I recently learned about the max power upgrade valve for the challenger and challenger bullpup big bores. I had to try it. The 1st video I saw was the Mr hollowpoint video. In that video he tests 3 weights, the lightest of which is 260 grain. Then I watched the bin tac video of how to install the valve, then I ordered it.
I received it and installed it. The first time I took it out, it worked wonderfully and exceeded my expectations. The second time, my velocities were down. I thought maybe it was a location, temp, barometric pressure or some such issue, I had observed some variance in performance with the gun before upgrading it. Before I could get all the data I wanted, the gun stopped cocking, I had to go home.
Turns out it was just a positioning problem with the bullpup trigger group and I hadn't tightened the screws enough, simple fix.
Went out the next day, and velocities were down even more. More than elevation, barometric pressure, and temp should account for. To give you an idea, in the stock configuration, the gun made about 900 FPS with a 200 grain slug, plus or minus a little depending on the day. After the upgrade, the same slugs were going 1145 FPS. Thats a difference between 400ish FPE and 580 FPE. I also tested a 366 grain and it made 706 FPE. Then on the subsequent two shooting days it made less and less velocity, until now, and it essentially indistinguishable from stock. Something is wrong, I message bin tac. Today he has his helper Jason message me. Here's the convo:
I never heard that it isn't for light slugs. They don't mention anything about not using light slugs in the product description. I can't think of a reason why using light slugs would be a problem. Mr hollowpoint used 260 grains in the test. Is that light? The lightest I can make that still fit in the mag are 240 grains. If I couldn't use the magazine anymore I wouldn't have bought it. Even if i did only ever want to use heavy slugs, they are making energy comparable to stock valve again now too, its not just the light slugs. I think this response is B.S., if you don't like it send it back and we'll sell it to someone who wants it? WTF kinda response is that?
I received it and installed it. The first time I took it out, it worked wonderfully and exceeded my expectations. The second time, my velocities were down. I thought maybe it was a location, temp, barometric pressure or some such issue, I had observed some variance in performance with the gun before upgrading it. Before I could get all the data I wanted, the gun stopped cocking, I had to go home.
Turns out it was just a positioning problem with the bullpup trigger group and I hadn't tightened the screws enough, simple fix.
Went out the next day, and velocities were down even more. More than elevation, barometric pressure, and temp should account for. To give you an idea, in the stock configuration, the gun made about 900 FPS with a 200 grain slug, plus or minus a little depending on the day. After the upgrade, the same slugs were going 1145 FPS. Thats a difference between 400ish FPE and 580 FPE. I also tested a 366 grain and it made 706 FPE. Then on the subsequent two shooting days it made less and less velocity, until now, and it essentially indistinguishable from stock. Something is wrong, I message bin tac. Today he has his helper Jason message me. Here's the convo:
I never heard that it isn't for light slugs. They don't mention anything about not using light slugs in the product description. I can't think of a reason why using light slugs would be a problem. Mr hollowpoint used 260 grains in the test. Is that light? The lightest I can make that still fit in the mag are 240 grains. If I couldn't use the magazine anymore I wouldn't have bought it. Even if i did only ever want to use heavy slugs, they are making energy comparable to stock valve again now too, its not just the light slugs. I think this response is B.S., if you don't like it send it back and we'll sell it to someone who wants it? WTF kinda response is that?
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