Hi all,
I was hoping I could get some advice, I put an 8mm wildcat/maveric hammer in my panthera .25 hunter compact and it opens the valve fine giving me about 860 fps on the altaros 49.5s. Same thing with my Dynamic 700mm .25, but now, my Dynamic .357 the valve does not seem to open how I would expect. I get no velocity increase past 175 bar, I bought an 8mm brass hammer, 9mm brass hammer and a 8mm tungsten hammer. The 9mm brass and 8mm tungsten are within 10 fps of each other, even though the brass is 10g lighter, pretension is a huge thing. So my question becomes what could be the issue? Is the .357 valve legitimately that much different and harder to open? I am also using 132g slugs, does the slug weight have an impact on opening of the valve, (no idea how but just throwing it out there).
I also converted a M3 impact .357 800mm barrel to use with the rifle, simple heat gunned the transfer port and swapped the dynamic port to it, and its maybe 20fps faster than the original 700mm barrel at identical settings( is that normal, I was expecting nearly 100fps boost, 10fps per additional 10mm of barrel was what I always saw before going from 500 to 600 to 700, but maybe diminishing returns). Again just including this incase these other factors point to other issues with my setup. The only difference in my installation of the hammers was I put some silicon grease on the hammer in the .357 dynamic and I did not do this when I installed the other hammers in my .25.
All three of the rifles were ordered from different dealers, pyramid sent me the panthera hunter, the pellet shop sent me the 700mm .25 and Utah sent me the .357 dynamic, so maybe there is different versions at play here, but I checked all of them and none of them have the updated pressure release valve on top of the reg guage, so all of mine would be considered earlier models.
Any advise would be appreciated as I was trying to build the most powerful .357 dynamic possible and its currently topping out at 900fps with the 132grains because I cant open the valve past 175-180 bar, I have the Huma gen 3 regulators, already described the hammers, the .25s all have slug probes as I am still waiting for Huma to send me a ,.357 pin probe.
TLDR - .25 dynamics I can open the valve with the gen 3 huma reg up to 190 Bar with the 8mm hammer, but I cant open the .357 dynamic past 180 bar even with a tungsten hammer!
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