Yet another shoulder bump question

[Mark611]

I do not run my loads hot, roughly 2550 +-30fps with 175gn SMK's with 41gns of whatever powder, like 4064, H4895. Varget, or 2495, I get good results from all of these powders, I'm also wondering is these powders at these charge weights are fully forming these cases? and if I need to fire them a few times before I resize them to get the correct shoulder bump? I do not agree with the firing from 1 rifle to another if set back to SAAMI spec, Brass is gonna flow, my new barrel is cut with a match reamer, smaller then SAMMI, the rifle is a TACK driver, no matter what the bump is, but I would like to see the shoulder bump more consistent, any suggestions?

 

[DLT]

DLT- You just rebarrelled so the new chamber may be fatter than your old and the die may now be mismatched to your new chamber. How many loadings did you get from the old barrel?

I didn’t shoot it much. A couple hundred rounds maybe. With new winchester brass. Got a new barrel and brass to start over. I started another thread with more pictures.

 

[LHSmith]

I do not run my loads hot, roughly 2550 +-30fps with 175gn SMK's with 41gns of whatever powder, like 4064, H4895. Varget, or 2495, I get good results from all of these powders, I'm also wondering is these powders at these charge weights are fully forming these cases? and if I need to fire them a few times before I resize them to get the correct shoulder bump? I do not agree with the firing from 1 rifle to another if set back to SAAMI spec, Brass is gonna flow, my new barrel is cut with a match reamer, smaller then SAMMI, the rifle is a TACK driver, no matter what the bump is, but I would like to see the shoulder bump more consistent, any suggestions?

Sorry, but I am not the best one to give you a promising answer. The most problematic reloading I encountered was a tight match chamber .222 which gave me fits. IME a SAAMI causes less problems. Like you said "brass is gonna flow" why try to restrict it's initial tendency to do so and also reducing case volume does not make sense to me.

 

[txtaxman]

After reading this thread I decided to check my shoulder bump for my custom 308win rig, the brass {LAPUA} was shot the 1st time thru a factory rifle, resized and fired thru my new set up, I went back to check my bump and it was 3k bump under fired, I have very good results with this sizing, so I thought? never checked it till today, I noticed that the bump Very's from case to case, I was shocked! I started off with a clean die, I use a lanolin mix for lube, I cleaned the die about every 10 cases, and still got a +- 1k on the bump, using a Redding body die and a RCBS shell holder, This thread has opened up a new can of worms for me, Now my LAPUA brass is from 2 different lots, 300being the same 200 different, and their mixed! by brass weight, I just wonder if the rims thickness is causing the issue? What say you!

Given your Redding body die and RCBS shell holders setup, I expect that there is a gap between the top of the shell holder and the bottom of the sizing die at the top of the sizing stroke when sizing a case. The gap will vary with the hardness of each case, consistency of the lube, and any flex in the linkage of your press. I found that using Redding Competition Shell Holders and setting the die for firm contact with the shell holder minimizes the variation.

I do not run my loads hot, roughly 2550 +-30fps with 175gn SMK's with 41gns of whatever powder, like 4064, H4895. Varget, or 2495, I get good results from all of these powders, I'm also wondering is these powders at these charge weights are fully forming these cases? and if I need to fire them a few times before I resize them to get the correct shoulder bump? I do not agree with the firing from 1 rifle to another if set back to SAAMI spec, Brass is gonna flow, my new barrel is cut with a match reamer, smaller then SAMMI, the rifle is a TACK driver, no matter what the bump is, but I would like to see the shoulder bump more consistent, any suggestions?

There seems to be a consensus that about three firings are required for a case to be fully fire formed to the chamber. This is easy enough to test by firing several cases three times without full length resizing, and measuring the cartridge base to datum of each case. Then set your bump from the longest case's measurement.

 

[DShortt]

After reading this thread I decided to check my shoulder bump for my custom 308win rig, the brass {LAPUA} was shot the 1st time thru a factory rifle, resized and fired thru my new set up, I went back to check my bump and it was 3k bump under fired, I have very good results with this sizing, so I thought? never checked it till today, I noticed that the bump Very's from case to case, I was shocked! I started off with a clean die, I use a lanolin mix for lube, I cleaned the die about every 10 cases, and still got a +- 1k on the bump, using a Redding body die and a RCBS shell holder, This thread has opened up a new can of worms for me, Now my LAPUA brass is from 2 different lots, 300being the same 200 different, and their mixed! by brass weight, I just wonder if the rims thickness is causing the issue? What say you!

If you aren't already make sure you deprime before measuring anything. The spent primer will throw your measurements off.
I presume you are, just thought I'd mention it.

 

[DLT]

If you aren't already make sure you deprive before measuring anything. The spent primer will throw your measurements off.
I presume you are, just thought I'd mention it.

I do but thanks for posting for any new kids around

 

[Mark611]

TX, I did just that with the longest case, my brass is always clean and unprimed, before any sizing is done, and I only use a Redding body die for my sizing, I probably need to fire the cases at least 2 more times before I try my bump set up again, thanks for the info!

 

[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.
They don't drop with or without die and S/H contact.

Cam-Over: Don’t Do It. Just Don’t.

This is a specially-adapted excerpt from the forthcoming book, “Top Grade Ammo,” by author Glen Zediker, owner of Zediker Publishing. Click here to order from Midsouth. by Glen Zediker My approach …

mssblog.com

I just found this. It’s a good read. Check close and let me know if your press does this. I’d like to find a spare chucker that is like yours.

 

[marine52]

Not if you set up the die properly to use Skip Shims. It's really quite simple. The shims allow you to increase sizing by selecting a smaller shim. I've been using them for many years, and they work flawlessly but you have to set up the FL die properly to use them.

I can PM you my procedure if you decide to go that route.

DLT is correct. If you have firm contact between the ram and shellholder and still need more bump, the shims won’t help. You will need to grind material off the shellholder or off the end of the die (not the best option).

 

[LHSmith]

DLT is correct. If you have firm contact between the ram and shellholder and still need more bump, the shims won’t help. You will need the Redding comp shellholders or you can grind material off the end of the die (not the best option)

You are missing the procedure involved. At set up, you add multiple shims between the press and die. When it is determined that you need to push the shoulder further back, you replace a shim with one that is 0.001" thinner (i.e. remove a 4 thou shim and replace with a 3 thou shim). This drops the die closer to the shell holder. The comp. S/H's raise the S/H closer to the die. Net result is the same except comp. S/H's only come in increments of 0.002" , cost 4x more and are cartridge head speciific. This works FOR ME without inducing hard cam-over because normally I only need to address a variance of 0.003" maximum in H/S from a segregated batch of fired cases (i.e. cases fired same number of times with like load parameters). 3 thou represents a tad over ~1/16 revolution of the die so it has little affect on what the Zediker article is recommending i.e.- cam-over is very slight.

 

[JFrank]

Still’ shims won’t help if more sizing is required beyond hard contact, I turn a few thou off the shell holder…My dies have threads and I know how to use a wrench, I have a feeler gage to measure in .001 increments up or down. It’s not that complicated. If I size to bolt fall it’s always touchy whereas if I create a couple thou headspace beyond bolt fall I don’t have issues when cycling rounds before and after ignition.

 

[Charlie-NY]

If a fully formed & fired case will easily rechamber; why is it customary to bump the shoulder back at all?

 

[jimmymac]

I have a sloppy old Partner press. Never needed a hard stop against a shell holder to achieve the shoulder bump I’m looking for. It’s shims or a PMA Micro Die adjuster for me. Couldn’t be simpler.

 

[LHSmith]

Still’ shims won’t help if more sizing is required beyond hard contact, I turn a few thou off the shell holder…My dies have threads and I know how to use a wrench, I have a feeler gage to measure in .001 increments up or down. It’s not that complicated. If I size to bolt fall it’s always touchy whereas if I create a couple thou headspace beyond bolt fall I don’t have issues when cycling rounds before and after ignition.

Explain "hard contact". Just like the term "cam-over". I searched through 6 current loading manuals and many older ones and no one offers a definition of what that means. RCBS mentions the term in some of their die instructions, but some press designs cant offer that. True there is a point where shims or comp. s/h's, or inserting a feeler gauge under the s/h won't help. Zediker, I believe, was pointing out that most reloading tool manufacturers instruct you to set up your dies in a manner that oversizes i.e. more shoulder setback than what is necessary- we get that may be required for the average reloader with multiple rifles, using various actions, and a variety of cartridge cases He is addressing resizing from an ultimate accuracy point of view.

 

[JFrank]

two pieces of Steele pushed together without clearance have made hard contact.

 

[JFrank]

LHSmith said
He is addressing resizing from an ultimate accuracy point of view.

Q-Resizing accuracy or target accuracy ?
Q- which is more important resizing to exact stripped bolt fall without headspace and hope the load isn’t too hot when the weather warms up and fight the bolt open or having a coupe thousanths headspace and be able to freely chamber rounds before and after ignition and not upset the rifle tracking and returning to battery during a record string of fire?
I wasn’t trying to be confrontational just sharing info and it makes no difference to me I have my dies set where they need to be.
Respectfully
Jim

 

[K22]

DLT is correct. If you have firm contact between the ram and shellholder and still need more bump, the shims won’t help. You will need the Redding comp shellholders or you can grind material off the end of the die (not the best option)

This is not true based on the manner in which I set up my FL die with the shims.

I set my FL die on the .01 shim with full contact of the shell holder, with all the flex in the press removed, no cam over other than that needed to remove the flex in the press.

I now have the option to increase sizing replacing the .01" shim with either the .008, ,007, ,006, ,005, ,004 or .003 shim. This gives me a wide range of sizing options.

I reload for 10 different 223 Rem bolt rifles, each having their own dedicated group of cases. I can easily and successfully custom FL size each group just my measuring the fired case, using the appropriate shim along with measuring the sized case. I've been doing this for years without issue producing anywhere from "0" bump to .002" bump depending on what the specific rifle / brand of cases needs to create optimum fit in the chamber. I have never had to change the position of the lock ring on the die despite loading thousands of cases with different brands of brass and different rifles.

Using the shims in this manner accomplishes the same results as the "competition" shell holders. I tried those shell holders (on loan from a friend) and two in the set were off dimensional. Using the shim method, I have a wider range and more precise sizing options.

 

[DShortt]

This is not true based on the manner in which I set up my FL die with the shims.

I set my FL die on the .01 shim with full contact of the shell holder, with all the flex in the press removed, no cam over other than that needed to remove the flex in the press.

I now have the option to increase sizing replacing the .01" shim with either the .008, ,007, ,006, ,005, ,004 or .003 shim. This gives me a wide range of sizing options.

I reload for 10 different 223 Rem bolt rifles, each having their own dedicated group of cases. I can easily and successfully custom FL size each group just my measuring the fired case, using the appropriate shim along with measuring the sized case. I've been doing this for years without issue producing anywhere from "0" bump to .002" bump depending on what the specific rifle / brand of cases needs to create optimum fit in the chamber. I have never had to change the position of the lock ring on the die despite loading thousands of cases with different brands of brass and different rifles.

Using the shims in this manner accomplishes the same results as the "competition" shell holders. I tried those shell holders (on loan from a friend) and two in the set were off dimensional. Using the shim method, I have a wider range and more precise sizing options.

So.... you're installing a thinner shim under the die in an attempt to increase the base to datum line measurement.

Yeah, no.

 

[K22]

So.... you're installing a thinner shim under the die in an attempt to increase the base to datum line measurement.

Yeah, no.

No.

Generally, I'm increasing the cam over (sizing) by using a thinner shim which results in the desired amount of sizing. For example:

223 X Bolt (Win Cases): Fire Case datum line: .045; sized with shim No. 6: .044, shoulder setback .001".

223 Tikka (Rem Cases): Fire Case datum line: .046; size with shim No. 8: .046 (zero shoulder set back - set back not needed at this point - cases chamber without issue)

223 Rem (Hornady Cases)" Fire Case datum line: .047; size with shim No. 6: .045, shoulder setback .002" (Note the same size shim (See X Bolt above) can produce different results depending on the brand of case, number of firing / sizing).

Each rifle, brand of cases, and useage history may require a different shim depending on how much shoulder set back I want. Also, it's not linear that is why you have to measure the fire case, then establish the shim that will give you the desired sizing. I record the shim number on the cartridge box along with the measurements of the fired and size case. Typically, I measure 3 per lot of cases. It may take 10 or 12 firings or sizing of a case due to hardening before I have to change the shim size, if ever.

This sound complicated by it isn't. It really quite simple once you determine the shim you need which is easy also.

 

[Bob in WI]

Redding comp shell holders and camover??

Ahh yes..camover..
Had that with a Hornady Lock-n-Load press. Drove me crazy till I realized what was going on.