seating depth

[Link]

How good does your group have to be at 100yd before working on seating depth? [after you have found a powder node]

ty Don.

 

[bozo699]

I’m not sure how to answer that but your not going to take a 2” group and get into the .2’s with seating depth changes alone. Your going to want pretty decent group sizes to start with
Wayne

 

[Murray Brook]

Maybe I do it the wrong way but I like to determine a good seating depth first as I feel that seating depth has a bigger effect on accuracy than does powder charge. At least that has been my experience. What @bozo699 is also true.

 

[JEFFPPC]

Looking for back to back 4 shot groups in middle ones or lower, jumping back and forth between powder charge (one tenth at a time ) and seating depth (.001 at a time). I ck and re-ck with 2 shot groups an verify with back to back 4 shot groups. I leave the tuner untouched thru this process. I will bump the tuner when I am done to see if it gets smaller or tighter but it often does not. I use the tuner mostly to stay in tune throughout the season. As long as I am competitive 9and shots match wind calls I stand pat. When I think I am losing shots I go to the tuner. Usually in a couple of bumps it's back.I usually start the whole process seated into the lands .015 playing with powder. When powder amount seems good I start backing away from the lands .001 at a time looking for a sweet spot. At this point I start the back and forth as described above, all this preliminary testing with 2 shot groups looking to shot in the hole back to back groups.

 

[joshb]

Depends on the gun. For a factory rifle, I run up thru the powder loads to find the best node then adjust seating depth. If I’m lucky, I get it under 1/2”. If I don’t, I might try another bullet/ powder combo or just call it good.
For a custom, I’ll do the same but add more bullet/powder combo tests if it doesn’t shoot under 1/2” for the larger cartridges and less for the smaller ones.

 

[RustyInBend]

That's a "Chicken vs. Egg" question. Asked differently ... How bad do you have to shoot before you worry about seating depth? See what I mean. I usually start on a precision rifle at 2/100th off the lands, see how it shoots, and then work back from there if I feel like my depth is too shallow. Usually that 2/100th (or max mag-size) gives me great results, and I let seating depth take care of itself. In my experience, a big jump to the lands gives lesser results than missing some sort of optimum seating depth. YMMV though.

 

[Bill Norris]

Maybe I do it the wrong way but I like to determine a good seating depth first as I feel that seating depth has a bigger effect on accuracy than does powder charge. At least that has been my experience. What @bozo699 is also true.

So do you just start with a nominal powder charge to check seating depth ?

 

[Murray Brook]

What I do is determine what is a max charge with the components I am using. I live in a somewhat remote area so I can just go outside and shoot, or in my wood shed to determine this. I will then start with a load appx 2.5-3grs under and do the seating test starting with a slight jam ( depending on if used in a magazine) out to .050 in .005 incriments. If this fails then I will do the Berger seating test all the way to .120.

 

[1911nut]

I think I got this here?

 

[Ned Ludd]

I reload for F-TR, so my response may not be exactly the same as you'll get from someone that shoots a different discipline. If you start with charge weight optimization first, you'll have to pick a seating depth to load the test rounds. I generally start charge weight testing with the bullets seated at .015" off the lands (-.015"). There are reasons for this. First, the various Berger .224" and .308" bullets I use will generally exhibit a seating depth optimum that is off the lands, usually within about .015" of "touching". Second, By carrying out charge weight testing at -.015", I can later test a seating depth window from approximately -.003" to -.030" in .003" increments without having to re-visit charge weight following seating depth optimization, because -.015" lies very close to the middle of that range. In my hands, changing seating depth for a given bullet [jumped] by about .015" in either direction does not cause a significant change in velocity due to altering the effective internal case volume.

On some occasions, such as when trying out a new [to me] bullet, I might first use a slightly reduced charge weight ands carry out a coarse seating depth test first, just to get some idea of where the bullet wants to tune in in terms of seating depth before moving to charge weight testing. For me, the order of steps taken to optimizing a load (i.e. charge weight and seating depth) doesn't really matter. You can end up with the same load using either approach. I typically use the approach I described first (above), simply because it usually minimizes the total number of loaded rounds and range trips. Regardless, you can usually end up with a well-optimized load no matter in which order you carry out the steps.

 

[Bill Norris]

28.5 @ .015 looks like a keeper.

 

[bozo699]

28.5 @ .015 looks like a keeper.

He has a nice node there I think I would go 28.3 !… he could throw all his charges with a Harrells or Neil Jones and always be in tune
Wayne

 

[divingin]

I'd go with 28.0 @ -.012". Wouldn't have to change as the lands erode a bit.

I'd be interested to see what the next step down in charge did as well.

 

[Orr89rocz]

For me, and maybe its sometimes my abilities with the gun, but if seating is way off, i see fairly large groups, but mostly its a 2 close one off. But sometimes 3 scattered. When seating is in the right spot it really does tighten up.

And i find charge weights first reading velocity to find the flat spots across a range of powder weight. Then seating. But sometimes its like a 1” 3 shot group or so, then will move into .25-.35” lol and it does seem to stay consistent after i find it. Idk, i dont seem to see fairly tight groups like the target above across a wide range of seating depths. 300 wsm, 300 win, 308 and even with my 257 bob.

 

[JEFFPPC]

For starters the term jam.....often used.....is stupid. I have seen "it" reached by various methods so the term it's self is counter to a known base starting point. I would suggest going from touch. Pretty consistent and repeatable. Given that I would take your 28.5 with -.015whatever and move in and out a.001 at a time 3 bumps either way then pick the best and go .01 either way several bumps with powder. When you put three shots around .1 or a tad over and it repeats your on to something. I do all the preliminary with 2 shot groups looking for 2 in the SAME hole back to back before going to 4 shot groups looking for back to back below .15. Your doing basically the correct thing but a bit course as far as the gap between test points allowing you to miss the real sweet spot. Of course, always shooting over flags so your shooting A group within A condition. The goal is it must repeat. Round groups are what you want, think cone of dispersion. If you have a tuner don't touch it at this stage of the game. It had 2 used. Best one is to keep the barrel in tune ad round count grows. Second use is to use it to find a load but that usually leave you in a narrow tune window. Yes, it can work but better to find the tune without it as it seems to leave a wider window. Use it as a tool, NOT a crutch.

 

[gjcamacho]

I think I got this here?

View attachment 1337500

Been learning this process, about two weeks ago I came accross a video with Satterlee explaining his method. Also saw the Erik Cortina video. Both awesome. From what I see here I would be liking .012 and .015 based on what I saw on the videos. Leaning more on .015 with 28.5, and it leave room for growth to move foward. Just mho. Still, nice shooting.