Bullet seating depth... seems to far out?!

[Brit Guy]

I have just taken to reloading for my T3 22-250, and after reading about how it is best to seat the bullet out so it is just “kissing” the rifling, I thought I would give it a go. I did this by firstly sizing a case and then putting together a dummy round (no primer or powder) which I fed into the rifle, carefully closing the bolt, then extracting the round. This gave me the “touching the rifling” depth, then I though to wind down the die (bullet seating plunger) a couple of thou.
Anyway, I was shocked to find that the bullet (measuring at the ogive using the seating micrometer of the Forster bench rest die) is 145 thousandths of an inch further out than commercial rounds! In fact it protrudes so far out of the case that it only has about just over an eighth of and inch in the case neck. I did it again with another round just to check to see if I had made a mistake, like partially pulling out the bullet when extracting the round etc… but I hadn’t, the second one was exactly the same!

Not having done this before, I don’t know what to expect, by which I mean is this normal? It seems that there is only about 5mm of the bullet actually pushed into the neck of the case, and it looks quite wrong somehow.

I realise that commercial ammo has tolerances which allow it to be used in any gun, hence a long jump to the rifling, but 145 thou seems a heck of a difference to me.


Any advice welcomed please.

[Grumulkin]

There are several things to consider in bullet seating depth:

1.  The round needs to be short enough to feed through the magazine.
2.  Enough of the bullet needs to be in the neck of the case to hold it firmly (usually at least half a bore diameter in depth).
3.  Seated so it's close to the lands but numbers 1 & 2 take preference.  Some guns, such as Weatherbys have so much free bore that you'll never be able to get the bullet close to the lands.  Some bullets (Barnes) shoot better if they're loaded a bit off the lands.

Of course, seating depth can make a difference in pressure for at least 2 reason.  If the bullet is actually engaging the lands, pressure can be excessive.  Seating depth also affects case volume but in rifle cases the size of 30/30, 22-250, etc. a little difference in depth one way or the other usually doesn't make a significant difference in pressure.

[Brit Guy]

There are several things to consider in bullet seating depth:

1.  The round needs to be short enough to feed through the magazine.
2.  Enough of the bullet needs to be in the neck of the case to hold it firmly (usually at least half a bore diameter in depth).
3.  Seated so it's close to the lands but numbers 1 & 2 take preference.  Some guns, such as Weatherbys have so much free bore that you'll never be able to get the bullet close to the lands.  Some bullets (Barnes) shoot better if they're loaded a bit off the lands.

Of course, seating depth can make a difference in pressure for at least 2 reason.  If the bullet is actually engaging the lands, pressure can be excessive.  Seating depth also affects case volume but in rifle cases the size of 30/30, 22-250, etc. a little difference in depth one way or the other usually doesn't make a significant difference in pressure.

Thanks for the info. There is plenty of room in the mag, the round feeds in okay. There is more about 6mm in the neck so I suppose its okay (going on rule 2)… I guess it just seemed strange to me to see that length of projection of bullet.
I haven’t loaded any yet, and I will back off on the powder in the test loads, as I realize that if the bullet is touching the lands, it has a slightly slower start (hence higher pressures), but thanks for mentioning it anyway.
So do you think that I have a “normal” amount of free bore? Or does it seem excessive to you?

[Graybeard]

So do you think that I have a “normal” amount of free bore? Or does it seem excessive to you?

Yeah I think that's pretty normal for factory mass produced rifles these days. They seem to make them with plenty of free bore to lower pressures a bit knowing that way too many reloaders push the envelope badly.

I've really never been much of one to try to seat out to touch the rifling with my guns really. I like to begin with the base of bullet seated about even with the point where the case neck begins to flare to the shoulder. Only after I've decided on a powder charge that gives me best accuracy with that seating depth do I mess around a bit with seating depth to see if I can improve accuracy. Most times I find a load that's plenty accurate for my personal needs with that seating and don't even bother messing with seating depth but at times I do alter it a bit. I seldom spend my time working toward the ULTIMATE most accurate load that can be found but rather accept one that meets my needs and then spend the time shooting rather than experimenting. I guess I really am a lazy sort.

[beemanbeme]

This "kissing the lands" is a bench rest loading technique that should be approached with circumspection in the real world.  Bench rest rifles are usually chambered and throated for a specific bullet, not a generic chamber like you find in commercial rifles.  Additionally, bench rest ammo is usually loaded on site at the match and is loaded into the rifle single fire.  Not carried about in a magazine or ammo wallet or pocket.  What you have is another case of hunters taking a single facet of bench shooting techniques and making a doxology of it.  
The rule of thumb for bullet seating is the bullet should seat at least one calibre into the neck.  I would suggest that you load and develop a accurate load using the book values of length, disregarding your bullet jump. I assume you will be neck sizing your cases only.  Once you've developed your best loading, then try lengthing the COL a bit and see if it gains you anything.  As posted, I certainly wouldn't go below a half calibre if that.

[Brit Guy]

This "kissing the lands" is a bench rest loading technique that should be approached with circumspection in the real world.  Bench rest rifles are usually chambered and throated for a specific bullet, not a generic chamber like you find in commercial rifles.  Additionally, bench rest ammo is usually loaded on site at the match and is loaded into the rifle single fire.  Not carried about in a magazine or ammo wallet or pocket.  What you have is another case of hunters taking a single facet of bench shooting techniques and making a doxology of it. 
The rule of thumb for bullet seating is the bullet should seat at least one calibre into the neck.  I would suggest that you load and develop a accurate load using the book values of length, disregarding your bullet jump. I assume you will be neck sizing your cases only.  Once you've developed your best loading, then try lengthing the COL a bit and see if it gains you anything.  As posted, I certainly wouldn't go below a half calibre if that.

I take your point, however I'm not really trying to take a bench shooting technique for hunting as such, but just to improve my hand loads as much as i can without resorting to extremes I thought that it really wouldnt take me any longer to seat to the most effective depth (as far as accuracy) than it would to just bang them together any old how (how i do my pistol rounds i'm ashamed to say )...

The reason behind this is because after shooting two of my mates guns and seeing what good handloads can do (same make/model of rifle), i just wanted to try to improve my accuracy in my rifle.

 

[Grumulkin]

The kissing the lands thing is a bench rest technique but I'm willing to apply bench rest techniques to make my guns shoot better.

That said, if the gun is well made with the chamber, throat and barrel lined up in a precise fashion, the gun should shoot well whether or not the bullet is kissing the lands.

[Davemuzz]

When I was trying a bunch of different powder\bullet combinations for my .223, I set my seating depth at the SAMMI max. When I came across the combination of BL-C2 and a 40gr Nosler BT, this combo was shooting 5 shot groups that could be covered by a dime at 100 yards. Now, Nosler recommends setting their bullets 20 to 50 thousands off the lands, and I do this with their bullets in other calibers. But honestly, with my .223 I couldn't tell you what the free bore is. If I could get a tighter group than this, those groundhogs that I whack at 350 yards probably wouldn't care anyway!

Dave

[Catfish]

   Recently I have been playing with a .22-6mm and have found alot of very interesting things. With some load it shoots best with the bullet seated hard into the lands, you can fell it when closing the bolt, these very lite loads if that makes a differences. With other loads it is more accurate backed off the lands.
   If you do seat your bullets into the lands the presure will will raise alot faster so you will need to start below the stated starting load. I never load ammo as short as SAMMI specs., because I have found that in all of the rifles I have worked up a load for longer loading has improved. That does not mean that all ammo is close to the lands as some was very accurate .050 off the lands and some even farther. The main thing to rember about accuracy is that it has to be good enough for it`s intended perpous and not alot better. What I mean by that is that if your hunting deer with a .30-30 and all shot will be less than 100 yrds. you really do not need a rifle that will group sub. MOA.

[Davemuzz]

    I never load ammo as short as SAMMI specs.,

I read this section of your post, then I re-read my post. I thought some clarification of my post was needed, and some comment on your statement was also warranted. 

To clarify my post, what my statement should have said was "I always start out a new load in accordance with the bullet manufacturer's instructions on OAL." I usually start with Hornady bullets, and accordingly, I will seat the bullet at the SAMI maximum, shoot these with different powders and different powder amounts, and see how they pattern. Then, if the groups are not satisfactory, I will look to adjust the OAL and see what that does. If that is not satisfactory, I will then move to a new bullet, and start the process all over. Yes, it is time consuming...and can be a bit tedious.....so if your in a hurry....you probably should just buy factory loads.

So, (with the above clarification)  that's how I ended up with a Nosler bullet loaded at SAMI max spec's. The SAMI spec's were gleaned from the Hornady .223 load data, and the chamber space for the Nosler bullets was never determined. (However, I do have that data written in the Hornady book for the Hornady bullets).
 
Now, as far as Catfish's comment on "never" loading rounds to SAMI OAL spec's, that may be all well and good for an experienced reloader. And that being a guy who has many years "under his belt" of reloading and shooting. But for me, I've been doing this for about 4 years now, and I don't believe I have enough experience to just start out beyond the manufacturer's guidance. But, that may just be me.

Dave