Yet another shoulder bump question

[DLT]

Were do you get the .450" measurement? Never understood over camming. Don't like mandrels. I used a Redding FL bushing die for the last 10 years a STD FL die without an expander ball or mandrels before that.. Never had any problems reloading for 50 years. Buy a bump gauge. If you want to use a mandrel I would lube it with something to make sure you are not pushing the shoulder a few thou. I always lube the shoulder and neck . It might be possible while sizing the neck the force on the neck may push the shoulder back a few thou? Slop in the linkage? I assume when you pull the handle all the clearances get bottomed out and the ram comes up the same amount you set up.

I never thought of while sizing the neck it could possibly push the shoulder back. The .450 should be 1.450 using the hornady headspace comparator from base to where the insert contacts the shoulder.

 

[LHSmith]

I seen that. Mine is a hard stop press. The ram doesn’t go down at all unless the handle goes up. The rock chucker is considered a cam over press though

There is never a concensus of what cam-over is. Consider this from the RCBS die instruction sheet on full length or neck sizing -"Be sure all play is removed from the press leverage system. To do this, adjust the die as above, lower the shell holder and set the die 1/8 to 1/4 turn further down so the press CAMS OVER CENTER". So apparently a press that has a hard stop design can cam over.
I go with Reddings instructions where you turn the die to just touch the S/H. I typically load small cases with custom dies that do not require tons of force to resize so I do not worry about removing play in the linkage and any press flex. Like you are doing -if the cases cycle though the action with the desired bolt drop nothing else matters.

 

[DLT]

There is never a concensus of what cam-over is. Consider this from the RCBS die instruction sheet on full length or neck sizing -"Be sure all play is removed from the press leverage system. To do this, adjust the die as above, lower the shell holder and set the die 1/8 to 1/4 turn further down so the press CAMS OVER CENTER". So apparently a press that has a hard stop design can cam over.
I go with Reddings instructions where you turn the die to just touch the S/H. I typically load small cases with custom dies that do not require tons of force to resize so I do not worry about removing play in the linkage and any press flex. Like you are doing -if the cases cycle though the action with the desired bolt drop nothing else matters.

Somebody will beep in wanting to argue. I’m wanting to learn. Why does a rock chuckers ram drop slightly when the handle is at the bottom of the stroke ? There has to be a reason for it I just never understood it. It’s why I went with the mec to be honest. They are both great presses.

 

[J.d. Popkes]

Somebody will beep in wanting to argue. I’m wanting to learn. Why does a rock chuckers ram drop slightly when the handle is at the bottom of the stroke ? There has to be a reason for it I just never understood it. It’s why I went with the mec to be honest. They are both great presses.

It doesn’t matter if it’s dropping a smidge after it cams over on the die firmly

Let me know what you find when you size those couple pieces tomorrow.

 

[LHSmith]

Somebody will beep in wanting to argue. I’m wanting to learn. Why does a rock chuckers ram drop slightly when the handle is at the bottom of the stroke ? There has to be a reason for it I just never understood it. It’s why I went with the mec to be honest. They are both great presses.

I have a '70's era and a 2000 era Rockchucker and neither ram drops at the bottom of the stroke. Even if the hard contact areas were worn as my older one is, I can't see how a small amount of wear would cause that.
They don't drop with or without die and S/H contact.

 

[DLT]

I have a '70's era and a 2000 era Rockchucker and neither ram drops at the bottom of the stroke. Even if the hard contact areas were worn as my older one is, I can't see how a small amount of wear would cause that.

Maybe I am crazy.

 

[LHSmith]

Maybe I am crazy.

Reloading can do that. I went there years ago.

 

[LHSmith]

I watched a You-tube video on the Marksman press and it looks like a solid well built press. Don't know if you got the elevated stand or not, but if you just mounted it to a bench top make sure your handle doesn't hit any part of the bench before reaching full throw of the arm. This is true for any press as I had to notch my bench for the old Rockchucker. The other presses are mounted to plates so they can be C-clamped to benches at the range.

 

[LHSmith]

One more thing. Mec offers a shorter handle which may give you more consistency with the small .223 case. The longer handle may give too much mechanical advantage and not provide enough "feel" when sizing. You may just try "choking up" on your handle to see if that helps. This is what I do with my arbor press handle when using in-line seating dies.

 

[marchx]

There are many reasons why your shoulder bump may vary. Regardless of your equipment, the most important part is the brass. Even lapua brass differs from lot to lot.

Apart from annealing it's good to track (a) lot of the brass,(b) number of firings. Doing this in my case helped a lot. Also I do one stupid thing which in all likelihood makes no sense- I weight the brass and sort them based on weight (brass is trimmed).
I use as little imperial wax as possible while sizing the brass and clean the inner part of the die after every second sizing process with a q-tip.

 

[Benchrest Braxton]

Posts like this further reinforce my investment into the area 419 zero press and shellholders.

 

[jimmymac]

Posts like this further reinforce my investment into the area 419 zero press and shellholders.

You got that right. I feel the same way about my RCBS Partner press.

 

[drop_point]

0.449" works, but 0.450" does not.

You're getting spring-back, and perhaps it is inconsistent. Add 0.001" more of bump and continue on.

 

[drop_point]

Posts like this further reinforce my investment into the area 419 zero press and shellholders.

They work great. I wish they came in smaller increments, but I'm still quite satisfied with them. More cost-effective for the guy using .223/.308/magnum cases.

 

[Benchrest Braxton]

They work great. I wish they came in smaller increments, but I'm still quite satisfied with them. More cost-effective for the guy using .223/.308/magnum cases.

i think an extra thou clearance is more beneficial anyways.

i load for every bolt face (except valk and ppc) so its super convenient for me.

i just wish they would make a ZERO XL with shell holders for lapua, cheytac, and bmg next

 

[DLT]

i think an extra thou clearance is more beneficial anyways.

i load for every bolt face (except valk and ppc) so its super convenient for me.

i just wish they would make a ZERO XL with shell holders for lapua, cheytac, and bmg next

It probably is. Good chance I just don’t have the die set up just quiet far enough.

 

[Benchrest Braxton]

It probably is. Good chance I just don’t have the die set up just quiet far enough.

i think i have about my process perfected.

screw die down to contact shell holder firmly plus some for some “camover”.

use -2 shim

given that your die is a pretty good match for your brass/chamber, you’ll probably bump back 6-8 thou. perfect. i then just work back from that point.

 

[47WillysGuy]

Consider this: If every piece of brass was truly identical, each would size to the same length. BUT, they are not. Some of the cases size to the dimension you want, other cases resist the sizing and come out different in length. Metallurgists would know why that is.

I have run into the same problem you have. And I believe its in the annealing process. I use a propane torch and a drill motor to anneal brass and I would heat the case neck till the neck blossomed a dark red.

I then would full size the cases to where a sized case chambered with a stripped bolt having to be pushed gently pushed but not falling closed. But some cases would cause the bolt to easily fall and other cases did not close with the same pressure on the bolt handle.

My theory is that the some case bodies are harder and some are softer and that the reason for the different sizing dimensions. I'm now placing the torch flame on the area just below the shoulder area for a period a 10 second count and watching for the necks to turn a brighter color of red. Annealing more of the case, I believe, is the answer.

Test the process. I'm not a machine but I think I can get closer to what I want by heating more on the body and annealing the shoulder and the neck instead of just the neck.

Or just screw down on the die and resize the cases that are a problem. Good luck.

 

[DShortt]

I appreciate it and I hope that’s not what’s causing it. No way I would go that route for no more involved than I am.

You might try going by color change in a darkened room and not by time. Room needs to be really dark. Light the torch and sit for 5 minutes or so and let your eyes adjust. You should be able to see well enough to anneal. At least this is my method and it's been working well for me.

 

[DLT]

Consider this: If every piece of brass was truly identical, each would size to the same length. BUT, they are not. Some of the cases size to the dimension you want, other cases resist the sizing and come out different in length. Metallurgists would know why that is.

I have run into the same problem you have. And I believe its in the annealing process. I use a propane torch and a drill motor to anneal brass and I would heat the case neck till the neck blossomed a dark red.

I then would full size the cases to where a sized case chambered with a stripped bolt having to be pushed gently pushed but not falling closed. But some cases would cause the bolt to easily fall and other cases did not close with the same pressure on the bolt handle.

My theory is that the some case bodies are harder and some are softer and that the reason for the different sizing dimensions. I'm now placing the torch flame on the area just below the shoulder area for a period a 10 second count and watching for the necks to turn a brighter color of red. Annealing more of the case, I believe, is the answer.

Test the process. I'm not a machine but I think I can get closer to what I want by heating more on the body and annealing the shoulder and the neck instead of just the neck.

Or just screw down on the die and resize the cases that are a problem. Good luck.

It’s either my annealing, or how I have my die setup. I couldn’t imagine the press having much slop in it although anything is possible. Or I guess it could be the brass no two pieces can be truly identical.