Vertical with powder / Horizontal with seating depth

[Puzzaz01]

First off this is just my opinion based on the last 4 years of pretty active competition and preparation for them. If you want scientific evidence fund a study with a scientist.
I've went thru over 20 barrels in the last few years. Won several yard ages and shot a fair amount of teen aggs and grand aggs in competition. So take this as you will.
Really doesn't matter to me if you agree or believe it or not
Some barrels show more horizontal with seating depth than others.
This could be coming from multiple things. I don't have an opinion on why it happens it does
I am talking about tuning at short range with a rifle and cartridge capable of extreme accuracy. If yours is not you may not be able to see this happen. If you do not tune on a single piece of paper it is harder to see and gets lost in the noise.
I will also say this was an exceptional barrel so it is easy to see the horizontal in the first couple test strings then you see it go away
The 29gr charge was just to hot a load for that day it just scattered and pitched shots out of the group at all seating depths
Take it for what you will. I would recommend not just dismissing this without doing some testing of your own

I agree 100% that seating depths are actually more important than powder charges. As you can see by the target below that when you arrive at the perfect seating depth the powder charge is less relevant.
This is a 3 shot group test with 3 different powder charges and multiple seating depths..... I generally shoot 5 shot groups but this test is mainly to get you where you want be quick. Look at seating depth 2.230 and you can see that they all group very well with 3 totally different powder charges.
Just my two cents.

Darrin

 

[JimSC]

Offtopic but when I look at the above groups I just see minor variations that could be due to shooter technique or environmental. I know experienced bench rest shooters can see much more but that just shows the difference between disciplines. For the bench rest crowd 3 shots in a single hole is the goal whereas for mid and long range shooters in F class or Tactical shooting getting 20 shots at 1/2 MOA centered is sufficient to get in the record books

I am still planning on taking those Nosler 70's and loading some at .030 and .035 off the lands to see if the horizontal stringing tightens

 

[howabouttheiris]

I just did a jump test on my .308 168gn load.

I have a great band ~0.5MOA from .080 to .050, then it gets worse, and then back to maybe 0.6MOA in the lands.... with quite a lot of horizontal shift (maybe up to 1 inch).

Would be interested in understanding why the really long jumps group when mid length jumps do not. Is it gas escape over distance that is centering the round? or some other harmonic effect? or a pressure difference resulting in a velocity change? or some of all of the above?

 

[gunsandgunsmithing]

Jmho, but I believe it's ultimately about optimizing muzzle position to bullet exit. Whether you do this with powder charge, seating depth, tuners, or any of several means to that end, we are managing vibration.

 

[butchlambert]

The only time you could observe this or that -and assert anything about it, is when you've thoroughly removed every abstract except for the adjustment in question, and qualified that assertion(every bit of it).
So 2 holes beside each other with a jam seating of a 6PPC can mean pretty much diddly to a 300WSM with different bullets, seated elsewhere, and 20kpsi lower in pressure.

I know we don't have every answer yet, but before accepting folklore, shouldn't we ask ourselves WHY it would be this way,, and then IF it applies under other circumstances.
For decades mob consensus was that VLDs had to be jammed to shoot well. Yet, all it took was an actual seating test to prove otherwise for many. That's someone wondering IF it was true, or hogwash.

Hey Mikeycr, does not a temp controlled tunnel take away atmospheric conditions? What about it being done with a rail gun? Folklore?

 

[gunsandgunsmithing]

I think that as a rule, we have to establish a base tune, where the rifle shoots at or very near it's potential. Once we have that, Boyers method of seating methodically for horizontal and powder for vertical are very real. Another tuner analogy but I see it all the time..group shapes predictably changing with a small tuner adjustment. In fact, I see both vertical and horizontal, pretty much just like what you see if changing the load or seating depth. By any method, you have to be very methodical and change anything in very small values until you can correlate the actual value of said change on the target.

For those familiar with a 6PPC, I'll give a very common scenario and try to correlate it with powder changes.

Tuner vs powder charge..In perfect tune I expect it to shoot dots! On a typical short range ppc I very often see a bullet hole or less of vertical when 1 mark out of tune. This often correlates well with about .3 of n133.

Two marks out is usually diagonal stairsteps from low left to up and right.
Ive seen this as well with powder and it pretty much tells you you're way off...about .5-.6 grains of n133.

Now this isn't meant to change the direction of the thread or to start a debate but I've seen it enough that I see a correlation there.
I'm open to hear from others that see the same but this is mainly to state that once you establish a solid base tune and have figured out how to methodically address changes in tune with either powder, seating or a tuner..and get predictable results, then what you're doing is working and can be effectively used to maintain tune.

So if Boyer determined that he could seat .003 longer to get rid of horizontal or he could get rid of a little vertical by adding .3 grains of powder..CONSISTENTLY....then he found a method that works. If I can do the same by moving my tuner a mark or two..CONSISTENTLY gets rid of one or both...the I have found something that works, too!

I strongly feel that tuning is about timing. You can change timing with all of these methods. Predictable results come from a methodical practice of whichever way you choose to use.

Big swings at powder, seating or tuner adjustment can give a good or bad result but where do you go from there unless you know the value of your adjustments.

 

[JEFFPPC]

I think that as a rule, we have to establish a base tune, where the rifle shoots at or very near it's potential. Once we have that, Boyers method of seating methodically for horizontal and powder for vertical are very real. Another tuner analogy but I see it all the time..group shapes predictably changing with a small tuner adjustment. In fact, I see both vertical and horizontal, pretty much just like what you see if changing the load or seating depth. By any method, you have to be very methodical and change anything in very small values until you can correlate the actual value of said change on the target.

For those familiar with a 6PPC, I'll give a very common scenario and try to correlate it with powder changes.

Tuner vs powder charge..In perfect tune I expect it to shoot dots! On a typical short range ppc I very often see a bullet hole or less of vertical when 1 mark out of tune. This often correlates well with about .3 of n133.

Two marks out is usually diagonal stairsteps from low left to up and right.
Ive seen this as well with powder and it pretty much tells you you're way off...about .5-.6 grains of n133.

Now this isn't meant to change the direction of the thread or to start a debate but I've seen it enough that I see a correlation there.
I'm open to hear from others that see the same but this is mainly to state that once you establish a solid base tune and have figured out how to methodically address changes in tune with either powder, seating or a tuner..and get predictable results, then what you're doing is working and can be effectively used to maintain tune.

So if Boyer determined that he could seat .003 longer to get rid of horizontal or he could get rid of a little vertical by adding .3 grains of powder..CONSISTENTLY....then he found a method that works. If I can do the same by moving my tuner a mark or two..CONSISTENTLY gets rid of one or both...the I have found something that works, too!

I strongly feel that tuning is about timing. You can change timing with all of these methods. Predictable results come from a methodical practice of whichever way you choose to use.

Big swings at powder, seating or tuner adjustment can give a good or bad result but where do you go from there unless you know the value of your adjustments.

I see the same thing as you with tuners. What sold me me on tuners was the predictability/repeatability. When I had my first tuner, 6ppc, I shot one complete revolution of the tuner on a strip target. A year later I took the same gun, barrel, and load and shot another strip target. Realized a week or so later it looked like what I remembered from the year before. Laid one on top of the other, they pretty much matched hole for hole every shot. That sold me on what I might be able to do with a tuner. Never looked back, love tuners.

 

[gunsandgunsmithing]

I see the same thing as you with tuners. What sold me me on tuners was the predictability/repeatability. When I had my first tuner, 6ppc, I shot one complete revolution of the tuner on a strip target. A year later I took the same gun, barrel, and load and shot another strip target. Realized a week or so later it looked like what I remembered from the year before. Laid one on top of the other, they pretty much matched hole for hole every shot. That sold me on what I might be able to do with a tuner. Never looked back, love tuners.

Me too, Jeff but my point is there are also remarkable similarities to mark values on tuners to powder and/or seating depth changes. The key is knowing the value of whatever change you make, by whatever means. At least that's my opinion. It gets us back to harmonics and timing. I think that ultimately, when we change any one of these things, we are changing harmonics and timing. The barrel movement and bullet exit have to happen at the ideal time in is vibrational cycle. Again, just my 2 cents worth. I may not have said that exactly right but I think you get what I'm trying to convey.

 

[jackieschmidt]

No one takes wind into consideration.

It is difficult to believe that in the year 2020 there are still shooters who sit down at a bench with the finest equipment money can purchase and bang away without a clue as to how the conditions are affecting their bullet’s flight.

But then, it is in truth the norm. I am a member of the Tomball Gun Club. Myself and my best friend are probably there more than any other members.

We always set our flags up just like we do as if we were at a Match. Other shooters will come over and take a look, and be amazed how much a “light condition” moves the different flags in all different directions.

The usual question is....”does that really make a difference”? Well, if you are serious about where every bullet you shoot goes in the relation to the one before, then yes, it makes ALL the difference.

If you are adjusting your loads by either seating depth, charge, neck tension, or with a tuner, you are wasting your time unless you have some viable means of telling you how the conditions are affecting the flight of the bullet from the muzzle to the target.

A lot of this ignorance comes from major publications and even manufacturers. The “BC” craze has seemed to install a false sense of confidence, because after all, this thing has a BC of over 600, and my shooting App on my smart phone says tells me all I need to know. Well, while I don’t shoot a lot of long range, I shoot enough to know that it’s amazing how much high BC bullets get kicked around out past 300 yards.

But then, without someway of knowing what the conditions are doing, you will never know.

I do not know who to attribute this quote to, but it rings true....”a well tuned and well handled rifle is one where the only thing that keeps one bullet from taking the same exact path as the one before is the conditions you are shooting into”.

 

[gunsandgunsmithing]

It is difficult to believe that in the year 2020 there are still shooters who sit down at a bench with the finest equipment money can purchase and bang away without a clue as to how the conditions are affecting their bullet’s flight.

But then, it is in truth the norm. I am a member of the Tomball Gun Club. Myself and my best friend are probably there more than any other members.

We always set our flags up just like we do as if we were at a Match. Other shooters will come over and take a look, and be amazed how much in what seems like a “light condition” moves the different flags in all different directions.

The usual question is....”does that really make a difference”? Well, if you are serious about where every bullet you shoot goes in the relation to the one before, then yes, it makes ALL the difference.

If you are adjusting your loads by either seating depth, charge, neck tension, or with a tuner, you are wasting your time unless you have some viable means of telling you how the conditions are affecting the flight of the bullet from the muzzle to the target.

I do not know who to attribute this quote to, but it rings true....”a well tuned and well handled rifle is one where the only thing that keeps one bullet from taking the same exact path as the one before is the conditions you are shooting into”.

I agree, Jackie. Shooting without flags is plinking. Trying to tune a rifle without flags is a waste of powder, bullets, time and money.

I wonder how many times a sweet spot is passed over due to a shot or more being blown out. Without flags, we'll never know the answer to that.

 

[mikecr]

Butch, great job assembling that counter in just two years..

 

[butchlambert]

Butch, great job assembling that counter in just two years..

Mikeycr, I'm getting older and slower.

 

[marchboom]

Not to hijack this thread, but how does the different seating depths affect accuracy? What is it about a bullet being at the lands, into the lands or .030" off the lands that makes a bullet group better or worse?

 

[Tim Singleton]

Not to hijack this thread, but how does the different seating depths affect accuracy? What is it about a bullet being at the lands, into the lands or .030" off the lands that makes a bullet group better or worse?

Oh my!
Million dollar question there

 

[marchboom]

+1 for wind flags. They can be a little expensive for some of them but they are fairly easy to make. Hell, a piece of surveyor's tape on a tall stick will work. The bullet is affected by wind the moment it leaves the barrel. Just because you can't detect wind (no tall grass, no trees, etc) doesn't mean it isn't there and affecting your bullet. This is one variable that you can control after the bullet leaves the barrel.

Trust me on this one. Once you use flags you'll never shoot again without them.

Have your wife, friend, etc. get you a set of flags for National Shooters Without Wind Flags Day...Sometime in August.

 

[Intheshop]

Too lazy to trim the weeds on the 50yd berm,but being halfway to 100yd target,watch the weeds in the side of scope. Not ideal but the tops of the weeds move with tiny amts of breeze.

Am dealing with horizontal now. 6MMR,85g Saeco (cast) @ starting IMR4350 loads. Vertical is staying around 1/4" at 100 but horizontal is a line like this ... with 3 and 5 shot groups. With some going in the same holes.

I'll figure it out,shooting/loading every day. It is seating depth IMO. Part of the problem is my skillset,just need more practice because of shooting other disciplines recently.