I'm not really intrested in spending $80-$100 on a concentric gauge, but was wondering if there was a way to estimate runout on the cheap (with, say, calipers)? Thanks!
Measuring runout on the cheap
- Thread starter nuclear_shooter
- Start date
You can't measure run out with a caliper but if you get a harbor freight dial indicator and a V block you can measure run out. Just make sure the end of the case is against the magnetic base of the dial indicator. Pm me your # and ill send you a pic text of what I mean.
A local guy was taking oak and glueing four ball bearings in the right spot to hold the round. The case head was against a stop then used the cheap dial indicator.
I wished I would have took a picture
I wished I would have took a picture
I guess I'm not gonna worry about runout for now then. Has anybody here ever studied how much runout effects their groups?
I have played with it a lot! I find that good quality dies properly set up will produce little to no run out. I use Redding comp dies and get 0.000"-0.001" with ease and my press is getting some age on it. I have also found that if I can see any wobble in the loaded round when rolled on a flat surface then I need to troubleshoot the problem and run out is getting over 0.002". I can consistently see 0.003" or more on larger rounds especially if you have a high contrast background. Here are some tips to help:
-remove the slop in the threads of the die/press by either lifting up on the die when you tighten the lock ring or use a thin o-ring under the lock ring
-remove the spring from the shell holder on the ram, this allows the sell holder to float and find center if need be (I put a small hair elastic around my shell holder/ram to keep it from falling out
-keep your shell holder clean as a lot of residue can build up from decapping
-keep your press cleaned and lubed this will reduce the wear on the ram and pivot pins
-run out is not always in the bullet seating process, it can also come from a bent decapping rod/expander ball (another good reason to run a bushing die), press that is misaligned, and even a chamber cut off center. So proper troubleshooting is important to get rid of run out if it is found.
-remove the slop in the threads of the die/press by either lifting up on the die when you tighten the lock ring or use a thin o-ring under the lock ring
-remove the spring from the shell holder on the ram, this allows the sell holder to float and find center if need be (I put a small hair elastic around my shell holder/ram to keep it from falling out
-keep your shell holder clean as a lot of residue can build up from decapping
-keep your press cleaned and lubed this will reduce the wear on the ram and pivot pins
-run out is not always in the bullet seating process, it can also come from a bent decapping rod/expander ball (another good reason to run a bushing die), press that is misaligned, and even a chamber cut off center. So proper troubleshooting is important to get rid of run out if it is found.
I have rolled loaded rounds on a hard surface. Anything will do, even the hood of your truck. If you can see it by eye, you are talking .004 or more. This is enough to show up on target. My concentric gauge explained alot of the unexplained flyers that I was taking credit for. .001 to .003 will take a very accurate rifle for you to see in the group. More than that, you need to look at your loading technique or equipment. The decapping rod and expander ball cause more of this than you would think. Lightman
