Seating depth value

[Salchi Papa]

So I’ve struggled with this for my entire reloading experience. I understand there is no set value here but each individual rifle has its own. When developing loads how important is it? Should an OCW and preferred boolit be the main focus and seating depth considered after? What about book values for seating depth some are max oal some are min oal some like nosler don’t give any seating depth at all. Is there a standard to begin with? I’ve heard it all from .01-.02 up to .05 or is it better to have a consistent to start from?

 

[wvbuckbuster]

As you stated each rifle is its own. Some reloaders start at 10 thou off the lands. Know a guy that claimed it was 20 thou as best. Me I usually start at 10 to see if there is potential for the load combo then seat deeper as needed. Just something you will have to find for your rifle and bullet that you are using at the time. Just me. Dan.

 

[RL338]

For standard calibers 0.020” is my starting point. Weatherby cartridges start at mag length. When loading Barnes I follow their listed COAL for starters. Then there is the single feeding which a lot of my rifles are done by.

 

[Salchi Papa]

For standard calibers 0.020” is my starting point. Weatherby cartridges start at mag length. When loading Barnes I follow their listed COAL for starters. Then there is the single feeding which a lot of my rifles are done by.

So this is kinda what I meant by “standard” ie starting at book length then increasing but not the case obviously. I normally start at .020 but I’ve had instances where my 243 in particular where I’ve jammed it into the lands .005 and get good groups and I do know a guy that does benchrest and he says to seat to lands but prefers .005 jam. I’ve only done it with my 243 and have not got any excessive pressures but it’s a little wonky for my liking. If seating .010-.020 is best what makes factory ammo work in most cases? Those are .1 or more off the rifling. Like I said this is been my struggle understanding it for 17 years

 

[hunter24605]

I usually start around 20 off, but I've found that cup and core bullets tend to like less jump while bonded and monos like a good jump and usually settle around .100 off. Although I'll never have hunting rounds closer than .010

 

[wvbuckbuster]

So this is kinda what I meant by “standard” ie starting at book length then increasing but not the case obviously. I normally start at .020 but I’ve had instances where my 243 in particular where I’ve jammed it into the lands .005 and get good groups and I do know a guy that does benchrest and he says to seat to lands but prefers .005 jam. I’ve only done it with my 243 and have not got any excessive pressures but it’s a little wonky for my liking. If seating .010-.020 is best what makes factory ammo work in most cases? Those are .1 or more off the rifling. Like I said this is been my struggle understanding it for 17 years

As stated by others I should have included those mono bullets state at least a .50 jump though some claim they've achieved accuracy at less. Just last year I was trying Nosler 130gr BT in the 270 and started at .20 but the best accuracy was at .10. Factory loads have to have an industry standard to go by to fit the majority of factory chambers. When you get into custom, match chambers that's a whole different ballgame. Dan.

 

[SJB358]

I’ll start a cup and core at .010 off and anything bonded or mono get .050 right out of the gate. 99% of the time I know I’m going to get shorter for best accuracy.

 

[jimbires]

a lot of good advice has been given . I find my COAL to touching the lands . then I see if it fits the magazine . if it does fit you're good , if it doesn't fit then you need to use the magazine length as your max COAL . start at max length , this way you can only go shorter . this takes out the question of , " which way should I go , longer or shorter "

it seems you get a gut feeling on where a certain bullet likes to be . if you use a lot of nosler ballistic tip bullets, or sierra game kings , or Hornady interlock , Barnes all copper , in a few different rifles you'll see a trend of where the bullet usually ends up being most accurate . I work up loads different than most guys , I find seating depth first , at the min powder charge . then I use this seating depth to work up my powder charge .


I feel seating depth is very important . I've worked a fair amount with reduced loads . I pick a powder and charge according to the recoil . by keeping this recoil amount , the only adjustment to the ammo is seating depth . you can dial it in by changing the seating depth .



seating depth is just as important in full power loads .




I find my seating depth at minimum powder charge , then I use this seating depth to work powder charge .
the red and white target was shot at minimum powder charge



this is the load after I worked up the powder charge .


another seating depth target .


I had a few more target pics of seating depth tests , but I can't find them now .

 

[Darkhorse]

When seating my bullets I look for the nearest node. Barrels osscilates (spelling?) when fired and the upper and lower limits of movement are the nodes. This is where the bullets should all exit from to shoot the tightest groups even if it means the bullets start at .100" from the rifling. I seat at .020 out then move shorter/or longer in .005" increments and shoot a 3 shot group. I do this until I get a group I like then test it with 5 shot groups.
I do the beginning load test adjusting powder and seat depth as I go. After I reach my max. charge I finetune my seating depth. My reasoning is when you change the speed of the bullet it changes where around the node the bullet exits the barrel, possibly opening up the group substantially.

 

[DrMike]

This!

 

[Salchi Papa]

Had a pretty successful range day today. Was there from 9-3 brought several rifles and a few different loads for each one. Most shot very well did a charge weight test in 243 with imr4831 and RL22 and at 43.5gr imr4831 I popped a primer; my first one ever most likely my last as well. I have to check but I’m 90% sure that was a full grain over max but weird 42.5 and 43 showed very little almost no signs of pressure and it was a beautiful 58 degrees today so temps are not in play. I’m sticking with h4350 in my 243 cause it just works so well and shot 3/4” groups with my regular load 41.0 gr
Thank to all that have helped I really appreciate you guys I was on the verge of selling this rifle; may replace the accustock and trigger though

 

[Wolfshead]

When seating my bullets I look for the nearest node. Barrels osscilates (spelling?) when fired and the upper and lower limits of movement are the nodes. This is where the bullets should all exit from to shoot the tightest groups even if it means the bullets start at .100" from the rifling. I seat at .020 out then move shorter/or longer in .005" increments and shoot a 3 shot group. I do this until I get a group I like then test it with 5 shot groups.
I do the beginning load test adjusting powder and seat depth as I go. After I reach my max. charge I finetune my seating depth. My reasoning is when you change the speed of the bullet it changes where around the node the bullet exits the barrel, possibly opening up the group substantially.

I have a brief understanding the nodes and barrel harmonics, and I use (try to) the OCW method of load development to get my handloads for all my rifles.
I don’t have a chrono, nor do I have access to one, and OCW has worked well for me.
Could you briefly explain how you go about developing loads for your purposes?

 

[Idaho53]

Such great advice and feedback given. In addition to everything already said, my loads (accuracy and velocity spread) have been greatly improved by consistent neck tension (I now anneal brass every time). Also, remember to check ogive on different lots of the same bullet...they do vary significantly.

 

[Salchi Papa]

Well this confirms my accuracy of my h4350 load at 210yds. He was limping pretty bad and has marks all over both shoulders

 

[pharmseller]

Jimbires and I share an opinion.
I use the Berger method, which is to start as long as possible, then shorten by 0.04” successively. It’s how I do it. Bullet type doesn’t matter.

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

Evidence: keep in mind the only thing that changes is seating depth.

First attempt



Second depth, 0.04” deeper



Last depth, 0.04” deeper



I stopped there.




P