tight bolt close

When forming/sizing cases for short chambers

I just saw UN last post so I'll post a pic on the feeler gauge idea as well . This lifts the case up and allows you to size the case even shorter then a standard shell holder will allow . That would make for a mighty short chamber though
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Not true, the shim between the deck of the shell holder and case head can increase the presses ability to overcome the cases resistance to sizing.

The reloader and smith use fixed gages like the go-gage, no go-gage and the field reject length gage; they are also locked into bumping the shoulder back. They all go for the .002" bump...and then they just quit.

The shell holder and die are designed to return the case to minimum length; minimum length is the same as full length sized. Again, I have always thought grinding the shell holder and or die is a bad habit. Anything that can be accomplished by grinding I can accomplish with a feeler gage.

When shortening the case from the shoulder/datum to the case head I can shorten the length of the case from the shoulder to the case head .011" with a RCBS shell holder and a feeler gage. If I find a rifle with a short chamber I determine how short in thousands with formed cases. There is another way but at this rate we will never get around to discussing the method and or technique.

Same with competition shell holders; the maximum length that can be gained with the competition shell holder is .010", with a feeler gage I go straight to .016" for my long 30/06 chamber. I use a feeler gage to adjust the die off the top of the shell holder. Again, When I want that .002" clearance I adjust the die off the shell holder .014".

When forming and sizing cases for critical fits I use new and or once fired cases.


F. Guffey
 
Using a .30-06 die doesn't move shoulder back, only sizes the bottom of the .308 case.
This lets you determine if the issue is shoulder or case diameter.
.30-06 dies are *About* 0.0005" smaller at base than .308 dies in my experience, and the longer case body allows you to push the lower sides of a .308 brass in just a smudge WITHOUT setting the shoulder back.

Then you run the same brass through a .308 die to set shoulder.
If it fits, it was a bloated case, if it doesn't, it's a shoulder issue.
I use it as a diagnostic tool to differentiate between bloat & shoulder issues when I get a 'Hard Bolt Close' complaint.

I don't see a need to reinvent the wheel before I know what the actual issue is, this allows you to track down the actual issue.
No sense in ordering a 'Small Base' die when it's actually a shoulder problem...
No sense in ordering 'Custom' dies when it's a 'Small Base' issue.

By the way, a crap load of 'Small Base' dies will push case walls in further, but NOT reach farther down the case.
Shaving a .30-06 die bottom for .308 will get you farther down the case, it's basically a 'Custom' body die for $20.

Shaving a shell holder for ONE SPECFIC rifle, not something you want to do if loading for more than one rifle.

Honing the neck of a die keeps from overworking the brass.
Not everyone counts the number of reloads and discard brass, several just load until brass fails. Honing the neck just keeps from overworking the brass and makes it live longer without counting or annealing etc.

.....

For what it's worth, I agree with Mr. Guffy on the feeler gauges.
Feeler gauges are a really easy diagnostic tool for shoulders.
If your shoulder is just 0.001" or 0.003" etc too long, a shim under the case lets you get your shoulders 'Perfect'.

If you consistently need to feed that case into the die 0.003" further, simply shave 0.003" off the top of the case holder, dedicated that $3 case holder to that specific rifle.
It's MUCH cheaper than buying a set of shaved case holders when you only have one or two rifles that need specalized equipment.
 
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Jeep hammer
Interesting fix with the 30-06 die , 45acp has bloat issues like that ,what would you recommend on a 45acp

Chris
 
If you consistently need to feed that case into the die 0.003" further, simply shave 0.003" off the top of the case holder, dedicated that $3 case holder to that specific rifle.
It's MUCH cheaper than buying a set of shaved case holders when you only have one or two rifles that need specalized equipment.
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Or the reloader has a .003" short chamber meaning the chamber is short .003" from the shoulder to the bolt face. 'OR' the reloader needs to anneal his cases.

If the chamber is short and the reloader is using a standard, common everyday die the chamber will be .002" shorter from the shoulder to the bolt face than a go-gage length chamber.

One more time: There are times the case wins and there are other times the press wins. When I want to know by how much I use a tension gage that measures deflection and measures in thousands (no tensions) and pounds.

F. Guffey
 
I better preface this to cw308 so it's not irrelevant to the thread...

The inexpensive way is an orifice die.
Just a 'Donut' in the die that sizes the case as it goes in the bottom & out the top.

There is something called a Case Pro 100 machine, it's a full straight line die plate roller that restores Rim diameter, extraction groove and pretty well resizes case to SAAMI specification from top to bottom.
It's about $1,200 last time I looked, so it's NOt for everyone.

Two benifits of roll sizing, cracked cases 'Chirp', the easiest crack inspection in the world!
The second, no case lube! No sticky lube issues at all since the case is already resized.

I do volume case processing, everything goes through a case roller here, it's the ONLY way I've fund to produce true SAAMI specification, since I sell to the public, the brass MUST be SAAMI and nothing less.
I roll size everything up to .308 for that lower case benifit.

I got a screaming good deal on 9mm brass a little while back, so I'm using a rotary (opposed to a straight line roller) and it spits SAAMI brass out at about 10,000 an hour, and that's all I can feed it, I'm sure it will do more, I just can't feed it faster yet...
 
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Metal God: Beautiful pictures and illustrates the points really well.

JH: Thanks, now my brain hurts, at least I can follow it but it hurts.
 
J Hammer
That's hardcore . I have 1000 cases max. of 45acp if I have a few problem cases I'll dump them.

Chris
 
Depends on your volume...
The Case Pro I have does about 1,300 straight wall cases an hour with optional (more $$$) drive.
Manual, it will do cases as fast as you can pull the handle.

For 1,000 cases, I would just run them through a bulge buster orifice die (about $30 last time I paid attention) and like you, scrap the cases that don't gauge out.
 
The only time I disturb the case head is when firing.

Bargains on cases: I was in Yonkers, New York looking for a mill and vats when the owner of an iron and metal salvage yard made me a deal on brass by the pound/volume. Bing in New York I found the deal difficult to refuse, they did not give me time to sort and count but the deal involved 23.000 cases.

F. Guffey
 
Mr. Guffy, depends entirely on what cases were shot through AND what your volume is...

Feed ramps protruding into chambers cause bulges. Period.
The size of the bulge depends entirely on how thick the brass walls were to begin with, how far the case was unsupported and how much chamber pressure the round makes.
These are factors.

Rims get hammered out upon firing. Period.
The entire recoil force is applied directly to case head/rim against the bolt face.
Brass is softer than steel, recoil force is more than sufficient to move brass.
These are the factors.

Let's not forget some bolt faces do not cover the entire case head, this is unsupported brass.
Same is true with ejector slots or holes in the bolt face.
Bolt rims aren't even close to 'Die' sized for case rims, this allows the rim to expand under the hammering recoil creates. Doesn't matter if it's rifle or pistol, rims are allowed to expand, the gap between case and bolt rim allows for clean ejection.

The firearm makers have ZERO interest in reloaders. Their OBJECTIVE is to sell firearms that load, fire and eject FACTORY ammo, more or less SAAMI specification.
It's up to the Reloader to get his cases/loaded ammo back to some sort of specification/size/shape that will function.

*IF* YOUR particular firearm functions with YOUR specific ammo, then you win!
You beat the brass, you got a loaded round that functions, YOU WIN!

This is about the guys that DO NOT win...
Bulges that keep rounds from correctly chambering, round that cause 'Hard Bolt Close', etc.

Then there is brass recyclers, they have ZERO idea which firearm/chamber/magazine these cases are going to go through...
From super tight custom to WWI machine gun sloppy, and everything in between,
And in very large volume!

I do my very best to get the lower case rim, the extraction groove & lower case sides to SAAMI specification, this is the ONLY way I can give a 100% guarantee my cases WILL WORK 100% of the time.
No home reloader has to do what I do since they aren't trying to please 100% of the people 100% of the time, they ONLY have to make a case that works for THEM.
It doesn't have to be SAAMI at any point on the case to work for them, it only has to fit back into their specific chambers...

Hard bolt close, where this thread started,
Bullet seated too long, case neck too long, case neck too large in diameter, shoulder length (Datum Length) too long, case bulged or bloated, rim hammered out over size can all cause a hard bolt close.

Telling the guy to cram the case further into the die, or worse yet, buy a 'Small Base' die, custom shell (case) holder set, etc makes no sense to me UNTIL YOU FIND THE ACTUAL ISSUE.
In the case of the guy knowing it was a bulge in handgun cases, small volume, recommending a bulge buster die will kill bulges AND resize hammered extraction rims.

It 'Smears' brass but at a volume of 1,000 and not for resale this isn't an issue.
Since it's a one at a time process, if the case looks bad, simply toss it, but the majority of bulged cases will feed/fire without issue.
He'll be reusing cases that are not functioning now, so the bulge buster (about $30) will have him reusing cases that are now scrap for him, pretty well paying for itself in the 1,000 cases he has currently.

You haven't run into case rims that were hammered out, or you scrapped the cases that were oversized.
That's your process, and it works for you.
I can't let an oversized/distorted rim out into the general public, so the rolling process is a requirement for my process.

Precision costs money, how precise do you want to be?
 
Feed ramps protruding into chambers cause bulges. Period.
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Feed ramps that protrude into the chamber is a bad habit. I do not have a ramp that defeats the purpose of the chamber, my chambers support the case. If I fire a case in a pistol that is ejected with a bulge I want my money back or I want cases with thicker case heads, no, I will settle for my money back.

That is a one off thing; I am the only reloader that measure the thickness of the case head from the cup above the web to the case head and again, I am not the fan of moving, rolling and displacing the brass in the case head.

F. Guffey
 
Forget the ogive. It doesn't matter and isn't how OAL is measured by SAAMI.
You can forget all the money for the assorted gauges too. A Dial Vernier is all you need.
Every chamber is different and you cannot use the same OAL based on the distance to the lands in all rifles.
When you're using the same brass in multiple rifles, you must FL resize every time. And you need to watch the case lengths.
 
Rims get hammered out upon firing. Period.
The entire recoil force is applied directly to case head/rim against the bolt face.
Brass is softer than steel, recoil force is more than sufficient to move brass.
These are the factors.
Click to expand...

Can you explain in a little more detail what you mean in the bold section ? The way I read that , it is completely false so I may be misunderstanding what you are saying .

Example : I have on numerous occasions fired my 308 rifles and had the primers back out of the pocket . This has only happened on load development at the low/start charges . The reason this happens as I understand it is there was not enough pressure to stretch the case head back up against the bolt face after the firing pin drove the case fully forward against the chambers shoulder . This results in there being a gap between the case head and bolt face throughout the entire discharge event . That gap allows the primer to push out of the primer pocket that same amount until it's stopped by the bolt face .


My question ( assuming what I just wrote is true ) where did all that felt recoil I experienced come from if the case head never touched the bolt face ?


You can look at it another way as well . The pressure that was necessary to expand the case and stick it to the chamber wall had to have been high . I don't know what that is but likely in the 50Kpsi range maybe 45Kpsi . That would seem to indicate that a 308 rifle can be fired and experience at least 45K psi of pressure and NO stress or load has been put on the bolt face or even the lugs .I believe the case expands and sticks to the chamber walls and does not stretch back to the bolt face until the chamber pressures are greater then 45K psi ( Numbers are approximate ) at which point the case will start to stretch back to the bolt face . Well the fact most of us are not loading to pressures any more the 62K psi and the case and chamber walls complete support the pressures up to about 45K psi . Would seem to indicate the max load a 308 bolt face ever actually has to with stand is 17K psi ????


I don't think the entire recoil force it s supported by the bolt face is all I'm saying ;)
 
This is the way I see it, if you have a different take, fine with me...

Primer is struck,
The powder burns,
Hot gasses expand,
The bullet starts to move as pressure is still rising,
Cases moved backwards in the chamber from the bullet plugging the barrel,

How exactly can a primer stay pushed out under the force of chamber pressure?

I've never had a primer back out past flush in a bolt rifle, the primers are sometimes flattened, but still flush with case head stamp surface.
It would take a super sloppy short case to bang the bolt face and rebound enough to leave space for a primer to keep moving backwards and protrude from the case.

The primer actually gets pressed into firing pin hole, but the primer face is still flush with the case headstamp surface.

The super short/sloppy case in the chamber would account for a primer 'Mushrooming', not just flattening out, which I have seen in a couple of rifles with completely junk chambers, or loads so hot they push the primer out into the radius of the primer pocket.
Loads this hot are usually busy trying to remove headstamps and flowing rims out of the chamber...

There is a CRAP LOAD more surface area inside the case at the head the pressure can act on,
Way more than the pressure can get through the flash hole and act on the surface area of the primer.

When looking down into a case, you can plainly see there is room for a ring of primers (and space between them) around the flash hole, this is all surface area the chamber pressure is acting on.
I can't see a primer ever holding the full force of recoil, keeping the case head off the bolt.
Plainly the case head would crush the primer to a pulp, or more likely, just push it back into the pocket.

I have seen primers back out of blowback & semi autos.
I attribute this to the case slamming the bolt face during normal firing, bullet plugging barrel (before the bullet exits) and the bolt starting to move, case rebounding from the impact with bolt face.

Now, primers are *Supposed* to be recessed into the case, not flush with the case head.
Case hits bolt, primer starts to move, case rebounds off bolt face... Bullet exits barrel and primer keeps moving until it hits the bolt (momentum, pressure or some of both).
With either blowback or semi auto, the case is in the process of being ejected with primer still unseated.

While the case and chamber will absorb some of the PRESSURE,
Case recoil is 100% directly opposed to the travel of the bullet.
And while there will be a crap load of argument about this, it's a basic law of motion/physics...
(For every action, bullet moving down the barrel, there is an opposite and equal reaction, the case moving directly opposite the direction of the bullet)

I see pushed primers more in semi autos than blowback, I have to think that's the bolt unlocking before bullet exits the barrel.
I would have to suspect this is the reason for crimped primers in military ammo which started with the Advent of gas operated machine guns, long before gas operated infantry rifles.

I'm sure down through the history of cartridge firearms there was staked or crimped primers.
Eject upon firing artillery cases come to mind right away, I have a couple empty WWI cases and they have staked primers... One of them makes a good Dillon primer tube holder...
No reason to stake a primer if there wasn't an issue with primers dislodging with about any bolt open upon firing actions.
 
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I've never had a primer back out past flush in a bolt rifle,
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Then you've never shot a low pressure round .

Primer is struck,
The powder burns,
Hot gasses expand,
The bullet starts to move as pressure is still rising,
Click to expand...

Firing pin strikes primer shoving the case fully forward until it stops on the chambers shoulder or extractor .
The case expands and seals to the chamber to the wall locking it in place BEFORE the case moves back to the bolt face .

Simple to understand if you understand how case head separation happens . If the case is ALWAYS pushed back against the bolt face there would never be case head separation because the shoulder would just blow forward rather then the case stretching at the pressure ring where the case thins out just above the head of the case .
 
So, what you are saying is, case moves forward with firing pin strike,
The case expands BEFORE the slip fit between case & bullet releases the bullet and the laws of physics take over,
The bullet hitting the throat won't push the case backwards in the chamber, or the primer in a slip fit pocket can overcome chamber pressure from acting on the case?

I guess everyone needs a 'Working Theroy'.
 
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Your 'Assumption' REQUIRES the chamber pressure be LESS than the pressure required to remove a case from a resigning die.
I can't even begin to believe that because it takes several hundred times the force your press required to size the case just to form the bullet to the rifling...
The bullet being solid core and MUCH harder to form than resize a case.

Not trying to start a crap fight, just pointing out facts of the situation...
 
The case expands and seals to the chamber to the wall locking it in place BEFORE the case moves back to the bolt face .
Click to expand...

He did not correctly cut and paste the step sequence.

BEFORE the case moves back to the bolt face
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That just does not happen, if the case is locked to the chamber the case has no choice but to stretch between the case head and case body. And then there is the neck; if the case fires with the shoulder of the case against the shoulder of the chamber the neck does not get shorter; the length of the case increases in length from the shoulder of the case to the case head.

And then? I have cases that increase in length .016" from the shoulder to the case head when fired. When fired the case shoulder does not move and the neck shortens. AND! the firing pin did not drive the case forward.

F. Guffey
 
Not trying to start a crap fight, just pointing out facts of the situation..
Click to expand...

I don't think you are even a little . I believe you believe what you are saying as do I . I like an honest difference of opinion and debate . If you can explain how case head separation happens in your theory I'm willing to listen . If the head of the case is firmly against the bolt face how does the web stretch and become thinner ? If the case head always ends up against the bolt face before pressures get real high . How can it be bad to have excess head space ( size your case to small ) from head to datum . In both instances the shoulders will just blow forward and form to the chamber and no stress will be put on the web area of the case ????
 
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