headspace challenge.

[shawn338lapua]

I just got my case gage for the lapua today so i went right to work. i checked my gage with brand new brass and they were sitting as expected so i moved onto my 2x fired brass that i had full length resized. They were sitting a little high so the instructions said to screw in the die, resize and check again. so i did, no change. i continued to try this but it is not fixing the problem. Am i missing something?
Could my resizing die (RCBS) be out of speck?

Anyways thanks for the help.


anther random question, thought on using brass that show ejector marks, ok/no go....

 

[acloco]

Do you have any way of measuring/comparing the new and 2x fired/resized brass from the just below the datum line to the base?

Do NOT do this yet, but you may have to take 1 or 2 thousandths off of the top of your shell holder. Is your shell holder touch the base of the die now after adjusting down?

Also, what brand/style of press are you using? Could be a touch of flew in your press.

 

[farout]

anther random question, thought on using brass that show ejector marks, ok/no go....

Should be ok. You may find the primer pockets loose when you prime them though. When I load a primer and is a lot looser than others, I mark that piece of brass, fire it, and toss it.

Also, you an clean the primer pocket, on the suspect brass, take a new primer and turn it anvel side down on the reloading table, but the brass over it and push the brass down over the primer, if the primer slides right in, I would toss that piece of brass.

Oh, and figure out what is causing the elector marks and quite doing it. That's usually a pressure sign.

 

[shawn338lapua]

its the lee challenger breech press.
yes the shell holder does come in contact with the die.
and no i don't have an accurate way to compare the 2 brass. what is the best way to do that?


farout, thanks for the info, thats what i am trying to do i have been getting pressure signs at pretty light loads so one thing at a time until i get this figure out.

 

[Bob the nailer]

I had a similar problem with some brass, the cases would actually grow slightly after F.L. resized. I milled a few thousands off the shell holder (as mentioned by acloco ) and was able to bump the shoulder right where I need them.

A simpler fix is to just buy a shoulder bump die.


Good luck with your loads.

 

[MagnumManiac]

Depending on the press, if the case is not fully into the die at the top of it's stroke, then FL sizing is NOT occuring. This can only be assessed with a case in the press, if it is not all the way into the die and the shell holder is not in contact with the bottom of the die, then only partial FL sizing is taking place, this will in fact lengthen the base to shoulder measurement because the walls of the case are being squeezed long before the shoulder is and all of that brass is being pushed into the shoulder making it longer.
You need to use your comparator on a fireformed case, not a resized one, then compare a factory case to a fireformed case, if you don't have the SAAMI specs for your cartridges headspace, this will give you your chambers dimensions and allow you to bump the shoulder back .002" below your chamber specs.
This is why I use the RCBS Precision Mic, it's simple to use and is furnished with the SAAMI specs for headspace in whatever caliber you're using it for, makes the job of determining the exact chamber specs very easy and gets your dies adjusted correctly with ease.
Unless you have an under minimum chamber, altering a shell holder should not be needed, although rare, it does happen. I have a 25-06 that is right on minimum and has to be FL sized with the press fully camming over to achieve the correct dimensions for my chamber, but neck sizing only poses a better option with the cases only needing to be bumped every 4-5 reloads and the brass has lasted a long time.

Hope this helps.

 

[shawn338lapua]

the shell holder comes in contact with the die. The body die seems like the most promising, but will i need to buy a neck sizer as well or can i bump the shoulder and send it through the FL to size the neck?

 

[gunwalker]

Before you buy a new die, if the 2x brass still chambers fine you don't need to size any further. Maniac was explaining that no two chambers are alike and why a comparator is so important to have. If the fired brass fits, sizing it back to the unfired cases is just gonna work the brass more which tends to wear the brass out quicker.

 

[shawn338lapua]

I had ran all my 2x through the FL die before i noticed they were fitting a little snug/ closing the bolt got a little tough. They had also shown OP signs. (flattened primers, ejector marks, heavy bolt lift)
I have a once fired, that i haven't resized. it sits a little high in the gage but chambers just fine.

I should note that not all of my brass is giving me trouble. just the ones that have had the most prominent OP signs. I have other rounds that have been through the FL die and chamber just fine

 

[boomtube]

"yes the shell holder does come in contact with the die."

When? I mean, with or without a case fully inserted? It hardly matters what touches where if there's no case in the die. And, given that the die makes the outside right, it hardly matters if you've over pressured the case; size it correctly and it will be right (.338 Lapua or not, it would be wise to pay attention to that passage in your loading manual about working up a load and backing off a bit if you encounter over pressure signs tho).

Using the RCBS case gage to obtain SAAMI specs sorta defeats it's primary purpose. The great advantage of proper hand loading is to make our ammo fit our chamber, not every chamber ever made, which is all SAMMI ammo specs are meant to sccomplish.

An FL die is basically a body/shoulder bump die with a neck sizer tossed in, doing the same thing in two steps with two dies wouldn't automatically change the end results.

 

[SidecarFlip]

I had a similar problem with some brass, the cases would actually grow slightly after F.L. resized. I milled a few thousands off the shell holder (as mentioned by acloco ) and was able to bump the shoulder right where I need them.

A simpler fix is to just buy a shoulder bump die.


Good luck with your loads.

Kinda suprised you could 'mill' the shellholder face in as much as good shell holders are case hardened. High Rockwell and milling don't work well together.

Now, if you said, I 'surface ground' the shellholder, thats more believable.

Shawn.... What I suggest, rather than reducing the shellholder height to obtain the 'bump' from the die, is to carefully grind the bottom of your FL die off. IU grind mine on my high precision surface grinder but you can hand grind it if you are careful and check often for overall length.

Be apprised that once you grind it, it's 'yours'. It's not resellable on Flea Bay or anywhere else, but then, I don't sell my die sets anyway.

The problem with reducing the overall height of a shell holder is being able to fixture it and grinding it so both the upper and lower surfaces are parallel.

When I grind mine, I fixture the shellholder or the die (base up) in an appropriate collet secured in a spin index fixtured on a magnetic chuck at exactly 90 degrees in relationship to the lineal travel of the table.

In that position, the base of the die or the surface of the shellholder stays true and parallel at all times and it's easy to remove exactly the amount of material you want to, to achieve the desired 'bump'.

I typically cut my dies 0.015 (after ascertaining just how much bump (setback) the dies will effectuate in stock form. keep in mind that all dies are not the same and some dies will set back shoulders more than others, even dies from the same manufacturer made at different times because the overall dimension from the top of the die, to the base is not considered a critical dimension so overall height varies.

I know that all sounds complex.

The easiest way to ascertain if, the die is setting back the shoulder and how much is using a headspace gage. The die will only set back whatever distance is obtainable when the die is in a 'cam over' position in the press, but once you grind the die base or shell holder, camming over becomes a thing of the past.
I never cam over my press to bump.

I typically set back 0.001 to 0.002 to achieve proper chambering and no, I don't get brass on my bolt face.......

 

[shawn338lapua]

Ah sorry Boomtube, when i am running brass they come in contact. And as far as the section in my book about Op, well lets just say i am learning. or trying to anyways....


"The easiest way to ascertain if, the die is setting back the shoulder and how much is using a headspace gage. The die will only set back whatever distance is obtainable when the die is in a 'cam over' position in the press, but once you grind the die base or shell holder, camming over becomes a thing of the past.
I never cam over my press to bump."

Which Headspace gage would you recommend? i do have the LE wilson non adjustable

I am ok with the idea of grinding my die, no plans on selling it. though i do not have access to a decent shop. suggestions?

 

[SidecarFlip]

Ah sorry Boomtube, when i am running brass they come in contact. And as far as the section in my book about Op, well lets just say i am learning. or trying to anyways....


"The easiest way to ascertain if, the die is setting back the shoulder and how much is using a headspace gage. The die will only set back whatever distance is obtainable when the die is in a 'cam over' position in the press, but once you grind the die base or shell holder, camming over becomes a thing of the past.
I never cam over my press to bump."

Which Headspace gage would you recommend? i do have the LE wilson non adjustable

I am ok with the idea of grinding my die, no plans on selling it. though i do not have access to a decent shop. suggestions?

I use the Hornady headspace gage that comes with an assortment of pre bored inserts for most popular calibers (and you can get from Hornady a blank insert you can custom bore for a wildcat if necessary. It clamps to the moveable jaw on your calipers. I clamp mine to my Starrett's.

I take a fired round (from whichever rifle you want to set the headspace on) and use that as the standard. It won't matter if that round has base issues like brass on the bolt face because when you fire it, the case is assuming the neck and shoulder imprint of the chamber and you are only using the shoulder (datum) to ascertain the amount of bump.

You just can't 'mix and match' because every rifle in any certain caliber, will headspace a bit differently. I segregate the case I use as the standard for a particular firearm by marking it.

My typical bump is 0.001-0.002.

I just happen to have the machinery (high precision surface grinder) to grind shell holders and/or die bases dimensionally square.

It would be impracrtical to attempt to 'mill' a shellholder or a die base because of the issues in fixturing them rigidly enough to actually employ a cutter in metal removal and most shell holders are case hardened anyway so the best way is grinding.

If you grind the die base it's not resaleable of course.

My issue with camming over the press (interference contact between the die base and shell holder) is, you really don't know how much the shoulder is being bumped back (without a headspace gage) and I don't care to cam over the press because it imparts a strain on the mechanism.

Because I load straightwall cases with carbide inserted dies for pistol rounds, 'camming over' is a no-no. You cam over a pistol die and it's shot because the carbide insert is brittle and will shatter.

You can buy dedicated bump dies that are basically a sizing die with an abbreviated base. I can't see spending the money for yet another die when the alternative is simpler.

I never really got into this 'bump' stuff until I started loading for longer range bolt guns. AR's and such care less about headspace. So long as it cycles in basically a sloppy enviroment, all is good. One reason I've never considered any gas blowback semi auto a viable long range hunting tool.

You can hand grind the base (of the die) after removing the decap rod and expander ball on a bench grinder with a medium (not coarse) wheel by engaging the wheel lightly with the die base and rotating it to achieve an even cut. You have to be **** careful about how much you remove and that you keep the base even and square to the die body.

I would use your calipers to ascertain the overall length of the die prior to grinding (for a base line about how much to remove) and then CAREFULLY GRIND the base as I suggest above. Grind a little, I mean a LITTLE and then check the overall length in 3 different spots around the diameter of the base (to insure that you are grinding evenly and keeping the base square).

Takes me about a minute with the surface grinder but can be accomplished by hand being careful.....

 

[SidecarFlip]

Additionally, don't attempt to grind a shell holder. You can't hang on to it for one and you'll never get it square (important because the cartridge base indexes on the shell holder) and if it's not square, the case is not perpendicular to the die cavity and while the die will align the case as it sizes, the cartridge is stressed and the case head may or may not be aligned with the body after sizing.

Just the die.