Thinking about converting my 10.5 upper to gas piston. It’s got a 10" midwest industries keymod rail on it with a carbine gas system. I know of adams arms and osprey. But do they make a kit that will clear my rail? Thank you. Any other companies that you can think of would be great too.
What do you want a piston to accomplish? Have you looked at adjustable gas blocks?
I don’t have an sbr, but it seems many people are going with high quality di uppers using adjustable gas blocks, and/or vltor a5 buffer systems.
Just something to research. A lot of info on above systems and piston conversions has been posted. If you havent, try a search using the search bar above on the right.
Well I was having cycling issues after I built it but got that sorted out. More or less I just want to do it really
Assuming that’s what you want to do, the Osprey has the lowest profile of any of them AFAIK. Their website should have a compatibility page for rail systems on it (at least they used to).
I have a fair degree of experience with the Osprey’s - having two of Carbine (one with the Fail Zero coating), a Mid Length and a Rifle size kits. They were provided for user evals. I will say this - great engineering, low profile - slick kits. But… even with the exceptionally low profile, they are virtually unusable with any forend rail system. It would take me an hour to write about all the mods that had to be done in order to get it to work. Suffice to say, they are built to interface with an OEM bbl nut and they need clearance ID for the forend greater than what was available. I had to machine a scallop cut at 12 o’clock on the ID of a YHM forend that was about .070 deep. I don’t have the sketches and dimensions in front of me at the moment. IIRC the ID of that forend was about 1.750 and I needed 1.820. Another issue is that the bbl has to be .875 OD or smaller. I ended up turning down the M4 heavy profile to meet this requirement. The YHM bbl nut had to be heavily modified to allow the piston a full stroke. This mod also necessitated the nut being timed to the rcvr. Also - a very odd situation developed - in that when the rifle was fired quickly (semi auto) - the gas flowed back through the openings in the bbl nut and into the operators face. Not fun. These holes were threaded & plugged with set screws. In the end - the system worked flawlessly. VERY reliable and actually fun to shoot. But it took a sh*t ton of work to get there.
I have some pictures of the machine work and mods that were required. I will post them later.
If the OEM handgurds are used - they clearly have no issues with clearance but there is no provision for rails or accessories and their handguard system precludes any type of free floating.
ETA - MI makes a railed handguard (MCTAR-17P) (2pc) that will fit the Osprey 416. It does not appear to be a free float system - but it will provide you a railed forend. Looks like that can be had for around $100.
FWIW