As a sort of proof-of-concept for another rifle project, I equipped my 552 clone rifle.

I intend to convert my "550SB" to a pseudo 550 sniper receiver setup. I'm going to remove the factory welded picatinny rail, and install a "boss" for the rear portion of a rail or other optic mount to interface with. All that just to say that I wanted to do some shooting in the meantime with the same setup I intend to use on that when it's complete.

The cocking handle on the "550SB" will have better clearance around the magnifier hinge than the 552. As a work-around for the 552, I made a little rod I can poke into the 552 cocking handle, which allows me to rack the rifle. Reloads are easy enough, using the bolt catch/release, but initial loading and/or malfunction clearance require the use of the extension rod. It's silly, but my 55X guns are really just fun guns, so I can justify less-than-optimal setups.

Another shortcoming worth mentioning, which will need to be addressed in the implementation on the "550SB", is the eye relief on the magnifier. As it sits now, I need to get my face pretty far up on the gun; as far up as I would if I was using one of the peeps in the rear iron sight. This prevents the use of the magnifier if employing a "squared-up" posture, with the stock planted more on your chest than in your shoulder pocket.

Because I love night vision, I gotta have the laser and IR light. It's also why the Eotech sits so high and the magnifier is in a QD mount. The pressure pad for the laser is stuck to the left side of the laser body. I can have my middle or ring finger on the light pad, while my thumb rests on the laser pad; allowing me to activate either or both.

Why am I removing the factory picatinny rail from a Swiss receiver on the other gun? Because it's been canted from day one. It's always driven me insane. Folks talk about the issue of canted top rails on the US-made guns; it's a problem on Swiss guns too.

Anyway, I thought forum members would get a kick out of the 552 build. I've got things zeroed, and I intend to do some shooting with it as soon as I finish rehabilitating my range and get things coordinated with a couple friends. I haven't done much shooting this year, so the range has become more than a little overgrown.

Historically, this gun has been kept in raw/bare form. These guns are pretty and fun to handle and shoot with irons. It weighs a million pounds now, especially considering it has a puny ~9" barrel. The weight makes it a soft shooter, and all the "crap" bolted to it adds enough capability to make the weight arguably worth it in most "direct action" CQB sort of roles, IMO.

I know more than a few forum members have more than a few 55X rifles. They don't get much post action though, so I thought this would be fun to share.

Some background on the base rifle: It's a US-born upper receiver, as identified primarily by the partially exposed trunnion. With the help of local craftsmen, a Swiss rear sight assembly and "crest" front accessory dovetail were fitted. This was after the original top rail bosses were eliminated. This build, being a 552, required further trunnion modification to allow the long stroke carrier assembly to pass through. The Swiss barrel was adapted to the US trunnion with an internally/externally threaded donut around the chamber area. This gun also plays host to a homebrew recoil assembly.

Picture inbound from the generous Mr. Sigfreund...

This message has been edited. Last edited by: KSGM,

Definitely looks nice.

At the request of KSGM:

Do you happen to remember who had the extra long picatinny rails for the 55x? I always thought that rail could host a laser, red dot, and a magnifyer on the low Arisaka flip mount. For the life of me I can’t find them. I think thought it was a B&T unit.

B&T does make (or made) them.

This place does too. Looks awesome. Costs not-so-awesome.

https://www.csr-precision.com/...-qd55x-rail-extended

It doesn't describe the construction either. If it's steel, which most of these 55X rails are, it'd be HEAVY.

The QD functionality is neat.

Upon closer inspection, it's likely aluminum. The crest interface portion looks to be a steel insert. This more dynamic construction, combined with the QD, more-or-less justifies the price.