Load work up...seating depth test first OR charge weight first?

[Mikecr]

The difference in views is in what people think seating testing is, and what actual FULL SEATING TESTING is.
Best seating testing is with a reduced load, far from any desirable node.
If you do any significant seating testing while at best powder load, you'll be collapsing powder tune while seating testing. That's 2 changes at once, which typically leads shooters to think whatever seating they pulled out of their butt for powder testing must have been the best. After all, any change from there seems to make it worse..
And wha-la, .020 OTL always SEEMS like the best place to start..

Let me suggest this: If you do full seating testing after powder, and find best seating >20thou different, or come into or off the lands different from as used in powder testing, then go back and start over with powder testing.
Yeah, it's tail chasing. But you'll learn while eventually reaching your best.

 

[dsculley]

Mikecr is right. Seating depth first with reduced load making coarse adjustments to find the seating depth node. Test for powder charge using your preferred method (We could debate the best method for this as well but would just be re-hashing the subject as has been debated many times). Fine tune your seating depth, fine tune your powder charge.
The advantage of this is you wind up with a very forgiving load. Usually, as you fine tune your seating depth and powder charge in the last step all your groups will be good, just that you will wind up with a combination that is best. So if your powder charge is off a bit, or seating depth varies a bit the resulting group will still be "good", just not "best". When I have found a good load using this method, I can just throw my charges without weighing for some activities. Or I can spend more time and weigh each charge for more precision shooting.

FWIW

 

[Mike 338]

The difference in views is in what people think seating testing is, and what actual FULL SEATING TESTING is.
Best seating testing is with a reduced load, far from any desirable node.
If you do any significant seating testing while at best powder load, you'll be collapsing powder tune while seating testing. That's 2 changes at once, which typically leads shooters to think whatever seating they pulled out of their butt for powder testing must have been the best. After all, any change from there seems to make it worse..
And wha-la, .020 OTL always SEEMS like the best place to start..

Let me suggest this: If you do full seating testing after powder, and find best seating >20thou different, or come into or off the lands different from as used in powder testing, then go back and start over with powder testing.
Yeah, it's tail chasing. But you'll learn while eventually reaching your best.

I'm slow in the uptake. Why is "reduced load" better?

 

[Defiance7mm]

Charge weight

 

[Lonewolf74]

I'm slow in the uptake. Why is "reduced load" better?

I believe the reasoning hear is when you move the bullet in or out of a case your essentially changing case capacity which can effect how a charge act's in a particular setup, I'm sure we have all seen the effects of changing brass in a load and I would think of it in the same way.

I don't think the actual charge weight matters as long as it's safe so it might as well be a lower charge weight. All your looking to find is the seating depth the bullet performs best at. Once you have that you keep that depth and work on powder charge, that way your relative case capacity stays the same and the charge always act identical.

This is what my reasoning tells me anyway so if I'm wrong chime in.

 

[Mikecr]

Lonewolf74 describes it well (probably better than me).

 

[lotek]

Lonewolf74 describes it well (probably better than me).

I'm no expert but I start with .035 my savage 10 likes so much and run my charges

 

[Korhil78]

Guess I've never really stopped to think about it but I do seating depth first and then fine tune powder charge. Too many variables for me the other way around. But it seems to work as a lot of people do it.

 

[Reload10]

Just made some rounds to do a seat test first. I normally am limited by mag length in other projects and seat as long as mag will allow then do a ocw Test. This 6.5x284 I started on the lands and worked back in 0.015" increments. Used 56gr Retumbo for all loads. We'll see what coal it likes, then I'm hoping to up the charge a grain or 2 to reach velocity.

 

[joep17]

Oh the beauty of our hobby. Like a road map, there are a dozen ways to get to the same place. All of us end up at our destination but might have chosen a different route.

For me I do a ladder test at 300 m and pick powder weight for the harmonics. I usually start this at 15 thou off the lands. Great part is that a chrono usually showed a low SD for these charges. Then I tweak the seating depth to get the best groups at 300 metres.

2 strange exceptions were a rem 700 in 308 that would not shoot unless there was bullet crush or jam into the lands before it would shoot anything well and a 270 that shot smaller groups at 300 than 100 which I put back to my bullet choice that did not stabilize until well into flight.

Every barrel and gun has its own personality. Keep up the experimenting guys.

 

[J E Custom]

The reason I start with powder first Is to find the best Powder and primer combination. What I want is a primer to get the best, most consistent burn from the preferred powder (SDs) this tells me that I have a very consistent pressure for best accuracy.

I try to eliminate one thing at a time to reduce the number of loads required to find an accurate load. for years I tried hit and miss changes trying one thing and another. Sometimes I was lucky and other times I wasn't and loaded many test before I found the one that was best.

With the price of components and barrel life becoming an issue, I decided to streamline my process buy taking a methodical approach and starting with one thing at a time and the first thing that was not effected as much as the others when other changes were made was the powder and primer combanation.

When building a horse power engine, You first decided what fuel you will use, Then everything else can be decided. Cartridges have the same requirements in order to get performance. So I start with the fuel (Powder) and go from there. This procedure works best for me and eliminates excessive testing. Other may have/use other processes that works for them. This is just the way I work up accuracy loads for my firearms after over 50 years of reloading evolution.

The best Method ? The one that produces the best results.

J E CUSTOM

 

[Rhovee]

I use to do seating first. If I have a good use from a gunsmith on seating depth with his reamer based on previous loads I will use that. Something that really throws you off is that the best seating depth can change with different nodes you are running. My 3000 node seating depth and 3070 seating depth are not the same. Very close but it's pretty obvious it's not exactly. For instance on a 28
Nosler and 195s. Seems almost everyone runs them at .015 or .020 off. So that would be a good place to start and then shoot a ladder.

 

[Lonewolf74]

Mikecr, have you found the optimum seating depth to remain constant regardless of powder or other components used?

I assumed it would but what Rhovee said makes me wonder and I have not done enough of my own testing to know.

 

[Lonewolf74]

JE, when first testing for powder are you using several different powder and primer combos at a lower charge to see which yields the lowest ES and SD?
Then from there do you test seating depth then do a ladder with your chosen powder to find the charge weight node?

Do you find with a particular powder primer combo if SD is good at a light charge it will continue to have good or better SD as you climb in charge weight to find a node?

Also if you find a good powder primer combo in virgin brass have you found it to remain good in fire formed brass? What I'm getting at hear is could you do this step (finding a good combo not a node) while fire forming your brass?