Seating depth - does it even matter?

[Packmansion]

Yes it matters. Biggest difference I’ve seen personally is kissing the lands vs not.

While not backed by any real data just general observations. I do agree with this. When im kissing the lands my groups have been tighter. I would argue for practical real world hunting the difference is not enough to matter. Sub moa is more than enough.

 

[huntnful]

Yes it matters. Biggest difference I’ve seen personally is kissing the lands vs not.

More erratic behavior when just touching the lands?

 

[solarshooter]

While not backed by any real data just general observations

Now you're just trolling me...

 

[khuber84]

More erratic behavior when just touching the lands?

Kissing or just touching is a relationship that changes very quickly. Throats move, that's a fact we all can agree on. Load 100 rounds at "just touching lands" and but he time that 100 rds is through the gun, that base to ogive can now be up to 9-12 thou off lands(extreme case scenario, as 28Nos)

 

[huntnful]

Kissing or just touching is a relationship that changes very quickly. Throats move, that's a fact we all can agree on. Load 100 rounds at "just touching lands" and but he time that 100 rds is through the gun, that base to ogive can now be up to 9-12 thou off lands(extreme case scenario, as 28Nos)

Yeah that’s why I don’t load into the lands anymore. Even though it normally shoots lights out. I’d see quick velocity drop as soon as I shot the lands out a little bit and some erratic dispersion. Much more simple to just stay out of them. Like in my little test. Held nearly the same velocity with a .200 jump difference.

 

[solarshooter]

Yeah that’s why I don’t load into the lands anymore. Even though it normally shoots lights out. I’d see quick velocity drop as soon as I shot the lands out a little bit and some erratic dispersion. Much more simple to just stay out of them. Like in my little test. Held nearly the same velocity with a .200 jump difference.

Also, once you've gone to extract a round and the bullet has stuck in the lands and you dump powder all over the inside of your action and trigger, you'll think twice about loading close to the lands haha.

 

[huntnful]

Also, once you've gone to extract a round and the bullet has stuck in the lands and you dump powder all over the inside of your action and trigger, you'll think twice about loading close to the lands haha.

I absolutely know it’s happened to people exactly as you described.

I’ve taken a chambered barrel off on its own, not attached to the action, so you can actually measure this stuff. Loaded a bullet really long, and shoved it by hand .080 into the lands. Pried it out with a screw driver and had no change in BTO measurements. And that’s only with .0015 neck tension.

So once I tested that a couple times I wasn’t really scared much of sticking a bullet. Considering I would only jam like .010-.015.

But I’ve seen it happen to someone else in person. Powder everywhere. Bullet stuck in barrel and have to knock it out with a cleaning rod lol.

Not sure how his ammo was loaded exactly. But yeah, it was a mess and pretty avoidable by just jumping the little bastards lol.

 

[justin davis]

Yes it matters. Biggest difference I’ve seen personally is kissing the lands vs not.

Yea interesting. I’ve actually seen some of my best groups and shooting to be around .040-.050 off the lands.

 

[6.5notcreedmore]

With regards to seating depth I think what matters most is consistency. If everything else is the same except the seating depth then you are effectively the case capacity which would directly effect chamber pressure and in return effect muzzle velocity. With that being said I would definitely say that seating depth matters.


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[Packmansion]

Now you're just trolling me...

Its just something I have noticed but its likely a coincidence and also it is negligible.

 

[Harvey_NW]

With regards to seating depth I think what matters most is consistency. If everything else is the same except the seating depth then you are effectively the case capacity which would directly effect chamber pressure and in return effect muzzle velocity. With that being said I would definitely say that seating depth matters.

See post #357.

 

[Rainierrifleco]

Seating depth make a huge difference
If you tak a given charge wt and seat the bullet out it increases case volume and presure drops
But also spike presure when bullet engage riffeling happens sooner in the presure curve
So there is no magic seating depth every rifle load combo will respond differently
I have every rifle set up backed off the lands
20-40 tho maybe more. I found that kissing the lands makes an immediate presure spike that would cause the rifle to shoot erratic when temperature or altitude changed
My approach has always been the most forgiving load for hunting
When I played around with benchrest there was a different aproach
I found using methods for benchrest doesnt
Necessarily give the best load for hinting
The rifle will tell you what it likes.

 

[JGRaider]

IME, seating depth has only made a difference when working with Barnes monos and Berger VLDH. The rest of 'em.....not so much.

 

[ddowning]

There is a threshold in field shooting where more precision does not equate to higher hit rates. When I was obsessed with winning Border Wars matches we would practice on 1 moa and smaller targets all the time. Had targets hanging from straps that were too long and shot the edges of them to get them to dangle again from over 400 yards multiple times. I don’t care how super human you are with a rifle. My gunsmith kicked my ass in most matches when we shot against each other. In positional shooting trying to shoot tiny targets, my wobble zone was way smaller than his. It didn't matter because we rarely shot those targets in matches and he would manage to hit them anyway. I watched him lay down and shoot a 6" circle at 1000 yards in one shot multiple times. We discussed guns shooting tiny groups a lot. It is fun to have a gun that will do it. Once you can put 30 rounds into 3/4 to 1 moa, you can shoot pretty small targets on a pretty regular basis. Having a gun that will put 30 in 3/8 moa is very difficult(a unicorn) to come across/build and is not noticeable shooting 1 moa targets from a gun that puts 30 into 3/4 moa.

Even going from 1.25 moa to 3/4 moa is not very noticeable anecdotally. A little, but not much. If you make the target 1.5 to 2 moa, instead of 1 moa the difference gets even harder to notice.

Field shooting is not f class or benchrest and hunting is not prs or nrl shooting. In situations where you get even two shots to make an impact, the likelihood of hitting goes up substantially. If you are in a hunting situation where only one shot is going to happen unless you hit the animal on the first shot, the wind is the problem. If you can use the first shot to get the wind call there are more and more guys every year that will put the second shot within the guns cone of fire on the target.

The point is, while these things are very interesting and fun to explore, the functional implications for hunting big game are very small.

 

[Harvey_NW]

Seating depth make a huge difference
If you tak a given charge wt and seat the bullet out it increases case volume and presure drops
But also spike presure when bullet engage riffeling happens sooner in the presure curve
So there is no magic seating depth every rifle load combo will respond differently
I have every rifle set up backed off the lands
20-40 tho maybe more. I found that kissing the lands makes an immediate presure spike that would cause the rifle to shoot erratic when temperature or altitude changed
My approach has always been the most forgiving load for hunting
When I played around with benchrest there was a different aproach
I found using methods for benchrest doesnt
Necessarily give the best load for hinting
The rifle will tell you what it likes.

See post #357, from .010" off the lands to almost 1/4" deeper the velocity average was 8fps different..

 

[barehandlineman]

If your are in a powder node your seating depth shouldn’t change your average speed much. Out of node it can. But doing a seating depth over .100 jump at time your missing many seating depth nodes. Seating depth nodes are smaller then most people can shoot but it exists. And stands out more the further you shoot. Its no different the barrel tuner. And most benchrest guys run tuners…

 

[Packmansion]

If your are in a powder node your seating depth shouldn’t change your average speed much. Out of node it can. But doing a seating depth over .100 jump at time your missing many seating depth nodes. Seating depth nodes are smaller then most people can shoot but it exists. And stands out more the further you shoot. Its no different the barrel tuner. And most benchrest guys run tuners…

I find this post deeply offenseive

 

[solarshooter]

If your are in a powder node your seating depth shouldn’t change your average speed much. Out of node it can. But doing a seating depth over .100 jump at time your missing many seating depth nodes. Seating depth nodes are smaller then most people can shoot but it exists. And stands out more the further you shoot. Its no different the barrel tuner. And most benchrest guys run tuners…

I know this is the current accepted theory. But I have never seen it proven out with >3 shot groups or any degree of repeatability. Any time it's tested more rigorously, whether with large increments in depth or small, there is no actual evidence of a pattern or trend in the data.

 

[barehandlineman]

Id disagree the trend is changing of telling people to shoot more. If you take a gun shoot it multiple days of 3 shot groups and every time its a .1 gun is it not a .1 gun? Shooting more does nothing but challenge a barrels thermal expansion. Or environmental impact and shooters ability. I do load work a lot for my customers. And what ive done that works is find a powder node and seating node and make it repeat itself 3x. Most people dont even truly know what that even is. Or can even shoot the difference to find it. But its a thing if it wasnt real shooters would be preaching it doesnt matter. But benchrest shooters say otherwise and top gun builders in the world say otherwise. In reality a hunting rifle only needs to hold together past 3 rounds. I personally want my guns poi to say the same every cold bore shot and the next two. Ive done it over 100’s of rifles now.

Side note i know if i was a bullet manufacturer id be telling everyone your groups are to small too and you need bigger sample size. Kills two birds one stone. Sell more ammo and clears your name of having 1 moa ammo.

 

[solarshooter]

Id disagree the trend is changing of telling people to shoot more. If you take a gun shoot it multiple days of 3 shot groups and every time its a .1 gun is it not a .1 gun? Shooting more does nothing but challenge a barrels thermal expansion. Or environmental impact and shooters ability. I do load work a lot for my customers. And what ive done that works is find a powder node and seating node and make it repeat itself 3x. Most people dont even truly know what that even is. Or can even shoot the difference to find it. But its a thing if it wasnt real shooters would be preaching it doesnt matter. But benchrest shooters say otherwise and top gun builders in the world say otherwise. In reality a hunting rifle only needs to hold together past 3 rounds. I personally want my guns poi to say the same every cold bore shot and the next two. Ive done it over 100’s of rifles now.

Side note i know if i was a bullet manufacturer id be telling everyone your groups are to small too and you need bigger sample size. Kills two birds one stone. Sell more ammo and clears your name of having 1 moa ammo.

I also always hear this. Even if you limit to 3 shot groups, say you shoot a ladder of different powder charges or seating depths with 3 shots at each. And you identify a "node". If you then repeat that full ladder, you will likely not find the "node" at the same place. Another way to do it, do your initial ladder, take your best group and your worst group, and shoot 10 more of each. See if the "best" and "worst" are still that different from each other.

You have to understand that there is an alternate explanation to the "load dev" process you're following. You shoot a ladder with 3 shot groups, pick the best group, test it a few more times, if it "holds together" like you said then it's a good load. If it "falls apart" then make a slight tweak and check again, until you find something that "works". But in reality, all you're doing is continuing to shoot until you get 3-4 3 shot groups in a row that are small. You haven't really changed anything, just got a lucky, random set of tight groups.

And by the way, I now shoot way fewer bullets doing "load dev" so this 100% works against bullet manufacturers incentives lol.