Beginner Checking For Case Separation

[stagpanther]

Grand scheme of things, small variation between gauge makers is a very questionable argument.

For 99.99% of the time--yes. But it has happened to me where a set of gauges issued with a barrel stacked the headspace tolerance way past .06. Granted, it was the newly-issued 350 legend which later was modified, but it did happen. PTG's that were out at the time did not go out nearly as far. I figured it out only after my AR blew up.

But I get your point and shouldn't "scare" a newbie with small probability things, stick with quality gauges like Manson and PTG and should be good to go, so to speak.

 

[tangolima]

I don't like using feeler gauge. The pressure from the press can crush it thinner. A measurement instrument shouldn't bear load. But it is just me.

Instead I use the lock ring to control the sizing depth. The thread pitch is 14 tps, or 0.071" per turn. The lock ring hexagonal. I divide each side into 4 equal divisions, and then into 8. I mark the 48 divisions on the lock ring with fine sharpie or even tattoo them on with electric pencil. Each division then corresponds to 0.015".

-TL

Sent from my SM-N960U using Tapatalk

 

[Unclenick]

khaines0625,

The feeler gauges will give you a sense of where you need to be. Some brass is a bit inconsistently springy if you don't anneal it, though. In that instance, you might want to look at the Redding Competition Shell holders. They have decks that are thicker on top than the standard deck in 0.002" increments. This makes setup to resize extra long a bit quicker than average.

I've found bad headspace gauges before, so it does require some caution. I have a set of "armorer's gauges" in .308 Win on which the individual length is given on each one, but which, if you measure them, turn out to be out of order in some instances (a gauge labeled 1.638" being shorter than the one labeled 1.637", for example). If you don't try to save money and buy them from Dave Manson Reamers or other higher-end reputable sources, you are better off.

If you look at SAAMI drawings, you will see your new case dimensions have a maximum value that just fits in the zero headspace chamber (these dimensions are hard to read because the case and chamber shoulder angles don't match exactly due to an old way of designing chambering) but a minimum that is seven thousandths shorter. To avoid feeding complaints, most manufacturers seem to form brass near the bottom end of their spec. So, stretch on the first firing is a combination of the case and chamber tolerance, which would be substantial in your case.

I have a long chamber like that in an old Columbian Mauser that was rechambered in 30-06 at some point in its career. To shoot it, I took new 30-06 brass, annealed the necks and shoulders, and fired a starting load in it to fireform the brass to the big chamber. After that, I used a 0.010 washer I cut from steel shim stock to slip over each case during resizing. This was in the 1980s before Redding came out with the tall deck shell holders. At any rate, that worked and could handle subsequent loads without the case life being excessively shortened.

You can draw or scratch a line on a lock ring to use with a printed scale for depth adjustment calibration:

https://thefiringline.com/forums/attachment.php?attachmentid=115651&d=1675279001

 

[khaines0625]

The precision that people talk about with doing the resizing confuses me sometimes. The die instructions don't even touch on being remotely that precise, nor do most basic reloading tutorials I see, including the manuals. I get that it's not the optimal thing, but for now I just want to fire some bullets.

All the instructions say is to get the die to barely touch the shell holder and then twist 1/8 to 1/4 of a turn. Following just this leads to crazy excessive shoulder bumps. The fact that the manuals still read it as that makes me think getting the die perfect isn't that important. Right now I just want some rounds to fire, not seek perfection.

The part that throws me off about the die instructions isn't quite so much adjusting the die down a tiny amount as the getting to the starting spot to begin with. Twisting the die to where it barely touches the shell holder in the press sounds simple until you realize that you can twist a little extra and that "little" makes massive changes in the shoulder bump.

I already resized them all. I started with the die pushed back a long ways.
I measured the headspace, twisted it down a bit, ran it through the resizer, and then measured again until I had .002 or so of a change and then set the die locking nut and then did it for all of them.

 

[tangolima]

That should suffice.

-TL

Sent from my SM-N960U using Tapatalk

 

[mehavey]

...measured the headspace, twisted it down a bit,
ran it through the resizer, and then measured again
until I had .002 or so of a change

Just right.
(Exactamundo)

My only add'l suggestion is to release sizing pressure at top stroke,
then "bump" up top again. That will gain you the most consistent
case for about 1 second of your time.

 

[Unclenick]

khaines0625,

How precise one is with ammo depends on purpose. Eric Cortina says he demands 1/4 moa accuracy from his rifles for his competition shooting. A rifle that does twice that is practically a miracle worker in Service Rifle matches. So you have to consider the context for all this stuff.

All the instructions say is to get the die to barely touch the shell holder and then twist 1/8 to 1/4 of a turn. Following just this leads to crazy excessive shoulder bumps.

It is crazy only in your gun's situation with the long chamber. In a gun with a typical new chamber about 0.002" bigger than the SAAMI minimum, it is just right.

The fact that the manuals still read it as that makes me think getting the die perfect isn't that important. Right now I just want some rounds to fire, not seek perfection.

The manuals address average conditions. A chamber near Field NO-GO maximum is actually pretty unusual in all but a heavily used military rifle.

The way to work with your chamber is to think of it as a custom wildcat chamber. The case resizing it needs is not the normal case sizing for chambers between 0.0000" and +0.004" size. You are at +0.010". That's not the standard resizing dies are made for. RCBS told me in an email that the tolerance on standard dies is 0.002". That is tighter than your chamber is, and it is sized for those 0.0000" to +0.004" chambers that new rifles usually have. For your rifle, you need to compensate for the bigger size. If you do that, the chamber is no longer oversized. It is just a custom size. Think custom. You are trying to adapt a standard resizing die to reload for your custom-size chamber. This means you have to resize a bit less than standard. The instructions you refer to are for standard. We don't want standard here. We want longer-than-standard in this instance. That means that when the die kisses the shell holder, you actually want to back it out about six thousandths. The threads are 14 threads per inch or 71.4 thousandths per turn, so you want to back it out about a twelfth of a turn.

The practical way to accomplish the above is to use a case head-to-shoulder gauge to measure your as-fired head-to-shoulder length and then adjust the sizing die position until it produces about 0.001" to 0.004" of head-to-shoulder length reduction when you resize fired brass. If you don't have a gauge, just back the die out about a twelfth of a turn (6 thousandths on my die scale) from contact with the shell holder, size a case, and then see if it chambers. If not tweak the die inward in tiny bits until it does.

 

[mehavey]

The practical way to accomplish the above is to use a case head-to-shoulder gauge to
measure your as-fired head-to-shoulder length and then adjust the sizing die position
until it produces about 0.001" to 0.004" of head-to-shoulder length reduction when you
resize fired brass. If you don't have a gauge . . . .

The OP now has a (Hornady) gauge , and is using it as in Post #84.

 

[HiBC]

Uncle Nick

See post 52 and 65 . It took light pressure on the bolt handle to close on the No-Go gauge. The field guage was never in the picture, except it did not go.

The No-Go was .006 longer than the go. I call it .006 over go for acceptable gauged rifle headspace.

The OP got the Hornady tool and measured .006 for case stretch.

I have no clue where .010 came from.

 

[Unclenick]

The thread is long enough that I sort of sped through it and missed some details, it seems. 0.008" or 0.010" and 0.015" are common civilian and military FIELD NO-GO numbers, respectively, so I inserted that. If there is a light force required to close on the New Chamber NO-GO gauge, the potential for stretch of the new case by up to 10 or 11 thousandths or so is still there if firing makes the case conform perfectly to the chamber, and that assumes the case is new and starting at near the bottom of the - 0.007" tolerance. Generally, that doesn't happen quite that simply. Generally, the case springs back a thousandth or so from the chamber size. The bottom line is that if it stretches 0.006" and you use shims or Redding Competition shell holders or even if your press and die mounting are repeatably rigid, you can cut that down to 0.002" of stretch per loading without sacrificing feed reliability. There is no need to resize the maximum amount the die will accomplish.

Now I'm not sure if that is addressing what the OP is after or not?

 

[mehavey]

... tweak the die inward in tiny bits until it does.....you can cut that
down to 0.002" of stretch per loading without sacrificing feed reliability.
There is no need to resize the maximum amount the die will accomplish.

Now I'm not sure if that is addressing what the OP is after or not?

That is exactly what the OP has done,
( Post 84 )

 

[stagpanther]

Occassionally, I see in big belted magnum cases, especially those with pronounced taper, that a tighter chamber and larger case dimensions can result in a cartridge jamming short in the chamber.

Based on the OP's photos, IMHO there's something more going on with the rifle than just "is it .06 or isn't it."

I keep going back to my legend experience--but when a rifle blows up on you it tends to make an impression. Hard to say what direction the head may have expanded in the OP's photo. In the case of my kaboom, the slack in headspace was enough that the top of the web of the case was unsupported and that is how the catastrophic failure was initiated. As silly as it may sound, both myself and MeHavey had several warnings that "something not quite right" with bulged cases before I finally had the detonation.

I'm not trying to confuse the OP with extraneous information or unnecessary worries, I still consider myself a newbie and always learning. I have things go wrong quite frequently--and even after I "fix" the problem I really strive to understand as fully as possible why the problem occurred in the first place; because Murphy is my constant shooting companion and it will happen again if I don't.

 

[khaines0625]

I'm not trying to confuse the OP with extraneous information or unnecessary worries, I still consider myself a newbie and always learning. I have things go wrong quite frequently--and even after I "fix" the problem I really strive to understand as fully as possible why the problem occurred in the first place; because Murphy is my constant shooting companion and it will happen again if I don't.

I appreciate the perspective. At this point I've taken it to the gunsmith and consulted this forum pretty extensively. I feel like I've done my due diligence.

I'll shoot the rest of what I have and buy ammo from another manufacturer (doesn't hurt to get practice & brass) and see if anything fishy happens.

After that I'll shoot my first handload wearing gloves, eye protection and while standing behind it grasping the butt of the rifle to hold it in place

 

[HiBC]

In the case of my kaboom, the slack in headspace was enough that the top of the web of the case was unsupported and that is how the catastrophic failure was initiated

We are going off topic here. OP,this will have nothing to do with your situation.

Stagpanther, I was not there for your kaboom. I'm speculating and I may be wrong.
A case failure MIGHT have to do with headspace, but it might not. I take it you were in on the early stages of the Legend.
I have zero experience with the cartridge.

Its fairly common for a rifle to be designed that does not fully support the cartridge case. An example would be any cone breech rifle such as The 1903 Springfield and M-70 Winchester.

The cartridge casehead is designed to provide adequate strength to compensate for the lack of chamber support. We are talking about the area between the breech face and chamber mouth. We have to be careful where the chamber support starts. This applies to doing Dremel work on the feed ramps of semi-auto handguns,too.

Was this in an AR type rifle?Perhaps in the course of designing the barrel extension, bolt, bolt face ,breech end of the barrel, and how that all works together someone screwed up in the design or execution(machining) .

All of those can occur whether headspace or headspace gauges are perfect to a few thousandths.

Remember the Go/No go are important to building a new chamber to work within our standards, But the gun is not red tagged out of service till it accepts the field gauge. A gun can pretty grossly be out of "No Go' spec and still be considered safe to use.

I'd expect a headspace kaboom to fail a field gauge check,

Its hard for me to imagine a variance in spec between headspace gauge manufacturers would be great enough to blow up a gun. Methinks there is more to this story.
Not that I need to know it. If I had a mongrel mix of Clymer, Manson, PTG,etc headspace gauges (I don't)I'd use them with confidence. If they disagree .001 its not going to blow up a gun. Remember,a gun that passes field is safe to use.
For a Mauser type rifle,(trued up) if I depth mic receiver ring to breech face,
Then depth mic barrel stub end to shoulder that contacts the breech face,
I can make a sketch and figure out how much my headspace gauge should protrude from the chamber. I can measure that,too.

All that tells me when I have .001 or .003 left to go by hand as I use the bolt and Go guage to establish the minimum chamber I generally cut. I use the No Go to verify, but the bolt does not close on the no go. Its just not that hard to control if you take your time and don't cut corners.

I handload to a target of .002 head clearance in a bolt gun. .004 to .006 in a Garand.It works for me.

 

[mehavey]

(Semi) Off-Topic con't'd:

Brass strength hardness wasn't the issue in this (StagPanther_350 Legend) instance (I think)
(Note Starline & Winchester cases are about the same in head-"base" thickness)

Rather, the problem is/was/appeared to be overly-long Bolt face-to-Chamber distance,
combined w/ thin case web floor that led to some interesting "belted" cases upon firing/extraction.

NOTE: Starline case:

(Lil`Giun didn't help)

See also https://castboolits.gunloads.com/sh...11FS-WARNING&p=5087739&viewfull=1#post5087739 for Hornday specs

 

[HiBC]

I think I see what is going on. I suggest taking your focus off headspace.

I realize you must deal with the rifle components you have,but imagine you could add steel to the barrel ,making the barrel stub longer. That would leave all the headspace features exactly as they are, headspace gauges will gauge exactly the same,but you would lengthen the chamber on the breech end to support more length of the brass.

I can hear the "Easy for YOU to say" It might not be easy but as people stuff different cartridges into the AR, sometimes they have to create new bolt geometry.

I built my .257 Ackley on a Mexican Mauser receiver, but it had no bolt. The Mexican is a 98 that is the shorter action. A standard 98 Mauser bolt won't work. But a Yugo bolt is close. The thing is,if I just used a Yugo bolt ,i'd have a problem like yours. The relationship between the bolt face and the chamber mouth would be wrong and the case wall would be unsupported.

Hmmm. I'll spare some details, but the barrel stub on my rifle is unique. Its longer. It screws deeper into the receiver ring than a standard Mauser.
The front face of the receiver ring and the shoulder on the barrel are in the same place but the chamber is longer,with the length added at the breech end..
The brass is well supported. I can here the gasps now!! That could blow up!!
You did something different!

Relax. When I first built it,I had a case of "Ackleyitis".I splt 8 lbs of IMR 4350 with a friend and bought a bunch of 100 gr Sierra boat tails.
I went to the range and there was a guy with an Oehler 33 chrono. I asked if he'd chrono my load.
He got all excited."What is that thing"? 3400 fps with about 12 fps variation.

Yeah,it was a little over book. Lets say its been proof tested.I've backed off considerably.I burnt up that 4 lbs of 4350 ,took a few antelope and prairie dogs.

Then Nosler introduced the 115 Ballistic Tip .I have not looked back!!I switched to H4831sc. I'm getting 3050 and cases last till the necks splt.Primer pockets stay good. I've shot that rifle a long time.

Anyway,stag,I'm thinking you can probably leave headspace alone you need a longer chamber with more steel on the breech end of the barrel.
Your bolt face to chamber mouth dimension is wrong. Your bolt face to headspace step dimension is not the problem.

 

[georgehwbush]

khaines0625; one last thought, you are not pushing our legs about this being Hornady factory loads, and not your first attempt at reloading? don't push our leg, it wont help you.

now assuming you are not pushing our leg, you might also want to get some very fine rouge and lightly honing the "chamber only" of that gun, to help cases normally slide easier. i have found that to help with extraction issues and other things. the smoother things are the better they work.

remember don't over do it. and always clean it out thoroughly before use.

good luck.

"me wonders if a good chamber cleaning might have been in order. some people seem to clean the bore but not the chamber. <shrugs/>"

 

[khaines0625]

one last thought, you are not pushing our legs about this being Hornady factory loads, and not your first attempt at reloading? don't push our leg, it wont help you.

I promise you I've not lied about anything. Not sure what the point would be, but I suppose there are lots of crazies out there. I'll give my chamber a good clean.