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Does anyone have any experience with this powder, specifically it's temperature sensitivity. What the quality is like. I'm thinking about it for a 300 WinMag. Thanks AB | ||
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one of us |
AB, Norma MRP has been a top performer in several cartridges I have loaded it: .243 and 100gr 6,5x57 and 140gr 6,5x65 and 120-140gr .270 and 130-150gr .300 WM and 165-180gr 8x68 and 180-200gr I have not tried all powders available within the same or similar burning rate, but my experience is that MRP might very well be close to being THE powder. I have found an average difference of 50 or 60 fps in muzzle velocity from 0 to 30 degrees (centigrade, sorry). My two cents, montero | |||
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MRP is extremely close (if not the same) as RL22. So close that, taking all the usual precautions of working up from below, you can expect to use the same data for both powders. I don't know for a fact, but I have heard people claim both powders come off the same production line. - mike | |||
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One of the issues with MRP (and its clone, RL 22) is that it seems to exhibit a greater lot-to-lot variation than most powders. This was also true of its predecessor, Norma 205. If you want to use MRP, I would suggest buying a long-lasting supply of the same lot number. Don't just go out and buy a can, work up some good loads, then decide to buy some more powder. You may find that the original lot with which you worked is no longer available and you're subject to going through the process all over again. | |||
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quote:Ask, and ye shall find (from another forum): "Gentlemen: there is a lot of anecdoctic evidence, much of it very valuable actually as far as it reaches, but fairly little proven and documented scientic research, outside the military field. One of the few documented and published pieces of research that I know of is the following (title translated into English): Friedhelm Kersting: An examination of the influence of tropical temperatures upon the pressures of the .470 N.E. cartridge (Untersuchung des Einflusses tropischer Temperaturen auf den Gasdruck der Patrone .470 N.E.), in: Jahresbericht 2002 der Deutschen versuchs- und Pr�f-Anstalt f�r Jagd- und Sportwaffen e.V., 2003 Altenbeken (self-published annual report) pp. 53-57, 3 ills., 1 data table *Very* worthwhile reading: they did examine 5 different testing configurations. It shows that these big one British cases are quite safe as they are loaded (slow powders, large capacity, low normal use pressure. 112 grains of Norma MRP were used here). Regards, Carcano" | |||
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quote:This is as wrong as can be, Stonecreek. I'm sorry, this is not meant as an assault on you as person. The MRP (magnum rifle powder) from Norma are very similar from lot to lot, actally one of the best on the market(I dont have any experience with the RL22, though.) The reason is that they test every lot the make, several times trought the prosess, to make sure there are NO variations in burning rate / and pressure. I they find any variation AT ALL, they sell it as "NORMA 15". This is "failed" MRP powder, sold in large quanteties to shootingclubs and alike. This Norma 15-powder variates in burningrate from lot to lot, and has some pressure examples (loads w/speed and pressure) on every box. | |||
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quote:Stonecreek, my experience, though limited, has been quite the opposite. I have never, ever, found any significant variation using different, sometimes very different, lots of Norma MRP. montero | |||
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Is there anywhere to find reloading data for Norma powders on the web? I've got a link for three calbers for the MRP-2 but none for the MRP. Or should I work it up like RL-22, which I've found to vary quite a bit it the two different lbs. I've owned. One lb. (lot # posted on Alliant web site) was faster than the RL-19 by quite a bit. BM | |||
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<rg1> |
I've used Norma MRP powder in my .300 Weatherby for many years. I've only used 3 lots of powder and all have been consistent. It does not appear to be very temperature sensitive, as my NEAR maximum load does not show overpressure in warmer weather. There are very slight signs of MORE pressure but not overpressure. As previously mentioned you should try to buy as much powder of the same lot as you can so that the one lot will last a few years. Federal 215's light this slow powder well. The Hornady 3rd Edition reloading manual lists MRP loads using Hornady bullets for the 300 Win Mag. | ||
one of us |
I second what 470wby and Johan said, the MRP is defenately a VERY consistent powder. It has been my sole and only powder for the last 15 years in my 338 winmag. I have not seen any variables from lot to lot. Temperatures have ranged from + 25 Celcius to - 15 and no measurable difference in POI or pressure have been observed. It�s a great powder !! | |||
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Is MRP a single or double base powder? I haven't seen a can of it in years and don't use it. VihtaVuori makes both (N100 single/N500 double)so I'm guessing Norma makes both too, but don't know for sure. | |||
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<eldeguello> |
MRP is a double-base powder, as are the Alliant counterparts. I love MRP, just like I loved N205 before MRP. Have never tried MRP2, which is allegedly like RE25.... | ||
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