milboltnut
Moderator
variations in pressure and velocity variations are less, technically a different load, understood. Thanks again
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Runnout and Bullet sorting
- Thread starter akinswi
- Start date
Bart are thinking of tight neck chamberings? As far as I know the most if not all barrel makers use standard SAMMI dimensions on the other areas of the chambers. Both of my 6 BR barrels both need the necks turned down to .012 or .011 neck wall thickness to allow for proper expansion. No other case mods need to be done however.
A perfectly straight 243 Winchester cartridge will have its neck and bullet perfectly centered in a 308 Winchester chamber when fired. This ain't a tight chamber neck scenario.
Well, almost. If the case pressure ring is against the chamber, the bullet tip will be a thousandth or so off bore center in the opposite direction. Very repeatable if all rounds are the same.
Well, almost. If the case pressure ring is against the chamber, the bullet tip will be a thousandth or so off bore center in the opposite direction. Very repeatable if all rounds are the same.
milboltnut
Moderator
Bart
the case shoulder centers the front end of the cartridge in the chamber...that's a given all the time I take it?
the case shoulder centers the front end of the cartridge in the chamber...that's a given all the time I take it?
milboltnut
Moderator
I just watched a vid about firing pins pushing cartridges forward before firing. What has been done prove this ? Just wondering the procedure, not doubting you.
here is a video of a guy firing the wrong calibers in his Glock, the extractor holds the 9 mm against the firing pin in his .40 cal tight enough to the round to fire. However the .223 had to be bushed out with tape for the firing pin to hit the primer with enough force to detonate
So I would give it a definite "maybe"
https://www.youtube.com/watch?v=lkJuu7rwNEc
milboltnut
Moderator
looking at my hornady load manual... I see what is happening in a chamber. They say the cartridge is moved forward by firing pin with HS. So all this time my COAL wasn't .006, but .002 due to my .004 HS.
I hope the OP is ok with us high jacking his thread... sorry dude !!
I hope the OP is ok with us high jacking his thread... sorry dude !!
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Check SAAMI's glossarylooking at my hornady load manual... I see what is happening in a chamber. They say the cartridge is moved forward by firing pin with HS. So all this time my COAL wasn't .006, but .002 due to my .004 HS.
I hope the OP is ok with us high jacking his thread... sorry dude !!
https://saami.org/saami-glossary/
For "headspace," "head clearance" and "cartridge overall length."
milboltnut
Moderator
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milboltnut
Moderator
I used to think like that.
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You might get runout due to a bullet seated out of square,or a bullet that is not round,or a cartridge that is bent,etc.
To get zero runout,the cartidge case and the bullet must be coaxial,and they must be round.
When they are rotating with a dial indicator on them,the needle does not move.
If,from high to low,the total travel of the indicator is .003,then you have .003 Total Indicated Runout (T.I.R.)
Runout does not apply to CQAL,as it is a static length. Referencing "runout" to "the flat spot" or COAL just does not fit. A "flat spot" does not have runout.Neither does a length.
Diameters have runout based on axis of rotation.
Perhaps a better word for you is "variation"
I'm not trying to criticize. I spent over 30 years earning my pay machining,inspecting,and reading blueprints. When a word like "runout" is misused,it tells folks the person misusing the word may not know what he is talking about. Its kind of like misuse of the word "headspace".
Folks who take the effort to educate are trying to help you express your ideas accurately.
Its done with respect.
You may search "Geometric Dimensioning and Tolerancing" to hind references.
or try this
http://proofengineering.com/white_papers/Introduction to Geometric Dimensioning and Tolerancing.pdf
Update and correction, You can measure runout on a flat face,such as a flywheel,or exhaust valve,or cartridge case head.
If you accurately could chuck a sizing die co axial with a lathe spindle, you could use it for a pot chuck and insert a cartridge case till the case taper adequately held the case with friction. Then you could set up an indicator on the flat base of the case head,rotate the spindle,and check for runout.
This would indicate if the case head (and perhaps bolt face) were square.
If you measure 50 cartridge cases for trim length and find the range of length variation is .013, its not runout.
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milboltnut
Moderator
post members name in the quote, I'd like to know
Runout.... concentricity. "variations" in a circle in this case.
actually no I did not misapply runout.......
He asked also about OAL instead of COAL
bullet and case COAL not OAL in relation to just the case. Maybe you could have picked up on that, I did.
Runout.... concentricity. "variations" in a circle in this case.
actually no I did not misapply runout.......
He asked also about OAL instead of COAL
bullet and case COAL not OAL in relation to just the case. Maybe you could have picked up on that, I did.
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milboltnut
Moderator
It’s what I and millions of other handloaders call it
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Thanks for all the info guys, After several tests For My M1 measuring each ogive didnt change anything as far as group size.
This is the best I could get . see attached file below, It was a 5 shot group the first shot was low underneath the enbloc clip. Next 4 was the best I could get.
This is the best I could get . see attached file below, It was a 5 shot group the first shot was low underneath the enbloc clip. Next 4 was the best I could get.
