Seating depth test

[Ucsdryder]

Curious how others would decipher this. I indicated distance off the lands on each picture, that's not group size. I felt like I was shooting pretty well today. The only shot that felt off was in target 2 and I noted "pull". I shot my 4th shot at .026" into the .029" target but the poi was in the same group as the .026, which was my best group of the day. I also noted 1st of the day. From these results I think my seating depth should be .023" which gives me some room as the throat erodes? I wouldn't be scared of .020" either, especially with that first shot of the day being high, then 3 shots in a small group.

100 yards, 3" spot targets, prone of a bipod and rear bag. Very slight wind right to left. 6.5 creedmoor shooting 147 eldms. Gun is new to me but has 600 rounds through the barrel. Not sure if I worry about throat erosion at this point seeing it's a 6.5cm and already has 600 rounds down the barrel.

 

[Dmagna]

Are you testing groups at .003 of depth change?

 

[Ucsdryder]

Are you testing groups at .003 of depth change?

Yes. .020", .023", .026", etc

 

[Dmagna]

Yes. .020", .023", .026", etc

Seems to me that all the groups are within a .5 moa of the same impact. Seating didn't change groups or impact because they are within the error size of .5 moa. So use whatever you feel like is easiest to seat.

 

[Jud96]

.023 all the way to .038 have very similar point of impacts. The groups open up a bit at a couple of those seating depths, but they're not bad. I'd start at .023 off and don't touch it until the accuracy falls off. I think this rifle will stay in tune for awhile by looking at these results.

 

[QuietTexan]

If that was a legit called pull before you saw the impact, I'd load 10-20 rounds at .026 and see how it holds together on a long string. The load 5x rounds at .023, .026, and .029 and shoot them all at random into a target.

 

[Ucsdryder]

If that was a legit called pull before you saw the impact, I'd load 10-20 rounds at .026 and see how it holds together on a long string. The load 5x rounds at .023, .026, and .029 and shoot them all at random into a target.

Yeah it was left when it broke. Only shot of the day I knew I wasn't going to n. Didn't need to see the target to know. I was thinking about doing 10 shot groups at .023 and .026 but I like your idea of mixing it up a little.

 

[Mikecr]

So where were you seated at powder development?

 

[Ucsdryder]

So where were you seated at powder development?

.020" is where I did my 650 yard ladder. I found a solid node with 4 shots in a row (.2gr per shot increment) in a 3.5" circle.

 

[ShootMo]

Well, my input is:
If it were me and my rifle, I would load 15 rounds @ .024" and only test them on a day with favorable conditions. I'd be looking for any inconsistencies.

I choose .024" because your group size AND placement are identical. And since that went from .023" to .026" that's worthy of further investigation. I feel it's much more worthy than any other two groups that you shot.

When I'm doing seating depth testing, I want as many groups in a row to be equidistant from the aim point as possible and mainly in height from the aimpoint. If you'll look at all those groups in the order they were shot, they look like a very low frequency wave form. And to me, there are only four groups that seemed flatter than the others. The tighter pair of groups lies between .023" and .026".

*My opinion is worth exactly what I charged you for it.

 

[Mikecr]

.020" is where I did my 650 yard ladder.

What was .020 OTL based on?

 

[Ucsdryder]

Hope and prayer.

 

[QuietTexan]

Hope and prayer.

Gotta start somewhere

 

[Ucsdryder]

Gotta start somewhere

Pretty much. .020 or .040 seem to be a decent place to start for powder development. I don't know that it really matters.