OK I think I know the answer to this but here goes...

If one owned a hk pistol, or clone, that was compatible with a registered sear pack, would one be able to mount a stock on that pistol while the sear pack is installed?

What about the dwell between when the pack is off and the pistol may have a stock on it? Does it go back to being a SBR if the pack is taken out before the stock is removed?

OR alternatively is the pistol never allowed to have a stock on it regardless of whether the sear is installed since the pistol itself is not the MG?

Bought a zenith zf-5 today and got me wondering.  Don't have a sear pack, don't know if that's going to happen this year but am curious.

Yes, it can have a stock, forward grip or whatever as long as the sear pack is installed without needing to be registered as a SBR.

If your remove the registered sear/trigger pack the host goes back to being a pistol/title 1 firearm. If you have multiple hosts it's usually easier to just SBR them so you don't have to worry about keeping them disassembled when not being use.

This. I think most people registered their hosts as SBRs so they don’t have to deal with the hassle.

I was the other way,  I have a few hosts that I bought as pistols. The rest I had built from parts kits and barreled receivers. I have a case for foregrips and stocks. As you must know by now OP, you can't remove the trigger pack unless you remove the endcap/stock assembly. I have never found it that tough to store the stocks away from the receivers. Since I have almost 25 host guns/barreled receivers, I wouldn't want to spend over two grand in stamps. I would much rather buy ammo than give it to the Government. Of course buying a sear today at over $40,000, so another couple thousand in taxes might not bother them. It is not like I am worried that a Tac Team is watching my house or me at the range switching hosts.

Scott

As mentioned above you can stick with the pistol route and do the stock and foregrip dance when you have the sear on that gun or just register the hosts as SBRs.

I have always just registering the hosts as SBRs.    

If I am driving around with half a dozen (or more) short barrel receivers and the stocks that all go to those different gun in the trunk of my vehicle on the way to the range or to a shoot that may be 1000 miles away, I just always feel more comfortable not having all of the parts to build half a dozen SBRs in my possession even if the stocks are in a different box.   However,  everybody's risk tolerance and comfort level is different.  $200 seems like really cheap insurance to me but maybe I am paranoid in the eyes of others.

Another consideration for me is many of my hosts either done by myself or done by another builder have an A3 stock that is for that specific gun.  i.e. the  backplate and forks of the A3 stock are finish and color matched to that gun at the time the receiver is parked and painted.  Each builder uses their own shade and sheen of HK Black paint and I have my own personal formula I like.  On some of the clones where the receiver dimensions are a bit "generous", the stock A3 backplate and/or forks has to be "tweaked" to fit that specific gun as well.    I wouldn't want to try and keep track of half a dozen plus different A3 stocks and which host gun they go to.  Its just easier for me to keep the stock pinned to that gun in my safe.

Now if you are primarily using the all polymer stocks or you don't care which A3 stock goes to which gun its not really a consideration.

I did not know that, this is my first HK style purchase.

Thanks for the info.

Since you had posted this, I had thought you might have taken it apart to see how it works. So you thought of the question. Sorry I made that assumption.

Scott