Seating Depth Matters

[rbp75503]

I am in the middle of load development of my recent Savage 6mm X 45 build. I had found a reasonable tight node and decided to tweak with changing seating depths. The distance to the lands is 1.925" so I varied the loads by .005" increments.

http://i993.photobucket.com/albums/af56/rbp71854/6-8-2015_Savage-Shilen_6x45mm_Sierra-95GR-1_zpsos8wofgw.jpg (http://s993.photobucket.com/user/rbp71854/media/6-8-2015_Savage-Shilen_6x45mm_Sierra-95GR-1_zpsos8wofgw.jpg.html)

[LongRange]

looks like .010 off the lands is the sweet spot.

[2scars]

I would think that the bottom right is a better group, at .005 off the lands. Unless I am missing something.

[LongRange]

I would think that the bottom right is a better group, at .005 off the lands. Unless I am missing something.

You must be missing the upper right....and i miss read his numbers...it is .015 off the lands.

[JTCrl]

You need to repeat this test to verify the results. You may be surprised at what you find.

[eddiesindian]

Great post. I'm in the process of load testing as well and am following your exact procedure as far as seating depth .
Great results!
I'm taking 10 shot groupings though.
Thanks for sharing!

[Bill C]

You need to repeat this test to verify the results. You may be surprised at what you find.

I agree with re-firing those groups.

Its great when you find the sweet spot for a load whether it is seating depth or powder charge or something else. It feeds the notion that we're good at what we do and that we can corral all these variables shoot successfully. However, there is something a little impractical about such loads. Any minor change, and accuracy is gone. I had a 223 load using ball powder that shot unbelievable 100 yard groups. However, as soon as temperatures changed, groups/scores opened up considerably.

I'd rather spend my time finding a no frills load that works the majority of the time.

Bill

[barrel-nut]

I agree with JTC and Bill C. If you look at all twenty rounds fired and overlay all the groups together, there are only four rounds that fall outside of the cluster in the center/right. Three in the first group (clean bore?) and one in the third group (flier?). I'd definitely try the whole thing again, and look for consistency. I'd say you're definitely on the right track.

[wingspar]

This is interesting. I just started reloading with the Lee Loader and just got a press that I have not set up yet. Until I get the press set up and find the distance to the lands in my rifle (.308) I’m just going by powder weight. I’ve seen plenty of conversation on where people think how far the bullet should be set back from the lands, anywhere from 0.001 to 0.020, but this is the first time I’ve seen this done, so I’m just posting to follow this. I’m sure the sweet spot off the lands would be different for all rifles.

[rbp75503]

Oh yes I am not finished with this powder/bullet combination. This was the 2nd round after finding the node at 20.5gr IMR3031. I also have a node at 21.5gr. After trying 21.5gr at 1.910" ogive the next step will be to load up 20 rounds of 20.5gr at 1.910" ogive to verify initial findings.


Of note I was very particular when seating the 20.5gr rounds. Each was seated with Wilson seating die and arbor press. And were measured and seated until they hit the correct dimension.I have found that the Sierras' ogive can be +/- .003" within a lot.

In the past I use to run 2-5 round groups for a total of 10 rounds for each powder weight. I have recently gone to one 5 round group with acceptable success.

Following is the 1st target for this powder bullet combo.

http://s993.photobucket.com/user/rbp71854/media/5-26-2015_Savage-Shilen_6x45mm_Sierra-95GR-1_zpsqhsfxzhs.jpg.html]http://i993.photobucket.com/albums/af56/rbp71854/5-26-2015_Savage-Shilen_6x45mm_Sierra-95GR-1_zpsqhsfxzhs.jpg

[eddiesindian]

Oh yes I am not finished with this powder/bullet combination. This was the 2nd round after finding the node at 20.5gr IMR3031. I also have a node at 21.5gr. After trying 21.5gr at 1.910" ogive the next step will be to load up 20 rounds of 20.5gr at 1.910" ogive to verify initial findings.


Of note I was very particular when seating the 20.5gr rounds. Each was seated with Wilson seating die and arbor press. And were measured and seated until they hit the correct dimension.I have found that the Sierras' ogive can be +/- .003" within a lot.

In the past I use to run 2-5 round groups for a total of 10 rounds for each powder weight. I have recently gone to one 5 round group with acceptable success.

Following is the 1st target for this powder bullet combo.

http://s993.photobucket.com/user/rbp71854/media/5-26-2015_Savage-Shilen_6x45mm_Sierra-95GR-1_zpsqhsfxzhs.jpg.html]http://i993.photobucket.com/albums/af56/rbp71854/5-26-2015_Savage-Shilen_6x45mm_Sierra-95GR-1_zpsqhsfxzhs.jpg

IMHO...Id load up 10 at 1.910 @ 20.5gr and ck the results. Im almost positive youll like the results. (providing everything is the same ie:temp.humidity, etc)
I think youve already hit paydirt.
You sometimes find yourself doing more load testing than actual compeditive shooting. Sure it pays off in the end but THeres always "another node" with another "threshold" somewhere.
The art of shooting and reloading for the same results "almost everytime" is a terrible addiction. Sure wish i could find a doctor to cure my desease. Havent found one yet......so I guess we just keep doing what were doing lololololo

[BowNut]

Once you hit your initial powder node and after you find your depth, go back and load up rounds in .1 increments a half grain above and below your powder node. This will tell you how wide your node is. After I did this I found out my node was .5 grain wide(maintaining .4 moa) which allows me to throw charges straight from powder dispenser without worrying about .1 or .2g variation.
Learned this from Erik Cortina thread on ACCURATE SHOOTER forum. 108 pages long.....but lots of information.

[mikgarus]

Once you hit your initial powder node and after you find your depth, go back and load up rounds in .1 increments a half grain above and below your powder node. This will tell you how wide your node is. After I did this I found out my node was .5 grain wide(maintaining .4 moa) which allows me to throw charges straight from powder dispenser without worrying about .1 or .2g variation.
Learned this from Erik Cortina thread on ACCURATE SHOOTER forum. 108 pages long.....but lots of information.

That's basically an OCW load.
http://optimalchargeweight.embarqspace.com/