Brocock Bantam Sniper HR - Information thread

[Hummer57]

I have a Sniper I bought used on AGN. I have not adjusted anything. It’s set at 130 bar. Original owner was shooting JSB 15.8. I scoped it and set it up for JSB 18.1. Shooting 1” at 50 yrds. My question is where are the trigger adjustment screw and hammer tension adjustment located? Do I have to disassemble to lube bolt shaft. As the gun shoots better then I can, I may not do anything to it. But I would like to know how. Overall my ignorance as I entered the PCP world 2 months ago with an inexpensive XM1. 

 

[mcoulter]

Howdy!

Here's a pic of my sniper hr magnum. Make VERY small adjustments to the read screw here where the allen is inserted. I would start out with at most 1/8 of a turn and then cock the gun, test the trigger (you should be able to catch the bolt after the sear releases so the gun does not fire). But of course you want to ensure the gun is unloaded before doing any of this! If you adjust too far, you will find the gun will not stay cocked. Off the top of my head I *think* these are small clockwise turns to lighten it, but I'm not 100% sure.

Here is the hammer spring. I strongly suggest you measure how deep the screw is seated so you can easily return the gun to it's "norm" hammer spring setting. Backing the screw out LOWERS velocity. After playing with this I found that I had to use a drop of vibratite thread compound to keep the screw from walking. There's not any physical lock on this screw preventing this adjustment from changing.

I have not felt the need to lube the bolt. I tend to worry about lubrication holding dirt/grit where I don't want it.

 

[Hummer57]

Thanks, in the second picture are referring to the screw inside the bolt? Info much appreciated!

 

[mcoulter]

Thanks, in the second picture are referring to the screw inside the bolt? Info much appreciated!

Sorry for my less-than-clear info. It is the larger allen in the recessed area:

 

[Ezana4CE]

Howdy!

Here's a pic of my sniper hr magnum…

Here is the hammer spring. I strongly suggest you measure how deep the screw is seated so you can easily return the gun to it's "norm" hammer spring setting. Backing the screw out LOWERS velocity. After playing with this I found that I had to use a drop of vibratite thread compound to keep the screw from walking. There's not any physical lock on this screw preventing this adjustment from changing.

Here’s where I’m confused. What exactly is being measured in order to measure changes in the depth of the hammer spring tensioner screw? Are you measuring the length of the back of the bolt protruding out? Or are you actually measuring how far down the recessed allen head has traveled into the threads after adjusting? If you’re measuring the distance the allen head traveled from being flush, how is this accomplished using calipers?

 

[mcoulter]

Sorry, the picture is misleading. 

I turned the calipers around to show the number on the gauge for the pic. On the other end of the caliper there is a small metal pin that protrudes as the caliper expands.

You use that pin to measure the depth of something that goes down into a recessed area like that screw as it goes into the receiver.

 

[L.Leon]

@ezana4ce, you use the other end of those calipers to measure the depth of a recess in a thing, in this case the hammer spring screw.

 

[Ezana4CE]

@ezana4ce, you use the other end of those calipers to measure the depth of a recess in a thing, in this case the hammer spring screw.

Thanks. I had to look up how to use the depth rod earlier. I extended the rod from the end the placed the tip of the rod on the flush surface of the tensioning screw ( NOT down into the hole that allen wrench goes into) and moved the rod in until the short flat edge of the calipers rested flush on top of the back of the receiver. Next I locked the small bolt on the side of the digital screen and recorded my starting measurement. I did the same after making the adjustment. I’m posting these pictures in case another less mechanically inclined soul comes behind me and is equally confused about this metric. Here’s a “how to” link as well https://www.wonkeedonkeetools.co.uk/calipers/how-do-you-use-a-vernier-caliper-to-measure-depth

Thanks to all who contributed to the great thread. It’s proven to be extremely helpful. Now back to my shooting. Cheers. 

 

[Ezana4CE]

Bottle pressure was at about 215 BAR (as I recall) when I picked it up in person. And the Huma regulator was set to 150 BAR.

After about 115 shots, the bottle pressure was down to about 150 BAR and the Huma regulator was no longer filling to 150, but down to about 125 or so. I did not take note as to what the rifle's bottle pressure was when the Huma regulator pressure was no longer maintaining 150 BAR.

NOTE: when the Huma regulator dropped down to about 125 BAR, due to the rifle's bottle pressure dropping to 150 BAR, the rifle seemed to be grouping tighter and more consistently with the 15.89 gr pellets. My thinking is that those pellets may fly more consistently with Huma regulator pressure being at the lower pressure of 125 BAR. At that point, I also had the power dialed down two clicks from what I call "Power 6" to "Power 4". At present, I don't have a chrony, so I don't know the pellet velocity. But my rifle seems to like the 15.89 gr JSB fired at these settings that I mentioned.

When I refilled the bottle, the gauge on my Omega cylinder (which I believe to be quit accurate) read 240 BAR when the Bantam bottle gauge read about 250 BAR, and the Huma regulator pressure was back up to 150 BAR.

It is recommended to re-fill the rifle's bottle s-l-o-w-l-y, so as to not overheat the valve.

Funny you mentioned this and I didn’t catch it the first time I read through this thread. My Bantam Sniper HR is doing this now. Reg was set at 150 and after topping off my SCBA tank to around 300 bar, I went to fill the Bantam and it was difficult to control the flow speed of the fill. I filled to 230 bar and that pushed the reg to around 165-170. When I shoot down about 40 shots the reg reads around 150. Wondering if I should replace the reg. I sent it in for repairs for the same issue earlier in the year.


Also, do you all think a Tatsu would be a good sized moderator for a .25? @DHart I saw that you had one for your .22. I was also looking at a Sumo and a Tanto. I really have no idea which is best. I want something that won’t spook squirrels.