Runout!

onehole · September 24, 2015

Hopefully I will be attaching some short Vids of an unturned and a turned neck and how they exhibit themselves to a dial guage on the lathe.Think the vids speak for themselves really,,,,The cases are once fired and then reloaded with redding dies.Resultant runout is down to 2 to 3 tenths rather than 2 to three thou!!http://i141.photobucket.com/albums/r64/onehole/th_MVI_0227.mp4 http://i141.photobucket.com/albums/r64/onehole/th_MVI_0217_1.mp4 http://i141.photobucket.com/albums/r64/onehole/th_MVI_0228.mp4 http://i141.photobucket.com/albums/r64/onehole/th_MVI_0230.mp4 http://i141.photobucket.com/albums/r64/onehole/th_MVI_0232.mp4

Chris-NZ · September 24, 2015

Might be useful to either list or label them.

It'd be more informative if we knew which was which (unless I'm missing something as I can't see any labels)

onehole · September 25, 2015

Ok,,,,,the first one shows a case set up to run with virtually no runout on the case,,,what you would expect from one formed in a well smithed chamber,,,the second one shows runout on the bullet from NOT turning the neck,,,,huge runout,,,the third one and the forth one show runout on the neck and bullet from a neck turned case,,,negligable runout,,,,,the fifth one just same case with bullet running sweetly and true in the lathe.

gbal · September 25, 2015

Ok,,,,,the first one shows a case set up to run with virtually no runout on the case,,,what you would expect from one formed in a well smithed chamber,,,the second one shows runout on the bullet from NOT turning the neck,,,,huge runout,,,the third one and the forth one show runout on the neck and bullet from a neck turned case,,,negligable runout,,,,,the fifth one just same case with bullet running sweetly and true in the lathe.

Just to be very clear,Dave.

Is the first one (no runout in a well smithed chamber) neck turned or not? "Set up" is a slightly vague phrase...tho' suggests neck turning?

Third and fourth (no runout) are from standard chambers (ie non smithed)-but maybe upmarket,like RPA-or just ordinary factory jobs?

Can we separate then 'neck turning' from ' well smithed chambers)- presumably both especially together,being advantageous.

Put simply,do neck turned cases shoot measureably better in factory chambers?...in normal varminting use..?

Sorry, this started as just a clarification question,interesting of course,but what's the payoff (satisfaction,importantly,apart?)

g

onehole · September 25, 2015

The first vid is just to demo that I had set up the case/cases whether neck turned or not to run true as not to influence any readings on necks or bullets.Quite simply lads the vid that shows the needle swinging wildly was from the guage put on the bullet loaded into a fired case but with an unturned neck and the other two vids showing only 2 to 3 tenths runout was from the guage placed on the neck and also the bullet and using a once fired neck turned case. I was only demonstrating that by neckturning a huge amount of runout can be removed and give" potential"l for better accuracy....

Neck turning for factory chambers,,,not sure benefits would be noticed,,,,,,rebarrelled and min spec chambers and obviously tight necked customs ,,,obsolutely!

An example,,,I once had a batch of Lapua 308 cases that showed around 4 thou of runout even after once fired,,,,I neck turned the lot and halved the group size ,,,,,,,,its not for everone ,,neck turning is a bit of a pain for some gain ,,definitely for me anyways,,,regds ,,,O