Bullet RUN OUT

[bryan]

Pete

You talk about weighing brass and bullets......some even weigh primers, but it never ceases to amaze me that Benchrest shooters routinely throw powder charges from a powder measure, seat the bullets while shooting the bull with whoever is close, don't weigh anything etc. etc.
The magazines tell the novice reloader to weigh charges, use a trickler, weigh the cases and everything else, check for runout, and all this for a .25-06 deer rifle.
Seems kinda backwards, ya know?
Bryan

 

[j mckinnie]

Bryan

There is no 2 shooters that do exactly the same thing.Pete may not weigh cases & bullets but don't be surprised if he weighs charges measures bearing surfaces etc.The best way to work out your way is do everything then decide what you don't feel is important.Good shootin Jim

 

[Pete Wass]

There is no 2 shooters that do exactly the same thing.Pete may not weigh cases & bullets but don't be surprised if he weighs charges measures bearing surfaces etc.The best way to work out your way is do everything then decide what you don't feel is important.Good shootin Jim

Let me splain: After having gone through the weighing thing with all the components and having tried brass from nearly every company that makes it I determined that cases are simply a holder for the two most important components to making a rifle shoot, the powder and bullets. From my experience, groups that are shot with those two components as close to being the same, one shot to another, are what makes accuracy- assuming one has a good barrel and a good platform.

Even though Gene Beggs and others have said that they can not see any difference in accuracy between weighing and throwing I know that I can not throw charges from any measure I have ever owned that are within .1g. In a run of 50 loads thrown I will have 5 or so that are as much as .5g under the load I want and usually several that are .2 over. I also know from having measured the bearing surface length on thousands of bullets that it is not usual to find a lot of bullets that have a consistent bearing surface length. In addition to that I know that the bearing surface length dictates seating depth consistency and I know that none of my rifles will forgive a .003 difference in seating depth.

I do think it may be possible to find some barrels that will shoot about anything you place in them well. I have owned a one. The rest of the barrels I have owned to date require precise loading paramaters to work at their best. I have determined that the powder charge and the bullets, specifically the bearing surface length are the two most important components in a load. I also have determined which primers give the best crono results and use them exclusively.

I think those who ignore these three things can improve what they are doing by "Putting their hand on the Radio".

 

[j mckinnie]

Pete

I wasn't saying your wrong merely pointing out that we all have our different ideas on what is most important or not.I ream my necks before I neck them up??? Then I turn them & I weigh my cases & booollets my time & money we will never get it so everyone does the exact same thing.
GOT TO LOVE BENCHREST
Good shootin Jim

 

[Al Nyhus]

It depends on what you mean by a little. Short answer, yes if it is over .002 on the bullet...longer answer, if your loaded round neck clearance is close, and your seating depth is near jam, closing the bolt will actually straighten, to under that limit. Check it out.

Boyd, I agree. 'On target' runout effects are diminished as you increase the 'jam'. As you come out of the lands, excessive runout can usually be seen 'on target'...but not usually at 100 yds. At 200, I could see it quite easily when I tested this. But it wans't a real scientific test..I didn't wring out all the variables.

My BR junk is all .30 cal. stuff and at least to this point all my barrels have liked a lot of jam. But if I had one that didn't like a lot of jam (regardless of caliber) I would sure be paying a lot closer attention to the T.I.R. than I do now.

The PPC shooters that have their stuff set up with a little jump have a very good handle on this....something us .30 cal. shooters should be taking note of. Not only are their rounds very concentric, the 'off the lands' setup lets the rounds chamber easily. It's pretty hard to run and gun with these .30's when you're jammed .030.

I'm working on my new 10.5 lb. 30BR right now and it's been a textbook 30BR to this point: .005 neck tension, .030 of jam and a case full of H4198 and it's stuffs 'em into a small hole. Next time out, I'm going to try the opposite approach ..way off the lands and light neck tension with minimal runout. 'Ya never know.....

 

[Pete in Surry]

I tried jumpin

With the three new barrels I had chambered up this year, one kreiger and two Rocks. None of em seemed to like jumping out to .015 anyway. I went the other way and found round holes south of .010 in. With the neck tension I use I can open the bolt and the bullet will stay in the case @ .010. The bolt closes easily as well.

 

[Wilbur]

Again....

Not knowing all the methods of measuring "bearing surface", I'm making an assumption that the typical measurement is taken from a point on the bullet to the base of the bullet. I see folks using calipers with a doodad that has a .243 hole that stops somewhere on the ogive while the caliper closes to the base offering a value which is referred to as "bearing surface". If I'm wrong about the method, please ignore the remainder of this post.

Using a Wilson type seater, the above measurement defines the relative length of the bullet that is inserted into the case and has nothing to do with the relation of the bullet to the lands. Bullets made in the same pointing die will seat the same relative to the lands regardless of the length of the "bearing surface".

Additionally, if measuring from a .243 point on the bullet to the base.....how is that "bearing surface" when the barrel measures .236 land to land?

And finally, I'm not here to argue methods, reasoning, or otherwise. Just offering the straight skinny on the "bearing surface"/seating depth concept.

 

[Pete in Surry]

Wilbur, you are not correct

Not knowing all the methods of measuring "bearing surface", I'm making an assumption that the typical measurement is taken from a point on the bullet to the base of the bullet. I see folks using calipers with a doodad that has a .243 hole that stops somewhere on the ogive while the caliper closes to the base offering a value which is referred to as "bearing surface". If I'm wrong about the method, please ignore the remainder of this post.

Using a Wilson type seater, the above measurement defines the relative length of the bullet that is inserted into the case and has nothing to do with the relation of the bullet to the lands. Bullets made in the same pointing die will seat the same relative to the lands regardless of the length of the "bearing surface".

Additionally, if measuring from a .243 point on the bullet to the base.....how is that "bearing surface" when the barrel measures .236 land to land?

And finally, I'm not here to argue methods, reasoning, or otherwise. Just offering the straight skinny on the "bearing surface"/seating depth concept.

I use a Comparitor I bought from Tubb but others sell them. It is a granite surface plate with a column and a fixture to hold a dial indicator which has another fixture on it that touches the bullet somewhere mid point on the ogive. The bullets sit in a fixture( sorry about killing that word) on the surface plate.

Bullets that vary will seat at different OAL's, measured on the ogive regardless of the seater one uses. I would agree that a die will apply the same ogive to a bullet but the ogive portion often appears in a different location on bullets. Rather it's the lube or the stroke or the jacket thickness , the core size or shape or any or all of the above is a question but bullets made in the same die do not all come out the same.

Some lots of bullets are a lot less consistent in bearing surface length than others and why when people say one lot of bullets shoots better than others it is because of the variations in length. If one measures them and segregates them to length, all of them work just fine. All one needs to do is to change the length of the seater stem to accomodate the difference in length. It is well worth doing, in my opinion. Of course, if you jam hard and adjust your tune with powder, this is a moot point.

 

[R. G. Robinett]

aaaAAAMen, Wilbur!

Not knowing all the methods of measuring "bearing surface", I'm making an assumption that the typical measurement is taken from a point on the bullet to the base of the bullet. I see folks using calipers with a doodad that has a .243 hole that stops somewhere on the ogive while the caliper closes to the base offering a value which is referred to as "bearing surface". If I'm wrong about the method, please ignore the remainder of this post.

Using a Wilson type seater, the above measurement defines the relative length of the bullet that is inserted into the case and has nothing to do with the relation of the bullet to the lands. Bullets made in the same pointing die will seat the same relative to the lands regardless of the length of the "bearing surface".
Additionally, if measuring from a .243 point on the bullet to the base.....how is that "bearing surface" when the barrel measures .236 land to land?

And finally, I'm not here to argue methods, reasoning, or otherwise. Just offering the straight skinny on the "bearing surface"/seating depth concept.

Amen, Amen, Amen! If you haven't guessed - I couldn't agree more with Wilbur's [highlighted] assessment! RG

 

[Pete in Surry]

I am loath to disagree

Amen, Amen, Amen! If you haven't guessed - I couldn't agree more with Wilbur's [highlighted]assessment! RG

With you too Randy but I have found otherwise and am more than willing to send you photos.

 

[Randy J.]

Peter Wass

I checked the last match you shot in which you used two rifles and you have listed different primers for each. Which primers gave you the best chrono numbers--the Win. or the Fed.? Randy J

 

[Pete in Surry]

Primers

I checked the last match you shot in which you used two rifles and you have listed different primers for each. Which primers gave you the best chrono numbers--the Win. or the Fed.? Randy J

I have found that Winchester small rifle and Federal large rifle give me the best crono numbers. I have had awful results with Winchester and Remington large rifle primers. There isn't a large difference in the small rifle from what I have seen but the price of the Winchesters, along with the better crono results made them the obvious choice for me. I don't recall a dud yet from the small rifle but I had some with the large rifle Winchesters as well as the Remingtons. I tried CCI too but the crono numbers with them were south of Federals. I don't buy Match Federals either. The standard primers are plenty good enough.

 

[greg]

Al...

Boyd, I agree. 'On target' runout effects are diminished as you increase the 'jam'. As you come out of the lands, excessive runout can usually be seen 'on target'...but not usually at 100 yds. At 200, I could see it quite easily when I tested this. But it wans't a real scientific test..I didn't wring out all the variables.

My BR junk is all .30 cal. stuff and at least to this point all my barrels have liked a lot of jam. But if I had one that didn't like a lot of jam (regardless of caliber) I would sure be paying a lot closer attention to the T.I.R. than I do now.

The PPC shooters that have their stuff set up with a little jump have a very good handle on this....something us .30 cal. shooters should be taking note of. Not only are their rounds very concentric, the 'off the lands' setup lets the rounds chamber easily. It's pretty hard to run and gun with these .30's when you're jammed .030.

I'm working on my new 10.5 lb. 30BR right now and it's been a textbook 30BR to this point: .005 neck tension, .030 of jam and a case full of H4198 and it's stuffs 'em into a small hole. Next time out, I'm going to try the opposite approach ..way off the lands and light neck tension with minimal runout. 'Ya never know.....

wouldn't one have to first measure the bullets themselves to see if they are round around the bearing surface where the seating stem contacts before you measure the runout on a loaded round? If it ain't round to begin with...

 

[BJS6]

Greg,

If the bullet isn't round to the extent that it would have any influence on the loaded round runout measurements you will not have to worry about a little runout influencing your accuracy since the bullet will do that all by itself !

Bryce

 

[Pete Wass]

Greg

wouldn't one have to first measure the bullets themselves to see if they are round around the bearing surface where the seating stem contacts before you measure the runout on a loaded round? If it ain't round to begin with...

I think a more important measurement is where the bullet will engage the lands. It is here where the problems arise.

 

[BJS6]

Pete,

If it is worth anything .......

I shoot Barts Ultra's exclusively. I have shot one batch of 66's and 68's from several sources over the last year, presumably all made at different times but from the same die.

Within the same order of bullets the seating depth will remain consistent but when swapping to an order that has been bought at a different time the seating depth needs to be checked and reset.

For some reason the bullets from different manufacturing times don't seat to the same comparator reading at the same seater seatting.

I believe that is what you were saying before, bullets apparently from the same die don't always behave the same. Do Barts bullets come out of one die set, I don't know ??

Bryce

 

[R. G. Robinett]

Pete [in Surry] . . .

With you too Randy but I have found otherwise and am more than willing to send you photos.

Are you saying that bullets from a single [point-up] die, seated with a single seater-die, at a static setting, will, as measured from the case head to the bullet ogive**, display differing lengths ? (Note: in this case, ogive**, being defined as the tangent point of the shank and nose sections)

The typical [ogive] 'comparators' measure the differences you point out - base to ogive. However, as Wilbur pointed out, the relationship between the throat (the portion of the lands from the root, at groove diameter, to the top of the lands) and the ogive as defined (above **), is not included in any base to ogive measurement - the critical dimension here - 'seating depth' , as it relates to the lands - is the distance between the seater-stem contact datum point (hoop diameter) and the tangent point (hoop Dia.) of the shank and nose radius (ogive).

Base to ogive comparators are nice tools for measuring, tracking, and/or comparing Lot to Lot variations, which are dictated by several factors - chiefly, that bullets are formed from the "point" (meplat) back, as opposed to from the base to ogive. A small book could be written regarding just the variables! A cored jacket must be pushed sufficiently into the point-up die to close the meplat to a diameter which insures ejection: some jacket Lots "flow" better than others, thus make for longer OAL and bearing length (base to ogive) . . . this only affects how far the [seated] bullet base rests down the case neck - not the relationship between the seater stem and the throat. A reliably precise method of comparing 'seating depth' is to seat the bullets using a single seater-die at a static setting, then, measure the case-head to ogive (hoop diameter) using a comparator - I don't envision another simpler or, reliable method.

My intent here is not to be argumenatative, but rather to help dispell another myth - I'm hearing enough about this that I will make time to seat and measure samples from several years and varying shank lengths, using a static seater setting (Note: final measurement will be case-head to ogive)! Perhaps I will have to eat crow . . . but I wouldn't bet on it. I will confess to not owning a barrel which does not SHOOT using a healthy jam-seat condition! RG

 

[Wilbur]

Pete

Everything you are saying and measuring is correct. If the point where the ogive "toucher" touches varies, certainly the loaded OAL will vary as will the length of bullet that enters the neck. Neither of these have relation to where the ogive lies in relation to the lands of the rifle....bullets being from the same point die. The relationship of the ogive to the lands is what I call seating depth.

 

[Al Nyhus]

Wilbur and R.G. nailed it.

With bullets from the same point die, the relationship from the lands to the bullets ogive on a seated bullet does not change regardless of how much the base-to-ogive figure varies between bullets from that same die. The only thing that will change is where the base of the bullet ends up. -Al

 

[Randy J.]

I am new to this debate, but this is what I know from measurements that I have taken. Different lots of the same bullet will read differently when I measure a seated bullet with my barrel stub gauge and calipers. The measurement is taken from the far end of the barrel stub to the back of the case head. Does this mean that my jam is different, I don't know. Were the bullets made from the same point up die, I don't know. I use Randy's or Allie's bullet exclusively to date. Those of you with more expertise than I can probably answer those questions. I assumed it meant that my seating depth would have been different and therefore I adjusted my seating stem to off set the difference between the readings. Randy J.