Malfunction - Brocock Bantam HP Sniper Magnum

[puddleglum]

Hello all,

I was shooting some airguns with my cousins this weekend. When my cousin was shooting my Bantam HP Magnum, there were four times where the gun went off on its own. The first time, he had a pellet chambered and was lining up for the shot, but hadn't placed his finger on the trigger yet. The next two times he loaded a pellet into the chamber and it went off as soon as the bolt was closed, while his hand was still on the bolt knob. The last, and final, time it went off the bolt was sitting open and he was getting ready to put the magazine into the gun and it went off on its own, sending the bolt forward, and spitting an o-ring out of the breech.

Any idea what could have caused all these misfires? I never adjusted the trigger on the gun, but it was very light when I got it.

I am going to talk to Jeff at Trenier Outdoors, where I bought the gun years ago, but I thought I would tap into the knowledge of the forum as well.

Thank you,

-pg

 

[Aimright]

I had a similar issue with my Sniper XR, just needed to adjust the trigger to be a little heavier. It has been fine since.

 

[lloydf]

I would start with the trigger. It sounds to me like it has come out of adjustment. The manual or on line will guide you through it and it's very simple. After you set it where you want put a little dab of clear finger nail polish on the screws and it will be good to go. I use the fast drying polish as in 5 minutes its dry and its shooting time.

 

[elh0102]

Yep, the adjustment screw needs to be turned out just a bit. The adjustment screw is not really a weight adjustment as such, although Brocock describes it that way. It's actually a sear engagement adjustment, so if it's turned in too much, it won't reliably hold a cocked position. If you can't get a safe adjustment without noticeable creep, the engagement surfaces might need polishing. 

 

[puddleglum]

That sounds managable.

What is the o-ring that got spit out of the breech, and is it hard to find a replacement, or to replace in the gun? I seem to remember that spitting an o-ring, if the bolt flies forward, is not uncommon with these, so I am guessing people will have experience with this.

Also, the shroud on the rifle is a little bit loose, and moves forward and backwards about 1/8" of an inch, is that something than needs to be tightened from underneath, or to I need to remove the shroud and tighten something inside?

Thank you,

-pg

 

[skohl]

AOA has an online video of replacing the Brocock breech Oring. I think they use a Compatto but they are all the same.

 

[elh0102]

Yes, the breech O ring is not difficult to install, but much easier with barrel removed. The size might be given in the manual. If not, a search such turn up an O ring list. Order from somewhere like The O Ring Store, or O Rings and More. For a few bucks you can get a lifetime supply. I had a Bantam, and my recollection is that the shroud simply screws on and off. But, if that is correct, I don't know how you could have that much lateral play in it. But no, it should not be that way. 

 

[puddleglum]

I found a copy of the manual. There are three adjustment screws listed:

A: First stage adjustment (in front of trigger)

B: First stage adjustment (behind trigger)

D: Second stage adjustment )near the back of the receiver)

Which one or ones do I need to back out to prevent misfires?

Thank you,

-pg

 

[elh0102]

Second stage, in the rear. It should take only a little, no more than a quarter turn.

 

[puddleglum]

Excellent. Thank you.

I have some o-rings on the way. Once they show up, I will adjust the trigger, make sure it is working well, and then take the barrel off to replace the breech o-ring. It may be a little difficult to do, as the shroud is rotating freely around the barrel, so I can't twist it side to side to help pull it out. I may have to just pull it straight out. I ordered some extra o-rings that fit over the barrel at the breech as well in case they are ruined in the process.

Hopefully while the barrel is off I can figure out why the shroud is rotating freely and moves forward and back a little.. Maybe there is some sort of set screw inside the endcap near the receiver that should keep it secure to the barrel.

My cousin offered to help me fix it, so a second pair of eyes and hands will surely help.

 

[Emu]

Unscrew a quarter of turn on the second stage adjuster. That is it!

 

[elh0102]

I can't offer any advice on the shroud. All the Brocock and Daystate rifles I have owned attached the shroud in one of two ways. It either screws into the an adapter at the receiver, which is secured by grub screws, or, the shroud itself is attached at the base by a couple of screws. If the latter, the grub screws are clearly visible at the base of the shroud near the action. They would be near the 5 and 7 o'clock positions, with 12 being the top of the action.

 

[puddleglum]

Got the Brocock all fixed up last night. Backed out the second stage screw a touch, replaced the breech o-ring, and got the shroud properly attached again.

There are two small grub screws in the shroud nut, in the thread area, that tighten down against the barrel and keep it in place while removing and reattaching the shroud.

My cousin tried it out, really liked it, and bought it from me. His brother, and his dad each bought a PCP from me last week that I didn't want any more, and they just got themselves a scuba compressor. So I have some people I can shoot air guns with, and they will be able to fill my tank.

Big win, all around.

-pg