Bullet touching the lands or 2000th back?

[skipglo]

Its a question that has been asked for eons.
And the answer is...………….is there is no right answer, BUT its whatever projectile you choose suits your rifle with the right powder charge.

If you search this forum the topic has been covered many a time, pretty much reaching the same conclusion...…………………..trial & error is the only way of knowing!

Pretty much what I figured... thanks for the response!

 

[aushunter1]

In a recent same subject thread I put up this picture of some recent LDI was doing for a new rifle.
I start all my LD at .010 off the lands.
This was my second rounds of LD after finding in the 1st that 58gr was around the right powder charge but I also wanted to check the 56 & 57gr as well.
For this projectile you can see even at all 3 powder charges that .005 out performed the .015 CBTO depth & were also better than the .010 as well.

I was also testing a Speer 150gr SPBT projectile & the opposite occurred, all the 0.015 seating depth groups were better.

I think there are a lot of factors like ogive shape for one, but yeh you just have to shoot em & find out what they like!

 

[johnnyk]

Ogive shape has a little bit to do with jump distance, I think. When you shoot bullets with tangent ogives (i.e. Sierra SMK's, GK's, Nosler BT's, AB's, Partitions, Speer's), with more "rounded" noses, these tend to be less finicky about exact seating depth and are "easier" to find a accurate load for. I ran these at .010" off and that was the norm, I never deviated. Accuracy was good, always. It was just a matter of finding the powder load that shot the best.
Then Hornady starting putting out (or I just became aware of) bullets with secant ogives (SST's, A-max's), which are more "missile", straight nosed shape. I tried them (using my old "norm" of seating .010" off) and I cussed and I cussed and swore that Hornady didn't know a darn thing about making bullets.

This is about twenty years or so ago, before LR became all the rage and the highest BC wins the race. Laser RF's were just coming out and "Trashco" was one of the first companies with one! My buddy had one and it was as big as a 8mm projector. Cell phones weren't everywhere, so no ballistic apps, bluetooth, etc.
I walked all the yardages and measured the bullet drops and wrote them down or committed them to memory. Whew! thank God for Silicon Valley!
With all that said; even now the seating depth can vary even on the same style bullet, especially if the bullets are different Lot #'s or you're not using a VLD type seating stem in your seating die. I'm not sure any one manufacturer can be that consistent all the time. Grab a box of bullets and with a precise caliper, measure the overall length, bearing surface and/or weigh them. Now weigh/measure your cases. Do you put heavier bullets with lighter cases or heavier with heavier? It's a wonder we hit anything over 500yds! Lol! But's it's dang fun and very addicting!

 

[Mikecr]

Anyone who declares up front what bullets 'like', has obviously never done full seating testing.

 

[Angelo Campana]

Overall, my 6.5 on both the Creedmoor and Grendel are ~.012" > .020", dependent on the bullet configuration, powder load, and the barrel configuration. I get the best MOA @ 100 meters using .020" on my one Creedmoor.

Ogive has a lot to do with this.

 

[sunsetpalms]

Any thoughts on the Hybrid Ogive, Like Berger?

 

[Jammer65]

The needed jump varies by bullet and in many cases, individual barrels. The only way to know is to test it.

 

[Jammer65]

Any thoughts on the Hybrid Ogive, Like Berger?

Much less jump sensitive than the VLD profile.

 

[thethirdpig]

Every rifle has a sweet spot. You have to test at different depths. 1/1000ths has been good in a couple of mine. I can shoot one hole at 100yds all day. But it is different for every rifle.

 

[Rick Richard]

Any thoughts on the Hybrid Ogive, Like Berger?

Most of mine shoot in that ten to thirty off the best out of several different calibers.

 

[johnnyk]

Any thoughts on the Hybrid Ogive, Like Berger?

I think this profile was designed to get the easy tune of a tangent ogive and the bc/aerodynamic's of the secant ogive.

 

[Mike Burns]

It all depends on the bullet and what the rifle likes. In my opinion, there is no one answer for all. Now with that said, most of my rifles like the Berger bullets anywhere from ten to thirty off the lands.

Great answer. Test different distances and see what works best.

 

[LongestShot]

I'm in the process of switching all of my rifles over to Hammer bullets. While every rifle and caliber is different, I've had my best luck just touching the lands and if necessary backing off from there. I've got three rifles changed over with another 5 to go. I've got a couple rifles that love Swift bullets and their performance is exceptional. For these rifles I'm going to keep the recipe I'm using now, It doesn't make sense to change bullets if you've already obtained excellent performance.

 

[cjl2010]

Every rifle has a sweet spot. You have to test at different depths. 1/1000ths has been good in a couple of mine. I can shoot one hole at 100yds all day. But it is different for every rifle.

You should shoot Benchrest.