Ballistic Coefficient vs. Accuracy?

[Distant Thunder]

Mike,

I don't get all anal about some of the little details, this stuff isn't benchrest shooting and while accuracy of the equipment and bullets is still important it's not the key to winning matches as much as is the ability of the shooter. IMHO

I don't think there is enough difference between a rifle/bullet/load that shoots 1 moa and one that shoots 1 1/2 moa to make a less skilled shooter a match winner. And make no mistake, I am a less skilled shooter compared to some that are out there. Some of those guys that are really good make it look simple, I don't, I have to work hard at it when I'm shooting.

Part of what I believe makes it a little easier for me to do well is the fact that I try to stick with known quantities. I know guys who show up with a different rifle almost every match, they are trying to find the rifle that will win. I like familiarity and I really only shoot one rifle for long-range, at least when winning is important. The same goes for bullets and loads, I don't change anything much if it's working and I only change things in small ways as I get closer to a winning combination.

The past two years I have been working with a .44-77 and at this point in time there is little chance I'm going to win with that rifle/cartridge, but I do believe I can eventually pull out a win with it. The rifle and cartridge are capable and I'm closing in on the load, but I am not there with the bullet yet. That is the main reason I have been thinking about bullet design and what's most important in a bullet to shoot well out at 1000 yards.

By shooting well I do mean winning matches or at very least placing close to the top consistently, in the top 5. I think a shooter would have to be a machine to win every match and there are always those who can beat you even when you're having a good day. So winning every match isn't my goal, but making sure the winner earned the win is. If the guy in the lead is worrying about me, I'm happy.

I don't sweat the little things too much. My bullets are not perfect, but they are consistent. I can accept a minor flaw, but not two. They must weigh consistently, but I have a wider range of what I would consider acceptable than some, plus or minus 1 grain is pretty good. I've been known to stretch that a little if I need more bullets to shoot a match. Any bullet that is on the edge is marked as a sighter and I use those for ranging and early sighter shots. However, I have often had to sort through my remaining bullets on Sunday looking for enough "good" bullets to finish a match. I have had to "upgrade" sighter bullets to "match" status and they all seem to go where they should. That makes me believe I don't have worry about my bullets or my patches as much some might think.

I also weigh each powder charge and I am very consistent in my use of the drop tube and my compression. I don't get too excited about my brass. I don't weigh my brass, but I do buy good brass to start with. I also toss any brass that causes problems, or rework them if that fixes the issue.

I do watch case length very closely and I don't trim them too short and try to stay as close as possible to the maximum and no more than .010" under max.

I sort of play with my bullet alloy some, but I don't mix things up in a single match unless I am testing one alloy against another. Whether we are shooting grease groove or paper patch the fact that our bullets upset at ignition, and bore diameter PP have to, is one of the limiting factors in the design of our bullets, or at least should be. PPB most upset and even grease groove bullet will upset whether they have to or not. With upset comes at least some nose setback. That setback affects the B.C. of our bullets by shortening the nose and making it bigger in diameter. The bullet you loaded in the chamber isn't necessarily the bullet that travels to that 1000 yard target.

The upset and setback must be controlled, and the alloy is the one way to do that. They must be hard enough, but not too much and they absolutely must remain concentric. The alloy has to be adjusted to balance with the load, the powder charge, to work best with the amount of force applied to the base of the bullet.

Bullet fit to the chamber and nose design can also help control upset and setback. Everything is a tradeoff.

I always use a paper that is proven to work in my rifles, but, as you know, I don't get carried away with my patches. I am trying to make them better and more consistent, but I just don't seem able to stay there and things vary more than I would like sometimes.

My loading process is simple, I clean and prime my cases. I don't anneal often, not unless I see a need to. I don't size my cases after they are fireformed. I weigh and drop tube (14" tube) into each case and seat the wad. Usually LDPE wads, rarely anything else.

I patch and size my bullets and finger seat them in the cases as I patch them. Each case is in some manner neck sized with the bore diameter bullet in place and just enough that I can lift the cartridge out of the box and it will hold together. The bullets can be easily pulled with just my fingers and reseated the same without damage to the paper or marking the lead beneath.

Each cartridge is place in the box and I'm ready to shoot for the center. It's almost too easy to load good match winning PPB. Way easier for me than grease groove bullets, I hate messing with lube. The only lube I use is the water-soluble oil that is in my wiping solution, and it does make a difference. It's 10 to 1 and I use it on bore pigs wiping between each shot, which is the only way to wipe during a match.

I hope some of this info has eased your mind and helps stop the hurting hair thing. I will add that the way I do it is not the only way to do it, it's just my way and it works for me, YMMV.

I haven't changed anything in my long-range load in several years now, I see no need to.

Shoot well!

[Kurt]

Well, there is a lot about the saying "be aware of the man that just uses one rifle"

[Semtav]

I liked your treatise DT.
Some of my methods differ from yours. Some of my methods have evolved over the years based on things other than accuracy.

I quit sizing my brass and went to fireformed cases for the simplicity. I never saw any degredation in accuracy so I stuck with it.

I went to paper patching for much the same reason. Plus now that I don't get much shooting in, my bullets can stay in the case for a year and I know they will be the same as the day I loaded them.
When I switched to bore gophers, I switched to plain water just for the simplicity and haven't seen any Iill effects.
I do anneal every time now. I didn't change because of any known accuracy improvement, but because when I was doing a lot of shooting with my 45-90, I gradually started to see random differences in all my cases over time. Since I started annealing, they are all the same,time after time.

[Distant Thunder]

Brian,

On your suggestion for wads, I just want to make sure I have it correct. You seat a .030 veg wad on top of the powder and then a .030 LDPE wad on top of that?

If I was seeing some change in my brass I would anneal, but since I don't really size my brass once fireformed I don't see a reason to anneal. Brass work hardens from sizing and can over time become brittle and split in the neck area.

Because I shoot bore diameter paper patch bullets I do "size" the case necks in one way or another to hold the bullet in place for handling.
For my .44-77 I only size my necks down about .100" and then only about .008" in diameter. This rifle has the Shiloh standard grease groove chamber. I find their standard chamber to be excellent for paper patching.

With my .45-70 I use a Lee Factory Crimp die to just close up the mouth of the case a couple of thousandths because of the tight paper patch chamber. Fired brass have an ID of only .452" and my bullets are patched to .4505" so it doesn't take much. These bullets are only in the case about .080".

I load my .45-90 the same way as I do my .45-70 except I used one .060" HDPE wad and the bullet is in the case .100". I had Lee make a .45-90 Factory Crimp die for this cartridge.

I load my .40-65 much the same, I use a 2-D PPB in this cartridge and a taper crimp die to tighten up the case mouths. These bullets are barely in the case but actually stay in surprisingly well. The 2-D bullet is because of the very long freebore in my chamber, .400" long! I had this rifle rebarreled many years ago and I had no idea what chamber the gunsmith put in it. I didn't figure out how to load for this rifle until about 5 years ago when I set out to design a paper patch bullet for the chamber. The results shoot very, very well.

I do believe in keeping things very simple. Which is why I stay away from grease groove bullets, they are much too complicated for me to work with.

[Semtav]

On the wads, yes. Best way to remember, is you can see that you didn't forget the veggie wad that way. If you put the veggie in last you don't know what's under it.
In my case, also known as idiot proofing.


As far as the brass, I was getting different degrees of expansion rebounding. Maybe cause I was trying a lot of different loads back then. Maybe once I settled on one load it wouldn't do that.

Also why I stuck with the patched to groove. No sizing at all. Altho in the case of my 45-110 that is shooting so wel, I do have to run the case in a .461 expansion die each time cause the very end must be getting pinched when fired. I have no idea why it shoots so we'll doing that, but I'm not about to change anything.

[Gunlaker]

To get back to your original question, I see it like this... The biggest room for error is in wind reading, assuming you know how to pull a trigger consistently and make good ammo. I'd pick a higher BC bullet if I thought the difference was enough to gain a few points over the match for an occasional misread of the wind. I mean it's not super rare to think your current windage is good for a 10 and you get a 7 due to a bad wind call. If I thought I could turn that 7 into and 8 I'd go with the higher BC bullet. But that high BC bullet would still have to be nearly as accurate as the lower BC one.

I would never pick a 2.5 moa load over a 1.5 moa load for instance. It would have to be closer than that. Mainly because every time the bullet doesn't go where you expect you wouldn't know if it's wind or lack of accuracy. That messes with your mind. Once your mind is messed then you have lost already :-)

Chris.

[Distant Thunder]

Patched to groove with BP is a very good way to go and especially when you're not worried about powder capacity. The other rifle I have that I didn't mention here is a C. Sharps 1874 in .50-70. That is the rifle I patch to groove for. It is another rifle I have with a generous freebore, .300" long, so a bullet patched to fit the freebore, which is .001" over groove, can be seated out a good bit. The bullets I prefer to shoot in this rifle are on the shorter, lighter side for .50 caliber and more in line with the bullets Sharps loaded back in the 1870s, 425 and 473 grains, so they leave plenty of room for powder with the bullet up in the freebore.

The mold I have and use the most casts just a bit heavy at 490 grains, it shoots very well with just my sporting tang sight and a Beach combination front sight.

This rifle is the most forgiving and easiest to load PPB for that I own. Almost any primer, wad or powder will work under any of the 3 PPB I load for it. It's not a long-range rifle but is deadly out to 400 yards even with these lighter bullets. It is loads of fun to sit on a hill and shoot at targets of opportunity such as rocks and stumps at unknow distances. It is a great hunting rifle and cartridge, very effective with a 490 grain bullet at 1200 fps.

[Distant Thunder]

Chris,

I agree with what you said about the high BC bullet getting a few more points in a match. The way I look at that is this. I don't think the bullet I shoot for long range has all that high of a BC, but what is does have is very good, stable flight thought out the 1000 yard journey. Being very stable it doesn't get knocked off course easily when hit by the wind. I have seen it a number of times when I get caught by an unseen wind or a change and my bullet will come up a minute or so closer to center than the shooters on either side of me. That can add 2 points to my score and if I tag a 6 or 7 and the other guys miss, that's a big gain in my score.

When I designed my Lodi bullet it wasn't for high BC, it was for accuracy and weight. I knew I needed accuracy and I felt the weight would just carry better to 1000 yards. Over time, as I learned more about what makes for a good stable bullet, I refined the design to improve the long range stability and it has worked well in all kinds of wind conditions.

[Distant Thunder]

As I read more on the transonic zone, I find that there is one group of shooters who are working hard at understand what it takes to travel through this troublesome velocity range and remain on course, that group is the long-range precision shooters. They are experimenting with different ideas in an effort to extend the maximum range of their bullets, which until recently was accepted as being whatever distance to which they remained supersonic and then they hit a wall, the transonic wall. Their super slick VLD bullets could not be counted on to transition to subsonic with accuracy reliably.

I think their efforts and the result could be helpful in understanding how our bullets can better travel through the transonic zone and emerge from it and still hold true to the original path.

The precision guys had been working on the idea of just spinning their bullets as fast as possible or faster and enter the zone at a high rpm, but since bullets degrade in forward velocity more rapidly than they do in rotational velocity they can end up with bullets that don't track on the trajectory path. Overspinning can cause the bullet to remain parallel to the axis of the bore due to the very high static stability, gyroscopic spin, and as the path arcs down toward the target the nose stays above the path of the trajectory, this lowers the dynamic stability which is needed to remain stable through the transonic zone where the destabilizing force are stronger.

Some of those boys are working with bullets that will just statically stabile when they enter the transonic zone and track much better with the nose down and following the trajectory arc. That leaves the bullet with better dynamic stability and they are having success with that approach. They are running bullets that are at the upper end of the length that will be stabile as the bullet slows to the 1346 fps upper end of the transonic zone.

They are even shooting different length, weight, bullets to match the conditions so as to time the drop in forward velocity with the rotation decay and be at a good dynamic stability as they enter the zone.

Looking at the velocity most BPTR shooters operate at and the 900 yard phenomenon this approach is most likely to help us at 900 and 1000 yards. However, when you factor in all of the things that can change the speed of sound and the velocity of our bullets downrange it's not going to be feasible to just load a different bullet/load for each match, each range, each altitude and the different times of the year. My guess would be that picking a bullet and load that hits the middle ground is the best we can do.

Still the information could be used to help fine tune a long-range bullet and load that will perform best in our velocity range.

As I read more on the transonic zone I gain a little better understanding of what bullet design works best and why. I'm slowly putting it all together, the main thing I took form what I've read lately is the difference between static and dynamic stability and for me that was a big hurdle. I find it fascinating that a bullet can be spinning at a high rpm with high static stability and be out of line with it's trajectory and lose dynamic stability. A good balance of the two is needed especially in the transonic zone.

[Kurt]

I have enough moulds that I could weld together and make a good boat anchor to hold a 50' houseboat in a 60 mph wind. I shot the money bullets in the .44's and .45's and they have never performed as well as my blunter nosed.
At the Mt. 1000 I started with a money bullet because I only had 23 left of the PJ .45's left and when the match started the first three 1000 yard targets I hit 5 rounds out of 10 plus a sighter shot 11 rounds. I told Carolyn to get the box PJ with 82 gr of 2F OE when she came back she said you only have 23 left I said I only need 11.
On the last 1000 yard target the sighter hit plus the 10 for record.
When Dan T started to come around with his long nosed MB it wasn't long that the ROT increased from 1/18 to 1/16 for the .45's and I also have the 1/16 and 1/17 ROT .45-90's and I hold the powder loads at 82 gr like some use for the .45-70 and the blind PJ bullet makes a round hole through the paper at 1000.

Going through some old score cards shot at Lodi by average I tend to get a higher score on the 1000 then I do on the 8 or 900.
I sooner put an extra spin on the elevation knob with the blunt bullet and hit what I aim at.