For the OLD reloaders (historical Q)

[mikld]

I came up with this question several years ago and did a little reading but forgot to continue the search (another gun came home with me and I got the attention span of a gnat.). I was reading my "Complete Guide to Reloading" by Sharpe and was comparing 30-06 loads to what I use today. I understand all items in the charts except one; bullet seating depth. For example a 150 gr MC bullet is seated ".240". In the section for bullet seating section in the text, Sharpe recommends seating into the "leade" or the bullet into the rifling. So my question is what is meant by a .240" seating depth? Is the base of the 30 cal. bullet only .240" into the case? Is the bullet .240" out of the lands?

I have been successfully reloading for quite a few years and even though this question arose several years ago I've not come up with an answer that seems logical...

[Sixgun]

That a good question to one I never thought of myself. My guess is that it's .240 from the lands as the 150 grain bullet is much shorter than the 220 gr. bullet for which 30-06's also have the room to chamber. Plus, this measurement is a lot easier to take than to measure how much of the bullet that goes into the case.-----6

Wait a minute...that don't make sense. I just looked at my notes from the same book and I saw the same thing. The 44-40 has seating depths of .220 for the 140 gr. bullet and .335 for the 200 gr. bullet...or something close, don't remember the exact numbers so that means that it must be the depth of which the bullet goes into the case which is figured out by measuring the entire bullet and minus the .240 and then leave the rest above the case mouth as 44-40's need to be seated pretty much as close to 1.600 as you can get in order to feed properly.----again-----6

#3......I read on and the 250 gr. In the 44-40 is listed at .357 depth. My "book" is really not a book but is lots of pictures I took from Jack Kort's book two weeks ago at the levergun Jubilee so I cannot read Phil's definition of depth.

You know something...I really don't know. I can make sense out of both ways

[crs]

I probably qualify as an"old reloader" since I began back in the early 1970s.

Looks like it has to do with the cartridge OAL and where/depth the bullet should be seated to just touch the rifling. IIRC, this is a fetish of bench rest accuracy shooters.
https://www.google.com/?gws_rd=ssl#q=bu ... depth+tool

This is something that I have never done for hunting ammo, especially for hot loads using solid bullets.

[Griff]

I probably qualify as an"old reloader" since I began back in the early 1970s.

Looks like it has to do with the cartridge OAL and where/depth the bullet should be seated to just touch the rifling. IIRC, this is a fetish of bench rest accuracy shooters.
https://www.google.com/?gws_rd=ssl#q=bu ... depth+tool

This is something that I have never done for hunting ammo, especially for hot loads using solid bullets.

+1.

[marlinman93]

I've never paid any attention to suggested seating depths or overall length of a loaded round. There's no way somebody can sit behind a typewriter or computer and know what fits and works best in a particular gun.
First off a cartridge has to chamber, so the bullet needs to be deep enough to allow the cartridge to chamber. Second, if the gun has a action or mag well that works the cartridges through it, the overall length needs to be short enough to fit a mag well, or cycle through the action. And finally every gun has a different amount of bullet jump it likes. Some do like a bullet touching the rifling, but others like a few thousandths or more jump from case to rifling, to shoot most accurately.
So if it chambers, cycles, and fits, then it also needs to shoot most accurately. My bullet depth will be determined by all these things, and not a book.

[Grizz]

OK Ok, but it needs to be mentioned that seating a bullet deeper into a case without compensating with the powder quantity or type can lead to busted guns.

I know all you all already know this, but not everyone passing through will know this.

[mikld]

In the chapter about bullet seating Sharpe talks about seating into the rifling; "...as far into the rifling as is possible". In the load data charts the "seating depth" is mostly less than one caliber (for .30 150 gr. bullets the largest measurement is .240, but for a 169 GC it's .375). So, I don't think it deals with depth into the case(?). Plus I've been reloading long enough to understand deep seating vs. pressure and chambering problems vs. buller depth/OAL. Less than one caliber into the case? Distance from lands? Distance into the lands? Certainly not OAL...

In all my manuals the seating depth is referred to as OAL, which is often determined by the bullet manufacturer. My original question was what does the .240 designate (as for a 150 gr. MC bullet in 30-06)?
So, if you know, for sure, please share with us...

[Grizz]

I don't know the answer to Mike's question and I agree that the terminology is less than precise.

This is a Public Service Announcement for those not as involved or beginning to reload ammo.

Here is an example of a Marshall Stanton bullet with two crimp grooves. He lists the seating depth as distance from nose to crimp to eliminate confusion.

seating-depth.png

I load this bullet seated 'out' into the lower crimp groove for my handgun. 444 shooters typically seat the bullet 'deeper' at the upper crimp groove.

This doesn't resolve Mike's question, but I hope it clarifies the opportunity for a careless or inexperienced reloader to blow his gun apart, more or less effortlessly. And that would be either a revolver or rifle chambered for this cartridge, if 'seating depth' is not considered rationally.

[Sixgun]

So, if you know, for sure, please share with us.....

Well, mikld, unless we dig up Phil Sharpe or if a Hornady ballistician stops by we are going to have to live with my juvenile investigation and make our deductions from there. ----6

[Old Savage]

Looks right to me.

[Sixgun]

OS,
YOU ALWAYS MAKE MY DAY!!------6

[Old Savage]

Sending my friend Cat Woman after you. We are looking into getting a DeLorean.

Seriously I think you answered the OP question. Now off to shoot my 1961 Model 94 if that works out.

[Pete44ru]

So my question is what is meant by a .240" seating depth?

Is the base of the 30 cal. bullet only .240" into the case ?

Yes, the seating depth = the length the bullet extends into the case mouth - which may or may not be compatible with seating the same bullet so that the bullet's ogive just kisses the start of the rifling.

The only caveat, AFAIK, when seating bullet far enough out to touch the rifling, is that the cartridge OAL may be too long to feed through a particular repeater's feeding cycle (from magazine to chamber).


.

[JerryB]

Reckon I must have led a sheltered life. I didn't start reloading until late in 1960, all I loaded was a bunch of Unique and 255 gr. lead swc bullets for my Colt SAA .45. I never heard such words and talk till I came here. Oh well

[oldguy]

O.S. cat woman !!!! you renewed my faith.
oldguy

[Old Savage]

Unless you like her better as a pirate. You know, I think they could use you, any experience as a cosplayer? I'll ask her, you would be a perfect Picard.

[Griff]

I might be talked out of a doubloon or two!!!

[Sixgun]

OS,
My goodness, I guess that's what the song "California Girls" is all about.

You California guys must all have to walk around with heavy duty fabric in the front of your pants to act as "suppressors".-----6

[Old Savage]

Six, Griff, oldguy - it is not just her, there is a group if them, you fellows would make fine captives!

[mikld]

Hmmm. Thanks Old Savage, this was a serious question/thread...

[Old Savage]

The question was answered, by Sixgun I think in the only way that made sense.

[mikld]

Sixgun's reply was speculation. (Thnx Sixgun for your post). I always thought a "rule of thumb" for bullet seating was at least one caliber inside the case. The 30-06 data I quoted was .060" less than one caliber. I appreciate all the fellers help,but none have admitted to knowing for sure what those dimensions really meant. I've been reloading for a while and love reading about it, and have only seen this "method" for bullet seating in this one book; Complete Guide to Reloading...

I guess if I had photos of a bevy of beauties I too would post them at any possible chance...

[Old Savage]

Might find this on point. Seems the same concept as Six's post.

http://youtu.be/FYmVy-VhXgM

[Griff]

I came up with this question several years ago and did a little reading but forgot to continue the search (another gun came home with me and I got the attention span of a gnat.). I was reading my "Complete Guide to Reloading" by Sharpe and was comparing 30-06 loads to what I use today. I understand all items in the charts except one; bullet seating depth. For example a 150 gr MC bullet is seated ".240". In the section for bullet seating section in the text, Sharpe recommends seating into the "leade" or the bullet into the rifling. So my question is what is meant by a .240" seating depth? Is the base of the 30 cal. bullet only .240" into the case? Is the bullet .240" out of the lands?

I have been successfully reloading for quite a few years and even though this question arose several years ago I've not come up with an answer that seems logical...

Unless stated otherwise, seating depth is the depth the base of the bullet is inserted into the neck of the case. If you'll look at the reloading manuals that give seating depths, you should note that nearly all are loaded to the same OAL. This is to provide functioning thru repeaters. What bench rest or single loaders do should not affect what is generally accepted practice. If the book you have is for a specific discipline, (say Schuetzen), then the definition of terms may vary from industry standard.

You'll find that the heavier bullets are seated deeper into the case to obtain that functioning overall length. And due to the reduced capacity in the case, powder is reduced to maintain safe pressures.

If I'm wrong, I've been wrong for over 40 years, and have taught other reloaders incorrect theory also... However, I don't think so! Check with Terry Murbach, I'm sure he's forgotten more than I've ever learned, but I doubt this is one of those things!

Edited: !@##$%%$# autocorrect!

[mikld]

Thanks Griff. I "suspected" that was/is the case but didn't feel 100% about it (.240" into the case for a .30 cal bullet seems pretty shallow to me). BTW the times I've seen this seating depth method stated, no OAL was listed, but Sharpe did mention a caveat that all the rounds had to fit the magazine ...

[Griff]

Thanks Griff. I "suspected" that was/is the case but didn't feel 100% about it (.240" into the case for a .30 cal bullet seems pretty shallow to me). BTW the times I've seen this seating depth method stated, no OAL was listed, but Sharpe did mention a caveat that all the rounds had to fit the magazine ...

Aye, I think that .240" is sorta shallow also, as far as .30-06 150gr pills, I'm only familiar with that basic round Sixgun pictured above... er, below:


But... on the other hand, 240" or .256", basically, isn't too awful noteworthy of a difference, differences in ogive can account for such a difference. Or, the difference between the top or bottom of the crimp groove.

[JohndeFresno]

(...yup. Asked and answered. Shoulda read all posts...)

[Sixgun]

Forget it...your beating a dead horse. O.S.'s pictures are the highlight. I think there are some incognito H lovers here----6