So....cam over ?

[M-61]

fguffey really had a lot on this

 

[K22]

I cannot bump the shoulder unless I have some cam over with my 50+ year old RCBC Jr. press, the amount needed varies depending on the lot / brand of cases and / or the specific rifle.

This is why I use Skip Shims - with my die set up, I can adjust the amount of cam over simply by replacing the shim which I sometimes have to do as cases age and / or I'm sizing for another rifle of the same caliber.

Standard instructions with RCBS dies specify using a 1/4 to 1/8 cam over which most of us know through experience that turning the die down that much may result in over sizing. That's why the amount of cam over / die setting should be based on measurements of a fired case versus a size case using a bump gauge to obtain the optimum sizing.

 

[Wolfdog91]

So why woul

The title of the next thread.

"Case head separation, what's up?"

So what would cam over dk that would cause case head separation?

 

[SKWERLZ]

I’ve been using a positive stop press (Redding Ultramag) for 40 years and have never had an issue sizing brass consistently and right where I want it. I suppose it’s all about learning the equipment you have and making it work for you. The only cam over press I have is a Harrell’s for sizing PPC and it works just fine too.

Same
Consistent brass(annealing)
Consistent lube
Consistent dwell at top of stroke
Consistent speed.

The smaller cases like my new 6BRA are really easy to be consistent, have to be a bit more vigilant for my bigger magnums.

 

[DaveTooley]

So why woul

So what would cam over dk that would cause case head separation?

Pushing the shoulder back to far.
Cam over and proper sizing are not the same thing. You adjust the sizing die to match the chamber. Not the press stroke. Once the FL die makes contact with the case do you need more sizing? Yes, all presses have some spring in them.

 

[Wolfdog91]

Pushing the shoulder back to far.
Cam over and proper sizing are not the same thing. You adjust the sizing die to match the chamber. Not the press stroke. Once the FL die makes contact with the case do you need more sizing? Yes, all presses have some spring in them.

Ok... But I have my press set to bump my cases back the .005" I want with a slight cam over so I'm kinda confused with what your saying.

 

[DaveTooley]

Ok... But I have my press set to bump my cases back the .005" I want with a slight cam over so I'm kinda confused with what your saying.

So you're getting your desired shoulder set back with the shell holder hitting the FL die? If so you're one of the lucky ones. The vast of people majority can't. I don't understand how adding stress to the press linkage is good and what it accomplishes.
Are people calling cam over the same as shoulder bump? Or as I understand what's being said, the shell holder is touching the die.

 

[chop house]

Ok... But I have my press set to bump my cases back the .005" I want with a slight cam over so I'm kinda confused with what your saying.

i think many here would say 0.005" is excessive bump. personally i try for 0.0015" but that is for bolt rifles and i am not running the loads at max. now, i know you shoot break actions too, and they stretch a lot so maybe 5 thou is needed there.

dave's point is that repeated over working of the brass, the brass flows from the head/body junction weakening that place.

 

[chop house]

Are people calling cam over the same as shoulder bump?

i hope not. i hope they are saying they can not get sufficient shoulder bump without the shell holder hitting the die. i fiddle a lot with nut barrels, and it occurred to me that with factory chambers and factory dies maybe i should not be setting headspace at the absolute minimum. i have caused myself some grief having to alter shell holders so i can get the brass deep enough into the sizing die.

 

[M-61]

Are people calling cam over the same as shoulder bump

I would hope not.
But then again, in today’s world……

 

[Florida Wally]

The title of the next thread.

"Case head separation, what's up?"

This is a problem when “cam over” is used if it causes too much shoulder bump. As RegionRat mentioned, the Redding Comp shell holders can be used to get the desired shoulder bump. I have found that the standard RCBS, Redding and Lee shell holders will bump the shoulder too much when “cam over” is used. This happens to me when I forget to put the correct Redding Comp shell holder on the ram. Sometimes .008 or more. The Redding Comp shell holders allow me to bump shoulders .002 with “cam over” and I a get consistent bump within +/- .0005.

 

[DaveTooley]

i hope not. i hope they are saying they can not get sufficient shoulder bump without the shell holder hitting the die. i fiddle a lot with nut barrels, and it occurred to me that with factory chambers and factory dies maybe i should not be setting headspace at the absolute minimum. i have caused myself some grief having to alter shell holders so i can get the brass deep enough into the sizing die.

I chamber tight to a go gage, +.001" or less unless instructed differently. I have never had a call saying someone had a problem bumping the shoulder. Die manufacturers don't want to make the phone ring either. But there are always exceptions.

SAAMI spec or not, in reloading we start with a wildcat and make adjustments.

 

[tommeboy]

All of my rifle seater dies will buckle a case from crimping the mouth if you seat the die down to touch the shell holder. Thats why you screw it down to touch then back the die out 1 turn or more so it will not crimp the case.

And just because you screw the FL die down to the shell holder does not mean you are going to have premature case failure. Only way that is going to happen is if you have a really long chamber that would probably fail on a Field type gauge. I FL all of my 223 brass for my ar rifles and have NEVER had a case fail from separation. I usually scrap them because they won't hold a primer anymore.

I just love how everyone on forums just regurgitates the same bad info over and over.

 

[6Creed73]

i think many here would say 0.005" is excessive bump. personally i try for 0.0015" but that is for bolt rifles and i am not running the loads at max.

I'd say 0.005 is too much even for a gas gun. For my gas guns, I bump 0.003, and my bolt guns get 0.001 to 0.0015.

I size on an Rcbs Rebel press with a hard stop and have no issue getting my shoulders sized consistently. Not sure I understand the thought that cam over provides more consistency.

 

[NorCalMikie]

I cannot bump the shoulder unless I have some cam over with my 50+ year old RCBC Jr. press, the amount needed varies depending on the lot / brand of cases and / or the specific rifle.

This is why I use Skip Shims - with my die set up, I can adjust the amount of cam over simply by replacing the shim which I sometimes have to do as cases age and / or I'm sizing for another rifle of the same caliber.

Standard instructions with RCBS dies specify using a 1/4 to 1/8 cam over which most of us know through experience that turning the die down that much may result in over sizing. That's why the amount of cam over / die setting should be based on measurements of a fired case versus a size case using a bump gauge to obtain the optimum sizing.

Could also have to do with the "hardness of the brass". That's why you anneal ever so often.

 

[Bill Norris]

All of my rifle seater dies will buckle a case from crimping the mouth if you seat the die down to touch the shell holder. Thats why you screw it down to touch then back the die out 1 turn or more so it will not crimp the case.

And just because you screw the FL die down to the shell holder does not mean you are going to have premature case failure. Only way that is going to happen is if you have a really long chamber that would probably fail on a Field type gauge. I FL all of my 223 brass for my ar rifles and have NEVER had a case fail from separation. I usually scrap them because they won't hold a primer anymore.

I just love how everyone on forums just regurgitates the same bad info over and over.

Redding Micrometer Seater Die instructions say to screw the die down until the threaded portion touches the shell holder and then un-screw it until the readable section on the micrometer is in a position so the user can read it. This allows from .050 to .070 clearance between the die body and shell holder. These dies do not crimp.

 

[jackieschmidt]

None of my 6PPC chambers or my 30BR Chambers are standard. Here is why.

I chamber my barrels to accept the case that my dies produce with the shell holder firmly against the bottom of the sizing die. If I do need a tad more bump as the brass ages, I can switch Redding shell holders.

This is one of the advantages of doing your own barrels.

 

[J.d. Popkes]

How people get 100% dead nuts consistent shoulder bumps without shell holders making hard contact with the die, I will never understand. Or maybe they don’t. Or maybe they’re not measuring. Either way it’s absolutely astounding that this topic has not reached a consensus. I guess I don’t care what others are doing, but it still amazes me.

Full length sizing. The first step in reloading, ever since reloading was a thing, is up to interpretation.

I’m getting increasingly interested in these dies where a guy makes hard contact on the die and then adjusts the bump from the top. I think 419, maybe Cortina, maybe SAC, might be others. Game changer there

 

[Coyotefurharvester]

Or are die setup instructions "just to hard to follow". LOL.

 

[K22]

Could also have to do with the "hardness of the brass". That's why you anneal ever so often.

I have no reason to dispute your assertion, I just don't want to go there. I'm trying to keep my reloading as simple as possible. As my very old tumbler burned out, I don't even use a tumbler anymore - guess what - my reload shoot the same.

I get about 15 to 17 reloads which is in my view, a good amortization of the cost of the cases.