checking shoulder set back

There are many, however, this Digital Headspace Gauge is simple, and works great: http://www.larrywillis.com/

Remove the primer. Take a reading before pushing the shoulder back, zero out the gauge, then take a reading after setting the shoulder back. Adjust your die as needed. Gravity [check that, gravity and a little spring inside the gauge's vertical shaft] does the work. :)
 
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Shoulder angle bump gauges and a caliper

IMG_0379.jpg


I have 3, one for 6mm in 30 degrees, one of 7mm in 35 degrees and one for 30 cal at 30 degrees

I do like the digital one above abintx posted, the Digital Headspace Gauge, no gauges needed! Very nice...
 
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dbaird said:
What is the best tool for checking the amount of shoulder set back when adjusting dies?
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What I have been doing requires no tool other than what is needed to disassemble the bolt. I chamber a piece of brass that has been fire formed in that chamber,(do not re size), close the stripped bolt (without the firing pin and spring). The bolt should close most of the way with no resistance, then require a small amount of finger pressure to close completely. Using this "Feel method" adjust your sizing die so that it bumps the shoulder just enough that the bolt will close with just the slightest bit of finger pressure required to completely close. If the bolt drops shut on its own, you have bumped too much, back the die out a bit, if the bolt requires more than the slightest amount of finger pressure to close, you haven't bumped enough, turn the die down a bit.

Hope that this is helpful,
Dick
 
ConRich said:
What I have been doing requires no tool other than what is needed to disassemble the bolt. I chamber a piece of brass that has been fire formed in that chamber,(do not re size), close the stripped bolt (without the firing pin and spring). The bolt should close most of the way with no resistance, then require a small amount of finger pressure to close completely. Using this "Feel method" adjust your sizing die so that it bumps the shoulder just enough that the bolt will close with just the slightest bit of finger pressure required to completely close. If the bolt drops shut on its own, you have bumped too much, back the die out a bit, if the bolt requires more than the slightest amount of finger pressure to close, you haven't bumped enough, turn the die down a bit.

Hope that this is helpful,
Dick
Click to expand...

+2 in my opinion the best way.......
 
Dick and Bill,
As long as the sizes of the chamber and die are in the proper relationship, what you do can work, BUT if the die is too large for that particular chamber, by the time that you get the bolt feel that you described, the shoulder will have been set back too far. I have had friends that ran into this exact problem, so it is not some purely theoretical thing. Measuring is fast and easy. That way, you know how much you are setting back the shoulder. As you are undoubtedly know, repeatedly setting shoulders back too far, can lead to incipient and then actual case head separations.
Boyd
 
Boyd Allen said:
Dick and Bill,
As long as the sizes of the chamber and die are in the proper relationship, what you do can work, BUT if the die is too large for that particular chamber, by the time that you get the bolt feel that you described, the shoulder will have been set back too far. I have had friends that ran into this exact problem, so it is not some purely theoretical thing. Measuring is fast and easy. That way, you know how much you are setting back the shoulder. As you are undoubtedly know, repeatedly setting shoulders back too far, can lead to incipient and then actual case head separations.
Boyd
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+2
 
ConRich said:
Using this "Feel method" adjust your sizing die so that it bumps the shoulder just enough that the bolt will close with just the slightest bit of finger pressure required to completely close. Dick
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Dick,

With all due respect and I'm not try to be sarcastic, but being able to feel a .001" to 002" of mechanical movement on the shoulder of a case, with finger pressure on a bolt, has to be a gift. What does .002" to .003" feel like? .003" to .004"? What happens if you injure the sensitive tip of your bolt pushing finger?

For all others, IMHO, I believe, for consistency in results, measurement with a highly sensitive gauge, no matter which one, is probably the best avenue to take, especially if one is looking for the precise .0005" to .002" of movement so often sought. :)
 
On the by feel thing...several years back, after a friend had poo pooed my suggestion that he use a gauge and measure bump, I challenged him to set his die by feel, several times, unscrewing it each time, and thing bring the cases over to my house to see how consistent his settings were. They were all over the place, whereupon he went home and made some gauges, that are similar to the ones that Harrell's furnishes with their dies. To be fair, he mostly shoots a .223 at pressures that allow him to get buy with neck sizing with a collet die.
 
abintx said:
Dick,

With all due respect and I'm not try to be sarcastic, but being able to feel a .001" to 002" of mechanical movement on the shoulder of a case, with finger pressure on a bolt, has to be a gift. What does .002" to .003" feel like? .003" to .004"? What happens if you injure the e tip of your bolt pushing finger?
at didn'e t hav
For all others, IMHO, I believe, for consistency in results, measurement with a highly sensitive gauge, no matter which one, is probably the best avenue to take, especially if one is looking for the precise .0005" to .002" of movement so often sought. :)
Click to expand...

With all due respect, have you ever watched a Gunsmith fit a chamber using a go or no go gauge or used a micrometer that doesn't have a readout on it. With all due respect, it is quite possible to feel a couple of thenths with ones hands and fingers. In some cases, with some things, it's just better to rely on one's sense of feel to do things; feeler guage use comes to mind, for instance. And on toppa that, how can one be sure exactly what the chamber length is unless they can feel it? Perhaps I have trust issues, I don't know - --

I once bought a rig from Sinclair that was suppose to give accurate chamber measurements. All it did was load up a bunch of error when trying to measure the chamber. Now, that said, cases must be properly full length sized to get accurate feel when using the bolt feel method. Fat cases Will give one eroneous feel. The other thing is, once on has their dies set up correctly, LEAVE THEM ALONE until that chamb goes away.
 
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For me this has nothing to do with whether or not feel has legitimate uses in precision work. It is about the assumption that the die is small enough in the back to as you say, properly size the case. It is all about what happens when the body of the case is not made small enough by a particular die, so that the case's shoulder in what keeps it from being forced farther forward in the chamber. I have adjusted many valves and other things using feeler gauges, and understand what that is all about. When someone advises adjusting a FL die by feel, they are making an assumption about the relative sizes of the chamber and the die, that may not be the case in that particular instance. Using a simple gauge, like the ones shown in post # 3 is really hard (at least for me) to screw up. What some seem to have trouble understanding is that if a die is too large for your chamber, you cannot remedy that by adjustment. A different die is required.
 
Another point...If you plan on .0005" bump, do you check every one and do you check them every time? Brass seems to work harden inconsistently, from piece to piece...especially when different loads or different number of firings are mixed. If you believe that it is important to keep the fit very close, the least you can do is to check them all, every time.
 
Boyd Allen said:
For me this has nothing to do with whether or not feel has legitimate uses in precision work. It is about the assumption that the die is small enough in the back to as you say, properly size the case. It is all about what happens when the body of the case is not made small enough by a particular die, so that the case's shoulder in what keeps it from being forced farther forward in the chamber. I have adjusted many valves and other things using feeler gauges, and understand what that is all about. When someone advises adjusting a FL die by feel, they are making an assumption about the relative sizes of the chamber and the die, that may not be the case in that particular instance. Using a simple gauge, like the ones shown in post # 3 is really hard (at least for me) to screw up. What some seem to have trouble understanding is that if a die is too large for your chamber, you cannot remedy that by adjustment. A different die is required.
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In my opinion, We can achieve precision to a point. It is sort of rediculous to talk about rifle chambers in half tenths, the majotity of them aren't made that close nor or they inended to be. Most people do not have the measuring equipment to reliably measure things to that fine a line. In my opinion, some folks make way to much of this issue. Rifle chambers, dies and cartridge cases are all different from each other in one way or another. When one full length sizes a case, that case is shaped like the die it came out of, which is very likely not exactly like the chamber it is meant to fit into, it having not been made with the reamer that made the chamber. So, you have a case, for a time, that is shaped like the inside of the die it came out of. As we know, brass that has been worked develops a memory and will return to it's memory position eventually, unless it is annealed. Who among us anneals anyhing much below the shoulder-body junction? Brass begins to work harden the first time it is moved.

So talking about tenths and half tenths in this particular situation seems somewant rediculous to me. In my opinion, if one achieves it, it is a temporary condition. Perhaps a more realistic way of viewing what is actually in play is a to realize we can't simply put our blind faith in what sizes are printed on things and realize we aren't dealing with absolutes, only what we can feel if we understand what we should be feeling. I received one of those brass guages with the Harrels die I purchased a few years ago. I have never used it. In my opinion, it wouldn't tell me what I want to know.
 
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I agree, Pete, especially about it being. But measuring consistently to a half thou is much different than measuring accurately to same. Isn't that what most are after. I mentioned the .0005" because there are a fair number of people who aim for that number in this regard..not that I think it's needed, nor do I strive for it with my brass.
 
"Hardest mechanical thing we do"

In his book "Extreme Rifle Accuracy" Mike Ratigan devotes an entire chapter to the subject of proper brass resizing. Mike says it is the hardest mechanical thing we do in benchrest and I agree wholeheartedly.

During the past nine years, I have worked in the tunnel with a great number of shooters and the subject of proper brass resizing has been the most difficult to teach. You would not believe the mismatches I have seen between dies and chambers and the misconceptions some shooters have about the entire process. At times it has made me want to pull out what little hair I have left and quit the game. But,,,,, I eventually get over it and agree to try to help another shooter who is having trouble. It often involves cutting a new chamber, sometimes a new barrel and/or replacing their sizing die with one that fits. After a rework, I've had many shooters exclaim, "It's now like a different rifle!"

This thread has provided some golden advice from some very knowledgeable shooters. I hope the newbies take it seriously. BTW, if you do not have a copy of both Tony Boyer's and Mike Ratigan's books, make it priority number one to get them. Between these two books, there is very little about benchrest that is not covered in detail.

Gene Beggs
 
Pete Wass said:
it is quite possible to feel a couple of tenths with ones hands and fingers.
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Pete,

A couple of tenths maybe, but we're not talking about tenths [.2"], or even hundredths [.02"], we're talking about thousandths [.002"] and 5 ten thousandths [.0005"]. I don't believe any human, gunsmith or not, can actually feel thousands or ten thousandths.
 
Gentlemen,
I also use the brass shoulder bump gauges shown in post # 2. AFTER I have adjusted the die using the feel method I use the bump gauge to measure that brass from the base to the shoulder, I record this measurement and use it and the gauge to check the brass after each re sizing.

Also, I believe that Pete was referring to Tenths of a Thousandth of an inch, not tenths of an inch.

Dick
 
:rolleyes:
abintx said:
Pete,

A couple of tenths maybe, but we're not talking about tenths [.2"], or even hundredths [.02"], we're talking about thousandths [.002"] and 5 ten thousandths [.0005"]. I don't believe any human, gunsmith or not, can actually feel thousands or ten thousandths.
Click to expand...

When one speaks of tenths when it comes to precise measurements, they are speaking about tenths of a thousants, I realize not everyone may be able to understnd that. I do not understand why you don't believe .001 can not be felt? It's pretty easy to feel .001 with a micrometer or any other measuring device, to include a stripped bolt closing on a brass cartridge case.

I agree with what Mr Beggs said above. It pretty much boils down to folks not knowing what they actually have with die and chamber fit, which was the point I was trying to make. Yo average shooter will not have any way to be able to determine if they do or don't


I'm done with this discussion. I know what I know and I guess I should be satisfied to keep it to myself and will in the future.
 
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LISSEN TO BEGGS!!!!

(And BTW Gene....."newbies"????...... I see guys who've been competing for 20yrs not have a CLUE about brass....)

I've got a shortcut to find out if your method is working. If you have to trim your cases in less than 20 firings, you're doing it wrong ;) (99/100 shooters don't believe this)

LOL

al
 
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