep enough to only move the shoulder back a couple thousandths, and you're good to go for that particular rifle.

6) It is my understanding, that a thousandth or two clearance in all directions/areas (properly FL sized) will actually result in better precision (let alone reliability), than brass that snuggly fits the chamber (neck sized). If the cartridge rubs/jams/etc in any area, this can actually result in more misalignment variation than having it sit freely on the bottom of the chamber. I don't have any real data to back that up, but it does seem logical...

Hope that helps.

Well said and spot on

 

[robert l]

I agree with you Orange Dust about the neck shoulder bump die. 2C I get and understand what you are saying. My point is that I have been reading that shoulder bumping worked our brass less or no more then neck sizing. I my self have been neck sizing now for 30 some years with out an issue. Yes no one else can use my ammo which may or may not be a plus. From what I under stand now basically any one with a bolt gun could chamber my shoulder bumped ammo. Which also leads me to believe this far less then custom ammo to my chamber. Now I under stand that seating depths may vary but a hot load just nudging into the lands of anothers rifle could be bad news for them. My thoughts are I should seriously look into the Forester neck size shoulder bump dies and gain the best of both worlds. A bonus of the Forester die is they come with 3 bushings included.

Ok then about how many chamber reamer companys are out there? Because if you have say 4 shops making reamers then the chambers should be all over the place like they seam to be? I shoot the 338 edge and nowing its a wild cat that should mean the chambers should be alot closer because of the lack of shops making the reamers.

 

[Orange Dust]

I agree with you Orange Dust about the neck shoulder bump die. 2C I get and understand what you are saying. My point is that I have been reading that shoulder bumping worked our brass less or no more then neck sizing. I my self have been neck sizing now for 30 some years with out an issue. Yes no one else can use my ammo which may or may not be a plus. From what I under stand now basically any one with a bolt gun could chamber my shoulder bumped ammo. Which also leads me to believe this far less then custom ammo to my chamber. Now I under stand that seating depths may vary but a hot load just nudging into the lands of anothers rifle could be bad news for them. My thoughts are I should seriously look into the Forester neck size shoulder bump dies and gain the best of both worlds. A bonus of the Forester die is they come with 3 bushings included.

I really dont think i have been clear. I dont think you need this die if you are running a hot 65000psi magnum. The primer pockets will expand before the beass wears out. The .002 bump is the recommended amount for minimual stretch above the web. 0 and .001 are fine too as long as it will chamber in your gun. The idea behind the bump die is to eliminate having to fl size after a couple of loadings just neck sized. In either case you want to set back the shoulder a minimual amount just so the round will chamber. Shoot for .002 max if you are measuring. Dont overthink this. Hope this is a better explanation. If you want to play with a new die, get a sinclair neck expander and some mandrels. Disable the expander in your sizing die. Expand the necks in the sinclair die. This will likely tighten groups at LR, but it will also most likely lower youe ES on velocity.

 

[WildBillG]

Ok so one more question here I resized some 257 Wby brass in my FL die just touching the shell holder and it would not chamber. Neck sized it would. I had to turn die down quite a ways to get the brass to chamber what was causing this situation.

 

[Orange Dust]

Ok so one more question here I resized some 257 Wby brass in my FL die just touching the shell holder and it would not chamber. Neck sized it would. I had to turn die down quite a ways to get the brass to chamber what was causing this situation.

Squeezing the sudes

 

[robert l]

Squeezing the sudes

Sounds like you should keep going down a quarter turn at a time until the brass will chamber.

 

[WildBillG]

I did do that not in quarter turn much smaller and they did chamber. I wish now I would have seen how much of a shoulder bump it was.
Orange Dust I under stood what you were saying and thank you for your help.

 

[ShtrRdy]

I did do that not in quarter turn much smaller and they did chamber. I wish now I would have seen how much of a shoulder bump it was.

That's where you can use a measuring tool to see where the shoulder is after firing and where it is after resizing.

If you measure where the shoulder is after firing be sure to push out the primer to avoid its influence on the measurement.

 

[L.Sherm]

Sounds like you should keep going down a quarter turn at a time until the brass will chamber.

A 1/4 is a ton, that could easily be .010.
I go no more than 1/16 -1/32 at a time.

 

[WildBillG]

L. Sherm that is about what I did turn the die. Those threads on a die are pretty coarse for sure. My fear at first was will these ever chamber again not a good feeling with Weatherby brass.

 

[Alex Wheeler]

I did not read all the posts in this thread but here is what you need to know about sizing. Measure the shoulder diameter before and after sizing, same with the widest point above the extractor groove. I like to see .002-.003" reduction in shoulder diameter and about .001" in base diameter. Bump the shoulder back .002" or so and you will never wear out a piece of brass, EVER. You need a comparator to measure the shoulder bump. This holds true for small 6mm cases in 1000yd Benchrest rifles through 338 lapua improved cases. Top accuracy and case life.

 

[Triple BB]

Easiest way I've found on getting proper head space is using a set of Redding competition shell holders. Broz on this site narrates a video on YouTube that makes it so easy, a cave man could do it...