I decided it was time to give my Maverick all the beans, and see how far I could really take it as a dedicated hunting rig. Especially, since I have another one that I can stick to target fun with(or a backup).
The Maverick I'm using hasn't been "stock" for a very long time. Below are what it's power mods were prior to this latest tuning session:
-700mm barrels in .22/.30
-custom 15-16 gram hammer weights
-Huma hammer spring
-Huma extra high pressure regulators
-Opened valve seat to 7.2mm, PEEK poppet
-Modified barrel ports
-Pin probes
All of that combined with high reg settings gave me a peak of around 85 fpe in .22, and 136 fpe in .30. That was with the reg at 205 bar and a 300 bar bottle. I'm not telling anyone to run their guns at that pressure, and you do so at your own risk and voiding of your warranty. The bottle is a true 300 bar bottle, and the regs are rated to 210 bar, fyi. My hunting tunes were usually around 80 fpe in .22 with 36 grain slugs, and 130+ fpe in .30 with 65.5 grain slugs. Those numbers are quite good for a "BB gun", and would drop most any critter I wanted. Still, I wondered what more I could get out of it...
This past few weeks I set about doing the only other things I could think of to get more power(without major valve re-design). First, I ordered another rear plenum section. I removed the front section containing the 2nd reg, and simply replaced it with the extra rear plenum section I had ordered. Given the high reg settings I was using for making power, the 2nd reg wasn't really necessary anyway. Now the gun has one regulator and a massive plenum which is probably over 125cc. The best part is, I just screwed the 2nd reg section off and screwed the plenum section on, and no other modifications were needed. It don't get much easier than that! That simple change managed to send 36 grain .218 slugs at 1060 fps for 90 fpe in .22! Next up, the .30 managed to send 78 grain slugs at 931 fps, for 150 fpe! That extra plenum definitely helped the .30 the most. Either one of those calibers would put the hurt on a porker noggin, haha.
While that was it for .22(until the 800mm barrel comes out), that wasn't it for the .30... I ordered myself a 1:16 twist .300 blank from TJs to take it up one more notch. I started with a 34" blank, but bored and ported the last 2" so it would vent into a custom shroud. I still want to keep this gun quiet. The resulting barrel is about 32" long, which I finished up today. Thank god for bullpups, otherwise, this gun would be way too long. Anyway, I added a 1/4 turn to the hammer spring and let some lead fly over the chrony. The NSA 65.5 grain slugs were cruising along at 1043 fps! Then, time for the 78 grain Griffin slugs. Those tripped the chrony at 967 fps! That's 162 fpe
NOW, the Maverick is a proper hammer 
On a side note, I don't know what the shot count is at these power levels, but it is better than you'd think. I didn't run full strings, because I didn't want to waste the slugs. I'm estimating 35-45 shots in .22 and 20+ shots in .30 at those power levels.
Of course, the real test will come down to how it shoots. I know the .22 is a laser with the 36 grain slugs, so not many worries there. The real unknown will be how that 16" twist TJs barrel performs. I haven't seen any info about anyone using that particular one, so I have no idea how it will perform. I've seen plenty of folks with the 26" twist TJs, but none on the 16". Heck, I didn't even know they had a 16" twist .300 barrel, until I emailed them and asked if they had anything with a faster twist. To my surprise, they did! It may be a couple of weeks, before I can test the .30 for accuracy. I don't like shooting those power levels at my house, it just isn't safe. I'll have to wait, until I can get to the range to test it. Hopefully, it won't all be for nothing. I'll try and post a picture in the next day or two for reference. Thanks for reading guys!
The Maverick I'm using hasn't been "stock" for a very long time. Below are what it's power mods were prior to this latest tuning session:
-700mm barrels in .22/.30
-custom 15-16 gram hammer weights
-Huma hammer spring
-Huma extra high pressure regulators
-Opened valve seat to 7.2mm, PEEK poppet
-Modified barrel ports
-Pin probes
All of that combined with high reg settings gave me a peak of around 85 fpe in .22, and 136 fpe in .30. That was with the reg at 205 bar and a 300 bar bottle. I'm not telling anyone to run their guns at that pressure, and you do so at your own risk and voiding of your warranty. The bottle is a true 300 bar bottle, and the regs are rated to 210 bar, fyi. My hunting tunes were usually around 80 fpe in .22 with 36 grain slugs, and 130+ fpe in .30 with 65.5 grain slugs. Those numbers are quite good for a "BB gun", and would drop most any critter I wanted. Still, I wondered what more I could get out of it...
This past few weeks I set about doing the only other things I could think of to get more power(without major valve re-design). First, I ordered another rear plenum section. I removed the front section containing the 2nd reg, and simply replaced it with the extra rear plenum section I had ordered. Given the high reg settings I was using for making power, the 2nd reg wasn't really necessary anyway. Now the gun has one regulator and a massive plenum which is probably over 125cc. The best part is, I just screwed the 2nd reg section off and screwed the plenum section on, and no other modifications were needed. It don't get much easier than that! That simple change managed to send 36 grain .218 slugs at 1060 fps for 90 fpe in .22! Next up, the .30 managed to send 78 grain slugs at 931 fps, for 150 fpe! That extra plenum definitely helped the .30 the most. Either one of those calibers would put the hurt on a porker noggin, haha.
While that was it for .22(until the 800mm barrel comes out), that wasn't it for the .30... I ordered myself a 1:16 twist .300 blank from TJs to take it up one more notch. I started with a 34" blank, but bored and ported the last 2" so it would vent into a custom shroud. I still want to keep this gun quiet. The resulting barrel is about 32" long, which I finished up today. Thank god for bullpups, otherwise, this gun would be way too long. Anyway, I added a 1/4 turn to the hammer spring and let some lead fly over the chrony. The NSA 65.5 grain slugs were cruising along at 1043 fps! Then, time for the 78 grain Griffin slugs. Those tripped the chrony at 967 fps! That's 162 fpe
Of course, the real test will come down to how it shoots. I know the .22 is a laser with the 36 grain slugs, so not many worries there. The real unknown will be how that 16" twist TJs barrel performs. I haven't seen any info about anyone using that particular one, so I have no idea how it will perform. I've seen plenty of folks with the 26" twist TJs, but none on the 16". Heck, I didn't even know they had a 16" twist .300 barrel, until I emailed them and asked if they had anything with a faster twist. To my surprise, they did! It may be a couple of weeks, before I can test the .30 for accuracy. I don't like shooting those power levels at my house, it just isn't safe. I'll have to wait, until I can get to the range to test it. Hopefully, it won't all be for nothing. I'll try and post a picture in the next day or two for reference. Thanks for reading guys!
