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Hello

I have a quick query for anyone out there using and reloading .243 Winchester and Quick load.
I normally reload in .308 and .223 and any loads I develop are generally coming out slightly less than quick load so on the safe side.
Just developed and tested a .243 Winchester load with IMR4895 and 37.50 gns. Bullet was a 90 gn Lapua Scenar.

all indications were this would generate around 2960fps through a 1:10 22inch barrel.
Powder was 85% of case volume and 99% burn rate. I was surprised to see an AVG of 3114fps over 6 shots with the lowest cold round being 3085fps
Any ideas as I am a technical type going through everything or is this just .243 being .243.
Mike

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Have you input your actual case capacity in to QL? 

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Yes i did that and altered my new OAL.
Double checked it all.
 This is a mystery nice that i have more FPS than i need just maybe need to go in at the start load rate with the .243 rather than near the Max end which i am used to doing with the .308 and .223

thanks
Mike

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There is a serial discrepancy between QuickLOAD results and manufacturers' pressure barrel based loads data for the 243 IME. It is not unusual  for what looks like a starting / lowish pressure charge weight in QL to be on or even above  published maximum loads in reloading manuals.

I always cross-check QL results against a selection of published loads for any cartridge and they're usually OK, but this is one number where I'd be extremely wary of using standalone QL data, with much more than normal discrepancies often apparent. Hodgdon quotes 34.0gn starting charge of H4895 with the 90gn Speer SP bullet giving 2,967 fps and a maximum charge of 36.5gn for 3,114 fps at 50,800 CUP pressure (a full SAAMI pressure load using the obsolete copper crusher measurement method) - and that in a 24-inch barrel, so equivalent to somewhat lower MV those you're getting in 22-inches! 

You have measured and input a water overflow capacity reading into QL. I'd check that again, also your COALs. In a factory Howa with little throat wear, I've found most bullet models are in the lands when seated anywhere near the SAAMI 2.710" maximum and COALs around 2.65-inch are common with 15 thou' jump. (Incidentally, the 1.1" OAL 90gn Scenar is barely stabilised at 3,100 fps in the standard SAAMI 10-inch rifling pitch under 'standard ballistic conditions'; it's reasonably OK if not optimum in Remington's 9.25 rate and custom rifles with 8-inch twists are obviously fine in this regard.)

The Hodgdon load mentioned above is in a Winchester case which one usually finds is high capacity compared to the norm in most cartridges. So, depending on your make of brass, the Hodgdon maximum may need to be dropped further. Here is an interesting comment on the 243 from Speer Reloading Manual #14:

"We found the 243 Winchester to be very sensitive to case make; we used Winchester cases. Do not substitute cases of other makes with these loads or excessive pressure can result."

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Thanks for your excellent feedback and comments Laurie

Yes you are right I did not compare

with other data and usually I do

have a good Easter 

will reply fully when back on Tuesday 

Mike

 

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Good Morning Laurie.
Yes mystery over should have checked my other data sources which do agree with the FPS I got.
Reference case volume yes found quite a difference between Federal which i am at present using for testing
and Sako which i I also have.
Eventually they will all be Lapua if the barrel and twist rate gives me what i want which i very much doubt
Probably rebarrelling this with a 1:8 twist 28 to 30 inch barrel as i am keen to keep the .243 rather than going the 6mm BR Norma route.

LATEST.

Bisley 1000yds failed miserably reason was a total scope windage malfunction combined with not the best feedback from the butts.
100 to 600yds shooting yes windage died on the scope but managed  very accurate results just using the windage mil dots. 90 gn Lapua Scenars in my 22 inch 1:10 twist seem fully stabilized  at 400 500 and 600 yds

Next test 900 metres.

Thanks Again All.
Mike

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