bullet seating depth

[magicman]

Hey Fella's,
I just wanted to check and see if my procedure is correct when trying to find bullet "sweet spot". I bought a used 22-250 and was able to buy some Lupau brass and some Hornady 55 gr SP and luckily enough I have some Sierra 55 gr Blitzkings on the way. I loaded with 33.2 gr of Varget and measured the ogive touching the lands. I loaded 6 bullets each off the lands as follows;
-.010
-.020
-.030
-.040
-.050
Even at .050 off lands it still looks long, all fit in mag and chamber. I guess I really want to know if a 22-250 is any different than most? I load for a 223, 6 BR, 6.5 CM, and 308. I have found that most of my guns like to be .030-.065 off the lands whether I'm loading Berger, Hornady, or Sierra. Just curious to see how others attempt this.
thanks

 

[Bc'z]

I'm willing to bet if you moved in .003" increments you'd find a sweet spot between .010-.025 and not blowing by it and using more components than necessary.
Here's a seating test I loaded for my nephews 22-250. I almost stopped the test 1.990 to save components, but I wanted nephew to see how minor adjustments in seating can really change things.
Don't ask me why a couple thou makes a difference but it does.
Test was shot by nephew, I'm just mentoring him in load tuning.
Were attacking his 300wsm next.

 

[K22]

A few years back Sierra published an article on this issue. The bottom line was that they claimed that each rifle can be different, some liking a larger jump than others. The only way to know is to test each rifle. I figure these guys know what they're talking about.

After shooting many rifle with many different loads I've found this to be essentially true but more times than not a .010" jump works quite well assuming the round will fit the magazine (hunting rifles) and you have enough bullet in the neck to provide adequate bullet tension.

In my experience, for hunting rifles, you want keep off the lands to prevent having a bullet stick in the barrel when you eject an unfired cartridge - can be very unpleasant when in the field.

I load and shoot for precision varmint and predator hunting and I've never found it necessary to jam a bullet into the lands to achieve excellent varmint level accuracy in the 1/4 to 1/2 moa range.

 

[D-4297]

Interesting that most TR shooters seat from .005 , to .020 on Comp loads , and have little issues with accuracy , once they find their rifles "sweet-spot" . I realize we generally don't load to a "Mag Length" , so maybe that creates a differentiation in the process .

 

[RegionRat]

My personal view of seating depth is that it pays to scan the largest practical range of depths before the case volume issues take over. The next steps require a little terminology explanation up front.

I then attempt a larger statistical sample at the best two nodes to see which one is widest. I then seat to the ”leading edge” of the widest node to avoid “chasing lands” as they wear.

Some PD trips are better than others and when you have a good one your round count will easily wear the bbl past any narrow nodes and sometimes even the wide ones. Learning to compensate for bbl wear with your pre loaded ammo for trips like these takes a little experience.

Service Rifles and Highpower Match guns are similar in that narrow seating nodes can mean you are out of tune during a match far away from home and your ammo had better take into account the wear from the start of a trip to the end.

Luckily, the rigs I have used were easy to live with and performed well enough in their wider nodes to leave no regrets even when those wider nodes are not the best one.

To anyone thinking about chasing HP, NRL competition or prairie dogs, I have always recommended learning with a good quality heavy bbl 223 in a tight twist. Pick your own style; bipods, rests like F-Class, slings, etc., but get to where you shoot enough to burn up a bbl. Learn to shoot your best at distances out past 300 yards and shoot enough to learn wind and the wear on the gun. This will teach lessons on loading depth, bbl wear, and wind, all without breaking the bank.

 

[Mikemci]

You taught your Nephew a lesson that he will use, all his life.
Good on you!

 

[magicman]

Well I guess I was thinking about the Berger VLD's and the way they explained to do a seating test to get close to the node and then dial in or tweak it in 002.-.005 increments. This is very interesting and I am just trying to learn from you fella's.

 

[CharlieNC]

Well I guess I was thinking about the Berger VLD's and the way they explained to do a seating test to get close to the node and then dial in or tweak it in 002.-.005 increments. This is very interesting and I am just trying to learn from you fella's.

I recently tried the Berger method and did find the best node at a far longer jump than I had evaluated previously. So in the future I will always use that approach as the first step in order to get in the right ballpark.

 

[JFrank]

I'm willing to bet if you moved in .003" increments you'd find a sweet spot between .010-.025 and not blowing by it and using more components than necessary.
Here's a seating test I loaded for my nephews 22-250. I almost stopped the test 1.990 to save components, but I wanted nephew to see how minor adjustments in seating can really change things.
Don't ask me why a couple thou makes a difference but it does.
Test was shot by nephew, I'm just mentoring him in load tuning.
Were attacking his 300wsm next.
View attachment 1216722

That’s a interesting difference between the depth’s you posted.
Which one are you likely to use and how well does it repeat?

 

[Bc'z]

That’s a interesting difference between the depth’s you posted.
Which one are you likely to use and how well does it repeat?

The OCW test was shot with a CBTO .0025" longer than starting depth of seating test. That group measured in mid .6's and I figured I already knew what it looked like was my reasoning.
I'm pretty confident it will hold through the firing of the remainder of his fresh brass.
We've already discussed case volume, velocities and tweaking his tune.
We started with 98 pieces of new RP brass.
I loaded the last 25 pieces and sent him on his way to go coyote hunting.
We've yet to do the chronograph report, and he hasn't shot it since the seating test.
Work and another covid lock down has been in our way.
Lock down is through today, range opens tomorrow.
I'll give you 3 guesses where I'll be....
1st 2 dont count. Lol

 

[Bc'z]

1 thought I might add.
I used Shooters World Precision powder for this load.
To say I was impressed with the lack of vertical dispersion over a 2gr OCW test would be a understatement.
Now I just have to wait for restocking of SWP, the 3#'s I had to try are now dedicated nephews rifle, along with enough 55gr Vmax and primer to keep him killing coyotes.

 

[JFrank]

I'm willing to bet if you moved in .003" increments you'd find a sweet spot between .010-.025 and not blowing by it and using more components than necessary.
Here's a seating test I loaded for my nephews 22-250. I almost stopped the test 1.990 to save components, but I wanted nephew to see how minor adjustments in seating can really change things.
Don't ask me why a couple thou makes a difference but it does.
Test was shot by nephew, I'm just mentoring him in load tuning.
Were attacking his 300wsm next.
View attachment 1216722

Well I would be at an inch nine ninety for a repeat test and hopefully the inch nine eighty seven flyer is just that.

 

[Bc'z]

Well I would be at an inch nine ninety for a repeat test and hopefully the inch nine eighty seven flyer is just that.

You can bet your very last primer, those 25 rounds are dead nutz 1.990 all bullets were sorted bbto to insure it.
Logan called the bad shot on .987 as he was grinning ear to ear from his prior group.
Guess he lost his composure for a moment. Lol

 

[JFrank]

So as a diagnostic tree would you say when they open up towards flat it’s time to move closer to the lands ?

 

[Bc'z]

So as a diagnostic tree would you say when they open up towards flat it’s time to move closer to the lands ?

If your talking horizontal flat line groups, I'm thinking table manners and how its riding the bags.
Possibly powder, I had a load I was working a while back for my 6x45 using H322 and 68gr barts Avengers and it kept giving flat groups.
Looking at powders I had on hand I decided to try some W748 as it worked well with a couple different 70gr bullets.
Done!! No more horizontal group nice and round.
Here's the part I cant wrap my head around both 80gr dominator and 68gr avenger
are running same exact charge
26.7gr W748, Cci450.
I'll shoot both loads tomorrow for chronograph report and conformation of load.

 

[magicman]

I have also heard that the farther you stay off the lands the longer the barrel will last or at least not burn the throat out. What's you fella's thoughts?

 

[mikecr]

There is no evidence that seating changes accurate barrel life.

 

[magicman]

Good to know!

 

[Coyotefurharvester]

You are below(light) starting loads for Varget and 55 gr. bullets. Maybe pretty sooting around the necks. Factory barrels in 22-250 for me have been best 0.005-0.025 over the coal in the loading books. I shoot a lot of Nosler 55 bt for coyote, trying to avoid the splash of the vmax. Also like Barts 52 ultra.

 

[Laguna Freak]

Hey Fella's,
I just wanted to check and see if my procedure is correct when trying to find bullet "sweet spot". I bought a used 22-250 and was able to buy some Lupau brass and some Hornady 55 gr SP and luckily enough I have some Sierra 55 gr Blitzkings on the way. I loaded with 33.2 gr of Varget and measured the ogive touching the lands. I loaded 6 bullets each off the lands as follows;
-.010
-.020
-.030
-.040
-.050
Even at .050 off lands it still looks long, all fit in mag and chamber. I guess I really want to know if a 22-250 is any different than most? I load for a 223, 6 BR, 6.5 CM, and 308. I have found that most of my guns like to be .030-.065 off the lands whether I'm loading Berger, Hornady, or Sierra. Just curious to see how others attempt this.
thanks

Because I’m trying to avoid chasing eroding lands, I generally start at 0.030” or 0.040” off lands and progress in 0.010” increments. When something looks promising, I narrow the search in 0.003” increments. If nothing looks promising and I’m out to 0.090”, I start hitting the fives; 0.045” to 0.085”.

I’ve only recently (2020) begun seating depth node ID as step 1 in load development. In two different 30 cal rifles with 2 different bullets, I have found a sub-half moa node (at 100 yd) that is atleast 0.003” wide. One rifle is at 0.070” to 0.075” and the other is 0.058” to 0.060” off lands.