H&K 91 with Suppressor

HK91 Suppressed.MTS - YouTube

Not mine, but there you go. I'm interested too.

Comments say that you need a "#17" LP. Maybe someone else can explain why...

Thanks for the Youtube info.

Any time you add a Suppressor you increase the backpressure on the rifle operating system.

I know in Vietnam, Republic Of, the Sionics suppressors for the M14's had a gas relief valve, to deal with the increased back pressure.

I would think that in non full auto fire a H&K 91 would not be that much effected.

But, where can I find a #17 Locking piece???

so a #17 LP is 36 degrees, a stock 91 LP is a #19, or 40 degrees.

The lower the degrees the more force it takes to unlock the action. Increased back pressure from the supressor requires a bit more locking resistance, hence the #17.

Where can I find one... well hk parts of course...

Interesting. Thanks. Kinda sounds like a PITA to have to swap out the LP every time you wanted to use a can. I'm not into FA, but there are things I could legally use a suppressor for so have been considering one.

If, for expediency's sake, you needed to leave one LP in the gun, and were not planning on rapid fire with the suppressor, which LP would be best to leave installed?

OldIronsights said:

Kinda sounds like a PITA to have to swap out the LP every time you wanted to use a can.

If, for expediency's sake, you needed to leave one LP in the gun, and were not planning on rapid fire with the suppressor, which LP would be best to leave installed?

Click to expand...

I'm not sure how rapid fire factors into the discussion at all....

The roller-locked system needs to be in balance. The LP must properly retard opening of the action so there is enough, but not too much energy, to cycle the bolt carrier properly without over function.

Different ammo, different barrel lengths, different suppressor, in various combinations will probably need different locking pieces.... which one? The only way to know is to try them out. You might find one combination that works well both suppressed and unsuppressed.

There are guides from H&K as to which LP for which guns/barrel/suppressor but they are a starting point. With the variety of ammo makers, and clone makers I've gone off the chart a few times to get a good functioning setup.

If you need to swap LP's you might just bring a full BCG & LP pre-installed, and swap it all over when its time to go suppressed, it would make the swap very quick and easy.

jdonovan said:

...If you need to swap LP's you might just bring a full BCG & LP pre-installed, and swap it all over when its time to go suppressed, it would make the swap very quick and easy.

Click to expand...

Good point. Thanks for the input.