Is there any point of adjusting seating depth if I use a Hornady OAL gauge?

[Point_Taken]

I was thinking about the necessity of adjusting seating depth across a broad range of depths and if there is any point if I'm using a fire formed case with a Hornady OAL gauge. If I get an exact measurement for a CBTO after putting the case in the chamber and that gives me my "max" CBTO, is there any point to trying different seating depths with a small CBTO? With the exception of a couple of bullets/powder/caliber combinations that "like" to be seated about .001"-.002" behind the lands, is there any point going beyond something like that?

 

[AJC1]

There seems to be some critical missing information. Are we talking gas or bolt gun. Why would you ever seat a bullet for .001-.002 jump. Most skip that area and seat .005 jump or .005 in to prevent variation contact. What do you consider a small cbot range and what caliber are we talking about. Are you shooting solid ever or just cup and core. Your question seems way to veg for a decent answer.

 

[mdi]

I'm jes ignert, what's CBTO?

 

[AJC1]

I'm jes ignert, what's CBTO?

Case base to ojive

 

[Point_Taken]

I'm shooting 6mm Creedmore out of my Ruger Precision Rifle. I'm using Lapua Brass w/ Berger 105g Hybrid bullets.

 

[AJC1]

So I don't shoot that combination but I believe that it has a long bullet shank like the 6mmbr and you should be able to run the Berger vld seating test to find out what the optimal seating depth is. If you already getting good results it may not be necessary

 

[TonyAngel]

I only used my coal gauge to know what i was working with. Some setups like a little jump. Some like to be kissing and some like to be jammed.

Seating depth is just one if those things you need to play with.

 

[Walkalong]

CBTO after putting the case in the chamber and that gives me my "max" CBTO, is there any point to trying different seating depths with a small CBTO? With the exception of a couple of bullets/powder/caliber combinations that "like" to be seated about .001"-.002" behind the lands,

It is very difficult to hold that close in real life, I would not try anything less than a .005 change when testing.

If you load into the lands you risk leaving a bullet in the bore and powder in your action if you have to eject an unfired round. I saw a guy have his rifle put out of service from this in a match last Saturday. I asked him "Are you loading into the lands?". He kind of grinned and said, "It's not supposed to be".

Fortunately with some help from the MPA trailer he was able to get it back in service.

 

[Ruger 15151]

It depends on the bullet and barrel. Some like a lot of jump and others like to be seated into the lands. If you try to develop a load that is right up to the lands, you will be constantly changing that load as your lands erode. To avoid this, some competitive shooters will actually load their bullets very long with very little neck tension and then soft seat the bullet as they close the bolt to ensure the bullet is seated into the lands. As Walkalong stated, there can be issues if you need to eject a round before shooting it because the bullet may stay in the lands, which means powder is going to be dumped in your action.

However, changing bullet seating depths can be an effective way to tighten groups and optimize accuracy. Here are some articles from Berger's website that explains how to do this:

https://bergerbullets.com/setting-loads-optimum-accuracy/

https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

Here are a few others that you might like as well:

https://precisionrifleblog.com/2020...4hTRrT_PmM8ytbl2Q7B4eSp9AjxxxX8m-U_gUuXUsqxyo

https://precisionrifleblog.com/2020/03/24/how-fast-does-a-barrel-wear/

You will find lots of information about 6mm long range shooting on the PrecisionRifleBlog.

Good Luck!

 

[Laphroaig]

It's become handloading lore that closer to the lands is always most accurate. I don't think that that always is the case, and as others have said near-touching comes with its own set of problems. I'd recommend doing some testing with different seating depths to see if it actually matters for your setup.

 

[Point_Taken]

What would you guys say is the maximum distance away from the lands, if such a thing exists? Like anything .005" away, .010" away and any more than that is pointless for example. Or does such a thing not exist?

 

[Walkalong]

My .222 Mag like Hornady soft points at .040 of the lands. More jump is ok with some bullets/guns. The only thing I ever loaded into the lands for was my 6PPC Benchrest gun. (That and fire forming loads)

 

[Ruger 15151]

What would you guys say is the maximum distance away from the lands, if such a thing exists? Like anything .005" away, .010" away and any more than that is pointless for example. Or does such a thing not exist?

One of the Berger links I provided explains this.

 

[AJC1]

What would you guys say is the maximum distance away from the lands, if such a thing exists? Like anything .005" away, .010" away and any more than that is pointless for example. Or does such a thing not exist?

Max I have seen is .120 on a new rifle but if your ever shooting military surplus arms it may be higher than that. The norm for monos are .050

 

[climbnjump]

I'm shooting 6mm Creedmore out of my Ruger Precision Rifle. I'm using Lapua Brass w/ Berger 105g Hybrid bullets.

Well obviously, my rifle is not your rifle, but I was shooting those bullets out of my RPR in .243 Win and found best accuracy .032" off the lands. The idea behind the hybrid design is, of course, that it is not as sensitive to seating depth variations as the VLD design is and is more tolerant of "normal" jump distances so you could try backing off some and see what happens.

But my rifle likes the Hornady 108g ELD-M bullets better - coincidentally also at .032" off the lands.

It also liked the Hornady 105g A-MAX when I could still get them and those shot best .035" off the lands.

 

[spitballer]

Bullet mfr recommendations notwithstanding, I generally stay .010" - .015" away from the lands with my .223 bolt gun.

 

[rkittine]

All my Benchrest rifles have free bore that allows me to optimize the projectile for the twist that my barrel is and allows me to set at Jump / Touch or Jam depending on what tests prove that particular rifle likes to be feed. Depends what accuracy you are looking for. When you are trying to throw 10 shots down range 1,000 yards and be in a group under 4 inches (winners are under 3.0), it means a lot.

Bob