6BR Seating Depth/Charge test

[mtang45]

I think this is a trap we can fall into from time to time, I admit I certainly have in the past.

The combo doesn't seem to be working for you and your barrel and that is all that matters. Ive wasted too much barrel life in the past persevering with what shot well for others instead of trying to find what shot well for my barrel and me.

Agree. I'm going to play with it just a bit longer around the suggested loads. If it doesn't work out, I'm ready to move on to something different in the load.

 

[steve123]

A little different but with my AR in 6mmFatRat I tried 105 hybrids as they are my go-to bullet usually in my 6x47L bolt rifles. After wasting a bunch of time and components I gave up, that AR just didn't like the hybrid.

Someone suggested trying the 95 SMK. Right off the rifle shot better and it wasn't long before I found a charge via ladder testing that shot great.

I gained another 100 fps in the process so to a certain distance the higher velocity gives the same windage as the 105 going slower.

 

[Curious]

OK I have been of the OCW school for many years. Run an OCW test find the node and then fine tune by seating depth. Recently I decided to try the Boyer method on a relatively new 6BR that I am having trouble getting it dialed in. Lapua Brass, Berger 105 Hybrid, Varget, CCI-450. I set up the test below to run loads 30.0, 30.3, 30.6, 30.9 and depths of .010 in the lands, .005 in the lands, 0 (touch) and .005 jump.

I'm sorry but I just don't see anything that I can say, yeah thats it right there. Anybody with experience, please feel free to tell me what you see.

I dont really see the point of this testing method, especially with those charge weight increments and the four fixed seating depths.

You have some nice small groups, if you looked 0.1gr either side on those powder charges and 0.002" either side of the seating depth and things were still repeating then you have a good load.

For extreme accuracy we can't expect a load to shoot its smallest over a broad range of powder charges and seating depths. I expect a 0.005" change in seating depth to open the groups just as I would a 0.3gr shift in powder charge.

 

[mtang45]

I dont really see the point of this testing method, especially with those charge weight increments and the four fixed seating depths.

You have some nice small groups, if you looked 0.1gr either side on those powder charges and 0.002" either side of the seating depth and things were still repeating then you have a good load.

For extreme accuracy we can't expect a load to shoot its smallest over a broad range of powder charges and seating depths. I expect a 0.005" change in seating depth to open the groups just as I would a 0.3gr shift in powder charge.

My first test using this method, which is highly promoted by several respected members here. The theory behind it is that a seating depth should stand out as being superior over all the others, regardless of charge weight. Using that info allows for more testing to fine tune the charge weight at the best seating depth. Works for many successful people.

These same folks claim that the seating depth should be into the lands, touching or very close to it.

 

[Nick_Mansfield]

Hybrids are very seating depth sensitive..Jump is usually even& jam if you prefer is odd...I suggest .008-.012 off touch. Neck tension plays a small part also...

 

[Curious]

My first test using this method, which is highly promoted by several respected members here. The theory behind it is that a seating depth should stand out as being superior over all the others, regardless of charge weight. Using that info allows for more testing to fine tune the charge weight at the best seating depth. Works for many successful people.

These same folks claim that the seating depth should be into the lands, touching or very close to it.

I understand the theory but in practice the target is not showing you that.

So because the test isn't showing the results it should people are advising you to change bullets which might help but might not. Your previous method of OCW then seating depth tuning also works, Ive done it that way many times myself.

As I said, if you ran 0.1gr either side of 30.9 just to centre the powder charge node and it still shot small at 0.005" in or out +/- a couple of thou either side of that you would have a good load. Im not being critical of you, Im just not convinced the method is any better or even as good as the one you were previously using.

 

[mtang45]

I understand the theory but in practice the target is not showing you that.

So because the test isn't showing the results it should people are advising you to change bullets which might help but might not. Your previous method of OCW then seating depth tuning also works, Ive done it that way many times myself.

As I said, if you ran 0.1gr either side of 30.9 just to centre the powder charge node and it still shot small at 0.005" in or out +/- a couple of thou either side of that you would have a good load. Im not being critical of you, Im just not convinced the method is any better or even as good as the one you were previously using.

30.9 +/- .1 and a seating depth of .005 in +/- a thou or two is a pretty small window, but certainly worth a try. I was hoping for a bigger and obvious one. I think the take away from the test is that this match up of components is not working in my rifle.

 

[mtang45]

Not to beat a dead horse here, but I've been staring at this target and came to the following.

• .005 in has the best "grouping" of all the seating depths across all 4 charges
• Charges 30.0 and 30.3 had the best grouping across +.010, +.005 and 0.

So in light of this, I'm going to run a smaller test with charges between 30.0 and 30.3 and seating depths +.002 to +.008, probably in .002 increments.
If something doesn't say "LOOKEE HERE", where there is a reasonable window, then I'm changing up powder/bullets.

 

[urbanrifleman]

A little different but with my AR in 6mmFatRat I tried 105 hybrids as they are my go-to bullet usually in my 6x47L bolt rifles. After wasting a bunch of time and components I gave up, that AR just didn't like the hybrid.

Someone suggested trying the 95 SMK. Right off the rifle shot better and it wasn't long before I found a charge via ladder testing that shot great.

I gained another 100 fps in the process so to a certain distance the higher velocity gives the same windage as the 105 going slower.

Berger 95 VLD shoots tighter too.

 

[Delfuego]

Try some h4895!

 

[JohnMill]

I'm going to work around that and see what happens. I do compete (just started last month) and have a match on 10 days.

The wind/mirage is your friend but not everyone elses. Learn all you can about her.

I think this is a trap we can fall into from time to time, I admit I certainly have in the past.

The combo doesn't seem to be working for you and your barrel and that is all that matters. Ive wasted too much barrel life in the past persevering with what shot well for others instead of trying to find what shot well for my barrel and me.

Hey Curious, I believe he can find the best for that by fiddling with the depth in .003" increments. I'm guessing everyrone has a "trap". Mine was striving for tighter and tighter group.I could shoot a screamer a couple times a week in practice and on rare occasions in a match but didn't start agging well until I learned to "settle" for .130-.150 (new equipment). So a caveat for Mtang 45. Verify the load If you read the wind on a repeatable load you turn a 2 and 1 into a bughole. you can try +.013 and a +.007 and you may establish bughole territory.