Bullet seating depth Q

bigHUN

bigHUN

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Finally today a first visit to my range this year.
I did my very first powder re-load back in December, but unfortunately the weather didn't cooperate.
In meantime also I collected my full set of Wilson tools I may need for any sort of scenarios I have learned along the way of re-loading diy.


Lapua W308 brass (inherited, history unknown), powder Varget, bullet 155gn Sierra Match 2155, seating depth 0.033".
I had five batches of powder in increments from 46gn to 46.8gn to test 5 shot groups each. Testing @ 300 Meters, 17C, 33% hum, 1006.8mb.

#1 group of 5 - 46.0gn - Av 2994 fps
#2 group of 5 - 46.2gn - Av 2997 fps this group seem to me the tightest, 1.1" width and 1.5" height elongated in 45 deg to Right side.
#3 group of 5 - 46.4gn - Av 3017 fps
#4 group of 5 - 46.6gn - Av 3013 fps
#5 group of 5 - 46.8gn - Av 3051 fps

Me personally I don't like to see these high speeds, I may create in the future couple batches less powder sub 40gn and re-test for groups.
The next step I will do bullet seating in increments, probably start from current 0.033 and going up and down several steps in 0.003"

My Question is:

All what I have seen pictures online and forums - people testing seating depth @ 100M/y and usually three shots?
Why 100? Why not 200 or 300?
Any valid reason? I am just trying to learn how to read ...
 
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Why 100? Convenience? That was what was available?
Making decisions based on a single group might not be worthwhile. Three shot groups? Why bother?
You mention 40 grains. I assume you mean 46.
What is your barrel length? Velocities around 3000fps with 155gr bullets should produce excellent results. 3000fps works for me, with barrels 28-30 inches long.
You mention seating depth of .033", and experimenting with increments of .003". A sixteenth of an inch is .0625". Surely .033 is a typo. Or are you referring to distance from the ogive to the leade?
The Sierra 2155 is very tolerant when it comes to jump to the leade. VLD bullets may be more sensitive.
 
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to save components
@100m/y groups are less sensitive to wind and form errors
the 3 shot groups (sometimes 2) are enough to find the depth (or depth range) that would work best for a hundred rounds or so.
 
I usually do 0.003” tests at 100.
Then I select the node and test 0.001” on either side at 300. It works well.
Also your group 1 and 2 look good fps wise. You could re test 1 and 2, and one step below group 1, for powder, at 300 as well.

This was my last seating depth test results.
 

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I would recommend using a proper load development methodology and sticking to it before working out seating depth.

If you are trying to optimize multiple data points at the same time. You will never be able to isolate one at a time so you will endlessly chase your tail.
 
Beeron said:
how are you measuring seating depth??
Click to expand...
I made a dummy brass (drilled out the primer pockets), loctite the neck and just started pressing in the bullet.
Take that load and close the bolt, let it cure in the closed position for a good hour.
That is my sample - zero distance from the ogive to the leade
I zero my Wilson seating die to that load length and back out 0.033". Why 0.033" it just happened, I had to start somewhere...
I made two of these just to make sure no rounding errors. Max difference is 0.001" between the two samples. Measured with the Wilson seating die (picture for sample only).

20241219_152934.jpg

I also have the Hornady Lock-n-Load comparator set, I don't really like it how is not consistent with ogive.

Yes I made a typo in OP, suppose to be 46.0gn, I have correct it.

A cold wave is coming again over the weekend, I will reload couple batches starting from below 45.6gn to 46.4 gn

I have more boxes of Sierra 2155 I want to shoot them up to 300M only.
For longer distances 500 and longer I hear the 2156 works better, saving those for now.

Also I just finished my press force meter, expecting shocking results when I start pressing the bullets into the brass.
This box of brass that I inherited the shells so inconsistent, I want to shot them all, anneal and start from fresh up.

Edit:
I forgot to say. For next visit I will glue the target paper on larger sheet of cardboard, today had a little problem with the backstop was not maintained for some time and all my shots were ripping up the holes edges.
I have a high power 10-50x60 scope, I can see how I am punching my holes at 300.
Also maybe next time I will test at 200, less wind less interference.
But testing at 100 probably won't show much other then a larger ragged hole. This why I asked why people testing seating depth at 100... how to read if any possible pattern not visible?
 
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bigHUN said:
I made a dummy brass (drilled out the primer pockets), loctite the neck and just started pressing in the bullet.
Take that load and close the bolt, let it cure in the closed position for a good hour.
That is my sample - zero distance from the ogive to the leade
I zero my Wilson seating die to that load length and back out 0.033". Why 0.033" it just happened, I had to start somewhere...
I made two of these just to make sure no rounding errors. Max difference is 0.001" between the two samples. Measured with the Wilson seating die (picture for sample only).

View attachment 923462

I also have the Hornady Lock-n-Load comparator set, I don't really like it how is not consistent with ogive.

Yes I made a typo in OP, suppose to be 46.0gn, I have correct it.

A cold wave is coming again over the weekend, I will reload couple batches starting from below 45.6gn to 46.4 gn

I have more boxes of Sierra 2155 I want to shoot them up to 300M only.
For longer distances 500 and longer I hear the 2156 works better, saving those for now.

Also I just finished my press force meter, expecting shocking results when I start pressing the bullets into the brass.
This box of brass that I inherited the shells so inconsistent, I want to shot them all, anneal and start from fresh up.
Click to expand...
MmmmKay.

Sounds serious.

I approach loads a bit differently.
But I admire the neurosis.

Do u use sizing dies and expander balls for the neck or mandrels?

I have been finding that if i start with the COAL in whatever load book, i rarely need to change that but thats my start point.
Once i have a desired velocity, i might play with Seating depth a bit but only if my groups open up outside of 3/4” or so.

I do focus on base-ogive if i change projectiles. But i dont “chase the lands” per se.

It sounds like u have all the necessary attention to detail to get it sorted.

My only advice, if u can call it that, is that 308 brass is pretty much ubiquitous and inexpensive. No need to mess with unknown “inherited” brass.
 
You can normally see seating depth changes at 100, I just do three shots per target, and the group shape will change, but you will need to verify and fine tune farther out later.
 
100 yds / meters is industry standard all loading manuals and powder manufactures and bullet manufactures do there testing at 100 yds if you shoot a 1// " group at 100 then mathematically it's 1 1/2 " at 300 yds
when you measure groups you measure from outside to outside at the furthest point not groups inside of inside groups
or centre to centre of the bullet hole
 
I got this Rem700 f-class Win308 second hand last summer. A friend of my was loading amo for me couple batches until he finally gave up with that :)
He loaded my trunk with any kinda extra tools he was collecting for years and just taking up space.
I just needed to buy the die sets, and I decided for Wilson all in, I am shooting a single calibre 308 only.
I think I have everything, the brass sizing die with several size bushings, case length cutter and gauges to check all around the brass, mandrel die.
Today test were my first step in reloading.
I feel confident what I am doing so far with mechanics, my background was in high precision fabrications.
And always asking you guys if I have a confusion before I make my next step.
Thanks a lot.
 
Silverado said:
Do you know where your ogive/land relationship is vs your seating depths? It'd be a lot cooler if you did.
Click to expand...
Sorry, I don't understand what you asking here. Maybe my language or the dictionary I did not learned yet.
I made two dummy amo where the ogive was pressed into leade, I would assume that is a zero jump length.
From that sample amo I backed my bullet sitting 0.033" only to start with something. Maybe I shall start 0.040 or 0.050 ...
 
bigHUN said:
Sorry, I don't understand what you asking here. Maybe my language or the dictionary I did not learned yet.
I made two dummy amo where the ogive was pressed into leade, I would assume that is a zero jump length.
From that sample amo I backed my bullet sitting 0.033" only to start with something. Maybe I shall start 0.040 or 0.050 ...
Click to expand...
Apologies are on me, I use some sarcastic language that was a bit confusing. I believe what you're saying is that you've located the distance to the lands, and have started with a seating depth which is 33/1000 of an inch less than that. Do I have that right? If so, you're in good shape, I used to only bother with adjustments of 10 thou at a time and it worked good enough for me. I was always really happy using a Hornady OAL gauge and caliper, but now that I've seen them I think you could just about make your own if you were careful. It just lets you stop the guess work and know exactly where the ogive starts relative to the case head. From there, it's just a matter of having a good seating die set up.

Edit: If those powder loads or MVs give you the creeps, I had one rifle that shot the same groups at 100-200 with 46.8gr Varget, and 42.5gr Varget, 'nodes' I think you call that. Different MVs by far of course, all other factors exactly the same.
 
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bigHUN said:
Sorry, I don't understand what you asking here. Maybe my language or the dictionary I did not learned yet.
I made two dummy amo where the ogive was pressed into leade, I would assume that is a zero jump length.
From that sample amo I backed my bullet sitting 0.033" only to start with something. Maybe I shall start 0.040 or 0.050 ...
Click to expand...
I'm no expert, but what I've seen and learned is the 0.033 is a reasonable place to start. I watched Eric Cortina's video on this the other day, and I think he starts at 0.020 off. He also has a different way of thinking about it too. Going up and down from 0.033 in 0.003 increments also sounds completely reasonable to me.

Let us know how it goes!!

SRS
 
Sounds like you're on the straight and narrow path to some great reloading !! I usually go up in .03 gr between loads and load 5 shots for each of my groups. Only cuz I love to plink..lol

For 45 yrs, I've done all my load development and testing @ 100 & 200 yds because that's all that was / is available for most of us. The odd time, during development, surprisingly, I've seen some very noticeable spread differences between those two sight in ranges with the same loads. By the same...I've had some incredible results @ 100 and 200 yds with my 223 / Varget / 75 gr A-maxes !
 
This is an inherited box of 100 brass, the primers were installed at the time I received, not much I could do.
I didn't had the tools neither basic knowledge to prepare the cases properly.
Pretty much I have to shoot these now like a drunken soldier to get to a point - annealing and start from scratch. I have no problem with that, I like plinking as well.

What I have seen yesterday, the ES/SD variations. Not a tightest SD gives the tightest groups.
This is pretty much a same situation what I have learned with my BR airguns.
If I tighten - in small steps - the ES/SD, playing with power and speed - there are the nodes where the groups shrinks, keep going and the groups spread, and so on.

Question:
For now just to start my shooting season.... I am focusing for distance up to 300 M ....
What is an acceptable ballpark with SD that shall keep the groups tighter?

I will be playing with case preps and seating depths next couple days. Homework only in my basement cave, expecting rain and mud in a next week or so.
 
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