Maverick Breech leak

[Florida_Man]

So I have a Maverick Compact 177 that is two weeks in use, around 500 pellets shot. It has developed a breech leak of some type.

I removed the breech o-ring and nothing was wrong with it. I still replaced it with a new one. 3.5x1.5mm. I lightly greased the o-ring.

I replaced the barrel and made sure it was seated correctly.

I still feel air hitting my face when I shoot it.

Is there anything else this could be?

 

[kmanca1]

On my Maverick the cocking rod linkage had slipped.
Left side of the gun. the silver rod. It attaches to the cocking lever with two grub screws.
my guess is that they are loose enough to allow the cocking lever & pellet probe to slip out of position in the breech.

Try loosening the grub screws a half turn. move the cocking lever forward just a smidge, and then tighten the screws again.
That will, in effect, force the probe a little tighter into position, sealing up the 'leak'.

Don't move it forward too far! If you do the probe won't retract enough into the breech to load or rotate a magazine.

 

[Florida_Man]

On my Maverick the cocking rod linkage had slipped.
Left side of the gun. the silver rod. It attaches to the cocking lever with two grub screws.
my guess is that they are loose enough to allow the cocking lever & pellet probe to slip out of position in the breech.

Try loosening the grub screws a half turn. move the cocking lever forward just a smidge, and then tighten the screws again.
That will, in effect, force the probe a little tighter into position, sealing up the 'leak'.

Don't move it forward too far! If you do the probe won't retract enough into the breech to load or rotate a magazine.

Thank you. I will give it a try in the morning.

 

[Rich_B]

It could also be the o-ring on the back end of the valve stem. Look at part #62, there’s an o-ring on there that has the potential to leak when the gun fires. I replaced mine and no more air on my cheek.

https://fxairguns.com/wp-content/uploads/2021/02/Maverick-schematic.pdf

 

[HogKiller]

Or the large set screw on the top under the cheek rest, thread tape to seal it, next option is the rear o-ring on the transfer port waved a fond farewell.

 

[Florida_Man]

On my Maverick the cocking rod linkage had slipped.
Left side of the gun. the silver rod. It attaches to the cocking lever with two grub screws.
my guess is that they are loose enough to allow the cocking lever & pellet probe to slip out of position in the breech.

Try loosening the grub screws a half turn. move the cocking lever forward just a smidge, and then tighten the screws again.
That will, in effect, force the probe a little tighter into position, sealing up the 'leak'.

Don't move it forward too far! If you do the probe won't retract enough into the breech to load or rotate a magazine.

Is it the two marked 37?

 

[GA_LeadHead]

Is it the two marked 37?

View attachment 362937

Yes. Also suggest using a little blue Loctite on them.

 

[kmanca1]

Yep. What LeadHead said!

 

[Florida_Man]

I found out the front grub screw came stripped from the factory, so I can't tell if its loose. The rear grub was still tight. I don't want to open up a brand new rifle and work on it myself, it should work longer then a week before issues arise. I can understand and was willing to replace a few o-rings, that happens. But no further.
I'm requesting it go back to UA since something is wrong and its a week old.

Device ID

LBR-0024532

Series No

6​

Total number of shots

19​

Units velocity

fps

Units distances

yd

Units kinetic energy

ft-lbf

Units weight

grain (gr)

Stats - Average

830.81​

fps

Stats - Highest

901.85​

fps

Stats - Lowest

647.25​

fps

Stats - Ext. Spread

254.6​

fps

Stats - Std. Dev

82.5​

fps

Shot ID

V0

V5

V10

V15

V20

V30

Ke0

Ke5

Ke10

Ke15

Ke20

Ke30

PF5

Proj. Weight

1​

820​

0​

0​

0​

804​

797​

15​

0​

0​

0​

15​

14​

0​

10.5​

2​

647​

622​

602​

593​

586​

568​

9​

9​

8​

8​

8​

7​

6.53​

10.5​

3​

902​

875​

848​

820​

790​

0​

18​

17​

16​

15​

14​

0​

9.19​

10.5​

4​

892​

866​

839​

811​

782​

775​

18​

17​

16​

15​

14​

14​

9.09​

10.5​

5​

883​

865​

846​

827​

807​

774​

18​

17​

16​

15​

15​

13​

9.08​

10.5​

6​

887​

865​

842​

821​

817​

0​

18​

17​

16​

15​

15​

0​

9.08​

10.5​

7​

734​

734​

734​

725​

725​

725​

12​

12​

12​

12​

12​

12​

7.71​

10.5​

8​

776​

764​

758​

755​

757​

757​

14​

13​

13​

13​

13​

13​

8.02​

10.5​

9​

776​

776​

0​

736​

732​

729​

14​

14​

0​

12​

12​

12​

8.15​

10.5​

10​

713​

714​

713​

708​

708​

0​

11​

11​

11​

11​

11​

0​

7.5​

10.5​

11​

889​

868​

847​

826​

814​

801​

18​

17​

16​

15​

15​

14​

9.11​

10.5​

12​

885​

866​

847​

833​

834​

834​

18​

17​

16​

16​

16​

16​

9.09​

10.5​

13​

892​

867​

844​

827​

812​

812​

18​

17​

16​

15​

15​

15​

9.1​

10.5​

14​

683​

678​

673​

650​

0​

650​

10​

10​

10​

9​

0​

9​

7.12​

10.5​

15​

881​

865​

848​

831​

810​

810​

18​

17​

16​

16​

15​

15​

9.08​

10.5​

16​

880​

861​

842​

823​

802​

777​

18​

17​

16​

15​

14​

14​

9.04​

10.5​

17​

882​

863​

844​

824​

802​

781​

18​

17​

16​

15​

14​

14​

9.06​

10.5​

18​

876​

859​

842​

823​

808​

808​

17​

17​

16​

15​

15​

15​

9.02​

10.5​

19​

886​

867​

846​

828​

803​

789​

18​

17​

16​

15​

15​

14​

9.1​

10.5​

 

[Florida_Man]

Update to the update.
I decided to call FX USA. Very good people there. I am sending it to them to be fixed. The tech believes it is a valve issue. And they will fix the stripped grub screw it came with. And they are in NC, so I don’t have to send it across the country.

 

[Florida_Man]

I just got a call from FX USA. My rifle had a bad block that ended up damaging the valve pin. I was actually a little shocked that much was wrong. Lets hope the repairs provide a long life.