![]() ![]() The irons printed a little higher being approx. I then flipped up my iron sights (standard front sight, GG&G MAD rear sight using the small aperature, also w/200 yard zero). This load shot about 1 1/2"-2" low at 25 yards. I started off using an Aimpoint M元 which was zeroed for 200 yards. In that 10 shot string, the fastest shot was 1054 fps and the slowest was 993 fps.įWIW: I did some informal shooting on paper just to get a rough idea of where this load would hit. Which of course, I am going to try and see what happens. So, it looks like I might be able to get away with using another 1/10th grain and still remain subsonic. I got out this evening and fired 30 rounds of the 77 grain SMK using 5.7 grains of Trail Boss powder. " Another SWAG: based on these two loads I am guesstimating that. Same goes for the winter: if I was shooting these same loads in bitter cold temperatures they would shoot slower than they do now. If I switch to my 10.5" upper then I could get away with more powder to bring that bullet up to just below supersonic. But, working that load up is only going to be good for the conditions today. This means I want the biggest bullet at just under supersonic speed. Meaning I want as much "power" as I can get while still remaining subsonic. To me, shooting is fun but I also want to have something that serves some practical purpose. To me, I want subsonic but as close to supersonic as I can get without going over the threshold. ![]() I never gave a lot of thought about what it takes to develop a good subsonic load before. If they stay subsonic that will be my load (at least for the summer and 16" barrel). So, I need to load up some 5.7s, and take them out in the heat of the afternoon. 5.5 grains is too slow and 6.0 is too fast. So, it appears I have at least one more trip to the range to make today. 90 degrees.Īt 6.0 grains, some but not all the rounds were going supersonic with an obvious difference in the report. This time using 5.5 grains and 6.0 grains of Trail Boss with the 77 grain SMK BTHP. Las Vegas doens't have very many good sources for powders other than the most common varieties. I don't have that powder and so far have been unable to find any locally. They advised me to use Accurate Solo 1250 powder at 4.5 grains. This would give me a load of 14 grains which obviously isn't going to be subsonic. I just called Hodgedon and they also advised me to use H4895 however they said that it could only be safely downloaded by 60%. Oh, one thing I forgot to mention: the first series of eight were fired without a suppressor and the second and third groups of eight were fired with a suppressor. The third eight were fired after holding the rifle muzzle down and tapping the stock three times prior to firing. Anyway, the second eight rounds gave me an average velocity of 1342 fps. This was to see if the minimal powder charge would ignite differently inside the case because of the positon of the powder in the case. The second eight were all fired after holding the muzzle vertical and tapping the stock three times prior to firing. The first eight were just randomly loaded and gave me a velocity of 1394 fps. Should give me 1011 fps at 7671 psi of pressure. ![]() I initally used the computer software Quick Load to come up with the H4895 load. With the 4.0gr load, case density was at least 50%. Shooting Chrony, indoors with light kit, ~3ft in front of muzzle. High temp up to +392Fīarrel lenth: 14.5" (polished with Flitz then oiled/cleaned/lubed bore) and leaves a VERY slippery coated bullet. RP cases, couple times fired, not trimmed.īullet: 50gr Siearra PSP, LUBED with HHS 2000 by Wurth. PLEASE consider using ALL availible information out there b/4 trying this. As usual, I will provide info on MY particular set-up which may not work with yours. I couldn't wait any more and did it myself. ![]()
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