Tony Leach's 22mm skirtless kit for a B40/TX clone

[Buldawg76]

Sorry guys for taking so long to get this thread done, life has been in the way.

I received my kit from Tony to install in the B40 and began the conversion knowing there would be some fitment work needing completed so off I went with the install.
1st was fitting the sleeve into the compression tube, I had to figure a way to chuck the sleeve in my drill press to spin it to reduce to OD of the sleeve for it to slide into the compression tube by hand. I found I had an inverted nut driver that the handle was a snug fit inside the sleeve with a wrap of blue masking tape wrapped around the handle. So I chucked it up in the drill press and began the sanding process with 1 inch wide emery cloth. After about an hour or so of sanding and allowing to cool and more sanding I had only removed about .002" of the diameter and it would not slide into the compression tube. My compression tube is an old one I had swapped out due to being out of round by approx .080" so thought it would be an easy job of fitting but that was not the case. Fortunately my neighbor is a machinist and hot really wanting to thin the sleeves OD any more than necessary I spoke with him about the fitment of the two parts and he said he could take it to work and sand out the ID of the compression tube to allow the sleeve to fit in and keep the sleeves OD unaffected. So that fixed that issue very nicely. The sleeve was installed  with pink Loctite to ensure it would not loosen but still allow easy removal in the future.

2nd was removing the piston rod from the piston ( remember the rod is pinned in place as well as threaded in the B40 piston, Tony machined the piston away in his mock up fitment ) I did not want to destroy my only stock piston in case I wanted to reuse it. So I measured and marked off the piston 180 degrees from where the pin is pressed in to the piston/rod in the bottom of the front guide ring groove of the piston. This way I could drill a hole into the piston on the opposite side to allow me to press the pin out of the piston. This proved to be a very easy process that worked perfectly. Luckily the piston is not hardened in the guide ring groove so was easy to drill. Then it was heating the piston to release the Loctite so the rod could be unthreaded and installed into the 22mm kits piston. The Loctite took a good amount of heat from a propane torch to get it to let go. So pin is out and rod removed from piston and ready to install in the 22mm kit piston.

3rd installing the rod into the 22mm kit piston the rod would not thread in fully by hand so had to chase the threads on the rod to allow it to thread in completely. Tony had stated that the depth the rod could be installed to in his B40 was 2mm from flush with the pistons face but at that depth mine would not cock so I back it out to 3mm from flush and all was good. The rod was loctited in place with blue Loctite.

4th assembling the kit in the gun and checking correct sealing. I found that my gun when latched in the firing position did not have any contact between the delrin breech seal and the barrel end. So did some careful measuring and found I had to add a 1mm shim between the delrin breech seal and pocket in the sleeve to increase the delrin seal by 1mm thickness to achieve a good seal at lockup when latched. There must be some variance's in the assembly tolerances of b40s as compared to the TX. No biggie to deal with.

Then testing and tuning the spring length and shims to get the fps/fpe I was after with the B40s favorite pellets the CPL 7.9. I ended up being able to use the first spring I cut and closed when tuning my TX that was not giving me the power I wanted out of my TX. It is at 207mm with 5mm of shims added to give me a fps of 815 with the CPL 7.9s for just under 12 fpe.

All in all I am very happy with the conversion and now have two very sweet FT rigs to enjoy in our matches. I am adding some pics specific to the B40 conversion since the swap in a TX has been very well documented by Steve already.   

[TonyL]

yay you got it done The breech seal just needs to be longer, if you know exactly how much i could machine one or get your buddy to do it, press in fit, email me for the specs.

I would add another coil on the spring over running 5mm washers, no rush for that though, it will probably feel less snappy with the added coil.

if you do this again with another BAM just run a 25mm reamer or adjustable reamer down the comp tube, mine was ok but i know some can be tight.

So now there are 2 B40s with my kits in, yours and mine ...we should start a club LOL

[Nitrocrushr]

Nice work Mike  How is it doing on target?

Steve

[Buldawg76]

Hey Tony

Yep I have actually had it done for a bit but just now got time to post the results. My machinist buddy found it easier to use a form of a grinding setup that uses some emery paper on a shaft chucked in the lathe and it worked very well. e were afraid of how hard the compression tube is that it may be difficult to ream it to size. No worries though since it worked out fine.

I did not actually measure the thickness of the breech seal you installed in the sleeve but know I had to add 1mm more to get a proper seal. So if you know the thickness you make them to and add 1mm or just a hair more I can hand fit it to be a perfect length.

Yes I have noticed that the spring with added shims is a bit snappy than the TX is with no added shims. I have another spring but just have not had the time to cut and close to reduce added shims yet. My TX is running the spring at 214mm and shoots the AA7.87s right at 815 to 820 very consistently and deadly accurate. It is less snappy as well. The B40 has a loose bore so needs pellets of 4.53 to 4.54mm to shoot accurate and I have several old boxes of CPLS that run on the large side.

I am all for the club Lol. I shoot mine in my local clubs matches which are following the UKHFT rules and we are actually the first and only US sanctioned member club at this point.

 https://www.facebook.com/eastalabamahftHeflinAL/?view_public_for=775027302838246

Pm sent on the breech seal.

Mike

[Buldawg76]

Nice work Mike  How is it doing on target?

Steve

Hey Steve

Its shooting very well indeed although a bit picky on pellet size due to a bit loose of a bore. I just make sure the CPLs it likes are at least 4.53mm or bigger. It does well with H&N FTTs in 4.53 also but not as well with CPLs. I am still the weak link though since my health prevents me from being as stable due to heart rates and breathing inputs. Lol

Very happy with both the TX and B40 for sure. Worth every penny for the kits.

Mike