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Post by mike.dawson on Feb 28, 2010 12:35:08 GMT -5
Has anyone on this forum done pressure traces on the various BP substitutes, i.e. Black Horn, Triple 777 powder and pellets, Black Mag. It would be interesting to view the pressure spikes and decline in a 50cal and 45cal with different bullets. Just my ramblings!! ;D
Mike
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Post by Al on Mar 1, 2010 4:33:55 GMT -5
been wondering that myself.
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Post by mountainam on Mar 1, 2010 8:24:56 GMT -5
I called Hodgdon Tech and they danced around the question. I also asked the question on this site and have not had an answer. Some speculate that T7 is higher than 35,000 psi. Hodgdon probably doesn't want to let out the info because of their concern with some of us interpolating that the pressures are in the smokeless powder ranges and then leaping to the next assumption of "Hey, why not"? Sorry, but the engineer in me wants to know the kip's. I shoot 160 grs. T7 FFG in my .54 700ML. I get great accuracy. At 170grs, accuracy degrades probably due to sabot stress. They told me at Hodgdon that I'll blow up my rifle if I use over 120grs. If they think that, then I'm sure that there is a figure to attach to that reason. They just won't give it out. If someone knows, I too want to know.
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Post by topusmc on Mar 1, 2010 16:00:45 GMT -5
While we are on the subject of powder, is there a powder measure available that will measure more than 120 grns.
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Post by edge on Mar 1, 2010 16:10:18 GMT -5
If you know the volume of your powder charge, the weight of powder sabot, bullet, any wads and you have a chronographed velocity then an approximate pressure can probably be calculated.
edge.
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Post by mountainam on Mar 1, 2010 16:16:05 GMT -5
Topusmc, There probably is, but it's just as easy to make one out of a scrap piece of copper tubing. I use 5/8"o.d. and solder a cap on the end. Cut it off to length when you weigh out the correct charge. Toby Bridges has a conversion chart for volume VS weight on all the BP subs. WWW.hpmuzzleloading.com. Don't forget to engrave the amount on the side of the tubing when you're finished. |
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Post by tpcollins on Mar 1, 2010 19:17:02 GMT -5
While we are on the subject of powder, is there a powder measure available that will measure more than 120 grns. Couldn't you measure out 60 grains and then 70 grains seperately to get 130 grains total? |
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Post by mike.dawson on Mar 2, 2010 7:57:39 GMT -5
Edge, would you PM the formula. It sure would be nice if RB would come back on board to do this.
Mike
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Post by edge on Mar 2, 2010 8:40:53 GMT -5
Edge, would you PM the formula. It sure would be nice if RB would come back on board to do this. Mike I do not have an exact formula. If I knew all of the information concerning a load I would try to work it backward with Powley and Quickload. The expansion ratio and the flame speed would be the most critical items. Without the information that I asked about in my other post I would have no way to calculate it. edge. |
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Post by topusmc on Mar 18, 2010 5:20:50 GMT -5
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Post by 10ga on Mar 18, 2010 10:52:23 GMT -5
Cheapest powder measures are once fired plastic 410 & 28 ga shell casings. Having a whole variety of sizes is cheap and easy. Measure, mark, cut off, permanent sharpie the volume on side. You can make up a whole range or one for each gun etc... 10 ga
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Post by wilmsmeyer on Mar 20, 2010 5:39:35 GMT -5
The few times I toyed with BP subs back in the 90's I did the following:
Volume measured 100 grains 10 times and weigh each charge. I would take out the 2 highest and 2 lowest charges and average the remaining 6. I remember that the highs and lows were never more then 2 grains from the average and even if I included them the average would be about the same.
Lets say that the number ended up being 75 grains of powder "x" was the equivilent of 100 grains volume: You could then take any volume amount you desired and multiply it by .75 and have a number you could weigh out. 150 grains volume of powder "x" would be 112.5 grains weighed IN THIS EXAMPLE
I never liked using volume measure with my BP guns as well as not liking dippers for smokeless. Never blew myself up either.
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Post by mountainam on Mar 20, 2010 7:37:59 GMT -5
I agree with Wilms. I don't think that it's a good idea to measure powder by volume whether real smokeless or substitutes. Every time I read a thread from a newbie asking for advice on this some of the answers given to them make my skin crawl. But then being a shotshell and metallic cartridge reloader for 40 some years makes it difficult for me to put myself in the newbie's shoes. There are conversion charts available for weighing BP subs on this webpage and others. In the days when most shot 70 grs ffg Goex and a .50 cal RB that barely generated 12,000 psi it probably didn't matter. But now we all SHOULD know that the BP subs do generate 2-3 times that. I will not use a reloading manual for shotgun or CF if they show no pressure values. I just feel it's incomplete information. Investment in a beam scale costs considerably less than a trip to the emergency room.
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