Does seating depth really matter?

[jackieschmidt]

I don't think the OP's intent was to say seating depth doesn't matter? At least I hope not. I firmly believe it makes a difference. I look at his target and think dang I need to tighten up my vertical. That could have been a 200-20X. My goal off a FTR bipod is less than .5 moa at 600-1000. F Open shooting off a rest would be half that. You can't get there without nailing down the best seating depth possible. How forgiving it is (wide) comes after that is determined and is only a beneficial byproduct of the bullet, barrel, primer and powder combination.

^^^^^^^^^

 

[Doug Casner]

I know its a different game but I had a world champ benchrest shooter tell me one time just seat em on the lands and forget it. Doug

 

[Ccrider]

I did not take the op to be saying that seating depth does not matter, nor does that target say that to me. I have to assume that the op’s gun is at least .25 moa or better gun in tune. If this is so, changing the seating depth has the gun shooting 3 times larger. That shows that seating depth definitely matters.

 

[Keith Glasscock]

My findings were a bit different. This is in the .020-.030 jump range:

ETA - These were two consecutive relays of the same match, same day. Left left target was shot first, then the right.

 

[F Class John]

I don't think the OP's intent was to say seating depth doesn't matter? At least I hope not. I firmly believe it makes a difference.

Thank you and you're correct. As I've said, of course seating depth matters, and yes I test for it BUT for F Class I personally (and I know others do too) find it's important to find the widest seating node possible. I will 100% take wider and more consistent nodes that are a hair taller over razors edge tight nodes that could fall apart as the day goes on.
This was simply a test to show how tolerant and/or how surprising small (yes I know that's relative but 3/4moa at 600yds is plenty small considering the variance) a group could shoot even with an overall seating change of .100", no more no less.

Would I take a 3/4moa gun to a match, of course not. But if I can at least open my mind to the fact that there might be wider and more stable nodes deeper than conventionally believed, I'm willing to try and this simple test says there is.

Yes more testing is needed, yes I would do larger samples.

 

[lukester]

Thank you and you're correct. As I've said, of course seating depth matters, and yes I test for it BUT for F Class I personally (and I know others do too) find it's important to find the widest seating node possible. I will 100% take wider and more consistent nodes that are a hair taller over razors edge tight nodes that could fall apart as the day goes on.
This was simply a test to show how tolerant and/or how surprising small (yes I know that's relative but 3/4moa at 600yds is plenty small considering the variance) a group could shoot even with an overall seating change of .100", no more no less.

Would I take a 3/4moa gun to a match, of course not. But if I can at least open my mind to the fact that there might be wider and more stable nodes deeper than conventionally believed, I'm willing to try and this simple test says there is.

Yes more testing is needed, yes I would do larger samples.

Great info, John, and thanks for the test and the video.

 

[jackieschmidt]

I know its a different game but I had a world champ benchrest shooter tell me one time just seat em on the lands and forget it. Doug

For many bullets, especially the ones made from Rorschach dies such as the Watsons and Fowler, this indeed held true.

For the double radius ogive bullets such as the Barts Ultra and the original Bruno 00, we used to jam them to where the marks were twice as long as the were wide in a Krieger 4 groove barrel, and they shot great.

 

[Doug Casner]

These were Barts, Jackie 100 yd. benchrest. Doug

 

[Ray123]

Yes, I in my experience seating depth matters in every caliber from .17 Rem to 50BMG. Sometimes it's way back from the lands, sometimes with flat base, or rd nose almost any seating depth, shoots well...but most of the time with long vld type bullets it's close to the lands...and sometimes velocity and seating depth are married...alot of variables, make drawing any hard conclusions seem in doubt...except, I believe in my opinion, seating depth needs to be explored by any serious rifleman looking for smallest groups.

 

[jackieschmidt]

These were Barts, Jackie 100 yd. benchrest. Doug

Years ago, we accidentally stumbled on that “jamming the heck out of those double ogive bullets.”
It was during a Registered Match at New Braunfels. I hsd Cleaned my point up die the eavning before, and accidentally had the Redding seater set 1/2 turn out. When he said commence fire, I felt the bullet seat into the lands Hard. Well, there wasn’t much to do, so I just went to the record and nailed a flat mid one.
Needless to say, I left it there. After the match, I checked the actual jam, and the marks were indeed twice as long as they were wide.

A lot of shooters did exactly the same thing. When Lester Bruno came out with that great 00 BT in 2005, I got 5000 of the first run, and they loved it. I won a lot of Aggs with those bullets.

 

[calgarycanada]

I suppose that's true if .75moa is acceptable for whatever discipline. What I see is the test shows how bad it can shoot and maybe, how good. Clearly, it matters to accuracy and even in your test, that seems clear. I guess it depends on your accuracy needs. But no, in no way do I see that test as saying seating depth doesn't matter. You're simply between as good as it can be and as bad as it can be. If you're ok with its worst, then yes...seating depth doesn't matter to you, in that scenario. It's important to know what it looks like when your gun is completely out of tune, when it's completely IN tune and everywhere in between, which naturally also shows how far it is between the two, in terms of powder chage, seating depth or tuner travel. These are certainly all of value.

You didn’t understand the test. Yes it’s 0.75moa across .100” seating depth change. That doesn’t mean john is going to run varying seating depth for matches. What that means is, that it almost doesn’t matter which seating depth number he picks and if loads all ammo to that length, the precision is just as good. So for example 0.25” off shoots just as good as 0.50” off and so does the 0.75” off. And that “good” in his case is 0.5 moa or better, which is excellent at 1000 yards.

To be fair that is correct for his bullets and his chamber/throat. Some bullets and chambers are finicky and seating depth can have big affect on precision.

 

[Doug Casner]

I used to call Ron Hoehn on the phone and ask him all kinds of questions about benchrest. He was always really nice and answered my questions so I bought a used b.r. rifle from him, sorry hes gone. He cut alot of corners for me. Any time a novice like me can agg. a .250 its gotta be the rifle. Thats me measuring groups though. Alot of guys would say bs. to that but I didnt cheat. Doug

 

[gunsandgunsmithing]

You didn’t understand the test. Yes it’s 0.75moa across .100” seating depth change. That doesn’t mean john is going to run varying seating depth for matches. What that means is, that it almost doesn’t matter which seating depth number he picks and if loads all ammo to that length, the precision is just as good. So for example 0.25” off shoots just as good as 0.50” off and so does the 0.75” off. And that “good” in his case is 0.5 moa or better, which is excellent at 1000 yards.

To be fair that is correct for his bullets and his chamber/throat. Some bullets and chambers are finicky and seating depth can have big affect on precision.

I disagree. I see that it likely won't shoot worse than .75 but that's all I see and I'm not happy with that level of accuracy. I also think that he could pick a random depth from any of those and it might be .75 or it could be great. I don't see how any further conclusion can be reached by that test. I'm happy to leave it at that. I'll add, there is the small possibility that his tune repeats at the intervals he used, so it might be as good as it can be, too.

 

[dcali]

This is just my observation, but I tend to find that really good depths are fairly narrow in range, as are the really bad ones. But the mediocre middle tends to be very wide. Sometimes the middle is good enough, sometimes not. And the location and width are definitely dependent on powder charge. they move around and intensify as you change charge weight.

Jamming is a bit different in that I find it *almost* always shoots well if you seat 5-10 thous longer than touch. Just touching has been a bit of a disaster for me, but just short of touching (maybe .003-004 off the lands) seems to work as well as jamming. I don't typically jam for practical reasons, but I wonder if others have had the same experience.

 

[gunsandgunsmithing]

This is just my observation, but I tend to find that really good depths are fairly narrow in range, as are the really bad ones. But the mediocre middle tends to be very wide. Sometimes the middle is good enough, sometimes not. And the location and width are definitely dependent on powder charge. they move around and intensify as you change charge weight.

Jamming is a bit different in that I find it *almost* always shoots well if you seat 5-10 thous longer than touch. Just touching has been a bit of a disaster for me, but just short of touching (maybe .003-004 off the lands) seems to work as well as jamming. I don't typically jam for practical reasons, but I wonder if others have had the same experience.

I've said on here many times, I typically find my best results between 10 in and 10 off..fwiw. Not that the node is .020 wide but that they often shoot best within that range.