I Failed To Prove Seating Depth Matters 

After handloading for the last 40 years of my life I have learned one thing for sure, there is a lot of dogma amongst our community! I feel the same way you do, information is evolving at a rapid pace and I continue to adjust my technique and am producing better loads. Thank you for your thoughts.

7:30 for those wanting to get straight to the results and explanation on how the test was conducted

Do the test from o to 0.125'' jump. I think your test window jumpwise is too short. I've had ''zone'' as big as 0.030'' where everything was stable like in your test.

Does load density percentages change with seating depth or is it measured from flash hole to bottom of the case neck ? Thanks, David.

Good info , look forward to more good meaty indepth info . Good stuff

Well… time has elapsed. And now it seems the flood gates might be about to open on this matter as the question is now drawing some broader attention. More and more people are sharing experiences and data that struggles to prove strong correlation between group size and seat depth. I’ve heard this in podcasts from Bryan Litz and the Hornady ballisticians. They aren’t concluding it has no effect but their large sample size tests aren’t showing it… and the folks in bench rest and F-class who extensively use small sample size seat depth ladder testing to “tune” their rifles are getting right bent out of shape and butt hurt offended by the sheer blasphemy of it all… which is an even more interesting phenomenon than the test results if you ask me. in order to move the needle with the hard core orthodox believers somebody is going to have to execute a thorough controlled study testing group size with seat depth varied in .003” increments. Any study conducted with increments larger than this will never be accepted by the F-class and bench rest community because they believe that “harmonic nodes” exist very close together with different widths. And increments larger than .003” must be skipping between the nodes. It’s interesting… F-class and bench rest shooters achieve outlandish precision using their gear and methods… this fact is undeniable… Their methods seem to have become elevated to the status of sacred…

Following this page for a while… lessons learned: Literally nothing in reloading matters at all and anything you do doesn’t mean anything 🤷‍♂️😂

Very good analysis! Would have expected though that keeping SD of velocity tight rules over seating depth. Shooting a variety of regular hunting rifles from a rail rest and eliminating most other variables, I find that seating depth variations of 3 thousands or 0.1 mm allows for finding a harmonic node, especially in long, thin barreled hunting rifles. Heavy shorter barrels react far less sensitive! For me as a hunter, who does not shoot anywhere past 500 yards even under favorable conditions, 1 MOA groups consistently shot out of every shooting position and from my shoulder are more than sufficient to guarantee clean kills. It is however fun to understand and explore the inner and outer ballistic of different barrels, projectiles and other variables on paper! Keep up the good work. I had to subscribe to your channel since your approach to the subject is good.

Thanks for sharing this with us 😊

If seating depth doesn’t matter, how does one determine the most accurately developed round for a particular gun?

Would you mind putting up that test including your first 10 rounds ? I'm not a competition shooter ,but am lead to believe some clean their barrel after a number of or between details . It may be of significance , depending on the number of sighters allowed it may possibly effect their scores on paper. You clearly put a lot of work in , thankyou.

How did you determine group size? Group extreme spread is itself a random variable, problematic for linear regression. Seems to me you'd need to use an invariant measure like mean ES or mean shot radius as your dependent variable to justify linear regression.

larger note pad, further behind camera. when speaking it will appear more that youre looking at camera and audience. great video! recently stumbled onto you're content. following.

Quick load and other load software utilize internal case volume to determine and predict what the pressure and velocity will be. Changing the seating depth changes the internal case volume. Which changes the pressure which changes the velocity. Seating bullets further out of the case increases case volume, as a general rule lowers the pressure of the load, unless it is jammed into the lands, .All of that changes the vibration imparted on the the barrel. The way to make a barrel stiffer is to Shorten it and make it larger than diameter. That limits the vibration of the barrel. Barrel tuners can also affect the vibration of the barrel and may or may not improve the consistency of the vibration.

Excellent video! I snickered when you referred to seating depth “ideology”😂 One thing you mentioned is your seating depth you usually shoot. I’m very curious… would you be willing to share that value? .020” from jam appears to be a common starting point for seat depth. I have recently experienced achieving very acceptable loads in two very different hunting rifles/bullet types with this starting point jump from jam.

Had to shoot 200 rounds then reload another 200 and reshoot them? Ahhh poor guy. 😂 Sounds like fun to me.. Awesome vid though mang. I'll check out your vids. Already learning a few things. Thanks

I’m not sure how everyone else will interpret this but based on your chart I’m thinking seating depth might matter but not for me. I know the BR crowd definitely believes in seating depth but they are also shooting 2” 10 shot groups at 1000. I would have like to have seen a greater variation on the jump though too. I have heard of people like Satterlee jumping as much as 0.250 and it not hurting accuracy too.

question. So for load development, how many rounds would you suggest shooting per group, and how many groups per, that specific load? cause I can't do 190 rounds per group. 😂 Great video man. Love this content.

what if the seating depth is finding the load density or vise versa. so basically you could say you want to start the load .020 off the lands then slowly work up the powder charge till your group shoots the way you want it too if you say seating depth doesnt matter not if you found the perfect load density as you move the bullet forward or back you have now changed your density. which makes sense other wise every bullet would shoot good at that ..020 but it wont because your load density changes

Try that test with a 6mm PPC and watch the magic begin and make tiny dots when you get the seating depth right.

I'm not trying to be rude, but if a bullet with a hybrid ogive is advertised as being insensitive to seating depth, then the testing you've done shows this type of bullet performs as advertised - or am I missing something important?

Statistical significance. Barrel life Component cost Repeatability Recent reloading process seems to be disproving the usual ideas...velocity node...followed by seating depth. Ie ...concentricity by f class john, I guess most can't throw that much time and resource at it. Then there is stable platform to shoot from and wind..for significant results.. If consistent velocity is key...then...case capacity measurements and powder weights most important .. All very interesting..

If you need more validation, it looks like the good folks at Hornady have come to an eerily similar conclusion through their own large sample size testing. Here's a link to their podcast, skipped ahead to 1:20:15 where they specifically discuss bullet jump, but the entire thing is worth a listen for understanding the benefits of sample size: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-QwumAGRmz2I.html

I noticed that you don’t mess around with cast. BUT maybe you can explain to me why. Cast rifle projectiles will give amazing results if you jam them in the lands.

So did you fail at your mission, or did you prove that seating depth doesn't matter?

The more I reload/shoot, the more I realize that basically all reloading “tests” are a waste of time/money. I think perhaps the only things that really matter are getting high quality components and bullet selection..

So only load density matters, right? But seating depth affects load density, right? But seating depth doesn't matter, right? Just trying to make sure I follow.

Shooting for groups with a Magneto tied to the barrel.....Hmmmmmmm