The 1st thing when building a load.....

[RDM416]

If half the bearing surface of a bullet is surounded by a steel cylinder that is
.0004" larger in diameter than the bullet diameter, and that portion of the bullet that is surounded by the steel cylinder is .250" long, how much "yaw" is in the bullet, in relationship to the cylinder? assuming the bullet is tipped in that cylinder to make contact opposite each end at both extreames, then measuring "yaw" relative to the center of the bullet in the cylinder to the bullets tip. On a 142 smk.

+1 on that! It's kinda hard for gravity to have much effect on the difference between a bullet jump of .005 to .025 (or more), when the bullet is still contained in the neck of the case and the chamber..... I've been at this a while and sometimes feel like I know less an less as time goes on, but I do know this: I have burned a lot of powder messing with seating depths with quite a number of rifle and bullet combinations.......... Some like it close, some like it far, beats me as to why.

 

[bigngreen]

Most everything I've learned about precision reloading has been in front of the target, if I get results it gets noted and after a few thousand round you kinda pick up on trends. I've always started just of the lands in load development and find the best load but then do a little moving of the bullet in relation to the lands and usually I can get a better tune, you can not ignore the target with groups side by side all with the best powder load and primer but only varying load depth, it would take pure stupidity to not believe it as the target don't lie!!

I've had a rifle go from 1.5 in groups to .38 just by adjusting the bullet .005 from .010 of the lands to .015, how does one ignore that!
Your method will almost certainly fail with a Weatherby throat, I can't even reach the lands but with one bullet in my 300WBY and it is barely in the case and it's shooting the best with the bullet at mag length which you can use a tape measure to see how far of the land you are.

I think you'll find most guys on this forum don't do things because someone told them without proving it to themselves at the target.

 

[Edd]

........ I'm just curious how much of what we are straightening exists.

If the tip of the bullet was 1 inch from the front of the .250" surface, The tip of the bullet would move .0019" in your example.

 

[pyroducksx3]

Now I am in no way agreeing with this as I completely recognize that different rifles like different seating depths. But I have a question, do you start your load development with a specific seating depth, I'm fairly confident the answer is yes. So if it is yes what depth? I was going to start .010 off the lands test powders find a load and then play with seating depth. I was just curious what depths some of you use. I have heard to start on the lands, now .005 off the land, .010 off the lands and so on. Thank you

 

[SBruce]

I think you'll find most guys on this forum don't do things because someone told them without proving it to themselves at the target.

+1

I've been recently testing loads in a new to me custom 22-250. I did start at the rifling, but after 300 rounds, 5 bullets and 2 powders; I've pretty much determined that this rifle just flat doesn't like bullets near it's throat. In fact, it doesn't seem to shoot worth a **** if they are any closer than .030 jump, and really seems to shoot best with a full 100 thousands jump............No VLD's just standard varmint bullets..............Some horses can be shot off of, some can't.

 

[DZelenka]

There has been some experimentation with the 82gr Berger in the AR service rifle. Typically, these bullets are loaded long and are single loaded in the rifle. .010" - .020" off of the lands is where most load them. The Pennsylvania Junior Team started loading these bullets to magazine length (2.260") which is about a .200" jump in a Wylde chamber. They are getting 1/2 MOA accuracy and not having issues with the guns being finicky or having to "chase the lands" to keep the guns at peak accuracy. I tried it and shot some pretty good groups. It runs counter to conventional thinking, but is worth experimenting further.

With respect to the musings of the original poster, I have been at this over 30 years and don't share his views. But what do I know?

Dan

 

[B-RAD]

I have some questions...


True or False - Does changing seating depth alter the pressure of a load ever so slightly?
True or False - Does changing the primer from std to mag alter the pressure of the load ever so slightly?
True or False - Does changing the manufacturer of your brass alter the pressure of the load ever so slightly?
True or False - When building up loads in .1 grain increments of powder alter the pressure of a load ever so slightly?
True or False - Does buying quality dies and quality press make more accurate ammo with less runout?
True or False - Is there such thing as bullet yaw in the throat of a rifle barrel?

After these questions, and after you answered yes to all of them, there is no way to tell me that all your doing by putting the bullet seating depth farther away from the throat to decrease pressure and increase bullet yaw, couldn't of been done by decreasing bullet yaw and decreasing the powder charge by .1 or .05gr, or moving from a mag primer to a std primer, or going to a different brass manufacturer?

Has the light went off in your 30yr experienced heads yet? Or are you too stubborn in your ways? lightbulb

 

[Coyboy]

If the tip of the bullet was 1 inch from the front of the .250" surface, The tip of the bullet would move .0019" in your example.

Ed that was real close, from actually measuring the bullets lengths I came up with .0016" at the very tip.

And that is the very worst it could be in a match chamber. With that said the mass center of the bullet would still be within .0002" centered in the bore with-out being jammed.

I suspect b-rad is accustom to using lose factory chambers and thus only can find accuracy by jamming to center the bullet, in a lead dia. that may be up to .004" over bullet dia. where actual "yaw" or run-out could exceed .010"

b-rad, the problem with your post is you use absolutes in every statement, it is not absolutly imperative that a bullet be .005" off or jammed to get the best accuracy in a rifle. Expressing your opinions this way to guys who know differently is not proving anything, and please tell us how much run-out in your loaded rounds is acceptable to you, and what you use to measure it and correct it.

 

[Mikecr]

B-RAD, we all wish it was so simple, because then we could just set seating at a 'standard' distance from lands & move on, never looking back.
We wish for simple, but we find that it isn't.
You also need to accept that it isn't so simple.

This is what is commonly observed:
#1: Best seating distance cannot be predicted, but has to be determined
#2: With some combinations, seating distance is the single largest factor in accuracy
#3: Just when you seem to hold a working notion about seating, it fails a test, back to #1

You really do need more experience here..

 

[Edd]

I suspect b-rad is accustom to using lose factory chambers and thus only can find accuracy by jamming to center the bullet, in a lead dia. that may be up to .004" over bullet dia. where actual "yaw" or run-out could exceed .010".

Could be, that would center it pretty well. The bore diameter would be .00013" larger than the bullet .005" away on a 1.5° throat.

 

[Franklin]

This is getting so boring it's making me "Yaw"n.

 

[pyroducksx3]

Has the light went off in your 30yr experienced heads yet? Or are you too stubborn in your ways? lightbulb[/QUOTE]

Wow brad even if you were right who would want to listen to you when you talk to people like you have been in this post! No disrespect but you might just be an a*%hole, so good luck trying to get people to see your point because before they do that they will have to get over the fact that they just don't like you. I do however agree with you that these guys with 30 yes experience probably don't really know what they're talking about either. It's pretty logical thinking that someone would just try something a few times till it worked ok and then just continue doing everything that one way without experimenting for the next 29+ years of their reloading lives

 

[boomtube]

"This is getting so boring it's making me "Yaw"n. "

Yeah, B-Rad is so brilliant and interesting and exciting I can't stay awake anymore myself.

 

[Limbic]

One thing that I really like about this forum is that there arent many B-rad type trolls running around. For the most part yall are pretty sound between the ears.

The most important thing I think about build a load is barrel harmonics. I'm not as concerned about pressure as I am about the harmonics of the barrel. When doing a ladder test there will be a point where bullets of a similar powder charge really hit the same area. Many time it will be a lower than expected POI, but not always. Once you know this you can work with neck tension and seating depth to find you "tuned in load"

FYI - very very very few reloaders are taught anything. We often come to the same conclusions be cause we observe similar experiences or results. ie. seating depth varies widely from bullet to bullet and chamber to chamber.

All I know is that it is alot easier to reload with the interweb around than without. There are lots of good resources and thousands of helpful members in the reloading fraternity. You are not one of them.