7x57 re loading powder

Acm

Well-Known Member
Evening all , I've got a load from quickload that is suggesting i use vectan sp10 in my new 7x57. it looks great with a speer hot cor 130grn. the case is quite under filled at 68%. it all looks good apart from the fact that sp10 is meant for smaller calibers and they actually suggest sp11/sp12. should i be okay or could i get problems?
 
Have heard that TU5000 is good in the 7x57 and the little vectan leaflet I picked up at one of the shows does not list SP10 for the 7x57 it does list SP7 though but with a 160 grain bullet. TU5000 is listed for a 145 grain bullet. Can you get vectan powders easily where you are? I do not recall seeing then often for sale.
 
I would never use a powder with SP10's characteristics in this roomy cased cartridge. A 68% fill-ratio is WAY too low. 90% plus is what you're looking to obtain with a normal pressure load, and even loads in the 80% range are 'lowish'. Doing a quick & dirty QuickLOAD run, I assume you're thinking of a charge weight around 40gn? If so, you're running at ~40,000 psi and this in combination with a low fill-ratio will likely give you very inconsistent velocities. As SP10 is a double-based ball type, it is possible it won't respond well to this mismatch - ball / spherical types often need quite high pressures, 50,000 psi and upwards, to perform as they're designed to and burn consistently.

Some years back a now defunct Portuguese outfit loaded FMJ ammo for various historic military rifles - 303, 8X57 Mauser, 6.5X55 and more. It also used the low fill-ratio / low pressure ball powder approach and although it worked in some cartridges, it was very poor in others (some say actually verging on dangerous), in particular 6.5X55mm Mauser where it produced sooted cases, large 'gas dents' in case shoulders, and it was alleged serious over-pressures on occasions.

Of the ball powders that are reasonably freely available, Ramshot Big Game is a near perfect match to 7X57 with a 130, 'Wild Boar' a little less so. The recently introduced Hodgdon CFE223 is an excellent match if you believe QuickLOAD (which you can't always, but it does usually point the right way at least), also the still slower burning long established H414, the only fly in the ointment a predicted 94.4% charge burn at 45,000 psi in a 24-inch barrel. (Will improve if you work charges up to the point where you break 50,000 psi.)

I personally would use Viht N150 here with this weight of bullet. For heavier projectiles, move to the slower N160. But there are many others - Alliant Re19, the 4350s, Lovex SO70, Reload Swiss RS62 which is also a very good internal ballistics match and gives higher MVs than N150 (which you may not particularly want of course). The Viht powder has the advantage of being one of the not quite as expensive as most and is very widely available in gunshops around the country, and is rarely out of stock waiting shipments from the factory.
 
I had Viht N140 recommended to me, but have yet to work up a load for this. Interested if anyone has done so for a modern action. 130gr FMJ and 140gr SP. The Viht website is good, but in comparison with other sites the loads/ velocities look a bit conservative.
 
I think N140 is too fast burning - you cannot fill the case with enough to get high velocities without getting too much pressure in the early part of the burn.

N150 would be better for even a 120-gr Sierra or 130-gr bullet in the 7x57 Mauser or 7mm-08. Start with about 39.0 gr for the 130-gr or 140-gr and work up to no more than 43.0 probably, because with some bullets, you will be approaching 100 case fill. But the loads up by 3.0 gr for the 120-gr Nosler or Sierra. I am guessing here, as I don't use N150 in my 7mm-08 or 7x57R, and didn't in my 7x57 Mauser - other powders work so well for me and cost much less in the USA. I use N150 and N160 in some other cartridges.

You may find your rifling twist too fast for a 120 or 130-gr bullet to yield best accuracy. If you want velocity and a good hunting bullet, the 120-gr Ballistic Tip and the Speer 130 will surprise you with how they retain weight and penetrate - very flat shooting and good for 150 to 250 yards on deer. The Sierra 120-gr Pro Hunter is cheap and great for a mild load inside 200 yards.
 
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