Seat depth test results interpretation

[Deleted noremaximus]

What I am trying to say in a nice way is that at this point your data is not worth much.

Start over with a test plan that will give meaningful results. I gave you an example of a test plan that involves five ten shot groups and will probably require at least one follow up test. Some will say that is a lot of rounds but you just conducted a 24 shot test that is worthless.

Mother Nature is a bitch and it takes a statistically significant set of data to draw a reasonable conclusion.

Best wishes and thanks for sharing data. Opinions are cheep but data is valuable.

thank you.

 

[JimSC]

Anyone that has shot the 140 RDF bullets, does this look normal? Or is something off in my brass prep? Thanks.

RDF = random damn flyer. I have 2 box's in the cabinet both half full . I tried them in .223 and .260 Remington and never could get a half way decent group. Just my opinion but they are a waste of powder and primers

 

[LCazador]

This is my interpretation of your groups. You have a powder charge that went from horizontal to vertical in a charge of 39.5 to 40.5, excellent information here. Then you have a .015" seating depth to a .021" that also went from horizontal to vertical also excellent info. I may not have the correct orientation here but that's not relevant. Try working without these two measurements. In other words try a 39.5 charge with .015", .018", and .021, a 40.0 charge with .015", .018", and .021". and a 40.5 charge with .015", .018", and .021" . That's 3 shot groups and let things cool off inbetween. Make sure you're shooting the same wind and condition for each group. Pick the three best groups out of that process and work those groups in three bullet tensions for each. with three sizing die bushings for each as well. It's a lot of work but you need to investigate the best of what you have. I hope all your brass is fireformed prior to doing any of this. I would also advise that every piece of brass has the same neck thickness, shoulder bump, and case length.

 

[Ccrider]

Interesting post. Lot of well reasoned guesses. Truth is, there could be one or more problems with your loading process causing those groups or it could be mechanical/equipment related. You may have a 1 inch gun.

Also, changing more than one thing at a time makes it hard to isolate cause and effect. I would pick a neck tension that generally works for this cartridge and use it testing powder charge. Once I found the most consistent charge, I would then test seating depth. Once I found the most consistent seating depth, I would then test neck tension for the best tension. If you do this, you will see your gun and your own reloading maximum potential.

Bouncing from one thing to another will do nothing but keep you confused; especially when you get a random lucky group thrown into the mix.

 

[JEFFPPC]

For starters if you want and good results, what I would call good, you need to sort the bullets. Trying to determine seating depth with unsorted bullets is tying one hand behind your back. Are you shooting these groups over flags, if not you need to. During initial testing 2 shot groups. When 2 go in the same hole shot 2 more at your next bull, they need to go into the same hole then try it with 4 shot groups. Goal is to produce a competitive load for matches not wear your barrel out finding a load. Pick a powder charge, start with bullets .020 in the lands. Fire 2 shots, back up iinto the case .003 fire 2 more and so on. When you hit a sweet spot take that seating depth and adjust powder .1 gr and .2 gr up and down, take best result and now go .001 and .002 up and down with seating depth. All this with 2 shot groups. Now shot this with 4 shot groups, you will be at a good place. At this point if you want and if you have a tuner give your tuner a tiny tweak or 2 or and st. If I am shorting around a flat . 1 at this point O save the tuner until the load starts to go away bit and use the tuner to bring it back in. That's usually not until after quite a rounds. This will give you a competitive rifle and not have 300 rounds down the barrel before you start matches .

 

[CharlieNC]

Those who have success with the RDF report long jumps are required, which echoes my experience. I have become a believer in the Berger seating depth test which ranges from very short to very long jumps as an initial screening trial, followed by fine tuning around the best. Often the best jump is far longer than most folks would even consider, and therefore miss the boat.

 

[Bc'z]

A couple other points to consider is brass prep, a lesson I learned myself recently.
Tuning a buddies 6.5 cm with new brass I ran brass in neck size die NO LUBE, didn't set primer pockets.
I was getting inconsistent seating depths both with primer and bullets. It looked like was shooting a 12 gauge.It left me scratching my head.
I grabbed 50 more pieces of fresh new brass only this time I Lubed cases before running through the neck die being sure to get some in the case mouth.
I set primer pockets for consistent seating of primers for a consistent ignition.
Results speak for themselves.

 

[cw308]

The two 3 shot groups with 39.5 and 40.0 , I would just stay in that range using a 5 and 10 shot groups. Looking for that One hole 5 shot group with me behind the trigger drove me nuts. If your capable of doing that then go for it. The rifle may be able to do it , add a human things change.

PS: At one time I thought I could pitch in the Majors. Know your limits make life easier.

 

[MattPeetz]

Go 60 thou and more off with a redone test.

 

[Bc'z]

I tried to stay in my lane lately but this thread has prompted some thought.
I'm not a professional at these Creedmoor or OCD formats but it seems to me that location of groups centers are what we are looking during this part not group size or shape that can be influenced by seating depth and NT so with that in the fore front and help me here @BCz there are 4 out of 5 groups that impact near the same location so with that in mind do you think 39.7 is legit or perhaps I'm not seeing something.

Looking @ OCW test 39.7 is where I'd look for sure.
Bullets need to be sorted and cases fully prepped.
I dont believe large depth tests such as the berger method are necessary, least I've never had to make such drastic changes in depth to find seating node.
I generally start seating test .0025-.003 deeper in case than the OCW test.
Moving in .003 increments you should see node roll in and out then back in.
This is visible in the last picture above.
Due to magazine restrictions in the Ruger American I was already .060 off the lands when shooting OCW, then progressed deeper into case with seating test.
I've never shot nosler RDF,and I gave away all my RL17 due to inconsistent results over multiple trips to range working on a load.

 

[Deleted noremaximus]

Thanks for all the great information. Accurate Shooter is a gold mine for people that are just getting started like me. Honestly, I'm quite overwhelmed. A lot of great information, but I am a bit over my head. I might have to re-read the post a few times. First, I will be reviewing my brass prep. I'm not to confident that my brass is all concentric. Second, I will be reviewing my neck tension. I feel that I can improve on those two sections quite a bit. I'm going to run OCW and Seat Depth test on lapua Scenar-L bullets once I'm sure I get my process down. Still have lots to improve on. Thanks again for all the help.

 

[Deleted noremaximus]

Also will be switching powder and primer for the new bullet. Will be using Winchester SRP, and H4350 with Lapua Scenar-L 136gr. I should not have any issues with the components right? if I still cant find a decent load then its going to be most likely me on either brass prep, neck tension, or something else.

 

[Bc'z]

Thanks for all the great information. Accurate Shooter is a gold mine for people that are just getting started like me. Honestly, I'm quite overwhelmed. A lot of great information, but I am a bit over my head. I might have to re-read the post a few times. First, I will be reviewing my brass prep. I'm not to confident that my brass is all concentric. Second, I will be reviewing my neck tension. I feel that I can improve on those two sections quite a bit. I'm going to run OCW and Seat Depth test on lapua Scenar-L bullets once I'm sure I get my process down. Still have lots to improve on. Thanks again for all the help.

If your referring to the 136L'S it's my favorite bullet.
2 targets above were shot with that bullet and new hornady brass.
I used a .288 bushing.
I'm not testing neck tension or primer in that load due to scarcity/lack of components my buddy has, and it's not my rifle.

 

[Deleted noremaximus]

can someone provide some insight on my brass prep. I'm a F-class beginner.
New Lapua Brass
Fire Form Brass
FL size without neck collet.
Run Brass through K&M Mandrel for neck turning
Neck turn the brass
Tumble Brass
Run brass trough 1.5 thousand K&M mandrel for neck tension
brush necks twice with brass brush
Clean primer pocket
Ready for load.

Once fired brass.
Anneal Brass
FL Size without Neck collet
Run Brass through K&M mandrel for neck tension
Check for brass length Trim, chamfer, and deburr if needed.
Tumble brass
Brush necks twice with brass brush
Clean primer pockets
tumble brass again
Ready for load.

I use die wax for both FL size, and Neck Size. Can this be simplified? Am I doing brass prep correctly? Am I missing steps? What do you guys think of using Dry lube when seating bullets? Any suggestions are welcome. Thank you.

 

[caihlen]

I’d think about annealing.

 

[Deleted noremaximus]

Sorry, I forgot to mention I anneal. I anneal as first step.

 

[urbanrifleman]

I think one set of groups means nothing. Any test that is reasonably conclusive will go through at least twice. At least.

 

[Deleted noremaximus]

I think one set of groups means nothing. Any test that is reasonably conclusive will go through at least twice. At least.

I understand, thank you.

 

[taylorw]

Good morning, I finished conducting the seat depth test for a 6.5 creedmoor 140gr rdf bullet. I already determined the powder charge. What do you guys thing of the seat depth test results. I'm not too fond. I started 15 thou off jam with 3 thou increments. This was at 100 yards 54 degree temp, sunny. Thank you.

I tried this same bullet in the same cartridge and started jumping farther when I couldn’t find anything between +15K through -30K. It ended up shooting ok at around -70K. If you started at 15k off jam and worked back another 20K, I’d say your around -10K off the lands now. Try going backwards in 10K increments (3shot groups to save on components) until you hit -90K. You can jump over seating nodes in these large changes but it can give you an idea of where to start also, when you don’t have a good idea. Sounds like a ridiculous jump but some these bullets are working around that -50 through -90 mark. If you have other bullets to test, you may be better off to stop with this one. I eventually ended up running only 130VLD’s in the 6.5 Creedmoor. Good luck!

 

[Deleted noremaximus]

I tried this same bullet in the same cartridge and started jumping farther when I couldn’t find anything between +15K through -30K. It ended up shooting ok at around -70K. If you started at 15k off jam and worked back another 20K, I’d say your around -10K off the lands now. Try going backwards in 10K increments (3shot groups to save on components) until you hit -90K. You can jump over seating nodes in these large changes but it can give you an idea of where to start also, when you don’t have a good idea. Sounds like a ridiculous jump but some these bullets are working around that -50 through -90 mark. If you have other bullets to test, you may be better off to stop with this one. I eventually ended up running only 130VLD’s in the 6.5 Creedmoor. Good luck!

Thank you, I'm hearing that the overall consensus is that 140 RDF bullets are pretty bad.