Annoying scenario I'm running into right now.

[DCRYDER]

Or he can increase the presses ability to overcome the cases ability to resist sizing. There is the 1/4 additional turn of the die, when that does not do it there is always the additional 1/4 turn to 1/2 additional turn. But! Before I grind a die and or a shell holder I want to know by how much. Then there is the case with head space, my cases do not have head space; I off set the length of the chamber with the length of the case from the shoulder of the case to the case head.

F. Guffey

Oi oi oi . What?????

How do you have no headspace???

Do you mean "no excess headspace"???

 

[fguffey]

How do you have no headspace???

Again, my cases do not have head space, the difference between the length of my chamber from the shoulder to the bolt face and the case shoulder to the head of the case is called clearance. I have case length gages because my cases do not have head space; of my cases had head space I would use case head space gages. I do have chamber gages and I have head space gages.

F. Guffey

 

[fguffey]

.002" is hardly a big problem.

I agree, .002" is the magic number.

F. Guffey

 

[Steve Ladino]

I have used a .308 FL sizer die with the expander plug removed of course to achieve a solid .469 or .4688 diameter measurement just above the extractor groove of the case
for correcting a similar problem in my 6 mm BR re cut chamber with the same reamer.
Sanding a shell holder on a thick piece of glass + 320 gritt paper.

 

[savagedasher]

I have used a .308 FL sizer die with the expander plug removed of course to achieve a solid .469 or .4688 diameter measurement just above the extractor groove of the case
for correcting a similar problem in my 6 mm BR re cut chamber with the same reamer.
Sanding a shell holder on a thick piece of glass + 320 gritt paper.

Fix the chamber on the the gun that takes..
.002 more sizeing.
Yes.002 is a lot when trying to close the chamber. You can make the the same if you have the reamer Good luck Larry

 

[butchlambert]

Have you measured brass from each chamber before sizing just above the extractor groove? In the olden days I had a similar problem and kept bumping the shoulder more and more until it would chamber. Guess what? I started having case head separation. This brass was not getting enough body sizing and of course screwing the die further bumped the shoulder too much, but finally sized the web of the case enough. If you have chambered many barrels you will find some where the base is a thousandths or 3 larger with the same reamer. It is all in your chambering method and setup.
REMEMber to measure the OD of cases fired in ea. chamber before sizing.

 

[DJSBRS]

I am the only person reading this thread that will never have this problem; because I do not use fixed gages, go-gages are nice, I will say the same for the no go-gage and field reject length gage; problem, there can be .005" difference in length between the go and no-go gage and .011" difference in length between the go gage and filed reject length gage.

And then there is the chamber cast.

F. Guffey[/QUOTE

So if I understood your quote " I am the only person reading this thread that will never have this problem; because I do not use fixed gages". Are you assuming no one else uses other methods than the common conventional methods?

I can use a ball bearing to measure the chamber depth and measure off the shoulder into the chamber until I get to where I want it.

There are many fascinating ways to chamber a barrel. The best I have seen is several done in a half day off a CNC machine that were exact.

And the CNC proprietor reads this forum often and will never post an opinion about head space dimensions and how it can be measured exactly.

I read once where " Not one of us is smarter than all of us".

Please excuse my .02¢ worth.

DJ

 

[conor m]

having your own reamer is a good idea , but you should aiso buy a set of headspace guages and have them used when setting the headspace , had a barrel fitted once where thay used a new piece of brass as a head space guage .chamber was 4 thou under min spec.

 

[Hunter2678]

Have you measured brass from each chamber before sizing just above the extractor groove? In the olden days I had a similar problem and kept bumping the shoulder more and more until it would chamber. Guess what? I started having case head separation. This brass was not getting enough body sizing and of course screwing the die further bumped the shoulder too much, but finally sized the web of the case enough. If you have chambered many barrels you will find some where the base is a thousandths or 3 larger with the same reamer. It is all in your chambering method and setup.
REMEMber to measure the OD of cases fired in ea. chamber before sizing.

Ill check that out butch...thanks

 

[q2hunter]

Have you measured brass from each chamber before sizing just above the extractor groove? In the olden days I had a similar problem and kept bumping the shoulder more and more until it would chamber. Guess what? I started having case head separation. This brass was not getting enough body sizing and of course screwing the die further bumped the shoulder too much, but finally sized the web of the case enough. If you have chambered many barrels you will find some where the base is a thousandths or 3 larger with the same reamer. It is all in your chambering method and setup.
REMEMber to measure the OD of cases fired in ea. chamber before sizing.

Yep, a likely culprit in this case.....maybe. It makes no sense that the fire formed case needs .006 for the shoulder to fit the chamber. I think the smoking gun is your statement of brass that have been fired more. More firings mean more times sized, and if you are shoulder bumping with an fl die that probably means you are barely or maybe even not on the bottom of the die with the shell holder at the top of the stroke (no cam over). I run into this with 2 of my belted magnums, haven't with non belted, but no reason it can't happen. Basically, you are not sizing a slight portion of the case just above the extractor groove. If you look on cases fired and sized multiple times, you can see a faint ring there. If you have a mic to measure .0000 it is measurable. It is highly possible, with all you've stated, that this ring is what is causing the hard closure, not the shoulder, and when you bump .006 you are sizing lower on the case and hitting this area. I would bet that newer brass, bumped .002 would work just fine. With that said, be careful, just as butch said here, when you bump .006 to compensate, your shoulder will move that .006 out when fired. You will eventually get a thin wall at this ring above the extractor grove and have case head separation.

 

[fguffey]

And then there are those that assume the shell holder made it up to the die. If the case has more resistance to sizing than the press can overcome there will be a gap between the top of the shell holder and bottom of the die.

When the case whips my press I want to know; on the other hand when the press wins I still want to know.

F. Guffey

 

[scpaul]

Please excuse my ignorance, but since he has the reamer that was supposed to have done both chambers, why can't he take the reamer and touch up the short chamber? I know with the level of experience in this conversation that there must be a reason.

If he took both barrels and cut them a little (?) and re-chamber them both at the same time, would that make ant difference.

I'll appreciate any answers/education. I realize that there's probably more than one answer and I'd like to understand as many as possible. Please answer this in redneck, I think that I can handle that so dumm redneck isn't necessary; famous last words.

Thanks Y'all, Paul

 

[fguffey]

scpaul, I always wonder why the length of the chamber in thousands from the shoulder of the chamber to the bolt face is not part of the history of the rifle. I do not understand why so many bench resters and smiths on bench rester forums have so trouble measuring the length of two chamber when determining the difference in length.

And then; there is the diameter if the chamber; the only answer is 'get a small base die', the answer is always 'purchase another tool'.

You are correct, it would be easier to lengthen the short chamber; to accomplish that it does not take a lot of tools but the person using the tools must know how to use them.

F. Guffey

 

[amlevin]

Please excuse my ignorance, but since he has the reamer that was supposed to have done both chambers, why can't he take the reamer and touch up the short chamber? I know with the level of experience in this conversation that there must be a reason.

The "Reason" is that we are a bunch of people who, when they hear hoofbeats they think Zebra's rather than horses. The simple solution is only to be considered last

 

[Zero333]

When I use the same brass for more than one rifle, I size them to GO-Gauge length. This way I'm only bumping the shoulders 0.0035" for the longer chamber. As longs as the rifles headspace is within specs, it should not exceed 0.0035", since a no-go gauge is only 0.004" longer than the go-gauge.

Assuming your rifles headspace is within specs...

Maybe one of the smiths didn't use your reamer, so maybe one of the chamber's is a lil smaller at the base. This would require you to screw the die down further for it to size the base of the brass smaller, and of course this also bumps the shoulder farther.
This is why fguffey is recommending a small base die.

But maybe you can determine the size of the chambers by measuring (preferably with a micrometer) the base of the fireformed brass from each chamber ?

Just Guessing.

 

[ultraedge]

I have seen this before.What probably happened is that the local gunsmith polished the chamber after reaming. It most likely will be larger in diameter than the other one. The easiest fix is to polish the tight chamber to the same diameter as the larger one. Don't change the headspace if the brass shot from each gun is the same length from base to datum line.

 

[Shaggy357]

One gun, one box of ammo. Two guns, two boxes of ammo. Just like gloves, they (ammo) may look the same, but they are for different hands (guns). Tailoring ammo to work in two guns will NOT reap the greatest reward from either gun.

My $.02 and experience with multiples of many calibers.

Steve

 

[Coolhand]

I have two .220 AI's, both have different barrels with chambers cut with different reamers by two different 'smiths, brass fired from either rifle easily interchange. Both chambers are identical in length and there is only 0.0005" difference in the case bodies.
I suggest you get two pieces of once fired brass one from each chamber have your gunsmith take the DIMS from both cases to determine if there is any discrepancy even though both chambers were cut with the same reamer. Then I suggest that the smith remove the barrel chuck it up in a 4 jaw clock the barrel both ends and then take each case one at a time put the case into the chamber and get a number from each your Gunsmith should know how to do this, that should accurately determine the length difference between the two.
Then it should be a simple matter of setting back the longer of the two chambers. Worked for me I had the same issue with the second of my .220's admittedly my chambers were cut with different reamers BUT the reamers MAY have come from the same maker, that I don't know. But my regular Gunsmith fixed the issue after he had got the numbers and I had 11 thou difference between the two chambers.
And as far as reamers requiring sharpening,quality reamers should be able to cut quite a few chambers and only the person doing the cutting will know if the reamers needs a touch up.

regards
Mike.

 

[SG4247]

Dont overthink all this.

Use a precision mic from RCBS to measure your fired brass. Then use the mic again to measure your resized brass. Shoulder set back of -.002" is usually perfect. Adjust your die to hit the -.002" shorter dimension. Grind the die where it contacts the shell holder if necessary.

I use my precision mic on all my 6 and 6.5 x 47 guns. Headspace - dont care. I make my brass always -.002 shorter than that chamber in the gun im loading for.

 

[/VH]

Dont overthink all this.

Use a precision mic from RCBS to measure your fired brass. Then use the mic again to measure your resized brass. Shoulder set back of -.002" is usually perfect. Adjust your die to hit the -.002" shorter dimension. Grind the die where it contacts the shell holder if necessary.

I use my precision mic on all my 6 and 6.5 x 47 guns. Headspace - dont care. I make my brass always -.002 shorter than that chamber in the gun im loading for.

SG,

He's already setting the shoulders back .004" and .006". Why would he grind the die?