JARACAL

dit werk nie so lekker met daai nuwe waardes nie

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Ek stem saam alles lyk skeef as jy die nuwe waardes in sit.

Hello manne

Was lanklaas op. Password mis gekuier n ruk terug. LOL
Ek moet nog self eendag bietjie sit en Quick Load leer ken. Ek hoor en sien dit is n goeie "Tool" om mens te help met Reloading.

Die foto onder is van Chris Long se skrywe oor OBT verkry. Ek sit dit spesifiek op om te wys op die metode hoe hy QL se ladings kalibreer. Dit is die metode wat ek gebruik en ook die meeste hier op Jaracal. Die aanpas van die koeëlgewig het ek sover nog vermy, maar ek dink hy raak dit aan in sy skrywe oor OBT.



www.the-long-family.com/OBT_paper.htm

Goeie more manne.. Dankie aan almal wat n bydrae gelewer het onder hierdie topic. Ek is n nuwe QL gebruiker en gaan vandag ladings toets soos uiteengesit in QL + jul raad.

Ek sal later resultate aanstuur



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Hi weer, ek is terug van my toetslopie. hieronder volg my data:

Ruger Precision Rifle .308
Loop lengte: 510mm Node op OBT tool : 1.0994 wat ek gesoek het
Dop: Lapua Punt: Nosler 155gr CC Kruit: Vihtavuori N140

QL se ek moet 44Gr kry om 1.098 te kry teen 2569fps

Resultate op 100m
43.8gr 2555fps Teiken - 1.5MOA (QL - 2558fps)
43.9gr 2564fps Teiken - 1MOA (presies dieselfde as QL)
44.0gr 2574fps Teiken - 0.433MOA (QL- 2569fps)
44.1gr 2584fps Teiken - 1.1MOA (QL - 2574fps)

Ek is baie baie beiindruk met QL en het my werk baie vergemaklik.


Baie dankie manne.

Groete

Ek wil iets vra. As julle quickload toets ladings ontwikkel. Hoe toets julle dit of dit groep? 50m 100m 150m? Mens moet tog human error ook inreken veral oor langer afstande. QL gee jou dalk perfekte lading maar jy maak droog agter die roer.

Dit is maar altyd 'n probleem. Al die berekeninge beteken niks as die skut nie behoorlike groepe kan skiet nie. Die data voorsien vir QL beteken ook dat slegs in gevalle waar blatante foute voorkom, die data netso aanvaar moet word.

Ek toets op 200m, maar het n geweer wat meeste ladings onder n duim skiet daar, so met hom toets ek op 300m

Ek het n vraag vir die manne met ondervinding.

Volgens 'n artikel oor die kalibrering van quickload in Jagter tydskrif moet beide die Ratio of specific Heats en Burning rate factor aangepas word om te kalibreer. as ek egter deur die vorige posts lees klink dit amper asof dit slegs nodig is om die burning rate factor aan te pas.(verstaan ek reg)
Daar is ook manne wat voel dat die standaard sonchem waardes beter resulate gee as die "nuwe" waardes op die website.

Wat sal dan die effek wees indien slegs die burnrate verander word en die ander standaard waardes net so uit quickload gebruik word.

Soos ek dit verstaan moet die burnrate in elk geval weer aangepas word indien van die ander waardes verander.
Uiteindelik pas jy tog aan totdat werklike spoed en voorspelling ooreenstem.

Dankie ek maak so.

In terms of the burn rate you are experiencing with Viht N550, you must remember that the default burn rate is an indicative factor.
It is purely an indication of how the propellant "performs" under test conditions in a "bomb test".
Please read here for a in depth technical discussion on the "bomb test".
https://www.chuckhawks.com/powder_cartridge_testing.htm

So indulge me if I get a bit technical here.
The bottom line is that this bomb test is purely an indicator of the propellants properties based on a small test sample run at "low" pressure.
The propellant manufacturer can not do this test and simulate a 50 to 60 000 psi load, and they can not determine how the propellant will react in every different cartridge with different components, jump to the lands,bearing surfaces, barrel length and a whole lot of different parameters that are unique to your rifle and components and which influence the powders performance (burn rate factor in other words)
Lets take an example.
Look at Vihtavouri"s website and take their reloading data for the 243 win with a 90 grain bullet.

Test barrel: 580 mm (23”), 1 in 10” twist
Primers: Large Rifle
Cases: Lapua, trim-to length 51,80 mm (2.039”)

Viht 243 win.jpg

If you reverse engineer these figures in quickload with N550 powder you will see that you have to change the default burn rate up substantially to calibrate their loads (exactly what you are experiencing at the moment).
The same will apply in the 22-250, 25-06, 270 Win etc as all these cartridges fall into the overbore category.

Lets now look at another cartridge.

Test barrel: 620 mm (24½”), 1 in 10” twist
Primers: Large Rifle
Cases: Lapua, trim-to length 63,10 mm (2.484”)

Hierdie inligting is baie relevant.

Posted by Dale SH

Viht N550 30-06.jpg

If you reverse engineer these figures in quickload using their exact parameters and components you will see that your predictions and their actual data is so close that you have to adjust the default BRF so slightly it is negligible.

Powder manufacturers test their powders across a spectrum of cartridges and give us guidelines to follow.
However once again these tests are done using specific components and test barrels.
Yours may be different so your results may also be different.

Bottom line is that you can not blindly believe that your initial prediction with QL will be accurate as there are too many factors to consider as mentioned above.
It is always best to follow the powder manufacturers guidelines and cross reference and reverse engineer their data with your QL prediction and see if you experience any major discrepancies.
Should you need to adjust your BRF substantially to calibrate with Their achieved figures you have to ask your self some questions:

For example:
Are you dealing with an overbore cartridge ?
Is your bullet in or too close to the lands ?
What barrel length are you comparing too ?

Once you have identified where your major differences are coming from you will have an idea as to where to rectify the problem.
In your case right off the bat you know you dealing with an overbore cartridge and secondly you may have had the bullet too close or in the rifling.
Now that you have shortened your TPL and the BRF hasn't changed much we can eliminate that particular criteria.
Now if we cross reference Vihtavouri's 243 Win load data we can identify that N550 does indeed burn substantially faster in this cartridge ( higher BRF near 0.51) than the default.
Our mind should be at rest now knowing this fact and we can continue to calibrate our load.

Dankie vir plasing Oom Driepoot en Dale vir die skrywe.

Hierdie wys op n baie belangrike aspek en dit is diegebruik van gesonde verstand. Deur dit te gebruik en toe te pas in die lewe laat jou gewoonlik so bietjie verder kom as die pattatkop vir wie daai opsie nie beskikbaar is nie.

Groetnis
Wouter