Initial powder testing

[Dave M.]

When starting with a new cartridge and developing the proper charge weight, I have typically used my go to primer for that cartridge, seated the bullets at 0.010-0.015” into the lands.
I’m curious what seating depth others use in their initial powder charge testing? And why?
I generally test powder charge starting about 2-3% under max charge weight and I work up in 0.2 or 0.3 grain increments. What increments are you guys using? And why?
Finally, I have always loaded rounds over where I think the max charge will be and I safely work up and upon first signs of overpressure, I won’t shoot any more rounds at or above that charge level.

Best regards guys,
Dave

 

[fisherman987]

I never jump . Start or finish. But that's just me. I do start at + .010 to +.011. That gives me room above and below to adjust seating depth to fine tune the load after powder charge is determined.

 

[RegionRat]

It is best to narrow the context of the kind of shooting or the type of gun we are discussing to get a more refined answer. Even naming the cartridge and bullet will help with keeping the discussion focused. What would be considered appropriate for one context, would be completely wrong in another. That said...

I’m curious what seating depth others use in their initial powder charge testing? And why?

The decision to even include jam in a new rig context, would depend on your willingness to run with all the factors that go along with it.
If using jam is on the table, and we have no pressure background data to pull from, I would still start with a jump of 0.010" - 0.020" for the first charge pressure tests and then explore the seating depth/jam.

I generally test powder charge starting about 2-3% under max charge weight and I work up in 0.2 or 0.3 grain increments. What increments are you guys using? And why?

Again, this is another "it depends" answer based on the context.
For example, the case volume and bullet weight will determine some of this, and the history determines the rest.
A higher energy rig is naturally going to use a higher volume case, so a fine step in one of those is going to look big compared to something like a 223.

If we have a history with the pattern of the gun, cartridge and bullet, then we don't need as much caution or fine data. We would already know roughly where to look and what to expect.

On the other hand, starting a wildcat where there is no published data means you will likely use a much finer step early in the explorations, and then decide on which charge weights to explore with follow up tests.

A 0.2 grain sweep is appropriate for something like a known design where you already have a good idea of where and how wide your window should be, but not if you are completely in the dark. Some rigs don't have known performance or a wide tune window, others could almost shoot anything you feed them.

I am not shy about using internal ballistics codes, both public and private, before I start to plan for a day at the range. I will also often only pre-load some of the test, and load the rest at the range so I can adjust plans on the fly.

New barrels take some shots to settle. If you are in uncharted territory with a new barrel, learning to load at the range saves a lot of time and you go home with more answers than questions.

If you are not talking about a wildcat that has no published pressure data or recipes, then it is better to name the details and your answers would be more focused. YMMV

 

[Straightshooter1]

When starting with a new cartridge and developing the proper charge weight, I have typically used my go to primer for that cartridge, seated the bullets at 0.010-0.015” into the lands.
I’m curious what seating depth others use in their initial powder charge testing? And why?
I generally test powder charge starting about 2-3% under max charge weight and I work up in 0.2 or 0.3 grain increments. What increments are you guys using? And why?
Finally, I have always loaded rounds over where I think the max charge will be and I safely work up and upon first signs of overpressure, I won’t shoot any more rounds at or above that charge level.

Best regards guys,
Dave

I always start with a seating depth that's .010" off the lands as I typically plan on hand feeding, unless I plan on seating to jam. Closer the the lands the pressure spike increase quickly from .010" and into the lands. When loading to seat into the lands with a jam to find a jam seating that works best, I'll start at .015 of jam and back out in .002 increments. Starting at .010" off the lands, I'll back off at .003" increments (the increments being dependent on the size of the cartridge). When I'm loading for a cartridge to fit into a mag, I'll start at mag length and move back in the seating from there by .003".

As for powder charges, I'll look for a powder that'll give me ~100% case fill and still be under recommended max charge. Then I'll use .3 gr increments to find a charge that works best (the size of increments, again depending of the size of the cartridge). I find I tend to get best results with my cases are filled closed to 100%.

Before I do any incremental tuning of a load, I want to know where the pressure limit is. So I always run a pressure test to find where my max is for the particular powder in my particular gun. The published max loads are rarely the max I find, mainly because I'm loading my cartridges much longer that what they do to come up with their max.

 

[Dave M.]

I never jam. Start or finish. But that,s just me. Tommy Mc

Jam to me is different than loading “into the lands”. Depending on how much “neck tension” I use, the difference between “hard jam” and “where the lands start” is between .020-032”.

Dave

 

[Dave M.]

It is best to narrow the context of the kind of shooting or the type of gun we are discussing to get a more refined answer. Even naming the cartridge and bullet will help with keeping the discussion focused. What would be considered appropriate for one context, would be completely wrong in another. That said...


The decision to even include jam in a new rig context, would depend on your willingness to run with all the factors that go along with it.
If using jam is on the table, and we have no pressure background data to pull from, I would still start with a jump of 0.010" - 0.020" for the first charge pressure tests and then explore the seating depth/jam.


Again, this is another "it depends" answer based on the context.
For example, the case volume and bullet weight will determine some of this, and the history determines the rest.
A higher energy rig is naturally going to use a higher volume case, so a fine step in one of those is going to look big compared to something like a 223.

If we have a history with the pattern of the gun, cartridge and bullet, then we don't need as much caution or fine data. We would already know roughly where to look and what to expect.

On the other hand, starting a wildcat where there is no published data means you will likely use a much finer step early in the explorations, and then decide on which charge weights to explore with follow up tests.

A 0.2 grain sweep is appropriate for something like a known design where you already have a good idea of where and how wide your window should be, but not if you are completely in the dark. Some rigs don't have known performance or a wide tune window, others could almost shoot anything you feed them.

I am not shy about using internal ballistics codes, both public and private, before I start to plan for a day at the range. I will also often only pre-load some of the test, and load the rest at the range so I can adjust plans on the fly.

New barrels take some shots to settle. If you are in uncharted territory with a new barrel, learning to load at the range saves a lot of time and you go home with more answers than questions.

If you are not talking about a wildcat that has no published pressure data or recipes, then it is better to name the details and your answers would be more focused. YMMV

7-6.5PRCW Berger 180g hybrids
Lapua 6.5PRC brass necked up to 7mm
New barrel
Planning to start at 53.6gr of N555 and work up through 56.0
Planning to seating all bullets .015” into the lands.
Will be using 2 thou “neck tension” for all initial tuning loads.

Dave

 

[Big Mc]

Jam to me is different than loading “into the lands”. Depending on how much “neck tension” I use, the difference between “hard jam” and “where the lands start” is between .020-032”.

Dave

Any way you sugar coat it Jam Is Jam. Tommy Mc

 

[potatoe]

 

[Clancy]

This is sort of a funny question to me, because I do seating depth first.

Although, I can remember working with a brand new cartridge for which load data did not yet exist, and I did a pressure test at .015 longer than touch.

I then did my normal seating depth test followed by powder. After doing seating first, I can’t imagine starting with powder ever again, because the tuning windows have been so much wider.

I’d say the short answer to your question is probably the longest you would ever intend to load- then you only have one way to go.

 

[6MMsteve]

I myself try to stay .015 to .020 off the lands it's what I'm thinking not exact but close..I'm just trying to not have issues

 

[Bottom Fodder]

I’m a jammer I’ve always been able to fine what I’m looking for with a slight jam

 

[JMayo]

Touch.
I see what others are successfully using, back off from there a grain or two and work up & pass by a few tenths .

 

[boltfluter]

When starting with a new cartridge and developing the proper charge weight, I have typically used my go to primer for that cartridge, seated the bullets at 0.010-0.015” into the lands.
I’m curious what seating depth others use in their initial powder charge testing? And why?
I generally test powder charge starting about 2-3% under max charge weight and I work up in 0.2 or 0.3 grain increments. What increments are you guys using? And why?
Finally, I have always loaded rounds over where I think the max charge will be and I safely work up and upon first signs of overpressure, I won’t shoot any more rounds at or above that charge level.

Best regards guys,
Dave

Dave,
I do it exactly like you. If a person has never tried seating .010 to .015 into the rifling, they don't know what they may be missing! I have never pulled a bullet from a case this way. When a bullet starts straight into the rifling magical things can and do happen. Tony Boyer won a few matches doing this. Lol.
Paul

 

[SKWERLZ]

I never jam. Start or finish. But that,s just me. Tommy Mc

Same.
With a new barrel I usually WAG a load about 100fps below my desired speed and I’ll play around with seating position while I get 100 round in it and see how it does at distance.

 

[Ringostar]

View attachment 1664551

The radar appears to be……JAMMED!

 

[ELR LVR]

When starting with a new cartridge and developing the proper charge weight, I have typically used my go to primer for that cartridge, seated the bullets at 0.010-0.015” into the lands.
I’m curious what seating depth others use in their initial powder charge testing? And why?
I generally test powder charge starting about 2-3% under max charge weight and I work up in 0.2 or 0.3 grain increments. What increments are you guys using? And why?
Finally, I have always loaded rounds over where I think the max charge will be and I safely work up and upon first signs of overpressure, I won’t shoot any more rounds at or above that charge level.

Best regards guys,
Dave

For me it depends on the caliber and bullet used
Most 224 cal cartridges are going to be off the lands
So I will arbitrarily use .010" off to start
Very often it likes it even though this may not be it's most optimum seating depth its good for load development until its time to hone in seating depth.
--------------
With long range rifles I almost always seat into the lands
Now come to think of it, I guess this is why I start with seating depth first because with Long range rifles and seating into the lands....... it usually does not shoot well until you've found the seating depth it likes which could be .060" in
So I play with seating depth first then hone in on the powder charge after
Good question there.

 

[Rat Rifle]

Seat .060” In? How is that done? Just Askin?

 

[BoydAllen]

For short range BR and light bullet varmint loads I like to start with marks on the bullet that are shorter than wide. If I am trying a new powder I will drop down to a lighter, but book safe load that is lighter than I ever plan to shoot and do a one shot per load pressure test, all on the same target, shooting over flags, on a day when the wind is easy to deal with. I shoot them all in the same condition, noting where each successive shot lands. I go all the way to pressure signs that a little more than I would want to shoot. After finishing shooting I examine the target for any clustering and do a three shot test on the middle or average value of the best looking one. Charge intervals are usually .3 for up to Swift and .5 for larger.

 

[Bronsin]

I recently did a test for my PPC in the same way, but with .005 jump. I was looking for higher nodes, and found them. Ran the test at 300 yards to see what charges grouped the best. Testing at 100 yards just wasn't separating the wheat from the chaff.

 

[Dave M.]

Seat .060” In? How is that done? Just Askin?

0.060” seems extreme. My experience says that from touch to jam is typically between 0.020-.032”, I’ve never seen more than 0.040” (and I’ve only seen that on one .308 win barrel).
Dave