6.5-303 Brit Loads

Sharps45-70

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I am building a period style Ross target rifle on an M-10 action. I have decided to have the barrel done in 6.5-303. I originally wanted 6.5x55 but I would have had to rework the bolt face and extractor, and the 6.5-303 reportedly provides similar ballistics.

I am looking for load data for this cartridge. Keep in mind, it will be a 800+ meter target rifle, so I will mainly be using 140+ grain projectiles in it. I have access to Varget, IMR4895, IMR3031, IMR4320, and Retumbo. I will be loading for accuracy, not velocity, but of course if I can find a node up higher I will use it. I just need some advice for min/max loadings using some different bullets.

Thanks for any help you all can provide!
 
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when I find the loaded ammo ill send you what I decided on for a load. id right at the bottom was the most accurate load with the 760. those were over a crony aswell so no guessing. all loads were out of a 24.5" RKS stainless gain twist
 
Thanks for the help Beater.

Does anyone else have any loads for this cartridge? I can make up my own of course, but I would like a handful of good starting powders that are known performers. So far my thought process has been to start with powders that work well in 6.5x55 and go from there.
 
Thanks for the help Beater.

Does anyone else have any loads for this cartridge? I can make up my own of course, but I would like a handful of good starting powders that are known performers. So far my thought process has been to start with powders that work well in 6.5x55 and go from there.

find a 6.5 cartridge with the same case capacity and use the start loads as max that's what I will be doing with the 6mm Musgrave(.303 necked down to 6mm/.243) using .243 Winchester starting loads as max and work up from there. a chronograph is a must when working with a wildcat.

you could probably use ADI loads for the .25-303 ADI powders hard re branded by Hodgdon
 
Beater's loads are in a 6.5/.303 Epps, so your loads would be a bit reduced, using the unaltered .303 body configuration. But you will also have at least 5 1/2" more barrel, so perhaps that will balance things out. I use the Lapua 139 Scenar in my .260 @ 2850. Needs about 31 minutes elevation from 100m to reach 1000m. I've used RE19, 4350, 4831 and 4831SC. Accuracy with Varget was outstanding, but the velocity just wasn't there. Varget is my preferred .308 powder, but not with a 6.5mm. The slower powders were better.
 
6.5 Brit is a good choice. The magazine should feed properly.

You could use 260 Rem data to give you an idea of load data. Start at the START load and go from there. 4350, 4831 and RL22 would be good choices.
 
.256 Mannlicher is a 6.5x303..................... a little weaker.The Ross will stand considerably more.
 
6.5 Brit is a good choice. The magazine should feed properly.

You could use 260 Rem data to give you an idea of load data. Start at the START load and go from there. 4350, 4831 and RL22 would be good choices.

Never having played with wildcats, I would concur that functioning with the rifle is more important than first considered.

If you are pulling the barrel, what will you do for the chamber reamer?
 
Thanks for the tips everyone, keep 'em coming! Excited to experiment with the loads and projectiles once the rifle is done!

It definitely seems the slower powders are the way forward with similar cartridges. The extra barrel length may help me pick up the velocity that was of concern. So far the top choices are RL 22, N160, and H4320 (from various forums on other similar cartridges). I will of course be testing more than that, but it is a solid start.

maple_leaf_eh: I concur with Ganderite, I think the rifle will feed fine as well. If it doesn't, it won't be very difficult to modify the feeding to get it to work correctly. Regarding the reamer, Beater has mailed me the one he used which I will use on a new barrel I am having KS Arms make.
 
Beater's loads are in a 6.5/.303 Epps, so your loads would be a bit reduced, using the unaltered .303 body configuration. But you will also have at least 5 1/2" more barrel, so perhaps that will balance things out. I use the Lapua 139 Scenar in my .260 @ 2850. Needs about 31 minutes elevation from 100m to reach 1000m. I've used RE19, 4350, 4831 and 4831SC. Accuracy with Varget was outstanding, but the velocity just wasn't there. Varget is my preferred .308 powder, but not with a 6.5mm. The slower powders were better.

just a correction, I know it says epps, but it is a standard case not an epps improved case. my mistake writeing it like that. there are so many better powders now but 4320 should still be one of the best ones for this cartridge

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Sounds good Cat.

I picked up some H4350, RL19, and I have some Varget and IMR4320 to play with. I also wanted to grab N160 but my LGS didn't have any, though I do think I have plenty to try at the moment.
 
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