Osprey Defence AR15 Gas Piston Conversion

I wouldn't so far only the HK rifles have really solved the issue of bolt tilt and such. Drop in conversions are not the way to go as the rifle itself was not designed as a dedicated piston operated rifle.
 
From some high round count Hk416's I have seen recently - I am not so sure they have totally solved that system.

I am happy with my 10.4, but just sold my 14.5 to some nice man in Jacksonville to finance some other projects (okay living room furniture...)
 
I agree with both Kevin and Reaper while these conversion might be OK for limted use IE civillian usage . I hardly think that these would hold up serious use and given the nature of the complexities of these add on systems that are required to fit under the OEM handguards and use the Factory FSB and may or may not use a modified bolt carrier.
 
KevinB said:
From some high round count Hk416's I have seen recently - I am not so sure they have totally solved that system.
Click to expand...

What have you noticed in high round count 416's? While the Osprey and HK416 run a different operating system (I believe so anyway... both gas piston, just a different system) the 416 is designed from the onset to utilize the piston system. I've read concerns over bolt tilt but as an engineer I'd think the force applied to the same area of the bolt, either DI or Piston should be the produce similiar tilting. The only difference should be there is no direct contact (metal-to-metal) with a DI system, which could produce (could, not is) possible stress/fatigue failures.

Its difficult to disceminate the propoganda between the rabid DI-AR advocates(change=bad(boo... scary) and those jumping on the bandwagon trying to make a few bucks with likely in-house tested(read:testing=time=money=less profit=bad), but potential game changing, systems. I tend to be 'leary' of salesmen who livelyhoods depend on whether they sell their product or not.

Given the choice though between 'backing the outhouse to the kitchen' (yes, yes... it works if you clean it... so does everything) with a DI system or a system that keeps the breach more importantly cool but also cleaner, then to me it's worth some investigation.

My AR has never failed(if it ain't broke, don't fix it), but then again neither has my G36K or 551 Commando, but I tend to be a bit detail oriented when it comes to cleaning. There are plenty of 'current' (read: not Vietnam but Afganistan-Iraq) where the mix of local conditions of sand, mud and herpes(ok... maybe not herpes) and the tight tolerances of the AR platform(as compared to say, the slop of an AK) when heated in a DI system in consistant firing is causing feeding failures. Apparently not so with the short stroke piston systems like the 416. But if the 416 platform isn't lasting that's a whole other issue I haven't heard anything about.
 
The difference is in a piston system the op rod impact the top of the bolt carrier - where the gas key would be.

In a direct impingement system the hot gas enters the gas key and pushed on the bolt forcing unlocking and reward impact - direct at the center of the bolt.

Thus there is no carrier tilt issue with a DI system.

Piston guns that are designed from the get go - use rails to guide the bolt and carrier so their is no tilt.

I'm not saying Hk is bad, I think its good system, but my point is there is still bolt tilt forces at work.

The AR receiver is still aluminum - which is soft, and even if the external surface is hard coat annodized the lower aluminum is still soft - and the bolt will bounce into it - effectively bumping up and down the length.
Even in DI guns this occurs since the tolerances of the upper and bolt are not 100% (they can't be to function).

Watch high speed photography of this and you see the bolt group actually banging from one side to another on the steel botl rails - this will eventually crush the unlying aluminum of the upper out of spec - loosening the upper and making this worse and worse.
 
What KevinB is describing is pretty clear if one takes out the bolt group. Just imagine slamming the area where the gas key is and expecting the bolt to go perfectly straight back.

A non-perfect analogy is taking a nail with a fat head and hammering it on the side of the head instead of dead center.
 
You must log in or register to reply here.
Back
Top Bottom