USFT troubleshooting process, my take

[Therealld]

I see and hear of folks trying to trouble shoot issues (mostly leaks), but they typically use a non-practical trouble-shooting sequence.
I just saw a msg on my email about a guy that had a leak on a regulated USFT, and went thru lots of extra work, but isnt out of the woods yet.

Here is what i believe to the the most straight-forward and simple way to troubleshoot leaks. Don’t fix anything til completing all four steps.

1. Fill the gun to just over the normal shooting pressure.

2. With the gun loaded and breech closed, put some tissue paper around then barrel/breech and fire to make sure the breech is sealiing ok (no obvious air blast).

3. With the gun unloaded and breech closed, Immerse barrel muzzle in water to look for air bubbles exiting the muzzle (indicates leaking firing valve). If Its a
‘tube gun” with air reservoir within inches of the muzzle, immerse until the entire front plug including its fastener screws is under water. Leaks can now be coming from pressure safety burst disc or o’ring seal for front plug.

4. Now remove entire buttplate/ stock assembly, with cheekpiece). scope, and the gripframe assy and hammer spring. This makes it ok to immerse the entire gun, or at least the back end of the gun all the way past the side gage and airtube retainer screws to check for leaks at fill plug, gage, reciever to airtube seal, and even the regulator to receiver
joint.

All parts of the gun can survive water dip by using the steps above. As long as you clean the barrel well after the immersion. Everything else is stainlness or aluminum. I use a Turkey Fryer tank full of water, but have used harbor frieght buckets, and even my bathtub with hot water (hot water often cures slow leaks).

Dont change oriings that are not leaking. Its not and erector set, don’t fix stuff if you don’t have to. Leaks pop up in cold weather, often go away when gun is warm.

LD

 

[Airgunoregon]

That's great advice Larry.. Thank you.

A leak can be frustrating, but having a list & order of procedures to go thru really helps a lot.

The leaks I've seen over the years have been few and far between and usually are such a small/slow leak it's not worth the time to find and fix them. It might make a difference of a few shots out of 60 before filling so why bother in most cases.

I had fears of trying to remove the grip frame, thinking parts might fall out of the trigger assembly or something, but that wasn't an issue when I finally tried it.
Like you said, don't forget to remove the wood cheek piece or you might drive one of the drift pins into it and split it.

Thanks again for designing such a simple, accurate, dependable and winning field target rifle... I really love all of mine!

Wayne

 

[RScott]

I see and hear of folks trying to trouble shoot issues (mostly leaks), but they typically use a non-practical trouble-shooting sequence.
I just saw a msg on my email about a guy that had a leak on a regulated USFT, and went thru lots of extra work, but isnt out of the woods yet.

Here is what i believe to the the most straight-forward and simple way to troubleshoot leaks. Don’t fix anything til completing all four steps.

1. Fill the gun to just over the normal shooting pressure.

2. With the gun loaded and breech closed, put some tissue paper around then barrel/breech and fire to make sure the breech is sealiing ok (no obvious air blast).

3. With the gun unloaded and breech closed, Immerse barrel muzzle in water to look for air bubbles exiting the muzzle (indicates leaking firing valve). If Its a
‘tube gun” with air reservoir within inches of the muzzle, immerse until the entire front plug including its fastener screws is under water. Leaks can now be coming from pressure safety burst disc or o’ring seal for front plug.

4. Now remove entire buttplate/ stock assembly, with cheekpiece). scope, and the gripframe assy and hammer spring. This makes it ok to immerse the entire gun, or at least the back end of the gun all the way past the side gage and airtube retainer screws to check for leaks at fill plug, gage, reciever to airtube seal, and even the regulator to receiver
joint.

All parts of the gun can survive water dip by using the steps above. As long as you clean the barrel well after the immersion. Everything else is stainlness or aluminum. I use a Turkey Fryer tank full of water, but have used harbor frieght buckets, and even my bathtub with hot water (hot water often cures slow leaks).

Dont change oriings that are not leaking. Its not and erector set, don’t fix stuff if you don’t have to. Leaks pop up in cold weather, often go away when gun is warm.

LD

Perhaps an alternative to #3 is to put a balloon over the transfer port arm? - see picture of what I found.
I've not tried to disassemble the hammer spring, gripframe assembly, or trigger. Not sure what I would find, and worried that I would not be able to put everything back together. I had that concern about the valve too but when I looked, I marveled at the simple, functional design on my unregulated gun.

 

[Therealld]

Perhaps an alternative to #3 is to put a balloon over the transfer port arm? - see picture of what I found.
I've not tried to disassemble the hammer spring, gripframe assembly, or trigger. Not sure what I would find, and worried that I would not be able to put everything back together. I had that concern about the valve too but when I looked, I marveled at the simple, functional design on my unregulated gun.

View attachment 316455

Looks like excuses to not try. #3 is simply dipping muzzle in water, how scary is that? Balloon idea poorly thought out, since transfer port is only aligned with breech closed, so a smaller amount of air might reach that poorly sealed ballon idea.

I wrote a tried and true sequence that is about the most practical for diagnosing leak sources. If you lack confidence, I understand, but give me some credit on how to work on a gun of my own design, ok?

LD

 

[Therealld]

Looks like excuses to not try. #3 is simply dipping muzzle in water, how scary is that? Balloon idea poorly thought out, since transfer port is only aligned with breech closed, so a smaller amount of air might reach that poorly sealed ballon idea.

I wrote a tried and true sequence that is about the most practical for diagnosing leak sources. If you lack confidence, I understand, but give me some credit on how to work on a gun of my own design, ok?

LD