Berger bullets optimal speed

[Gyro]

Hi damping materials = hidamets.

Pure Mg in bar stock is easily bought.

[pjifl]

My reference to Unobtanium is to a damping substance that actually damps before the bullet has left the barrel !
Plenty of things that damp - but do any of them actually work the way people think they do. ?

Damping means absorbing the energy present in a vibrating barrel. It can reduce the amplitude of vibrations - but never can it stop the vibrations from forming. Damping can only work after the vibrations build up. In fact, huge vibrations mean plenty of damping. which only then subsequently reduces the amplitude for each oscillation.

[Gyro]

My reference to Unobtanium is to a damping substance that actually damps before the bullet has left the barrel !
Plenty of things that damp - but do any of them actually work the way people think they do. ?

Damping means absorbing the energy present in a vibrating barrel. It can reduce the amplitude of vibrations - but never can it stop the vibrations from forming. Damping can only work after the vibrations build up. In fact, huge vibrations mean plenty of damping. which only then subsequently reduces the amplitude for each oscillation.

Just use rubber and brass/bronze Peter. Everyone else does so they must be the best materials !

[RDavies]

If it costs more then it has to be better ??????
Add in an elastomer made of unobtanium to damp the increased barrel vibrations at great cost as well. Gotta win somehow !!!!

Sorry for the cynicism

Peter Smith.

A lot of people are spending lots of money trying to get back to the consistency of accuracy they used to get a few years back.

[pjifl]

Well, I must admit Brass and Bronze look good. That's the main thing !

[Gyro]

Just a little more learning for ya Kianga1971 : I recrowned my FO gun the other day due to a ‘mishap’ that buggered it and it would NOT shoot when I took it to the range last nite. This was after recrowning it, and after a very anal lathe setup. It had gone from a ¼ minute gun to a ½ minute. Re crowning it by about 60 thou, just enough to remove the damage, had changed it. Lord knows why. I only went to the range to check it, assuming everything would be fine. My borescope showed the crown was now perfect.

Anyway, lucky my range is only 4 ½ minutes away as after 6 trips and trying different things it was still shite. So I seated the boolits out a bit, 1st by 8 thou, then 16 thou and Boom now its golden again with the bullets about 10 thou off the lands now. EC and RD taught me that this year and maybe they wuz rite. Whodathought !

BTW all I did to totally destroy the crown was bump into it (hard) with my cleaning rod handle when removing a feral lead fire-forming boolit that got stuck in the throat. Instead of just a few dings to the crown there was a bunch of chips broken off ! Surprised me.

[pjifl]

Just a comment on crowning.

A 90 degree crown does not need a perfect lathe setup. Just a very fine feed and the last few cuts wafer thin outwards. Then smooth the end as you would do normally.

I can see no difference in the effectiveness of a 90 degree crown to any other fancy angles or shapes. Just one step (two levels) - the inner one being fairly wide.

I am not suggesting a really poor lathe setup but a reasonably good 3 jaw chuck is good enough.

I do like a good crown. There are some reports that poor crowns can shoot very well. Others that a crown touchup has made all the difference. Whatever is true, it is a very simple thing to do a new crown at 90 degrees.

Peter Smith.

[ned kelly]

G'day All,
As I recall Gene Beggs did a lot of short range BR that meant using Vit133 which had to be kept in tune due to its temperature sensitivity.
There were two ways to keep it in tune,
1. Adjust powder weight as necessary during a competition based on previous group - if it really tightened up, you had better back off the load or
2. Use a tuner to try and compensate. Gene Bukys developed a particularly good tuner for that discipline.

You all must consider that the SR BR barrels are usually parallel or #7 HV contour and around 21" long, a completely different set up to F class

Hope this adds some context to the debate

Cheerio Geoff

[KHGS]

Hmmm, looks as if this thread has gone way of topic??
Keith H.

[Gyro]

Miles off topic Keith but Alan waves his big stick much less now when that happens haha.

[KHGS]

Yup, I am moving on!!
Keith H.