Met a serious benchrest fanatic at the range last trip out and he was explaining to me how to get the right seating depth by resizing the neck on an empty case,starting a bullet into it,then forcing the bolt all the way forward to find the lands. He said then to back off my seating die from there by about .005-.010 and that would give me a good starting point. I did just as he told me and the result was a coal of .162 longer than the book says!!! Did I eat a big spoon-full,or can that actually be possible? Sure looks to be a long way out there. I've been very slowly creeping the bullet forward by just .005 or so at a time trying to find a more accurate round. My rifle is a factory 22-250 Ruger M77 w/bull barrel,and my die set is just an off-the-shelf RCBS 2-die that I've just been using to resize the neck,not even kissing the shoulder. Winchester cases very carefully trimmed after each firing.
Seating depth question.
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MtnCreek
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The factory barrel probably has a good bit of free bore before the rifling starts and you're probably using 55 gr or less weight bullets; I don't think you're going to be able to load yours that way.
I don't benchrest, but I'm sure those guys are using heavy for caliber projectiles (long) and aftermarket barrels.
I don't benchrest, but I'm sure those guys are using heavy for caliber projectiles (long) and aftermarket barrels.
243winxb
Member
The COAL listed in reloading manuals is simply the overall length that they used in their load development. It is not written in stone.
Don
That will work just fine. Loading longer won't hurt a thing unless you are jammed into the lands, and even then as long as you start low you will be OK.
That method can work, but it depends on neck tension and how hard the lands grip the bullet after jamming it into them. It can sometimes pull the bullet forward as you extract it, giving a false reading.
That method can work, but it depends on neck tension and how hard the lands grip the bullet after jamming it into them. It can sometimes pull the bullet forward as you extract it, giving a false reading.
OP was advised...
The Bullet (if the neck tension can hold it) will be jammed into the lands by an indeterminate amount.
And if the neck can't hold it, the bullet will be pulled (somewhat) from the case upon extraction.
Either condition will give you false readings.
Barring availability of a Stoney Point gauge to do it "right," the best technique one mentioned the other day:
1. Close the bolt and run a cleaning rod down the muzzle until it contacts the bolt face and mark the position at the muzzle (razor blade works). Remove rod
2. Insert bullet (only) into chamber and hold it very gently up against the beginning of the lands using a dowel or a second cleaning rod.
3. Run the first (previously marked) cleaning rod down the muzzle until it contacts the bullet (make sure any hole in the rod tip is plugged so the surface is flat). Mark the rod again. (You might do step 3 again for a few different bullets from the same box to get an "average mark")
The distance between the marks (with/without bullet) is the "cartridge distance to lands" overall length. Reduce that by 0.030" (paper clip diameter) for a starting point for load development.
No.
The Bullet (if the neck tension can hold it) will be jammed into the lands by an indeterminate amount.
And if the neck can't hold it, the bullet will be pulled (somewhat) from the case upon extraction.
Either condition will give you false readings.
Barring availability of a Stoney Point gauge to do it "right," the best technique one mentioned the other day:
1. Close the bolt and run a cleaning rod down the muzzle until it contacts the bolt face and mark the position at the muzzle (razor blade works). Remove rod
2. Insert bullet (only) into chamber and hold it very gently up against the beginning of the lands using a dowel or a second cleaning rod.
3. Run the first (previously marked) cleaning rod down the muzzle until it contacts the bullet (make sure any hole in the rod tip is plugged so the surface is flat). Mark the rod again. (You might do step 3 again for a few different bullets from the same box to get an "average mark")
The distance between the marks (with/without bullet) is the "cartridge distance to lands" overall length. Reduce that by 0.030" (paper clip diameter) for a starting point for load development.
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I use a simular method to obtain the longest functional OAL obtainable. But I would personally think that by resizing the neck fully would create to much neck tension to accurately identify when you are at the lands, rather than jammed into the lands. I barely size the neck just enough to hold the bullet with light neck tension, and I also smoke the bullet or use a magic marker so I can see that it has contacted the lands. I've loaded a few that were slightly into the lands and all went well. But I think it's a matter of determining how much into the lands is going to produce the best results by not create a negative effect, such as increasing pressures significantly, or effecting accuracy. This kind of reminds me of a guy I saw on You Tube who had apparently just started reloading and it was for the .50 cal. BMG. His rounds were really long, so much so he had to use a hammer to close the bolt on each one. The result was after a few uneventful chamberings, he hit the bolt with the hammer and the round detonated and blew his gun and him up!
As Walkalong said, as long as you start low and work your powder charge up, you'll be OK. Oh, and don't try to force the action closed with a hammer or other means that involves impacting the bolt.
As Walkalong said, as long as you start low and work your powder charge up, you'll be OK. Oh, and don't try to force the action closed with a hammer or other means that involves impacting the bolt.
A couple of you mentioned the bullet possibly being dragged out of the case a bit. Now I recall him saying something about using a wooden dowel to tap the round out. Maybe that's what he was trying to say. I should carry an audio recorder with me...I had about 5 minutes with him and about 500 questions. There was a benchrest competition there 2 days later that he said many BR shooters would eagerly share their knowledge,but,sadly,I had to be elsewhere...and my mentor is out of town for quite some time. The guy also said he saw signs of too heavy of a load,but I was on the very low end of what the book calls for. Can I expect lower pressures with the bullet way out ahead of where it has been,using the same powder data? I'll try the procedure again and watch closely for things that may have thrown my results off. I just thought .162 longer seemed out of line. Thanks for your comments and suggestions everyone.
Uh, no. That's backwards. Screw the seating die down an additional amount. Well, some benchrest shooters seat the bullet into the rifling, but traditionally you seat the bullet a little bit shorter to keep it off the rifling plus a little room for error.
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If I want to know the distance to the lands and not have information for a specific bullet I use the rod technique with a cartridge but put the bullet in backwards. Boat tails work well for this because the taper is much greater than the gradual taper of the ogive.
243winxb
Member
Finding The Maximum COL
As you remove the dummy round from the action, place your finger on the case to keep the ejector from pushing the bullet into the side of the action. You may get different measurements, you will need to do it till you get 3 that measure the same COL.
A Bench Rest shooter is using bushing dies and very little neck tension. Don't size the neck with your RCBS dies, just pinch it with plyers so the neck is a tiny bit oval. Just so the bullet will not fall out of the case.
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How to determine the maximum overall length for the chamber: WHY? Because if a reloader is going to seat 'off the lands he/she must know where it is located in reference to the bolt face I do appreciate the bench raster taking the time, in my opinion he was not much help, but the next group of helpers will have you shredding the neck, again for what reason? I do not know, that is because I want to transfer the maximum overall length of the case from the chamber, to the seater die and then back to the chamber as I said that is most difficult with a case that looks like a squid, so, I use bullet hold, that is determined by the ability of the case neck to hold a bullet, a case with good bullet hold is a case that makes a good transfer for setting up the seater die, a hose clamp around the shredded case neck could improve bullet hold but will it fit into the seater die????
I drill the flash hole/primer pocket, some insist on using a .250 (1/4") drill bit, I reach for the .375 (3/8") drill first (depending on the diameter of the case head). Then it is a matter of removing the bolt, chambering the test case then with a cleaning rod, I push the bullet out of the case and into the chamber, when the bullet stops I remove the cleaning rod, remove the test case THEN install the test case in the shell holder, back off the die and seater plug then raise the ram, after raising the ram I adjust the die top the test case, and that is how I transfer the dimensions of the chamber to the seater die.
After transferring the measurements to the press I measure the height of the seater stem with a height gage and that measurement (.000) is off the lands, when seating off the lands I use a height gage or dial caliper to measure adjustment of the seater stem, lowering the stem .040 thousands would be .040 thousands off the lands.
After a reloader has found the distance from the bolt face to the lands and if the reloader saves the transfer or information gained it should not be necessary to continue making transfers, unless they are resistance to change.
F. Guffey
I drill the flash hole/primer pocket, some insist on using a .250 (1/4") drill bit, I reach for the .375 (3/8") drill first (depending on the diameter of the case head). Then it is a matter of removing the bolt, chambering the test case then with a cleaning rod, I push the bullet out of the case and into the chamber, when the bullet stops I remove the cleaning rod, remove the test case THEN install the test case in the shell holder, back off the die and seater plug then raise the ram, after raising the ram I adjust the die top the test case, and that is how I transfer the dimensions of the chamber to the seater die.
After transferring the measurements to the press I measure the height of the seater stem with a height gage and that measurement (.000) is off the lands, when seating off the lands I use a height gage or dial caliper to measure adjustment of the seater stem, lowering the stem .040 thousands would be .040 thousands off the lands.
After a reloader has found the distance from the bolt face to the lands and if the reloader saves the transfer or information gained it should not be necessary to continue making transfers, unless they are resistance to change.
F. Guffey
And all of my seater dies are micro adjust regardless of the threads, again I use height gages, that includes the dial caliper, it is mindless to adjust the seater plug stem, lower the ram, remove the case from the shell holder, measure then start over with another wild guesstimate of a turn, again, I am a big fan of the transfer, I can transfer a measurement from my dial caliper to the seater stem, I am also a fan of verifying.
F. Guffey
F. Guffey
I do that, but at the same time I do "shread the neck" of a case I dont use. I cut it in a couple of places to make sure there is very little neck tension and then slide the bullet in (can seat it easily by hand) and chamber it. Then I push the bullet back out from the muzzle. 1/4 to 1/2 inch turn of the seating die from that measurement is where I start when I don't have a good starting load (IF I have a load from the factory that works well, I start with that length). I also don't shoot well enough to be a bench shooter.
All of these methods will give you the max COAL. But that's not necessarily what you want to use.
First, for some rifles, the freebore is so long that your bullet might barely be in the mouth of the case. Sometimes it's not even possible to seat to the lands at all, the bullet is not even in the case. You want the bullet seated at least one bullet-caliber deep into the neck of the case.
Second, you might find that the seating depth required to put the bullet up against the lands makes the cartridge too long to fit into the magazine. Fine for target shooting, maybe not so ideal when hunting rhinos.
Finally, there is no guarantee that seating to the lands, or 0.015" away is the most accurate seating depth. It might be. But it might be 0.050" or 0.100" or 0.136" for all you know.
But it is a handy reference point and a good thing to know. Once you know the COAL max length, you can start there and shorten it up in increments of 0.015" or so until you find the accuracy node for that rifle, bullet, powder weight.
First, for some rifles, the freebore is so long that your bullet might barely be in the mouth of the case. Sometimes it's not even possible to seat to the lands at all, the bullet is not even in the case. You want the bullet seated at least one bullet-caliber deep into the neck of the case.
Second, you might find that the seating depth required to put the bullet up against the lands makes the cartridge too long to fit into the magazine. Fine for target shooting, maybe not so ideal when hunting rhinos.
Finally, there is no guarantee that seating to the lands, or 0.015" away is the most accurate seating depth. It might be. But it might be 0.050" or 0.100" or 0.136" for all you know.
But it is a handy reference point and a good thing to know. Once you know the COAL max length, you can start there and shorten it up in increments of 0.015" or so until you find the accuracy node for that rifle, bullet, powder weight.
A method I stubbled onto recently is using teflon tape wraped around the bullet so to give it enough neck tesion, and not so much that it lets it jam into the lands.
I'll have to try the teflon tape. I have used masking tape and electrical tape before to do the same thing. They are both just a tad too thick for a lot of the cases.
I had my gunsmith measure the barrel and he said a good starting point would be .080 longer than what I've been seating them. Try some rounds to check for accuracy,then push it out a little bit at a time until I get the most accurate oal. The lands were well beyond that and,since it's a 22-250 with about 1400 rounds through it,moving out all the time. Make sense?
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