high velocity with cast.

[Larry Gibson]

this thread is about DISCUSSING High velocity with Cast Boolits.
ANYTHING beyond that discussion will be removed.
ANYTHING detrimental to the discussion will be viewed as trolling or baiting by myself [and other mod's]

it's an open thread.
mixing powders, Duplex type loads, fillers, alloys, buffers, etc. can be discussed.


INTERPRETING THE WRITTEN INFORMATION IS AT THE USERS RISK.
THIS IS NOT A RELOADING OR INSTRUCTION MANUAL,,, REMEMBER IT IS A DISCUSSION !!!!
NOT AN ARGUEMENT!
ANY PERSONAL ATTACKS WILL BE DEALT WITH ACCORDING TO THE RULES!
[PERIOD]

If that's the case and it applies to all of us then check post 192. Frank is trolling and just wants to argue.

Larry Gibson

Larry, Frank fixed his post.
and he explains himself below.

[frnkeore]

Larry,
I'm truly sorry that you are taking it that way. It was not ment to start a arguement at all. What I was doing was pointing out that ES can and will cause larger groups, especially at longer distance (200, 300 or more yds).

While you can get reasonable grouping with ES in the 50 fps range, you will get better grouping with with lower ES, even with the same basic powder charge by trying different primers, raising or lowering the charge by as little as .2 gr and even changing the seating depth by small amounts, as well as duplexing (see below).

Also, it is harder to get lower ES with slower burn rate powders, in smaller cases, because the pressure isn't where the powder manufactor designed those powders to be. You also get incomplete burns until the pressure gets to the upper range.

Duplexing might be one way to over come that. I cleaned up the unburnt powder in a 45/70 using pistol powder to burn 4831 and reducing ES to 10 and SD to 4, with a .60 5 shot grouping @ 100.

Frank

[leftiye]

Rick, it's not you. I have yet to talk to or read about a shooter who got RELIABLE and REPEATABLE improvements from inside neck reaming. I'm sure others will disagree with me, and that's quite OK, but here's what I found when trying both methods:

When you turn the necks (outside turning) with the normal tools supplied for the task (Forster/RCBS/Lyman mini-lathe) or a hand held neck turning tool (I use a K&M neck turner), you are cutting against a mandrel and therefore achieving a controlled and even neck thickness.

An inside neck reamer will attempt to remove high spots in the inside neck area, but since there is nothing pushing against it on the outside (no outside "mandrel"), it will remove metal without at the same time controlling thickness.

I have never had any luck with inside reaming; while outside neck turning -when needed- usually helps my groups.

Agree. The only way you could inside turn [the tools extant do not inside turn, they ream] accurately would be in a lathe type tool where the outside of the neck was say forced into a jig/tool with a chamber in a chuck and then single point the inside. Also, this would eliminate the shoulder sometimes created at the inside of the case at the case's shoulder by outside neck turning.

[btroj]

Yes, lower ES is good for longer range shooting. I'm pretty sure it is quite important to the BPCR guys. For 100 yard shooting it may not matter much but as you reach out farther and farther it grows in importance, unless you like vertical stringing.

I don't plan on shooting much past 100 so I don't really care too much about ES but I still look at it anyway. A low ES isn't always a sign of a good shooting load but I find that high ones generally indicate a poor shooting load. That is MY experience, others may have other experiences.


Inside neck reamers follow the existing hole. They may clean up tight spots but they do not uniform the neck thickness. We want uniform neck thickness so outside turning is the way to go.

[runfiverun]

if you push all the uneven-ness to the outside.
I have seen some brass that was shaped similar to a barrels bore and groove relationship.

[cbrick]

A low ES isn't always a sign of a good shooting load but I find that high ones generally indicate a poor shooting load. That is MY experience, others may have other experiences.

Your experience mirrors an article by Dr. Ken Oehler, that's been my experience also. I think I have that article, I'll look and post it if I find it. It makes understanding S.D. & A.V a bit easier.

Rick

[Doc Highwall]

As I have said here before, a low extreme spread does not take into consideration barrel vibrations, but they will show up on the target. I have even shot 10 shot groups showing two distinctive groups right next to one another. The shooter has to keep records of what the velocity was, and see of this happens again with another load at the same velocity showing that this is a velocity range to avoid if they want a good load.

Even a barrel that has been stressed relieved and measures good with a air gage might not be homogeneous throughout it's entire length, giving bad vibrations with velocity and pressure/time curve adding to dispersion of the shots.


The target is the only true proof the load worked at least once, and multiple groups over time prove the load.

[geargnasher]

+1, Doc. If your load is dancing right around a bad spot in muzzle position upon exit, the ballistics can be excellent but slight variations can throw the hits around on target. Often just a very slight change to powder weight will bring things together without really affecting the internal or external ballistics that much, just where the muzzle is pointed upon exit. Sudden vertical stringing during a load workup can indicate the bullet is exiting right around the peak or valley of longitudinal muzzle whip. There's also that radial vibration thing, the one that makes the muzzle diameter change slightly at certain predictable points, about four cycles while the bullet is still in the barrel.

Gear

[dtknowles]

+1, Doc. If your load is dancing right around a bad spot in muzzle position upon exit, the ballistics can be excellent but slight variations can throw the hits around on target. Often just a very slight change to powder weight will bring things together without really affecting the internal or external ballistics that much, just where the muzzle is pointed upon exit. Sudden vertical stringing during a load workup can indicate the bullet is exiting right around the peak or valley of longitudinal muzzle whip. There's also that radial vibration thing, the one that makes the muzzle diameter change slightly at certain predictable points, about four cycles while the bullet is still in the barrel.

Gear

Gear

Do you have any links to research on Harmonics, whip, modes, ect. for barrels. I have read some stuff but no real research or testing.

Tim

[geargnasher]

Here's one, Tim.

http://www.varmintal.com/ashot.htm

Read the several pages linked on the sidebar related to barrel harmonics, tuning, movie, etc. There is an article somewhere, perhaps there, about using Quickload and a little calculating to predict exact muzzle exit timing and how to get that to coincide with the radial harmonic. Get the bullet to exit when the two directions of vibration are sync'ed at the ideal point, and you're golden. It's jacketed data, but it's the same idea for cast.

Gear

[geargnasher]

Here's another one, couldn't remember the man's name earlier but Google turned it up. Chris Long is his name, and he talks about the "traveling wave theory", or radial harmonic.

http://www.shootingsoftware.com/barrel.htm

Gear

[frnkeore]

This is the best one that I have found on barrel vibration. this site also has the best info on BC, twist rates, too.

http://www.geoffrey-kolbe.com/articl...vibrations.htm

Frank

[dtknowles]

Here's one, Tim.

http://www.varmintal.com/ashot.htm

Read the several pages linked on the sidebar related to barrel harmonics, tuning, movie, etc. There is an article somewhere, perhaps there, about using Quickload and a little calculating to predict exact muzzle exit timing and how to get that to coincide with the radial harmonic. Get the bullet to exit when the two directions of vibration are sync'ed at the ideal point, and you're golden. It's jacketed data, but it's the same idea for cast.

Gear

Thanks, I will search more for myself and if I find something good, share it. The FEM's show that which I already understood. His tuner testing kind of left me puzzled. It just goes to show that there might be more than one school of thought about what finding the node means.

Tim

[tomme boy]

Here is a little test I have done before, but wanted everyone to see. Like someone said "it only matters if it matters!"

The first target is shot with mixed headstamp brass. What I did was FL size, trim and chamfer inside and out of the neck. Then powder was thrown straight from the powder dispenser and the bullet seated.



This was then shot right afterwards with out waiting. This brass is all Remington brass from the same lot, once fired. I FL sized this with the expander removed. I then go back and size with a Lee Neck sizer. The necks are chamfered in and out. The primer holes are cleaned and reamed. The inside primer hole has the hole reamed to remove any burrs. Powder is dropped straight from the hopper and the bullet is seated half way. After all are loaded I come back and finish seating the bullet to the length for my throat.



The group would have been a little better except for that one to the right. The bipod slipped a little as I was pulling the trigger. All were shot off a bipod and a monopod. The gun is a Savage Axis heavy barrel in a Boyds stock. The gun is unbedded and nothing has been done to it. The scope is a 4x20x44.

[tomme boy]

Oh ya. The bullets are Midsouth Shooters Dogtown 55gr HP. Hardly a match bullet by any means. I know it is a jacketed load, but it shows that some of what we have talked about works.

[cbrick]

Neither a low standard deviation or a low extreme spread are the final word on anything, of course the target is. The S.D. and E.V. are one of many tools and to me well worth paying attention to. A good group combined with good chrono reading makes me far more likely to pursue that load as opposed to one with poor chrono numbers.

I don't buy into these numbers only apply to longer ranges and mean less at only 100 yards. I think what your looking at is simply that it's easier to see the difference at longer ranges, doesn't mean they don't apply at shorter range. Same idea when working up long range revolver loads, very difficult to have an idea of a loads potential at 20 or 25 yards, very easy to see what the load it worth at 150 or 200 yards.

Rick

[45 2.1]

What you need to do is list things you think matter, then discuss the merits of each. Several things do matter, but which are important.

[45 2.1]

I don't buy into these numbers only apply to longer ranges and mean less at only 100 yards. I think what your looking at is simply that it's easier to see the difference at longer ranges, doesn't mean they don't apply at shorter range. Rick

It is very easy to have a very tight grouping load at 100 yards that falls completely apart and strings horribly at 300 yards. SD and ES help identify some of those problems.

[nanuk]

I have read some interesting articles discussing reaming/turning of necks

outside turning of a neck leaves it as much off center as when you started, requiring a full length resize, then possible re-turning

inside reaming with a lathe style tool allows the neck to move around

in one article, a respected (by some?) wildcatter recommends inside reaming, with the RCBS style, fully supporting reamers.

this makes the most sense, but has the highest cost.

[frnkeore]

In my sport, we do 95% of our shooting at 200 yards with CF and 95% at 100 yards RF.

I used to do all my experimenting and testing at 100 yards, mostly for my convenience until I got caught out with it after finding a very good 100 yard load that totally fell apart at 200 yards. (.8 - 3.25). Since then, I've done ALL CF at 200. I've not found a load that grouped well at 200 to fall apart at 100 yards.

Frank