Powder charge and seating depth

[werth338]

I was listening to a podcast with Satterlee about a little less then a year ago on ModernDay Sniper. He does a depth test first at a safe charge and then a ladder test. I always did ladder 30 off and then depth. I have since changed to the new method and has worked well for me. There are multiple ways to do it and not sure one is better than the other. I think pick one and be consistent and meticulous with the process.

 

[waveslayer]

I tried it with a laser mic trained on the muzzle, and feeding DAS sampling. Didn't work.
It was sensitive enough but not fast enough. When I looked into resolving that, the price of the endeavor went out of control. $10K+ just for the needed sampling software..
The vibrations definitely matter though. Press against your action tang with a thumb in the middle of your next group.
Jam a piece of cardboard between your barrel and stock. It doesn't affect your load, but look at what it does to POI.

Oh I agree. Like you said, harmonics are almost impossible to get actual data for...
But touching the barrel will change the POI

 

[waveslayer]

Litz even had a podcast or something on it and said harmonics aren't as important as we think

 

[Will Gray]

I seat bullets with a goal of one diameter of contact with the brass and off the lands and short enough to fit and function from the magazine unless I am planning to single load each round. Normally I load hot, until pressure signs are present and then back off a bit. I often use magnum primers (because that is what I have the most of) on anything 243 and larger. Most of my barrels are from Shilen and yield better than 1/2" groups without fail.

 

[skipglo]

When doing the powder tests I normally take 20 to 30% under what the book says is the "Max" charge and then work back up in .3 gn incriminates to pressure

Most Min to Max loads are only a few grains difference, certainly not much more than 10 %. Reducing max by 30% would have a loader chasing their tail for a long while and burning ammo at the speed of sound! On a 60 gr load reduced by 30% and shooting in .3 back you would require 54 shells and then more to find pressure. However to each our own!

 

[Chas1]

Good video.

 

[Csbc4fun]

I usually seat the bullet for what it calls for from the book or bullet makers website, then I start low on charge and work up till I get good groups but what if my es is high say 30 fps it would mean my load is not good cause the high es. So Cortina says to start with seating depth 20 thousands shorter than what your bullet jams into lands, for 223 that would put me at 2.290, work up charge till you get low es and don't worry about group till you get that, once you do then go down on seating depth till groups are good and pretty much your done, besides getting at least 2 good and seating accordingly. Well the bullet manufacturer is saying to seat at 2.225 so it will take a lot of shots to get there from 2.290 if it does shoot better at 2.225 so now let's say I have a good powder charge and my bullet shoots best at 2.225, well the pressure is going to increase and is my es still gonna be good like when I started at 2.290 to find that charge. I will also say that I'm getting good groups at 2.225 and I tried making it longer and the groups fell off more the longer I made it, I went to 2.250 and stopped there cause it kept getting worse. Because of the cold and lots of snow here I haven't been using the Chrono so my groups are good at 100 and hopefully my spreads are low, if not, then what, change powder, primer? But my main question is why not seat or at least start where manufacturer recommends and if my final seating is very far from where I worked up charge will the charge stay the same, I don't think it would.

The information that helped me the most was from Mr. Cortina when he explains that the seating depth plays out like a sign wave. It will get better and then worse and then better again as you move in the same seating direction. Where you start doesn't matter. I start at the longest length my magazine will accept and go shorter from there which happens to be about 0.050" off the lands. The pattern for my rifle is good groups and about 0.020" further down the seating depth path good groups again. That's just me and my rifle, following EC's advice. It works and it is pretty "EC".

 

[WYMIKE]

Wow my seating depth for a 73 grain ELD-M in a .223 Wylde is 2.295" with an ES of 9 using CFE-223.

 

[Paulstarr]

I use an OAL gauge to the lands and then look at the manufacturers length for that bullet and take the one from the other in a lot of cases it can be as much as 200 thou.
Then I load up in 10 thou increments back from the lands to the recommended OAL and use the best group size as my length.It's easy to do with a micrometer sizing diet works for me.

 

[Mikecr]

Just keep in mind that a declaration(from anyone) that fails a test (any test), is not a truth.
Don't be star-struck from magazines, podcasts, and videos. Instead, wash every notion through skeptical & logical thinking of your own.

 

[waveslayer]

Just keep in mind that a declaration(from anyone) that fails a test (any test), is not a truth.
Don't be star-struck from magazines, podcasts, and videos. Instead, wash every notion through skeptical & logical thinking of your own.

amen, that's why I used my example of FGMM real world results. but too many variables to accurately have proof unless you can repeat specific variables and are measureable

 

[Gobbler256]

I usually seat the bullet for what it calls for from the book or bullet makers website, then I start low on charge and work up till I get good groups but what if my es is high say 30 fps it would mean my load is not good cause the high es. So Cortina says to start with seating depth 20 thousands shorter than what your bullet jams into lands, for 223 that would put me at 2.290, work up charge till you get low es and don't worry about group till you get that, once you do then go down on seating depth till groups are good and pretty much your done, besides getting at least 2 good and seating accordingly. Well the bullet manufacturer is saying to seat at 2.225 so it will take a lot of shots to get there from 2.290 if it does shoot better at 2.225 so now let's say I have a good powder charge and my bullet shoots best at 2.225, well the pressure is going to increase and is my es still gonna be good like when I started at 2.290 to find that charge. I will also say that I'm getting good groups at 2.225 and I tried making it longer and the groups fell off more the longer I made it, I went to 2.250 and stopped there cause it kept getting worse. Because of the cold and lots of snow here I haven't been using the Chrono so my groups are good at 100 and hopefully my spreads are low, if not, then what, change powder, primer? But my main question is why not seat or at least start where manufacturer recommends and if my final seating is very far from where I worked up charge will the charge stay the same, I don't think it would.

Shoot what your gun tells you it likes best!! The book is a general guide and every guns bore is different. Set the OBL according to your gun.

 

[Philward]

I always start about 0.030 off the lands and load the desired powder in steps of 0.5 grains up to close to max in whatever reference manual I decide to use-if its a bullet manufacturer manual of the bullet I'm using or the powder manufacturer load data for the weight of bullet I'm using. Look for velocity and pressure signs and when I get the velocity I'm satisfied with and no pressure signs I'll shoot for a group. If it shoots well I'll play with seating depth a bit. I never start at what the book says and anytime I have, because I've read where somebody says book seating depth is usually great, it doesn't shoot good at all. I'm not wasting hundreds of bullets and pounds of powder and primers. Exhaustive testing and record keeping over multiple trips to the shooting range under varying conditions invites a lot of chance for errors and not to mention the changing shooting form and feel you may have from session to session. I make it good enough and call it good.

 

[Mikecr]

I always start about 0.030 off the lands

It takes full seating testing to know where the best place to start is.
Pulling 30thou out of your butt is merely adding another abstract to your development.