THE ACCURATERELOADING.COM FORUMS


Moderators: Mark
Go
New
Find
Notify
Tools
Reply
  
Seating Depth...how much difference.
 Login/Join
 
One of Us
Picture of Mike_Dettorre
posted
I have never varied seating depth. I have always simply loaded 10/1000 off the lands and then found a powder charge that worked.

What has been your experience varying seating depth? Dramatic changes in group size or no?


Mike

Legistine actu quod scripsi?

Never under estimate the internet community's ability to reply to your post with their personal rant about their tangentially related, single occurrence issue.




What I have learned on AR, since 2001:
1. The proper answer to: Where is the best place in town to get a steak dinner? is…You should go to Mel's Diner and get the fried chicken.
2. Big game animals can tell the difference between .015 of an inch in diameter, 15 grains of bullet weight, and 150 fps.
3. There is a difference in the performance of two identical projectiles launched at the same velocity if they came from different cartridges.
4. While a double rifle is the perfect DGR, every 375HH bolt gun needs to be modified to carry at least 5 down.
5. While a floor plate and detachable box magazine both use a mechanical latch, only the floor plate latch is reliable. Disregard the fact that every modern military rifle uses a detachable box magazine.
6. The Remington 700 is unreliable regardless of the fact it is the basis of the USMC M40 sniper rifle for 40+ years with no changes to the receiver or extractor and is the choice of more military and law enforcement sniper units than any other rifle.
7. PF actions are not suitable for a DGR and it is irrelevant that the M1, M14, M16, & AK47 which were designed for hunting men that can shoot back are all PF actions.
8. 95 deg F in Africa is different than 95 deg F in TX or CA and that is why you must worry about ammunition temperature in Africa (even though most safaris take place in winter) but not in TX or in CA.
9. The size of a ding in a gun's finish doesn't matter, what matters is whether it’s a safe ding or not.
10. 1 in a row is a trend, 2 in a row is statistically significant, and 3 in a row is an irrefutable fact.
11. Never buy a WSM or RCM cartridge for a safari rifle or your go to rifle in the USA because if they lose your ammo you can't find replacement ammo but don't worry 280 Rem, 338-06, 35 Whelen, and all Weatherby cartridges abound in Africa and back country stores.
12. A well hit animal can run 75 yds. in the open and suddenly drop with no initial blood trail, but the one I shot from 200 yds. away that ran 10 yds. and disappeared into a thicket and was not found was lost because the bullet penciled thru. I am 100% certain of this even though I have no physical evidence.
13. A 300 Win Mag is a 500 yard elk cartridge but a 308 Win is not a 300 yard elk cartridge even though the same bullet is travelling at the same velocity at those respective distances.
 
Posts: 10181 | Location: Loving retirement in Boise, ID | Registered: 16 December 2003Reply With Quote
One of Us
posted Hide Post
Hi Mike,

Seating depth is usually the last thing I adjust, after I have found the best weight for a given load/combination. Some times my seating depth adjustments make a big difference, some times they don't.

The most recent example was yesterday. I tested loads for my 6.5x55. The components were Lapua cases, 130 grain Nosler AccuBond and VV N160.

With three powder weights, a 0.05" decrease of the Cartridge Overall Length (COl) improved the group sizes by almost an inch at 100 yards.

I haven't seen this much difference before and was also surprised to see an improvement when decreasing COL. I would have thought that the closer the bullet was to the lands, the more accurate the load would be.

It was a good reminder for me never to take anything for granted and always test all variables.

Cheers,

Christian


www.redkettle.co

Specialised clothing for rifle hunting.
 
Posts: 35 | Location: United Kingdom | Registered: 08 April 2012Reply With Quote
One of Us
Picture of bartsche
posted Hide Post
[QUOTE]Originally posted by Mike_Dettorre:
I have never varied seating depth. I have always simply loaded 10/1000 off the lands and then found a powder charge that worked.

ConfusedReally? beerroger


Old age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone..
 
Posts: 10226 | Location: Temple City CA | Registered: 29 April 2003Reply With Quote
One of Us
Picture of Mike_Dettorre
posted Hide Post
Roger,

Yes, really. Is there something silly about my post I should know? Please enlighten me oh wise one.


Mike

Legistine actu quod scripsi?

Never under estimate the internet community's ability to reply to your post with their personal rant about their tangentially related, single occurrence issue.




What I have learned on AR, since 2001:
1. The proper answer to: Where is the best place in town to get a steak dinner? is…You should go to Mel's Diner and get the fried chicken.
2. Big game animals can tell the difference between .015 of an inch in diameter, 15 grains of bullet weight, and 150 fps.
3. There is a difference in the performance of two identical projectiles launched at the same velocity if they came from different cartridges.
4. While a double rifle is the perfect DGR, every 375HH bolt gun needs to be modified to carry at least 5 down.
5. While a floor plate and detachable box magazine both use a mechanical latch, only the floor plate latch is reliable. Disregard the fact that every modern military rifle uses a detachable box magazine.
6. The Remington 700 is unreliable regardless of the fact it is the basis of the USMC M40 sniper rifle for 40+ years with no changes to the receiver or extractor and is the choice of more military and law enforcement sniper units than any other rifle.
7. PF actions are not suitable for a DGR and it is irrelevant that the M1, M14, M16, & AK47 which were designed for hunting men that can shoot back are all PF actions.
8. 95 deg F in Africa is different than 95 deg F in TX or CA and that is why you must worry about ammunition temperature in Africa (even though most safaris take place in winter) but not in TX or in CA.
9. The size of a ding in a gun's finish doesn't matter, what matters is whether it’s a safe ding or not.
10. 1 in a row is a trend, 2 in a row is statistically significant, and 3 in a row is an irrefutable fact.
11. Never buy a WSM or RCM cartridge for a safari rifle or your go to rifle in the USA because if they lose your ammo you can't find replacement ammo but don't worry 280 Rem, 338-06, 35 Whelen, and all Weatherby cartridges abound in Africa and back country stores.
12. A well hit animal can run 75 yds. in the open and suddenly drop with no initial blood trail, but the one I shot from 200 yds. away that ran 10 yds. and disappeared into a thicket and was not found was lost because the bullet penciled thru. I am 100% certain of this even though I have no physical evidence.
13. A 300 Win Mag is a 500 yard elk cartridge but a 308 Win is not a 300 yard elk cartridge even though the same bullet is travelling at the same velocity at those respective distances.
 
Posts: 10181 | Location: Loving retirement in Boise, ID | Registered: 16 December 2003Reply With Quote
One of Us
Picture of woods
posted Hide Post
Seating depth will change velocity, extreme spread of velocities and standard deviation of velocities



If you have a decent shooting rifle that will not effect your group size much but you can find a node that is the most stabile. That way you can reduce flyers and your drop spread will be less at distance.


____________________________________
There are those who would misteach us that to stick in a rut is consistency - and a virtue, and that to climb out of the rut is inconsistency - and a vice.
- Mark Twain |

Chinese Proverb: When someone shares something of value with you and you benefit from it, you have a moral obligation to share it with others.

___________________________________
 
Posts: 2750 | Location: Houston, Tx | Registered: 17 January 2005Reply With Quote
One of Us
Picture of Nakihunter
posted Hide Post
I have been reloading centre fire ammo for about 17 years and for about 8 or 10 calibers and less than 25 HUNTING rifles.

In the early years I tried all the tricks from the books and magazine articles. I slowly found the priority that worked for me - the bullet is the key. If a particular projectile gives 3" groups in the first random load, it is unlikely to become a 1" shooter. If the first group is 1.5" to 2" then I look at changing brass, powders & then fine tuning loads.

Regarding seating depth I did find that seating bullets very close improved accuracy in some instances but it caused other problems in the field. Finally I got a scare with Barnes X (old first model) where pressures spiked like a volcano. So I started seating all bullets 30 thou off lands and X bullets at 50 thou.

All my rilfes are good shooters and some will even do under 2" groups (5 shots) at 200 meters. All of them are loaded with bullet seated 30 thou off lands.

John Barsness did an article on this subject in Handloader magazine about 6 or more years ago. I found that article very enlightening.


"When the wind stops....start rowing. When the wind starts, get the sail up quick."
 
Posts: 11420 | Location: New Zealand | Registered: 02 July 2008Reply With Quote
One of Us
posted Hide Post
Woods, Ya know I just got into reloading a year back. I reload 6.8, 338 fed in AR's that I hunt with. Also reload 7 mag and 30-378 mag Weatherby. So I started out seating depth from factory specs (70/1000's) to 15/1000's off. After close to 100 reloads, I also couldn't find a rhyme or reason to my groups and was quite befuddled; none were really way out there but none were much better than the rest outta the Weatherby; ended up going with 20/1000's off and killed a bunch of caribou, several moose and bear with the reloads last fall. I finally got a chrono over the winter and plan on seeking more insight to why I have spent so much money on reloading gages & equipment that seemingly don't improve my groups, ha ha.

I'm glad I saw your post.
 
Posts: 521 | Location: Alaska | Registered: 12 April 2010Reply With Quote
One of Us
Picture of IanD
posted Hide Post
But this is kinda useless if you shoot a Weatherby with factory freebore. Can never touch the lands or anywhere near and still cycle through magazine, right? Just wondering..
 
Posts: 366 | Location: Alberta, Canada | Registered: 13 November 2005Reply With Quote
One of Us
posted Hide Post
I did pretty much the same with a rem 700 in 7 mag. The groups weren't much different which led me to question how much bullet seating depth changes anything for me.

Too many you guys on this site argue back and forth. I'm just trying to improve my ammo by reloading and quite the novice. When I did have barnes X bullets like 50/1000s out further than Weatherby factory shells, they still fit in magazine.

Bottom line, 4 moose, bunch of caribou, 6 blk bear and one grizz were killed by family members with those two guns and bullet seating depth wouldn't have made a difference.

When I saw Wood's picture, I thought, there ya go, looked just like mine.
 
Posts: 521 | Location: Alaska | Registered: 12 April 2010Reply With Quote
One of Us
Picture of Hunt-ducks
posted Hide Post
I use the same starting point with all rifles .025 off except with Barnes .050 settle on a powder primer charge that shows accuracy to start with while checking FPS then I move the bullet in or out to see if I can tweek the load if needed.

I shoot a lot of Nosler bullets and find that if a gun can't shoot Nosler to start with it usully won't shoot there are a few exceptions but not many.

Right now i'm trying to get 160gr Barnes TTSX to shoot in my 338WM I finely put a good 4 shot group 3/4" @ 100 using IMR4350 and i'm .070 off
 
Posts: 450 | Location: CA. | Registered: 15 May 2006Reply With Quote
One of Us
posted Hide Post
FWIW, I look at varying the bullet jump as a means to fine tune an already good load. I've had it help slightly and again not at all. I've never experienced a bullet jump adjustment that would change a spray and pray load into a one-holer like I've read about in here.
YMMV


Aim for the exit hole
 
Posts: 4348 | Location: middle tenn | Registered: 09 December 2009Reply With Quote
one of us
Picture of ramrod340
posted Hide Post
I used to play with jump. I never found enough gain to worry about it. So I spend my bulletrs powder and time on other things.


As usual just my $.02
Paul K
 
Posts: 12881 | Location: Mexico, MO | Registered: 02 April 2001Reply With Quote
One of Us
posted Hide Post
Sometimes you can change a variable like the seating depth and think you have found the load.
You can repeat the experiment the next time at the range and often get dompletely different results.
 
Posts: 13978 | Location: http://www.tarawaontheweb.org/tarawa2.jpg | Registered: 03 December 2008Reply With Quote
One of Us
Picture of MickinColo
posted Hide Post
I’ve played with bullet jump and its effect on barrel timing. It makes a difference. “Woods” shows you some of the same results I’ve had.

If barrel timing (vibration timing) is not important why do we worry about free floating barrels? Barrel timing is an interesting study.
 
Posts: 2650 | Location: Lakewood, CO | Registered: 15 February 2003Reply With Quote
One of Us
Picture of bartsche
posted Hide Post
quote:
Originally posted by Mike_Dettorre:
Roger,

Yes, really. Is there something silly about my post I should know? Please enlighten me oh wise one.

popcornMy post wasn't meant as a flame or any derogatory blast. My surprise stems from the fact that many of my rifles' throats will not allow seating of light for caliber bullets to be seated any where near the rifling. Sorry if I came across as a possible slam intended. However , Thanks for the compliment. beerroger


Old age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone..
 
Posts: 10226 | Location: Temple City CA | Registered: 29 April 2003Reply With Quote
one of us
Picture of D Humbarger
posted Hide Post
Here's a group that I shot with my 284 win that I cut WAY too long a throat. I must say that I am VERY suprised because I have repeated this goup as I thought it must be a fluke. I will shoot that load over a chrony wednesday & find out what the velocity is. Any predictions?




Doug Humbarger
NRA Life member
Tonkin Gulf Yacht Club 72'73.
Yankee Station

Try to look unimportant. Your enemy might be low on ammo.
 
Posts: 8351 | Location: Jennings Louisiana, Arkansas by way of Alabama by way of South Carloina by way of County Antrim Irland by way of Lanarkshire Scotland. | Registered: 02 November 2001Reply With Quote
One of Us
Picture of bartsche
posted Hide Post
[QUOTE]Originally posted by D Humbarger:
Here's a group that I shot with my 284 win that I cut WAY too long a throat. I must say that I am VERY suprised because I have repeated this goup as I thought it must be a fluke. I will shoot that load over a chrony wednesday & find out what the velocity is. Any predictions?[/QUOTE
dancingIt'll do just fine. beerroger


Old age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone..
 
Posts: 10226 | Location: Temple City CA | Registered: 29 April 2003Reply With Quote
One of Us
Picture of woods
posted Hide Post
quote:
Originally posted by D Humbarger:
I will shoot that load over a chrony wednesday & find out what the velocity is. Any predictions?



2800 fps

You will lose a lot of velocity from seating so far from the lands


____________________________________
There are those who would misteach us that to stick in a rut is consistency - and a virtue, and that to climb out of the rut is inconsistency - and a vice.
- Mark Twain |

Chinese Proverb: When someone shares something of value with you and you benefit from it, you have a moral obligation to share it with others.

___________________________________
 
Posts: 2750 | Location: Houston, Tx | Registered: 17 January 2005Reply With Quote
One of Us
Picture of Mike_Dettorre
posted Hide Post
Roger,

I didn't take it as a flame...I just assumed you thought I said something stupid which is a common occurrence for me. Big Grin


Mike

Legistine actu quod scripsi?

Never under estimate the internet community's ability to reply to your post with their personal rant about their tangentially related, single occurrence issue.




What I have learned on AR, since 2001:
1. The proper answer to: Where is the best place in town to get a steak dinner? is…You should go to Mel's Diner and get the fried chicken.
2. Big game animals can tell the difference between .015 of an inch in diameter, 15 grains of bullet weight, and 150 fps.
3. There is a difference in the performance of two identical projectiles launched at the same velocity if they came from different cartridges.
4. While a double rifle is the perfect DGR, every 375HH bolt gun needs to be modified to carry at least 5 down.
5. While a floor plate and detachable box magazine both use a mechanical latch, only the floor plate latch is reliable. Disregard the fact that every modern military rifle uses a detachable box magazine.
6. The Remington 700 is unreliable regardless of the fact it is the basis of the USMC M40 sniper rifle for 40+ years with no changes to the receiver or extractor and is the choice of more military and law enforcement sniper units than any other rifle.
7. PF actions are not suitable for a DGR and it is irrelevant that the M1, M14, M16, & AK47 which were designed for hunting men that can shoot back are all PF actions.
8. 95 deg F in Africa is different than 95 deg F in TX or CA and that is why you must worry about ammunition temperature in Africa (even though most safaris take place in winter) but not in TX or in CA.
9. The size of a ding in a gun's finish doesn't matter, what matters is whether it’s a safe ding or not.
10. 1 in a row is a trend, 2 in a row is statistically significant, and 3 in a row is an irrefutable fact.
11. Never buy a WSM or RCM cartridge for a safari rifle or your go to rifle in the USA because if they lose your ammo you can't find replacement ammo but don't worry 280 Rem, 338-06, 35 Whelen, and all Weatherby cartridges abound in Africa and back country stores.
12. A well hit animal can run 75 yds. in the open and suddenly drop with no initial blood trail, but the one I shot from 200 yds. away that ran 10 yds. and disappeared into a thicket and was not found was lost because the bullet penciled thru. I am 100% certain of this even though I have no physical evidence.
13. A 300 Win Mag is a 500 yard elk cartridge but a 308 Win is not a 300 yard elk cartridge even though the same bullet is travelling at the same velocity at those respective distances.
 
Posts: 10181 | Location: Loving retirement in Boise, ID | Registered: 16 December 2003Reply With Quote
One of Us
Picture of Nakihunter
posted Hide Post
My guess would be around 2700 to 2800 fps with that Re15 load.

You should get 3000+ fps with 4530, N160, Re 19. I would stick to the same bullet as my experience is that any bullet that shoots a good group with one load will often do well with other powders as well - USUALLY Wink

quote:
Originally posted by D Humbarger:
Here's a group that I shot with my 284 win that I cut WAY too long a throat. I must say that I am VERY suprised because I have repeated this goup as I thought it must be a fluke. I will shoot that load over a chrony wednesday & find out what the velocity is. Any predictions?



"When the wind stops....start rowing. When the wind starts, get the sail up quick."
 
Posts: 11420 | Location: New Zealand | Registered: 02 July 2008Reply With Quote
One of Us
posted Hide Post
There are a few things to point out from woods very useful photo. First, the load at .045" off the lands had the second best ES and SD, yet was the least accurate of 6 loads. Second, as the bullet was seated deeper in the case, velocity (and therefore pressure) decreased with each and every increment. Third, the velocity difference between the .015" and the .090" off loads was only 53 fps, certainly not enough to make a difference on game.

I always try to start .015" off the lands, and when a max powder charge is found, seat deeper until the magic accuracy is found. Pressure will always be less than max with this system.
 
Posts: 421 | Registered: 07 January 2012Reply With Quote
One of Us
Picture of woods
posted Hide Post
quote:
Originally posted by whelenite:
There are a few things to point out from woods very useful photo. First, the load at .045" off the lands had the second best ES and SD, yet was the least accurate of 6 loads. Second, as the bullet was seated deeper in the case, velocity (and therefore pressure) decreased with each and every increment. Third, the velocity difference between the .015" and the .090" off loads was only 53 fps, certainly not enough to make a difference on game.

I always try to start .015" off the lands, and when a max powder charge is found, seat deeper until the magic accuracy is found. Pressure will always be less than max with this system.


Exactly

And I would add that the usefulness of getting data on the velocity of each load is to find the least ES and SD. IMO this accomplishes what the Audette and OCW methods are striving to do and that is to find the load where minor variations in load or climatic conditions will stand the least chance of having a major effect on POI and trajectory.


____________________________________
There are those who would misteach us that to stick in a rut is consistency - and a virtue, and that to climb out of the rut is inconsistency - and a vice.
- Mark Twain |

Chinese Proverb: When someone shares something of value with you and you benefit from it, you have a moral obligation to share it with others.

___________________________________
 
Posts: 2750 | Location: Houston, Tx | Registered: 17 January 2005Reply With Quote
  Powered by Social Strata  
 


Copyright December 1997-2023 Accuratereloading.com


Visit our on-line store for AR Memorabilia