i like the paddle release on the hk mp5
that i use to have at work but no hk clones
have them is it hard to install? is it legal?
want to buy a ptr 91 and add one.
thanks for your help bill

Yes they are legal.  A little tricky and time consuming to install.

You can purchase the parts here:

http://www.pof-usa.com/hk91pl.htm

To install one:

http://www.geocities.com/miketheelectrician1/paddlemag.html

WARNING !

If while installing the HK paddle style mag release you drill
the hole all the way through the receiver ,it is an unregistered
machine gun according to the BATF.

You must not break through the other end when drilling the hole !

Look up the information before considering doing it yourself.

2 other options :

1.Pay an HK builder to install it .Usually around $200.

2.Install the TAC LATCH II US made paddle mag release.
This is an after market release that when installed works
from side to side instead of front to back.
It's doesn't have the same look as the HK paddles because
of how it's mounted and it's lack of checkering,but it's very functional.
It also doesn't require welding or drilling like the original.

I installed one on mine myself .
I have put around 500 rounds through my PTR since installing it ,and
it functions perfectly.
Costs $50 bucks.

Some PTRs do have extra material that needs dremmeled 1/16th to make
it fit perfectly.Some also have a small divit where you must add gunsmiths
epoxy (or weld a drop) as a spacer.
The same mods would also be necesarry to make the HK paddle release
fit correctly.
JLD puts extra supports and materials in their PTRs that make these spots
thicker than true HKs.

Once you use it ,the side to side motion becomes natural.
You wouldn't believe how much it speeds up your mag changes.

The original button release can also still be used when the Tac Latch is
installed.

http://www.investmentgradefirearms.com/services_G3.htm

They can install the paddle release for 150 (+30 for parts is you dont supply them) which seems really reasonable after doing it myslef on SAR8.