Problem with BNM complete kit on Disco

[gnef]

Considering how tight the tolerances are, even a small burr could have started something that would've eventually lead to the galling (at this point, I am still assuming it galled).

I doubt that I would've been able to torque down either of the two screws that would've been able to twist the breech itself. One of the screws is tiny, and by the very nature of the hex key size, it limits how tight you can get it.

Once I receive the new breech, I will do a good amount of testing even before I install it. The first probe felt a bit rough when cocking - I thought it would burnish out, but it galled instead. Once it was installed, and pushing against the hammer to cock the rifle, I think that caused it to scrape with greater force against the breech, and then galled after a few dozen shots (I shot a total of 37 or 38 shots)

[woogie_man]

Ok

Will be nice to see the side by side of the old and new.

Good luck and keep us posted!

[gnef]

The new breech came today. I actuated the probe for quite a while, and noticed some roughness, particularly when the front shoulder went over a lip. Sergio told me to go ahead and install it, and I cocked and dry fired it many many times before pressurizing the reservoir.

I've only taken 20 shots so far, but it is significantly smoother than the previous one.

Only one oddity - when I cock the rifle, and put in the clip, the first shot was a dud - the poppet didn't open. Then everything worked well for the remainder of the first magazine. The dud happened again when I put in the second magazine.

It is dinner time right now, so no time to troubleshoot. I am hoping it was just a random coincidence, and hopefully it won't happen again.

I did take more pictures, but I haven't uploaded them yet. It  looks as it should, like on the BNM website, but I'll still post them.

[gnef]

Here are some pictures of the new breech:



The arrow shows where the shoulder rubs against a bit.

[gnef]

Well, things are looking good so far. I've put a total of around 80 shots through it. I may have lost a bit of power, but I will need to run more strings over the chrony over time to see how things go (I was around 17FPE with the last string when completely stock, and now at around 16 FPE after the install). I really don't mind the slightly lower power.

The bolt seems to be getting smoother even, so I have high hopes for the longevity of the kit, and I think I just got a lemon the first time around. It did have me worried though.

I have used all three magazines that I have, and they seem to work equally well. I haven't had another dud issue since earlier.

Sergio definitely took care of me!

[rivraton]

I may have lost a bit of power, but I will need to run more strings over the chrony over time to see how things go (I was around 17FPE with the last string when completely stock, and now at around 16 FPE after the install). .

I think that the loss is due a combination or the way the bolt seals and the longer transfer tube, the increased volume between the valve and pellet has to have some adverse effect.

[gnef]

Well, I have now put in over 300 shots after installing the kit, and things are still working smoothly. I definitely have to pump more often now!

I am retesting pellets, and it looks like CPHP will still be my standard pellet for this rifle.

I will need to do more chrony work later to double check the power being produced.

So far I've only double-fed pellets once. I hope not to do that again, I had to take off the shroud and bolt to push the pellets through, and then had to resight the scope after.