I tried to post on benchrest.central but cannot figure out how! I did not want to bother you guys as I have already many times! I am still trying to digest the newer fl sizing instead of neck sizing but even if I do, how do I "bump the shoulder" .001 " with RCBS full length dies or Redding dies?! I have micrometers, vernier calipers, and tube micrometers but I cannot figure out how to "bump the shoulder" .001 and know that I really did it! Patience guys! Thanks, Tom
bumping the shoulder .001?
- Thread starter tcr1146
- Start date
You need a shoulder bump gage / comparator. Hornady, Sinclair, and others make one. The Hornady is called a head space gage, I think. It attaches to your calipers.
You measure the unsized case with the "head space" gage and note the length. Turn your die into the press in small increments until it moves the shoulder the desired amount. If you are way off the shoulder with your die, as you approach touching the shoulder, it is likely the shoulder bump dimension will actually lengthen. Keep going in until it shortens.
You measure the unsized case with the "head space" gage and note the length. Turn your die into the press in small increments until it moves the shoulder the desired amount. If you are way off the shoulder with your die, as you approach touching the shoulder, it is likely the shoulder bump dimension will actually lengthen. Keep going in until it shortens.
let me try and help. If you have the tools to remove the firing pin from the bolt do so.
Now take a fired case and insert in the chamber and see if the bolt closes on it, if not take that case and set it up in the press with your die and run it thru the cycle. Once done go back to the rifle and insert the brass and close the bolt. If the bolt falls down you sized the brass too much. What you want is for the bolt to close on its on for about 80-90% of its throw and then you ever so slightly lower the bolt into its firing position.
It's best to set the die loose and screw it down a 1/4 turn until you get close to what I've described and then once close get another fired brass and run it thru the die and see how the bolt falls. If still a little tight turn the die this time 1/8 a turn and run it back thru. Then check it again, once you get the die set lock it there and you're good to go. Once set go back and size the previous cases back thru your die.
You may go thru 3-5 pieces in order to get that die set. The reason you don't want to keep using the same piece is you'll push it back too far but it'll still feel ok. That ones kinda hard to explain you'd have to do it and see what I'm trying to say.
If you do it like mentioned you won't need to buy a shoulder gauge to measure by this way you are fitting the case exactly to your chamber.
Now take a fired case and insert in the chamber and see if the bolt closes on it, if not take that case and set it up in the press with your die and run it thru the cycle. Once done go back to the rifle and insert the brass and close the bolt. If the bolt falls down you sized the brass too much. What you want is for the bolt to close on its on for about 80-90% of its throw and then you ever so slightly lower the bolt into its firing position.
It's best to set the die loose and screw it down a 1/4 turn until you get close to what I've described and then once close get another fired brass and run it thru the die and see how the bolt falls. If still a little tight turn the die this time 1/8 a turn and run it back thru. Then check it again, once you get the die set lock it there and you're good to go. Once set go back and size the previous cases back thru your die.
You may go thru 3-5 pieces in order to get that die set. The reason you don't want to keep using the same piece is you'll push it back too far but it'll still feel ok. That ones kinda hard to explain you'd have to do it and see what I'm trying to say.
If you do it like mentioned you won't need to buy a shoulder gauge to measure by this way you are fitting the case exactly to your chamber.
potatoe
Silver $$ Contributor
The basic answer is that you need a shoulder bump gauge. Many smiths will make this for you they run about $25 ish, Whidden has several and sinclair also makes inserts for different cartridges as well (i've never used these but same concept). It's a piece of metal that is partially reamed, it only has the neck and shoulder reaming into it. *note re-seat the fired primer so that it does not throw off your measurements
Where I start is run the press ram all the way up and run the die down till it touches the shellholder and back it off about 3/4 turn. Measure your fired case with the guage and size it and measure it (hopefully it didnt bump the shoulder back if it did back it off another 1/2 turn and start over with another fired case) then slowly (about 1/8th turn at a time) turn the die down measuring after each sizing. You might go over a bit and have to back it out till you get the .001 bump. They do make shims for sizing dies which help a lot for fine tuning the shoulder bump. Those one's that got bumped too much and sized a bunch will be fine just use them as foulers.
But even with just a .001 bump check the for a proper fit to you chamber by taking the firing pin assembly out of the bolt and try to chamber it, if you have too much resistance you might have to bump a little more. There are some more in depth details to it but thats the quick and basic of it
Here's a link to a bump guage measurement. Click on the little video and go about half way through.
http://www.sinclairintl.com/reloading-equipment/measuring-tools/bullet-comparators/sinclair-bump-gage-insert-prod35265.aspx
Where I start is run the press ram all the way up and run the die down till it touches the shellholder and back it off about 3/4 turn. Measure your fired case with the guage and size it and measure it (hopefully it didnt bump the shoulder back if it did back it off another 1/2 turn and start over with another fired case) then slowly (about 1/8th turn at a time) turn the die down measuring after each sizing. You might go over a bit and have to back it out till you get the .001 bump. They do make shims for sizing dies which help a lot for fine tuning the shoulder bump. Those one's that got bumped too much and sized a bunch will be fine just use them as foulers.
But even with just a .001 bump check the for a proper fit to you chamber by taking the firing pin assembly out of the bolt and try to chamber it, if you have too much resistance you might have to bump a little more. There are some more in depth details to it but thats the quick and basic of it
Here's a link to a bump guage measurement. Click on the little video and go about half way through.
http://www.sinclairintl.com/reloading-equipment/measuring-tools/bullet-comparators/sinclair-bump-gage-insert-prod35265.aspx
The "unsized case" DosXX is referring to must be a case fired in the specific rifle that you are loading for. What you are essentially doing adjusting the die so that a fired case is sized with a slight shoulder set back, i.e. For bolt rifles the desired set back in .001 to .002".
The instructions with the bump (headspace) tool will explain in detail how to use the tool. The Hornady Tool works quite well. Get yourself a Sinclair International Catalog, it has a lot information and tools to choose from.
The instructions with the bump (headspace) tool will explain in detail how to use the tool. The Hornady Tool works quite well. Get yourself a Sinclair International Catalog, it has a lot information and tools to choose from.
CaptainMal
Silver $$ Contributor
Sure you will need a "comparator" to measure the shoulder. What you want is not only the ability to measure the .001" but the ability to actually do that small of a bump and do it on a consistent basis. i find it hard.
I have three presses mounted. Each has a bit of spring depending on resistance. The sizing die may offer different resistances based on differences in each case. I just cannot guarantee any setting will actually give me .001", case after case. Some will be .002" and some might not show me anything at all.
My experience with "normal" dies and presses is that tiny of a standard will be hard. Right or wrong, you need a comparator to measure your attempts. Both Hornady and Sinclair sell them. Get one and have at it but don't be surprised if it's often + -.
I have three presses mounted. Each has a bit of spring depending on resistance. The sizing die may offer different resistances based on differences in each case. I just cannot guarantee any setting will actually give me .001", case after case. Some will be .002" and some might not show me anything at all.
My experience with "normal" dies and presses is that tiny of a standard will be hard. Right or wrong, you need a comparator to measure your attempts. Both Hornady and Sinclair sell them. Get one and have at it but don't be surprised if it's often + -.
This is the tool we use.
http://bulletin.accurateshooter.com/2015/08/measuring-shoulder-bump-harrells-tool/
http://bulletin.accurateshooter.com/2015/08/measuring-shoulder-bump-harrells-tool/
CaptainMal said:
First in reality on normal dies and presses one can not unlock and adjust a die in .001 increments. And as you mention even finer measurements than that. It just not gonna get done you'll need a die setup with a micro adjustment and most presses can not use these type setups. The method I explained will set his die to his chamber and be as close as one can be without the speedy micro adjust dies and so forth.
I have set my dies like this for many years and I now have 8 barrels from the same reamer and not one time do I readjust the die when I switch barrels. This goes for barrels that are fitted to different actions and all. Once this guy decides he wishes to get more involved then he can look deeper into specialty tools but for now I'm pretty sure the method I describe will get him as close as he can be.
potatoe
Silver $$ Contributor
I agree with you James to some point but you still need something to measure your bump (at least initially) to verify that your die (keep in mind he is not using custom matched dies/reamers) does match your chamber. He could wind up with a die that oversizes a great deal before getting the before he gets that slight resistance closing his bolt at the end of closing. I think what Mal was saying that don't take every measured resized case as "gospel" that each case (even fired with same load) will have different work hardness and springback which will reflect in the slight variation of bump measurement. That is probably going to be a topic he would come across in the future as he keeps diving deeper in this. But he seems to just be wanting to understand (even if its not as overly important) how to measure a bump to .001.
trc1146 I know how to do this and I do it with all my reloads. But if I had never done this and had to depend on the information you have received I would be totally confused. Before the forum bullies show up let me say that I am not criticizing anyone, they are all trying to help. But the problem is that you are being fire hosed with several ways of doing a very simple thing. If you have a friend that can give you a hands on walk thru of how he does this, that would be a good place to start. Best wishes to you and all those who are trying to help.
potatoe
Silver $$ Contributor
He asked what might seem like a simple question and got pretty much the same answer from everyone. Even though James has a different approach, who I might add did hold a world record. These are not bullies they are valid proven methods from people who have a car's worth of money in their guns and an angry wife because they spend all their free time shooting/tinkering (well at least mine is) but you can't dive into advanced reloading without a barrage of input and it is very difficult to explain to someone through typing a post how to do these things let alone all the other details that come with it. I think the forum members did a great job of giving some good, basic, foundation building input for this. I know without all the input I received at the beginning from threads like this I would still be shooting .5moa. . .just sayin
JamesnTN said:
You can, it's just a PITA.
Same as others above I use the Hornady headspace comparator tool to measure the case shoulder dimensions on a fired case, actually will measure a whole bunch of fired cases to know where the consistent, average dimension of fired brass is. I use the same process of adjusting the dies a tiny bit at a time to set the target shoulder measurement after sizing, and check the resulting size on multiple cases since there is some variation and springback as mentioned above.
Fine tuning the die to hit your target dimension to .001" is where it gets tricky. I use the Hornady Sure-Loc die lock rings that clamp down with an allen wrench and don't mess up the threads on your dies. Very nice and well worth the $3. Instead of trying to move the die in the press, I use the markings on the die referenced against the lock ring to fine tune the adjustments.
Remove die, loosen lock ring, slightly adjust lock ring to new index point, tighten lock ring, reinstall the die hand tight into the press, size brass and take a measurement, repeat as needed. You get down to the point where you are just moving the lock ring maybe just 1/16" against the index mark on the die to hit that last thousandth.
The positive side is that you only need to do this once. After you set it once you just spin the die on hand tight and it will give you consistent accurate shoulder bump.
I agree completely. I was not referring to those who had responded so far as forum bullies, quite the contrary, the replies so far are giving good advice, I was referring to those who would respond to my reply. I dealt with this successfully forty years ago and we have better tools and methods today.potatoe said:
He asked what might seem like a simple question and got pretty much the same answer from everyone. Even though James has a different approach, who I might add did hold a world record. These are not bullies they are valid proven methods from people who have a car's worth of money in their guns and an angry wife because they spend all their free time shooting/tinkering (well at least mine is) but you can't dive into advanced reloading without a barrage of input and it is very difficult to explain to someone through typing a post how to do these things let alone all the other details that come with it. I think the forum members did a great job of giving some good, basic, foundation building input for this. I know without all the input I received at the beginning from threads like this I would still be shooting .5moa. . .just sayin
Good explanation, it is much harder to describe than do. I would add that the Redding competition shell holders are a good tool to aid in the process that you describe, when you get close you can change out the shell holders rather than adjust the die 1/16.Sheldon N said:JamesnTN said:
You can, it's just a PITA.
Same as others above I use the Hornady headspace comparator tool to measure the case shoulder dimensions on a fired case, actually will measure a whole bunch of fired cases to know where the consistent, average dimension of fired brass is. I use the same process of adjusting the dies a tiny bit at a time to set the target shoulder measurement after sizing, and check the resulting size on multiple cases since there is some variation and springback as mentioned above.
Fine tuning the die to hit your target dimension to .001" is where it gets tricky. I use the Hornady Sure-Loc die lock rings that clamp down with an allen wrench and don't mess up the threads on your dies. Very nice and well worth the $3. Instead of trying to move the die in the press, I use the markings on the die referenced against the lock ring to fine tune the adjustments.
Remove die, loosen lock ring, slightly adjust lock ring to new index point, tighten lock ring, reinstall the die hand tight into the press, size brass and take a measurement, repeat as needed. You get down to the point where you are just moving the lock ring maybe just 1/16" against the index mark on the die to hit that last thousandth.
The positive side is that you only need to do this once. After you set it once you just spin the die on hand tight and it will give you consistent accurate shoulder bump.
I think you can use a neck bushing from a bushing die and improvise an effective bump measuring bushing. See the pic. Note - I have tried it with a 223 which has a relatively short neck. A larger case may have a neck that sticks out the top of the neck bushing. Then you could use two bushings.
I also feel it's important for newbies to use a proper tool for measuring the bump. Feel is a nebulous thing. Numbers on a dial are real.
If you want to try the neck bushing idea you should get a bushing that sits on the shoulder about 1/2 way in from the edge.
ETA- Die shims are the hot tip. Start your initial die adjustment with a .006 shim under the lock ring. Then when you get real close with the lock ring threads you can then leave the lock ring cinched down on the die and use the shims to get you down to the .001 to .002
If you want to try the neck bushing idea you should get a bushing that sits on the shoulder about 1/2 way in from the edge.
ETA- Die shims are the hot tip. Start your initial die adjustment with a .006 shim under the lock ring. Then when you get real close with the lock ring threads you can then leave the lock ring cinched down on the die and use the shims to get you down to the .001 to .002
bobinpa
Gold $$ Contributor
It's not difficult at all once you see it and try it a couple of times. You just have to have patience and the ability to use your tools properly. This video will help you tremendously.
https://www.youtube.com/watch?v=V2Wt8-VqeAE
Keep asking questions, the folks on this forum are a wealth of knowledge.
https://www.youtube.com/watch?v=V2Wt8-VqeAE
Keep asking questions, the folks on this forum are a wealth of knowledge.
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.