Runout gauge?

[RED333]

On another forum the talk is high speed cast boolit shooting.

I want to push my 7mm RM to 2500 FPS with a powder coated cast boolit that I make

There was a post about "runout" and reloading. I have not been reloading long, thought I was doing a good job.

Well now I am a bit ticked off as I have not been paying close enough attention to runout as I should.

i did not have a gauge, do not have the money to buy one, so I made one.

Old heat sink, dial indiactor from my Cabin Tree hardness tester.

It is not good looking, but does work, it did show me that 2 in 10 rounds I checked are under .005.

The rest are .010 and more out. Back to learning how to reload for groups before speed.

If you projectile does not engage the rifling square it will not group.

[URL=http://s896.photobucket.com/user/redintn/media/Runout%20gauge/DSCF1255_zps7077ce9f.jpg.html][/URL]

[URL=http://s896.photobucket.com/user/redintn/media/Runout%20gauge/DSCF1256_zpsb459ebbd.jpg.html][/URL]

[mikegideon]

That should work just fine

[Caster]

Inconsistencies in powder coat thickness and the textured surface finish of the powder coated bullet will account for a few thousandths of runout.  

[RED333]

Well I did check Jacketed loads as well, I am thinking something is wrong with reload process, size die is on the list to check.

[Caster]

You should be neck sizing only for that ole BB rifle of yours.



BB = backwards Browning.

[DaveTN]

I’m not a reloader, but just curious. As soon as the bullet enters the barrel it is locked into the lands and grooves and “runout” should not be a factor?

[Caster]

Ohh no, not at all. I've seen bullets where the rifling engraved on one side is noticiably deeper than the opposite side. This means the bullet is eccentric in flight. Imbalance = pisspoor accuracy.

[RED333]

Caster is right, accurate groups start right after the pin hits the primer and ends when the bullet hits the target.

If the bullet is not straight going into the lands it will come out of the barrel not straight, depending on the twist rate

of you barrel, the bullet rotates at mind blowing 150,000 RPM, think about you tire just a little bit out of balance.

 

Bullet RPM Formula
Here is a simple formula for calculating bullet RPM:

MV x (12/twist rate in inches) x 60 = Bullet RPM

Quick Version: MV X 720/Twist Rate = RPM

Example One: In a 1:12″ twist barrel the bullet will make one complete revolution for every 12″ (or 1 foot) it travels through the bore. This makes the RPM calculation very easy. With a velocity of 3000 feet per second (FPS), in a 1:12″ twist barrel, the bullet will spin 3000 revolutions per SECOND (because it is traveling exactly one foot, and thereby making one complete revolution, in 1/3000 of a second). To convert to RPM, simply multiply by 60 since there are 60 seconds in a minute. Thus, at 3000 FPS, a bullet will be spinning at 3000 x 60, or 180,000 RPM, when it leaves the barrel.

http://bulletin.accurateshooter.com/2008/06/calculating-bullet-rpm-spin-rates-and-stability/

[RED333]

In checking my cases I did find that my Lee die is making the case necks run out.

Ran a few in a RCBS die and fixed them.

Lee close to .003 to .005 out.

RCBS less that .002, most less than .001 out.

I did rotate the cases 180* and ran them twice.

One step closer to 2500 FPS with powder coated lead.

I am gona have to find a neck die for this rifle.

 

ETA: checked a few fired, unsized cases and found my chamber has .001 run-out, not perfect but usable.

Edited October 9, 2014 by RED333

[RED333]

Ran 50 unloaded cases in the RCBS die, all less than .001 run-out with out the expander ball.

Reran a few with the expander ball and the .004 to .007 run-out came back, so ran them in the sizer die to fix them again.

Now I have a Lyman 7mm M die expander that kept the run-out below .001, however I did find

7 cases that has run-out after the M die, ran the 7 with the Sizer die back out a bout 1 turn, case

are straight again, back into the M die expander, run-out came back.

These 7 cases are now culled for brass thickness not being the same around the neck.

This rabbit hole is very deep, gona be a long road to HV.

[TN Volunteer]

"Caster is right, accurate groups start right after the pin hits the primer and ends when the bullet hits the target.
If the bullet is not straight going into the lands it will come out of the barrel not straight"

My accuracy rounds were always less than 0.003" TIR. That was always my minimum standard. Less was ALWAYS best. Now the benchrest folks will beg to differ I am SURE. From my experience not using a bench, it also boils down to how well I can hold my firearm and breathing techniques. Close range, a non issue. Further out, you better have something that goes down the pipe that is right from the get go.

Everything else went into the practice box.

Runout does make a difference. Edited October 14, 2014 by TN Volunteer

[RED333]

I had a few cases that I could not get right, so I think I have cases that are not the same thickness all the way around.

I needed  way to check this, being a cheap SOB, I made me one.

Took the mandrel from a 7mm Lee case length cutter, drilled and taped the base block and now have a case neck thickness checker.

[URL=http://s896.photobucket.com/user/redintn/media/Runout%20gauge/DSCF1258_zps270b5a8c.jpg.html][/URL]

[URL=http://s896.photobucket.com/user/redintn/media/Runout%20gauge/DSCF1259_zpsf868e391.jpg.html][/URL]

Now to check all the cases again to check for proper neck thickness.

[mikegideon]

I had a few cases that I could not get right, so I think I have cases that are not the same thickness all the way around.

I needed  way to check this, being a cheap SOB, I made me one.

Took the mandrel from a 7mm Lee case length cutter, drilled and taped the base block and now have a case neck thickness checker.

Now to check all the cases again to check for proper neck thickness.

 

That looks like it will work as well as my Sinclair neck gauge.  :up:

[mikegideon]

"Caster is right, accurate groups start right after the pin hits the primer and ends when the bullet hits the target.
If the bullet is not straight going into the lands it will come out of the barrel not straight"

My accuracy rounds were always less than 0.003" TIR. That was always my minimum standard. Less was ALWAYS best. Now the benchrest folks will beg to differ I am SURE. From my experience not using a bench, it also boils down to how well I can hold my firearm and breathing techniques. Close range, a non issue. Further out, you better have something that goes down the pipe that is right from the get go.

Everything else went into the practice box.

Runout does make a difference.

 

If you're not shooting from a stable rest, I doubt that reasonable runout is going to be a factor. Just holding to less than a half moa is something I probably can't even do anymore without a good rest. You can drive yourself crazy with all the ammo tweaks that some of the benchrest guys do. I think in some cases, they get more enjoyment out of dinking with ammo than real results.

[RED333]

My goal is to shoot a boolit I cast, powder coat, and load to over 2500 FPS and hold a 1 inch group.

With jacketed it is doable, however with cast it is a long road.

Cast boolits come apart when twisted to fast, some tend to "slip" past the lands of rifling.

Some go way out of balance, this the "want" to do things right.

[TN Volunteer]

If you're not shooting from a stable rest, I doubt that reasonable runout is going to be a factor. Just holding to less than a half moa is something I probably can't even do anymore without a good rest. You can drive yourself crazy with all the ammo tweaks that some of the benchrest guys do. I think in some cases, they get more enjoyment out of dinking with ammo than real results.

"If you're not shooting from a stable rest, I doubt that reasonable runout is going to be a factor."

I agree whole heartedly. Everyone wants a perfect round that will do one hole groups at some distance that they expect good results from, no matter what the distance may be. If one is not proficient at all in the other skills necessary to achieve that, the perfect round won`t matter.

"Just holding to less than a half moa is something I probably can't even do anymore without a good rest. You can drive yourself crazy with all the ammo tweaks that some of the benchrest guys do."

Words of wisdom & very well stated. You get it. Sounds like to me you have been around the block a few times and learned a LOT over the years. I tip my hat to you and smile! :)

Now if one is a benchrest shooter, I`m not even going into all of the possibilities of how one can tweak a load & the equipment that they use. It gets WAY too involved.

Boiled down and put in a nutshell, if one is shooting a pistol, practice on pistol skills and all that comes with it. If you like using a rifle, practice shooting one and learn to read the wind at the longer distances, breathing techniques, bullet velocities, judging distances.......I am going to stop with this. My head hurts.

[TN Volunteer]

"My goal is to shoot a boolit I cast, powder coat, and load to over 2500 FPS and hold a 1 inch group."

Red, At what distance are you wanting to attain that accuracy?
Are you using irons or optics?
In the real world, will you be shooting from a bench? Edited October 16, 2014 by TN Volunteer

[Tempest455]

Yep distance is the factor. Shorter distances will not be an issue as much. I would offer a blanket statement and say unless you are shooting past 500 yards, I would not worry about it. 

[mikegideon]

"If you're not shooting from a stable rest, I doubt that reasonable runout is going to be a factor."

I agree whole heartedly. Everyone wants a perfect round that will do one hole groups at some distance that they expect good results from, no matter what the distance may be. If one is not proficient at all in the other skills necessary to achieve that, the perfect round won`t matter.

"Just holding to less than a half moa is something I probably can't even do anymore without a good rest. You can drive yourself crazy with all the ammo tweaks that some of the benchrest guys do."

Words of wisdom & very well stated. You get it. Sounds like to me you have been around the block a few times and learned a LOT over the years. I tip my hat to you and smile! :)

Now if one is a benchrest shooter, I`m not even going into all of the possibilities of how one can tweak a load & the equipment that they use. It gets WAY too involved.

Boiled down and put in a nutshell, if one is shooting a pistol, practice on pistol skills and all that comes with it. If you like using a rifle, practice shooting one and learn to read the wind at the longer distances, breathing techniques, bullet velocities, judging distances.......I am going to stop with this. My head hurts.

 

I've done some ammo dinkin'. I suppose it helped...

 

 

[TN Volunteer]

I've done some ammo dinkin'. I suppose it helped...

Mike,I have to say from your photos that you posted, you are not a novice to the shooting world! You have some nice measurement gear! Sinclair makes some good equipment. How do you like the press that you are using? Looks like a twin beam supported press. I`m not familiar with it. What brand? Lee press maybe? Edited October 16, 2014 by TN Volunteer

[TN Volunteer]

Red,

Is that a KB electronics DC motor controller heatsink that you used for your measurement "stand"?

[mikegideon]

Mike,I have to say from your photos that you posted, you are not a novice to the shooting world! You have some nice measurement gear! Sinclair makes some good equipment. How do you like the press that you are using? Looks like a twin beam supported press. I`m not familiar with it. What brand? Lee press maybe?

 

It's a Forster Co-ax, the best single stage press in the world!

 

109 Reviews, all five star...   http://www.midwayusa.com/product/265719/forster-co-ax-single-stage-press

 

I have a lot more stuff. I'm kind of an ammo geek.

Edited October 16, 2014 by mikegideon

[TN Volunteer]

It's a Forster Co-ax, the best single stage press in the world!

109 Reviews, all five star... http://www.midwayusa.com/product/265719/forster-co-ax-single-stage-press

I have a lot more stuff. I'm kind of an ammo geek.

Sometimes we all get kind of carried away on better equipment! LOL! :)

I wish that my skills were as good as my gear. I also wish that my eyes were as sharp today as they were in my younger years. I hate getting old.

[mikegideon]

Sometimes we all get kind of carried away on better equipment! LOL! :)

I wish that my skills were as good as my gear. I also wish that my eyes were as sharp today as they were in my younger years. I hate getting old.

 

Just use good optics :) ...  

 

[TN Volunteer]

Just use good optics :) ...

Optics are a wonderful thing! :)

Very nice!