Chrony data question

[grauhanen]

Imagine a genie made ten identical copies of a consistent box of high end .22LR match ammo. Each box was shot over an accurate chronograph with a rifle with a good barrel. Some barrels may be faster or slower than others. That's okay and not relevant.

The question is, while they may not be identical, will the different barrels produce fairly similar ES ranges and SD figures? (This is not a trick question. Chronograph data is welcome.)

 

[BowChamp]

My experience with my barrels says yes.

 

[Defender32]

not necessarily. I have seen Phenomenal Numbers out of Lapua lot tested ammo in one rifle shot in another and be ES of 40+. I have also seen a trigger swap that had more sear engagement/ drag on the firing pin cause a very simile effect. This is why lot testing for your rifle is so sought after. It is the best ammo for your setup.

 

[grauhanen]

Thanks for the replies.

If it makes things simpler, allow me to add a detail. The rifles shooting the identical ammo not only have good shooting barrels, they are without ignition issues with the ammo in question. All rifles testing the exact same ammo in this hypothetical example are excellent rifles working as they should.

Do different barrels with the same ammo produce similar ES ranges and similar SD numbers?

 

[justin amateur]

I thought about this on the drive home this evening.
Identical cartridges in mechanically correct actions.
From a fixture in a tunnel with controlled conditions,
the only difference being the barrels.
The chambers, leades, rifling, lengths, bore diameters would vary.
The coefficient of friction would vary.
The barrel differences would affect final muzzle velocity.
But if the cartridges were theoretically identical,
then there would be no ES and no SD. Null values.
Once the wet fouling coated the bore,
the barrel would produce the same mv every shot.
Each barrel would produce a different mv based on chamber shape, bore finish, bore length.
I think, based on imaginary napkin scribblings.

I relate the concept to my centerfire reloading.
I keep improving my cartridge assembly to where my ES and SD are in the single digits.
Assuming practice makes perfect, then one day I will assemble 50 identical cartridges, and end up with zero ES and Zero SD.
Theoretically speaking, right?

 

[BowChamp]

Thanks for the replies.

If it makes things simpler, allow me to add a detail. The rifles shooting the identical ammo not only have good shooting barrels, they are without ignition issues with the ammo in question. All rifles testing the exact same ammo in this hypothetical example are excellent rifles working as they should.

Do different barrels with the same ammo produce similar ES ranges and similar SD numbers?

My experience with my barrels still says yes.

If a rifle has mechanical issues, they should be fixed.

 

[grauhanen]

But if the cartridges were theoretically identical,
then there would be no ES and no SD. Null values.

Not quite. You may be overthinking. The genie doesn't make perfect ammo.

The genie makes identical copies of a box of high end .22LR match ammunition. No box of high end .22LR match ammo is made up of identical ammo. The identical boxes made by the genie are the same as the box of Tenex or Midas or X-Act or whatever it is, with whatever variation there may be within that box.

 

[justin amateur]

30 minute drive, plenty of time to overthink.

I fear this is "If a rooster laid an egg on the peak of the roof,
wind blowing northwest, earth is rotating east, which way would the egg roll?" question.

Roosters don't lay eggs and there are no identical boxes of cartridges.

 

[Coyote777]

I know this isn’t exactly on the same topic but this past weekend I shot 75 rounds over my lab radar (1 shot didn’t pick up) of my RWS 50 that shoots pretty damn good through my DI precision Vudoo. Just wanted to see a big sample size over the chronograph. I would say it’s pretty good for rimfire and 74 rounds.

 

[Lastsaint21]

I don't know if this helps, and do I do not have all the data to present. I had an old 20'' Ace MTU barrel that was the pickiest damn barrel on the planet..It would shoot though if you nailed it on the ammo.. It loved certain lots of RWS50 334m.. That barrel is long gone..That ammo has shot well in every gun I put it in. gunsmithing from Modacam, Vudoo DPG, barrels from Kreiger, shilen..barrel lengths from 20'' to 25''..Vudoo and RimX actions. For a while it was pushing me to rethink some things.. Then came a Ravaged Chambered Kreiger at 25''...and that stuff sucked..in that gun. SD's that had been in the 5-9 range went to 20-25 range..That gun loved Lapua/SK and that was then end of that.. I will say, even though it was a pain, all the ammo I have that that Ace said was good..has remained great in a lot of guns.

 

[grauhanen]

30 minute drive, plenty of time to overthink.

I fear this is "If a rooster laid an egg on the peak of the roof,
wind blowing northwest, earth is rotating east, which way would the egg roll?" question.

Roosters don't lay eggs and there are no identical boxes of cartridges.

This isn't a trick question.

The ammo is the same, the barrels are different. Do different barrels shooting the same ammo results in different or similar ES ranges and SD figures. They either do or they don't.

 

[justin amateur]

I don't know...and I don't have a method to determine the answer.

There is likely a mathematical way to calculate the answer.

https://www.researchgate.net/figure/Muzzle-energy-vs-powder-charge-as-predicted-by-QuickLOAD-V36-for-H4895-and-the-60-grain_fig4_277790998

Muzzle Velocity versus Barrel Length

Genitron.com - Articles and Reviews - A study of values, conditions and formulas for approximating changes in muzzle velocity due to handgun type and barrel length.

www.genitron.com

Change the chamber pressure and coefficient of friction along with bullet weight,
apply it to different bore lengths and compute the muzzle velocity for each cartridge/barrel.
With the theoretical muzzle velocity for each barrel and cartridge
It's probable that the velocity spreads end up similar.
Maybe. I think.

 

[Hi-NV Shooter]

30 minute drive, plenty of time to overthink.

I fear this is "If a rooster laid an egg on the peak of the roof,
wind blowing northwest, earth is rotating east, which way would the egg roll?" question.ie's
Roosters don't lay eggs and there are no identical boxes of cartridges.

There are also no genie's as well. key word you missed was IMAGINE! again fantasy theories!

Lee

 

[Hi-NV Shooter]

I don't know...and I don't have a method to determine the answer.

There is likely a mathematical way to calculate the answer.

https://www.researchgate.net/figure/Muzzle-energy-vs-powder-charge-as-predicted-by-QuickLOAD-V36-for-H4895-and-the-60-grain_fig4_277790998

Muzzle Velocity versus Barrel Length

Genitron.com - Articles and Reviews - A study of values, conditions and formulas for approximating changes in muzzle velocity due to handgun type and barrel length.

www.genitron.com

Change the chamber pressure and coefficient of friction along with bullet weight,
apply it to different bore lengths and compute the muzzle velocity for each cartridge/barrel.
With the theoretical muzzle velocity for each barrel and cartridge
It's probable that the velocity spreads end up similar.
Maybe. I think.

Remember this rimfire

Lee

 

[justin amateur]

Even rimfire has to obey the laws of physics, right?

Suppose you could simplify the variables involved?

Each theoretical barrel gets a different length, coefficient of friction.
Each cartridge has a set chamber pressure and bullet weight.
Input the variables into the basic formulas for mass/pressure/acceleration/friction.
Initial acceleration could be calculated as well as the pressure drop per inch of barrel traveled.
Deceleration could calculated from the coefficient of friction and barrel length along with dropping pressure.
That establishes the theoretical muzzle velocity for each bullet/barrel/cartridge.
It would be possible to do this....a spreadsheet could be set up.
Input the base variables and compile the results.

Right?

Now, if only I was any good at programming spreadsheets, or physics.

 

[grauhanen]

I don't know...and I don't have a method to determine the answer.

That's fair. I don't know either and it's why I asked. Apparently there's no published information, online or in print, regarding the question.

It seems that except for the experience shared by BowChamp (thanks!) there is no other info available on the question.

There are also no genie's as well. key word you missed was IMAGINE! again fantasy theories!

Lee

Lee, while you're right that there are no genies, you're wrong about fantasy theories. A question was asked. Theories haven't been offered. Do you think you see one?

To offer an explanation for the genie, it was to make it possible for each different rifle to shoot the exact same ammo over the chronograph. This would make the comparison one of apples to apples. I could have simply said boxes of ammo from the same lot of high end .22LR match ammo but as you may know each box is not exactly the same.

 

[Hi-NV Shooter]

That's fair. I don't know either and it's why I asked. Apparently there's no published information, online or in print, regarding the question.

It seems that except for the experience shared by BowChamp (thanks!) there is no other info available on the question.


Lee, while you're right that there are no genies, you're wrong about fantasy theories. A question was asked. Theories haven't been offered. Do you think you see one?

To offer an explanation for the genie, it was to make it possible for each different rifle to shoot the exact same ammo over the chronograph. This would make the comparison one of apples to apples. I could have simply said boxes of ammo from the same lot of high end .22LR match ammo but as you may know each box is not exactly the same.

I see nothing as this whole thread is pointless, unrealistic and fantasy based you can't find an answer to your question because there will be no identical boxes of match ammo.
your statement in trying to explain what you mean in itself is fantasy based and pointless. why even bother to post this stuff? it is a theory when the question is what if.

To offer an explanation for the genie, it was to make it possible for each different rifle to shoot the exact same ammo over the chronograph.

 

[flatland1]

Don't know if this helps or is irrelevant, but this past weekend, I took three rifles with custom barrels out after I'd had the scopes & barrels off all three to CeraKote the bbls. 1st rifle was a Rim-X with a Green Mountain bbl purchased as an 1.20" straight blank, sent out to be contoured, and then sent to another 'smith to be chambered with Padom's Eachus reamer, finished at 23". 2nd rifle is a Vudoo 360 with a Krieger blank, EPS chamber that I cut with my reamer, finished at 23". 3rd rifle is a Browning 52C repro with a Krieger that I chambered with the same EPS reamer used in the 360's bbl, finished at 24". Years ago, I bought a case of Wolf Match Extra (made by SK) that turned out to shoot poorly. I've tried it in various rifles, including several full customs with Stiller, Vudoo, & Rim-X actions. It never shot worth a damn in anything until I tried it in a V22S/Shilen ratchet that I chambered with a Nevius reamer, and that was only once - have yet to shoot it in that rifle again. Whatever - last Saturday, I took a couple of boxes of this stuff out to use as foulers, as I'd patched & bronze brushed all three of these bbls to make certain I didn't have any blasting or CeraKote residue in the bores. I'd plugged both ends of each of these bbls, but I always clean thoroughly after CeraKoting, just for peace of mind. After putting 30rds of Wolf, SK Std+, and SK Rifle Match through each of these 3 rifles, I put 10rds of a new lot of Lapua LR through each. The Rim-X & Vudoo each have TT Diamond triggers, while the Browning still has the repro copy of the Win Micro Motion trigger, modified only by the removal of the 'lawyer pin' that limits how far out the trigger return spring can be backed off (it's still got far more creep than I can tolerate, thinking it will be sent off to Dokey for his Kenyon-type mods). I'm still using the original version of the CED Millennium chrono, which has always given me pretty decent results. One more variable that I just remembered - the Kriegers are both SS, while the GM is CM. Kriegers are cut-rifled, while the GM is buttoned. Bound to make some difference in the coefficient of friction if nothing else

Wolf ME - Rim-X - ES-113 Sd-38 Avg-1030; Vudoo 360 - ES-90 Sd-28 Avg-1025; Browning 52C - ES-79 Sd-31 Avg-1061

Lapua LR - Rim-X - ES-53 Sd-14 Avg-1090; Vudoo 360 - ES-27 Sd-9 Avg-1097; Browning 52C - ES-27 Sd-9 Avg-1106

I hadn't even seen this thread when I took these rifles out to shoot - main purpose was to get the scopes zeroed again, and to get more rounds through the GM & the 52C barrel, since they are both still pretty new. And since I was shooting out of the same box of ammo for each brand/grade of ammo, that might reduce the ammo variables by a bit. The main reason I chrono'd all strings was to compare the new lot of Lapua LR to the existing SK Std+, Rifle Match, and LR Match that I have on hand.

 

[Defender32]

Imagine a genie made ten identical copies of a consistent box of high end .22LR match ammo. Each box was shot over an accurate chronograph with a rifle with a good barrel. Some barrels may be faster or slower than others. That's okay and not relevant.

The question is, while they may not be identical, will the different barrels produce fairly similar ES ranges and SD figures? (This is not a trick question. Chronograph data is welcome.)

Here is how you can prove all of this data you are wanting to know and be the person that publishes said data and makes MILLIONS off of it.

Buy 10 actions all built 100% identical, 10 triggers 100% identical, 10 barrels 100% identical & 1 gun smith to spin them up.

Buy Thousands of Cutting edge bullets Load your own kits and the proper powder to go with them. Load the ammo 100% identical.

Then buy the 3 top chronographs used by the majority of shooters in the sport. Magneto speed , Lab Radar & FX True Ballistics.

shoot all the ammo across all systems and compile the date and produce the report of all of us to read.