Gunfixr 76 Posted May 19, 2011 Report Share Posted May 19, 2011 Well, after fighting with the LRBHO for several days, I came to the conclusion that while it can be made to work, the amount of fitting required is prohibitive (for me at least), and the gun will likely be at least somewhat finicky. To that end, I came up with my own LRBHO design. Since Tom has said that he patented his design, and my own designs hve been copied, I have gone to some length to try to be sure to not infringe on his patent. I searched the online database of the US Patent office for a couple hours, but could not find it. I went by his posts on what he included in his patent. Perhaps he will chime in here. Also, based on what I thought should be different changed it rather significantly from his design anyway. My required features were to be simple. First, it was not to change how the gun functioned more than minimally, to keep the basic reliability it already has. Two, it was not to require a lot of fitting, or significant modifications to the magazines. Third, it was to only have one major feature: lock the bolt in the open position when the last round had been ejected. Trying to add all kinds of features, such as the ability to externally operate it, or it's automatically disengaging was trying to please everybody, and complicating the design. Really, it's all about an easier, faster reload. Not having to push the top round in with the bottom of the bolt already makes the reload much faster. Since the drums will not go in at all under a closed bolt, they no longer need to be downloaded. Therefore, there is no provision to externally operate this BHO, nor will there be. As for automatic disengaging, that did happen anyway, to an extent. While seating a fully loaded factory 5rd mag will not drop the bolt, nor will seating a fully loaded 8rd Surefire mag, seating a full 10rd AGP mag will, as will seating a full 12rd Promag drum or a full 20rd MDArms drum. The bolt closes and chambers the first round. However, during one test the bolt didn't quite fully close, with a 20rd drum inserted. I believe this was due to the full drum exerting quite a bit of drag on the bolt and carrier, and the limited amount of "running start" that the bolt had before engaging the round. I may see if I can eliminate the auto-closing entirely, but since the drums don't allow the round to go down any, they may always drop the bolt. As for feeding, the rounds go all the way up to the magazine feed lips, and so the gun feeds just as it was originally designed to do. The bolt modifications are about the same, although the slot is in a different place, and slightly shallower, as well as the same depth all the way through. The slot is similar in the ejector block. The factory manual BHO can either be left in place, or removed. It will serve no real purpose. My BHO has nothing to do with the factory BHO, nor does it go back down either side of the receiver. In hand cycling it works fine. Live fire testing is tomorrow. At this time there will be no pics, until I determine whether I will even mass market it, patent it, or what. 1 Quote Link to post Share on other sites
yooper14.5 84 Posted May 19, 2011 Report Share Posted May 19, 2011 (edited) awesome. Competition would drive the prices down hopefully. if I had one I wouldn't want auto closing though. Edited May 19, 2011 by yooper14.5 Quote Link to post Share on other sites
Cobra 76 two 2,677 Posted May 19, 2011 Report Share Posted May 19, 2011 Good. As the LRBHO market keeps filling up....the one I'm gonna release is still not in danger at all. Glad to see all the options. Quote Link to post Share on other sites
topmaul 42 Posted May 19, 2011 Report Share Posted May 19, 2011 nice Quote Link to post Share on other sites
pedal2alloy 206 Posted May 19, 2011 Report Share Posted May 19, 2011 Hey Gunfixr - How about not having to cut into the bolt? Also, it seems to me that auto closing is not good, so you would need an external lever or button. Quote Link to post Share on other sites
jmacken37 4 Posted May 19, 2011 Report Share Posted May 19, 2011 Nate, Sounds good. Can I send the "beast" in for a LRBHO upgrade? I'm really loving the "beast" by the way and it puts the biggest grins on folks faces. Of course, you already know this! Jake Quote Link to post Share on other sites
theorangeplanet 968 Posted May 19, 2011 Report Share Posted May 19, 2011 Hey Gunfixr - How about not having to cut into the bolt? Also, it seems to me that auto closing is not good, so you would need an external lever or button. Agreed, on both those points... I'd prefer a button or lever or something if possible with the design. I'm guessing that without an automatic bolt releasing action you'd just slingshot the bolt again to send it home? And of course the less metal work for the amateur DIYer the better, as long as its not sacrificing the system's performance. The level of modification needed for the CGW LRBHO is what's kept me away from it. Quote Link to post Share on other sites
TwentyNizzo 66 Posted May 19, 2011 Report Share Posted May 19, 2011 The guy on youtube has a fully working BHO with release lever. And it's not the Tom Cole one. But he's not responding to any messages so I doubt he'll be making any more for anyone. Quote Link to post Share on other sites
mcpp 1 Posted May 19, 2011 Report Share Posted May 19, 2011 PAtent office takes many months to get approved patents on thenet Quote Link to post Share on other sites
mscottrogers 56 Posted May 19, 2011 Report Share Posted May 19, 2011 I'll be in the market this summer for a minimum of 2 but I have 5 s12's to convert. sounds like a winner so far. Quote Link to post Share on other sites
JohnnyE 81 Posted May 19, 2011 Report Share Posted May 19, 2011 Would you provide a link to the vid on Youtube? I've searched there for awhile and can't seem to find it. THANKS! The guy on youtube has a fully working BHO with release lever. And it's not the Tom Cole one. But he's not responding to any messages so I doubt he'll be making any more for anyone. Quote Link to post Share on other sites
Gunfixr 76 Posted May 19, 2011 Author Report Share Posted May 19, 2011 (edited) Well, the auto closing was an accident, not something I was actually looking for. I sent an email last night to the owner of the gun that it's fitted to, and he's already said I could eliminate the auto closing and he'd be quite happy. Yes, slingshotting the bolt releases it. Really, the bolt is close enough to the mag to possibly cause occaisonal first round feed problems anyway, whether it auto closes or is manually dropped via a lever or button. Because of the design, there really isn't a good way to put a manual release on it. Other things are in the way. As for not grooving the bolt, that just isn't doable without redesigning how it works. The one thing it has in common with the Cadiz version is that it goes out over the magazine and the rounds deactivate it as they come up. Because of the height of the round in relation to the bottom of the bolt, if the bolt isn't grooved, it will push down the "hawks beak" and the round with it, keeping the gun from feeding. The groove isn't really critical, and can easily be cut with a Dremel. It's location and the fact that it is straight through makes it easier than the Cadiz one. The cut to the ejector block is almost the same. It clears all the mags listed, but just touches the AGP mag. It could be notched just a bit, but works as is. Drums may always auto close, simply because they are pretty much bottomed out when full, and the amount of pressure that is required to push the top round down when they get close to full. The design is quite simple, and will require a bare minimum of fitting once the required cuts are made. I think that if you can do your own conversion, you can do this. No welding is required, just some Dremel work, drilling, tapping. Unfortunately, it is right in the way of the FA sear, just as Toms is. The only way to get one in an FA gun will be to do something other than going through the ejector block to get activated by the rounds coming up. Edited May 19, 2011 by Gunfixr Quote Link to post Share on other sites
grima 15 Posted May 19, 2011 Report Share Posted May 19, 2011 the U tube guy is me, Type in grima101 there are 2 vids 2 Quote Link to post Share on other sites
Gunfixr 76 Posted May 19, 2011 Author Report Share Posted May 19, 2011 Well, test fired it, using low brass Winchester game loads in a full 5rd, 8rd Surefire, 10rd AGP, 12rd Promag drum, and 20rd MDArms drum. I started by loading the 5rd mag under the closed bolt, slingshotting the bolt back and firing it empty, then going to the next larger mag. No problems, as I kind of expected. It's not even hardened yet. I did recut the engagement end, hoping to eliminate the autoloading, and it did keep it from dropping w/the 10rd AGP mag. I think I may put a stronger spring under it, but cannot go too heavy or it'll lock open before the last round is gone. I can recut it again, and put an interlocking contour on the bolt, so that it cannot autoload. However, the top round of a fully loaded MDArms drum cannot be pushed down far enough to not drop the bolt. The 12rd Promag drum allows further movement, but I still think the bolt will drop a lot of the time. Quote Link to post Share on other sites
jmacken37 4 Posted May 21, 2011 Report Share Posted May 21, 2011 For those that don't know, Gunfixr is a master gunsmith who has really done some beautiful work. Jake Quote Link to post Share on other sites
gremlinx 20 Posted May 23, 2011 Report Share Posted May 23, 2011 I'm subscribed. Nate's getting my business to do my sbs when my F1 comes back Quote Link to post Share on other sites
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