Concentricity of factory ammo?

[Killswitch Engage]

I am curious if anyone has checked the average concentricity of ammo like FGMM or M118LR. considering this ammunition generally performs well in most .308 rifles; i was curious of how straight it is. i have measured OAL and come up with a .005 to .010 variation in seating depth but i have not had the chance to measure it for run out.

thanks

 

[DocB]

Re: Concentricity of factory ammo?

dgunn,

For FGMM, what I've measured has about the same runout as OAL variation. Not to mention the variation of where the indicators has its average measurement.

HTH,
DocB

 

[Victor N TN]

Re: Concentricity of factory ammo?

Remington factory 25-06 100 grain bullet 0.0 to 0.007"
Hornady factory Gold "match" 300 WinMag 165 grain bullet 0.0 to 0.005"
Winchester factory 300 WinMag 200 grain bullet, 0.0 to 0.005"
I'm not sure which of the Lake City match I checked. But it had the knurl near the extractor groove. It was all under 0.004"

The contact tip of the indicator on all tested, was on the main bullet diameter as close to the ogive as I could place it. I had to use a standard .001" indicator. I couldn't get repeatability on a 1/10th indicator. The ammo was all turned in the same direction to keep a vibration from starting in the indicator.

 

[Killswitch Engage]

Re: Concentricity of factory ammo?

thanks gents!

pretty much what i figured. i assume they are trying to just stay under the .005 mark wouldn't you think?

 

[Victor N TN]

Re: Concentricity of factory ammo?

They are just trying the cheapest thing they can to keep some kind of accuracy. Factory "standard" ammunition is all about cost. Their accuracy standards have a bigger window of acceptance than most of us would knowing accept.

 

[918v]

Re: Concentricity of factory ammo?

Just goes to show you that TIR is not all that detrimental to accuracy, if you find half-MOA acceptable.