I'm lost. I need some advice. I am setting up 300 Win Mag dies. Following everyone's advice and one of the member's instructions I set the sizer/decapper without issue. The bolt closes with slight pressure.

Its the bullet seating aspect of this that has me thrown. I am trying to determine my chamber OAL without a Stoney Point by using a deprimed case and seating a 180 grain Sierra GameKing BT bullet. After setting up the die per what I thought were the instructions the first two cases folded at the shoulder when I was trying to just barely seat the bullet. I backed off the die until on the third try the bullet seated with the bullet seating stem all the way out. The case/bullet combination not only fit in the magazine, but chambered in the gun at OAL of 3.500. I was unable to determine if this is my chamber length with bullet against lands/grooves? Is this combination off the lands and grooves and how much, etc.? I don't find a mark on the bullet so gather it is off the lands and grooves, but unsure how much.

Secondly, Sierra lists the OAL to be 3.340 with this bullet. At 3.5 we are talking .16 difference. Does that seem like a lot of difference in freebore/throat? The barrel is a factory barrel

Third, I went to check all of my measurements. Different books list a bit different dimensions. In my Barnes book I note a case neck diameter of .335 and in my Sierra book it shows .340. My case neck diameter with a Sierra bullet is .335. Is this too much? Do I need adjust the die? And won't this affect case neck tension and pressures? Or am I just too worried and being anal?

RenegadeRN

If you folded the shoulder my guess is you had too much tension on the bullet. Take a fired case and bend the neck in a little to allow the bullet to still slide.

It is not unusual for a factory chamber to have the neck so far forward that you can't reach it and still fit the magazine. A factory chamber and factory brass you should not have a neck issue.

quote:

Originally posted by RenegadeRN:
Secondly, Sierra lists the OAL to be 3.340 with this bullet. At 3.5 we are talking .16 difference. Does that seem like a lot of difference in freebore/throat? The barrel is a factory barrel

No, that is quite normal. Chambers come in all sizes - including the throat dimensions. The Sierra OACL number is meant to be guaranteed to fit all rifles (SAAMI minimum). Most (factory) rifle chambers are quite a bit more sloppy than that. That is part of the advantage of reloading, you can tailor your rounds to the chamber at hand - within reason naturally.

Whether it is a good thing that your chamber has a longer throat than the spec says depends. If you can still seat bullets sensibly in the case neck when close to the lands, and if this seating depth allows the rounds to work through your magazine, you will just have won a bit of powder space. It is your choice whether you use that space to stay on the safe side of pressures, or whether you try to utilize the extra room for just a bit more powder and speed - all done safely and with great care.

- mike

quote:

Originally posted by RenegadeRN:
Third, I went to check all of my measurements. Different books list a bit different dimensions. In my Barnes book I note a case neck diameter of .335 and in my Sierra book it shows .340. My case neck diameter with a Sierra bullet is .335. Is this too much? Do I need adjust the die? And won't this affect case neck tension and pressures? Or am I just too worried and being anal?

RenegadeRN

Are you talking about the neck diameter of the loaded round here?? If yes, and if you are getting any bullet grip at all, then you can't influence loaded neck diameter with your dies. The difference in numbers will come from brass made by different manufacturers - or even in different batches.

Different brass will have different neck wall dimensions. With 99.999% certainty, this will be of little consequence in a (sloppy) factory chamber. The (large) inside chamber neck diameter will allow the brass to expand properly and release the bullet without producing undue pressure.

However, if this had been a custom chamber cut with a (semi) tight neck, you would have to worry about what loaded round neck dimension your chamber was cut for. If too large, you'd have to turn case necks.

- mike

Hey RenegadeRN

Are you using a Lee Seater? I have had 2 Lee Seaters that came in a combo deal that would not act right and had to get another kind. The thing you have to remember with the seater dies is that there are 2 adjustments. You can raise the die up and down by threading the whole die in farther and then you can adjust the seating stem itself.

It sounds like you need to back the whole die out further and that will allow you to screw the seating stem in farther.

The easiest way to find where you bullet will hit the lands if you don't have a Stoney Point is to use a one piece cleaning rod or 1/4" wooden dowel.

1. Make sure your gun is cocked so the firing pin is out of the way
2. Close the bolt and insert the cleaning rod/dowel in the muzzle down to the bolt face
3. Mark the cleaning rod/dowel as precisely as you can at the muzzle
4. Remove the rod, remove the bolt and hold the rifle muzzle down
5. Lightly drop a bullet into the chamber, lightly hold the bullet against the lands with a pencil eraser or something
6. Level the rifle and carefully insert the rod back in the muzzle and lightly push it down until it touches the end of the bullet
7. Mark the cleaning rod/dowel as precisely as you can at the muzzle
8. Measure between the marks, that is the COAL from the case head to the bullet tip.

Now do it 3 more times and if any 2 of the measurements turn out the same then you're pretty good. However they should be close and allow you to guess at how deep to seat the bullet.

After seating a bullet, measure the COAL and then carefully chamber it, eject it and check the measurement to see if the bullet hit the lands and was seated further.

I would recommend subtracting about .020" to .030" from the COAL when hitting the lands to get your COAL of your finished load.

mho is right about the .340"/.335" thing. The books vary because that measurement will depend upon how thick the neck brass is of the load they tested. Essentially the bullet diameter should be .308", if you subtract .335"-.308"=.027" which is what the neck brass thickness added. You divide that by 2 to get the actual neck thickness of either side and it would be .0135" which is entirely normal. Brass neck thickness usually runs from .012" to .015". This measurement will not matter unless you have a custom chamber with a narrow neck. For instance I have a 280AI Hart barrel that is stamped .313" neck. .313"-.284"(caliber)=.029" then .029"/2=.0145". That is a pretty tight neck and tells me that I can not use brass thicker than that .0145".

Normally, you want .0015" to .002" clearance on either side so I neck turn the neck brass thickness to .0125". .0125"(neck brass)+.0125"+.002"(clearance)+.002"+.284"(caliber)=.313"

You can measure the outside dimension of the neck on a fired case and see what the dimension of you neck is. Factory chamber it will probably be .342" or so. So in your case .342"-.335"=.007" then .007" divided by 2 is .0035" clearance between your loaded round outside neck and the chamber neck walls.

If you can seat the bullet at all then you will not have too much grip on the bullet. The pressure of the powder burning will have no problem pushing the bullet out of the neck, just like mho said.

What mho said is dead on, I am just adding details so you can understand fully.

That seating thing is worrisome, but just take your time and you will get it worked out. If you have a Lee seater then it will be harder. If you have an RCBS seater make sure you are far enough out so you don't crimp.

All these years I've been doing it wrong? I simply chambered a loaded round with no crimp and the bullet just barely started in the case. Take the "chamber seared" round out of the gun and put it in the bullet seating die (screwed way out), run the press fully up, and then screw the seater down to touch the bullet. Lower the ram and screw the seater down another 1/2 turn and that's my starting point. Comments PLEASE!

quote:

Originally posted by MikeMichalski:
All these years I've been doing it wrong? I simply chambered a loaded round with no crimp and the bullet just barely started in the case. Take the "chamber seared" round out of the gun and put it in the bullet seating die (screwed way out), run the press fully up, and then screw the seater down to touch the bullet. Lower the ram and screw the seater down another 1/2 turn and that's my starting point. Comments PLEASE!

Questions before comments

Do you have any way of determining if the lands grabbed your bullet and pulled it part way out? A lot of time bullets will pull out if jammed into the lands and fill your chamber full of powder.

Do you have any way of determining how far into the lands you jammed the bullet? I have seen some bullets get jammed as much as .02".

I'm guessing and it will depend upon the seating die, but 1/2 turn could seat the bullet another .05" or so. Is that how far you want to seat off the lands?

Certainly, if seating depth is not all that important then your method will work to get close enough for government work.

First. thanks to everyone for their input. It's really helped me get a handle on this. Now that I've adjusted for chamber OAL, seen the dies and inspected them, crushed a few shoulders, crimped a few bullets where I didn't need a crimp, and basically played...along with adjusting the dies per instructions it makes a WHOLE LOT more sense.

Of course there has to be at least one more question. I've followed everyone's intructions, including the manufacturers. After sizing the case and on a deprimed case I lightly seat the bullet. I smoke/magic marker the bullet and chamber the round. The chamber OAL is from those land and groove marks on the bullet to the rim. To ensure proper case and bullet OAL for my chamber FOR ALL bullets I use that measurement from the case rim to those land and groove marks and set the bullet seating stem accordingly. Is that about right? This way I don't have to redo the whole process again for each bullet.

Thanks.

quote:

Originally posted by RenegadeRN:

Of course there has to be at least one more question. I've followed everyone's intructions, including the manufacturers. After sizing the case and on a deprimed case I lightly seat the bullet. I smoke/magic marker the bullet and chamber the round. The chamber OAL is from those land and groove marks on the bullet to the rim. To ensure proper case and bullet OAL for my chamber FOR ALL bullets I use that measurement from the case rim to those land and groove marks and set the bullet seating stem accordingly. Is that about right? This way I don't have to redo the whole process again for each bullet.

Not exactly,

Those land marks are at the point of the bullet where it first reaches caliber diameter and is called the bullet ogive. You need to measure from the case head rim to the end of the bullet and that will be your OAL for that type of bullet only.

Then you can seat the bullets by duplicating the OAL during the seating process. You will have no way of measuring the distance to the ogive during the seating process (unless you have a set of comparators).

The OAL measurement will change for each type of bullet because they all have different shapes and the distance between the ogive and the meplat (bullet tip) varies. An extreme example would be a round nose bullet and a ballistic tip bullet. The distance between the ogive and the meplat on those 2 different type bullets is a lot.

Theoretically, the distance from the case head to the bullet ogive (comparator length) should always remain the same. But like I said you would have no way of duplicating that on an unmarked bullet without the comparators.

Woods

quote:

Do you have any way of determining if the lands grabbed your bullet and pulled it part way out? Not really.
A lot of time bullets will pull out if jammed into the lands and fill your chamber full of powder. That would be self evident but it has never happened to me.

Do you have any way of determining how far into the lands you jammed the bullet? No, good point.

I have seen some bullets get jammed as much as .02".

I'm guessing and it will depend upon the seating die, but 1/2 turn could seat the bullet another .05" or so. Is that how far you want to seat off the lands? No, just a starting point.

Certainly, if seating depth is not all that important then your method will work to get close enough for government work.

It is important and this is just my way of finding a starting point but I'm open to learning more.

Thanks for your advise (now or in the future)