Tuning Another FX question

[DonaAna1]

I have a maverick .25 compact tuned to 893 fps on PW5. I went out today to chrono what speed Pw 6&7 would do. I also wanted to replace the scope. All went well until I chronoed the slugs. I was now getting 656 fps on PW 5. It was at 893. PW 6&7 were higher, but, still below 800 fps.

I had no leaks from the breech. I just didn't have any power. Regs are set at 150/125. I could find nothing wrong or out of place.For S&G (poops and giggles) I removed the barrell and reseated it. Power wenl back up. In fact I now have 944 fps on PW7.

Any idea what happened?



I really don't trust this gun at the moment.

 

[Butch]

Sounds like had a breech seal bad and or a chrony acting up. 


Butch

 

[Jlowe]

Yeah, your barrel wasn't seated correctly. I did that once changing barrels around and not paying attention when I replaced the barrel. What pellet are you referring to shooting 944fps? 25.39? 

 

[DonaAna1]

29 grain nielsens.

Seeing if I can tighten up groups a little bit. Right now it is 2moa.

 

[Jlowe]

Thats good power for the compact. The 25 Compact is a really cool set-up. I had a Maverick 22 Compact that I transformed with a 600mm barrel and a 480cc FX tank. Now I kind of miss the compact size. 

 

[Bigragu]

If you didn’t have your barrel seated correctly that means either the alignment notch wasn’t used or it was used, just not seated all the way till it stopped. Regardless, by either happening, that means your air passages (transfer port openings) that lead into the rear of the projectile we’re not in line, and only partial air flow made it thru. 

typically when velocities drop all of a sudden and it was noted that barrel removal or gun disassembly was performed, it is a high percentage that the transfer ports were not reset to line up PERFECTLY with each other upon reassembly. 
seals at the breech failing you would know immediately when the air blow back upon firing blows your toupee off

 

[DonaAna1]

I was very careful to seat the barrel correctly. But, I lost 300fps and after reseating I gained the velocity back.

I could have had it wrong. The velocity loss confirms it. But, I was careful. 

Result, a loss of confidence in gun.

 

[Airgunmann]

Why would you lose confidence in the gun it was a mishap nothing wrong otherwise like stated above the pellet was probably over top the tp and only getting a part of the charge it would normally get stuff like this happens to all of us once in awhile at least you figured it out and we're not digging into the gun farther trying to figure out what happened makes sense though probably weren't quite in the notch it happens now go shoot some to get your confidence back up 

 

[DonaAna1]

I will continue to test it. It wasn't a single pellet. It was half a mag.