17remhunter
Well-Known Member
Can bullet seating depth change the velocity of your load and point of impact?
Bullet seating depths
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Mikecr
Well-Known Member
It can change MV with a significant step as you near touching of lands.
It can greatly affect POI, and grouping.
You should do Berger's recommended full seating testing.
It can greatly affect POI, and grouping.
You should do Berger's recommended full seating testing.
sourdough44
Well-Known Member
Are we talking rifle load? Then for what round? Used in only one gun or multiple?
Hard rock
Well-Known Member
Some bullets are mor fi
Some bullets are more finiky too seating depths than others I usually find my max overall with what ever bullet of choice move away from lands around . 20 and work from there that way there's only one way too move unless your loading touching lands if touching lands back off powder charge and work back up safely
If you develop a load with a certain powder charge and a certain COAL and you are wanting to seat the bullets deeper and deeper trying to find a sweet spot your powder charge will get more compacted and hence a higher velocity and pressure. I generally back off just slightly as I go down with the seating depth to get back to my initial powder velocity. If will do the same pressure building when you get into the lands. It shouldn't do it so much before your length is approaching the lands though. It may actually decrease some until lands are touching and you start running the bullet into the lands.
shinbone
Well-Known Member
For velocity change, sometime yes, sometimes no.
Very very good Shinbone. Glad to see you putting that graph up. Very nice.
Okanogan
Well-Known Member
Especially when I'm trying to load subsonic, I find it makes a huge difference. Some powders like 300 BLK really like a compact charge and are hard to get consistent MV without being compact. While it isn't mentioned too much on this long range focused forum, seating depth can also greatly affect the ability of a semi-automatic to feed properly.
Berger Hybrid and Hammers are the easiest to load. Give at least .020 + and they don't care. I've heard of 0.500 jump on Hammer Hunters shooting well. But not personal experience.
I'm sure ButterBean will jump in on this.
I'm sure ButterBean will jump in on this.
nksmfamjp
Well-Known Member
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- Jan 5, 2004
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What software??For velocity change, sometime yes, sometimes no.
Berger Test
Load 24 rounds at the following COAL if you are a hunter (pulling a bullet out of the case with your rifling while in the field can be a hunt ending event that must be avoided)
1. .010 off the lands (jump) 6 rounds
2. .050 off the lands (jump) 6 rounds
3. .090 off the lands (jump) 6 rounds
4. .130 off the lands (jump) 6 rounds
Shoot 2 (separate) 3 shot groups in fair conditions to see how they group. The remarkable reality of this test is that one of these 4 COALs will outperform the other three by a considerable margin. Once you know which one of these 4 COAL shoots best then you can tweak the COAL +/- .002 or .005. Taking the time to set this test up will pay off when you find that your rifle is capable of shooting very well.
Hard rock
Well-Known Member
Touching the lands used to be the best way too go for your best accuracy when I started loading 50 yrs ago thats what I allways did but today things are a little different with monos etc so now in the lands or off the lands may work best you just have to play with seating depth and find out the hammer bullets seem too be real versatile with a lot of jump or closer to the lands that really helps with these mag lenght restrictions
shinbone
Well-Known Member
No special software - it is an Excel spreadsheet. The graph is made with the graphing function in Excel. It is not the easiest graphing software, but it is what I have on hand and am familiar with.
I am happy to send an Excel file to use as a template for you to experiment with.
