Page 2 of 4
Re: Powder selection....
Posted: Mon May 23, 2016 6:36 pm
by RDC
I'm so glad this topic was started, I was going to myself!
Re: Powder selection....
Posted: Mon May 23, 2016 6:38 pm
by DW58
Laurie wrote:There are LOTS of suitable powders for 7.62X54R, 308, and 7.92X57mm. Tac should be OK, although I'd prefer Vihtavuori N140 (or Reload Swiss RS50 which used be known as TR140) for this trio. Extruded types such as N140 and the very similarly performing RS50 tend to be very accommodating in their pressure range requirements, whilst ball powders such as the Ramshot grades often work most efficiently in a narrower (and higher pressure) band.
You can't include 7.62X39mm into a single powder grouping with the others basically because it has very different internal ballistics characteristics. While sharing the others' bore size (give or take a few thou'), it utilises a much smaller capacity case, one that holds ~35.5gn water compared to 56gn for 308 and 64gn for the X54R. This makes Tac and N140 etc too slow burning for its expansion rate (the distance the bullet travels down the bore to double the size of the combustion chamber from the unfired state). Also, it's rated at a PMax that's 10,000 psi lower than 308 for instance. All of these require a faster burning powder. Milspec 7.62X39mm nearly all uses fast burning dense ball powders. Current commercial equivalents are Hodgdon H335, Alliant Re7 and in the extruded line Viht N120 which may be the best bet.
http://www.vihtavuori.com/en/reloading- ... -x-39.html
We've had superb results with Reload Swiss RS50 in .308/7.62x51mm (also in .223 Rem) - also suggest RS52 for .308/7.62x51mm.
Re: Powder selection....
Posted: Mon May 30, 2016 4:35 pm
by meles meles
And so, oomans, continuing the theme, what might be a useful powder for .243 shot from a 16", 1 in 8 " twist barrel, at 300 and (very occasionally) 600 mards ? We're thinking a slow burning powder so as to reduce wear, but not so slow that it is still burning as the bullet pops out of the barrel. Maybe Ramshot Big Game again ?
Re: Powder selection....
Posted: Mon May 30, 2016 8:27 pm
by Alpha1
If you check out the manufactures web site it will tell you what powders are suitable.
Re: Powder selection....
Posted: Tue May 31, 2016 4:14 pm
by meles meles
Oh indeedy, Alpha1, indeedy. However we were seeking knowledgeable advice from the sages here on the forum that might temper the somewhat upbeat claims of many powder purveyors. The likes of Laurie, snayperskaya and Dromia often throw in a soupçon of knowledge and hard won experience that makes us view things from a slightly different perspective to that we get when just studying a manufacturer's listing and taking it as gospel. It's one of the many benefits of these fora...
Re: Powder selection....
Posted: Tue May 31, 2016 4:21 pm
by dromia
Ask away, like all true sages if we don't know we simply make it up.
Re: Powder selection....
Posted: Tue May 31, 2016 4:33 pm
by meles meles
Our present conundrum is centred on .243.
We're thinking of (full length) sizing down some of our GGG 7.62 cases to make some .243 cases and then selecting an appropriate powder and bullet (or boolit) for shooting at 300 and, very occasionally, 600 mards. The barrel is 16 inches long and 1 twist in 8, so we think it will stabilise quite heavy bullets if necessary. We're wondering if a slow burning powder like Ramshot Magnum or , a little faster, Big Game, might be the way to avoid burning out the barrel too quickly. We'd need to make sure it was all burnt by the time the bullet popped out of course. How do we calculate that ? The GGG is a military case so likely to have lower internal volume than a commercial case. How do we compensate for that ? Maybe we don't need to if we're only shooting mild loads at short to medium range rather than trying to lob bullets out to 1500 mards at Mach 5? We don't see these issues discussed in the manufacturers' listings...
Re: Powder selection....
Posted: Tue May 31, 2016 4:39 pm
by Sandgroper
I like the Ramshot powders that I've used but sometimes there isn't the data available for a particular calibre so you have try a powder you haven't used before and before you know it you have a collection of different powders!
I tried to have one powder for all my rifles and settled of H4895 as seemed to fit the bill but it fell apart when I couldn't get to work in my 6.5x55, so I had to choose another powder for it.
As an option in for a one size all approach for 30 cals is to shoot cast and use Trail Boss or a pistol powder...
Edit: Why go through the hassle of necking your 7.62 down to 243 - if you're that desperate, I can get some 243 once fired brass off a mate of mine!
Re: Powder selection....
Posted: Tue May 31, 2016 4:48 pm
by snayperskaya
I aquired a tub of Viht N140 today so tonight could be the night my first 54r handload is born, time to put all the reading etc into practice
Re: Powder selection....
Posted: Tue May 31, 2016 4:48 pm
by dromia
For all my cast boolit shooting out to 600 yrds in any rifle calibre over .222" and up to .45" I use fast rifle powders like Vihtavuori N110 or N120, Alliant 2400 or Reloader 7, Ramshot Enforcer, IMR4227 4198 or 3031 and such like powder.
Quickload is a useful predictor for powder with no data for a starting load