Tweak the load or the seating depth

[beenjammin]

My new AI unfortunately does not like my old go to varget load of 44gr. I have my seating dies set up to pretty much 2.80 with 178 amax.I have tried to seat off the lands in the past but found my spec loads just seemed more accurate so I stopped doing this( not saying my depth was not still wrong... could have been touching or doing it wrong).

So I was considering dropping to 43g and working up to try and find a good load, but someone mentioned try adjusting the seating depth.

In order to not change too many variable at once , which is suggested first. tweaking the load and find the best, then tweak the depth to see if it tightens even more? I have come to realize I was lucky having the 44g shooting so well for so long. Now I got to start over.

 

[Dthomas3523]

If the chrono numbers are good and stable within a few tenths up and down, just adjust the seating depth.

You can literally take any random load and make it group well with seating depth.

It’s velocity that gets you at distance.

 

[beenjammin]

If the chrono numbers are good and stable within a few tenths up and down, just adjust the seating depth.

You can literally take any random load and make it group well with seating depth.

It’s velocity that gets you at distance.

+ or - 10 fps ??

 

[Dthomas3523]

+ or - 10 fps ??

If it’s +/- 10fps from like:

43.9 2800
44.0 2810
44.1 2820

And the sd/es is acceptable for all three, then yea, I’d just mess with seating.

 

[isofahunter]

Seating depth can make a huge difference IME. Scott Satterlee did a load development podcast for Modern Day Sniper #14 where he talks about now he finds the seating depth first then works the velocity vs his old method of velocity then depth. Jumping can be much more accurate than being right next to the lands, so many get wrapped around being close to lands verses the best load for their rig.

 

[Dolomite_Supafly]

I start load development with a chronograph. I find a load with low SD numbers then I adjust seating depth to tighten up the group.

I load .010” long then use a handheld press to seat deeper while at the range.

308 Winchester firing a 155g A-Max

6BR shooting 115g DTACs.

 

[fujam]

What intervals do you guys generally find best to step the seating depths for accuracy tuning? For instance I have a load I'm trying to tighten up with a decent ES but it's accuracy is not great @ slightly over 1" at 100 yards. The current jump is .005. What would you recommend loading up from this starting point?

 

[TheBoctor]

What intervals do you guys generally find best to step the seating depths for accuracy tuning? For instance I have a load I'm trying to tighten up with a decent ES but it's accuracy is not great @ slightly over 1" at 100 yards. The current jump is .005. What would you recommend loading up from this starting point?

Depends on what you're shooting. I've always had good luck with Bergers @ 0.020" jump, some like a little more, some like a little less.

Berger published an article that's a good guide for testing seating depths.

Getting the Best Precision and Accuracy from VLD bullets in Your Rifle

VLD bullets are designed with a secant ogive. This ogive shape allows bullets to be more efficient in flight (retain more velocity = less drop and wind deflection). While this result is desirable for many rifle shooters the secant ogive on the VLD bullets produces another result in many rifle.

bergerbullets.com

 

[fujam]

Depends on what you're shooting. I've always had good luck with Bergers @ 0.020" jump, some like a little more, some like a little less.

Berger published an article that's a good guide for testing seating depths.

Getting the Best Precision and Accuracy from VLD bullets in Your Rifle

VLD bullets are designed with a secant ogive. This ogive shape allows bullets to be more efficient in flight (retain more velocity = less drop and wind deflection). While this result is desirable for many rifle shooters the secant ogive on the VLD bullets produces another result in many rifle.

bergerbullets.com

Thank you for the response, I'll check out the article!

 

[beenjammin]

Thanks for the help. I went 8 thou off with same load and it tightened right up.