Rebuilding the Herbert Schmidt Model 71 (HS-71) pistol.

A place to discuss and share pictures, reviews, of your pistols.
Post Reply
Leonardj
Marksman
Marksman
Posts:128
Joined:Sun Dec 23, 2012 4:58 am
Rebuilding the Herbert Schmidt Model 71 (HS-71) pistol.

Post by Leonardj » Tue Oct 29, 2013 9:00 pm

A few years ago, I had the opportunity to finally add a very nice, boxed specimen of the HS-71 pistol to my collection. Can't really explain my fascination with this gun, but I had to have one. Sadly, when tested back then, it shot very weakly, not even able to punch through a target paper at seven yards. I set it aside until I had the time to rebuild it. Fast forward at least five years later, and the time had finally come.

The gun as purchased was in the original box, complete with the owner's brochure, the loading funnel, and a tin of H&N 4.5 mm lead balls.

Image

As I began to disassemble the gun, a few things were noted. First of all, there was a surprising amount of pre-load on the mainspring - a good 2.5" worth. The mainspring is quite long at 8.3" overall length. Next, it was discovered that the trigger mechanism pieces did not have to be removed in order to withdraw the piston. Just had to hold the trigger fully back, and the sear cleared the piston. Once the piston was removed, the problem became obvious - the piston seal had begun to crumble. Examining the piston, it now becomes clear that this gun isn't quite a true "air" gun,but rather, more of a spring operated catapult with air assist. The long probe on the front of the piston drives the lead ball the first bit of the way, and the air assist takes over.

Image

Image

While the gun is built largely of alloy castings, the design is very well executed, in that steel reinforcement is used at all high stress points in the gun. Using the piston as an example, the rear of the cocking slot has a steel pin embedded to reinforce the point that the cocking lever contacts the piston. Note the arrow - the pin goes in from the side of the piston, and just breaks through the rear edge of the cocking lever slot.

Image

The point at which the sear acts against the piston is reinforced by a hardened steel "C" shaped insert, as noted by the arrow.

Image

The full length of the piston inside diameter is protected by a steel sleeve, which is pulled out a short distance for clarity in this pic.

Image

A new piston seal was fabricated from 90 DU urethane, and fitted to the piston. The little bit of excess material at the center probe was trimmed flush with a razor blade prior to the piston being installed in the gun.

Image

This pic shows the simplicity of the anti-beartrap mechanism. As the cocking lever is drawn rearward, the top of the lever engages the slot in the rear of the trigger, and remains there until the cocking lever is returned to battery.

Image

Looking at the breech end of the barrel, we can see the two opposing dimples in the breech opening that hold the lead balls from falling out the bore if the gun were pointed downwards. It appears that the piston probe knocks the lead balls free of that dimple as it begins it's forward travel.

Image

The barrel has a long tapered flat on it, which, in conjunction with features cast into the inside of the muzzle end of the frame, guides the lead balls into the breech opening. The magazine holds 100 shots.

Image

The muzzle plug, which retains the barrel, and also acts as the magazine plug, is turned a quarter turn to load the magazine. Once the magazine is filled, a quarter turn back closes the magazine filling port. A ball detent locks the muzzle plug in position.

Image

Once the HS-71 was re-assembled, it was time to test. Information on these guns isn't too readily available, so I had nothing to compare my chrony readings against to determine how close to Factory specification the gun was shooting with the new piston seal and fresh lubes. After a few shots just to work the lubes in and let the mechanics settle, I put ten shots over the chrony, using H&N 4.5 mm lead balls. The average was right around 270 FPS, which I'd say was quite acceptable for the little gun.

Next up, a check to see what it would do for accuracy. Being a smooth bore, and considering that it is basically an air-assisted spring catapult, I decided to shoot my test targets from 7 yards. Once sighted in, I shot a couple targets to familiarize myself with the gun's firing behavior and trigger break. Once I felt comfortable with the gun, I shot for score at a regulation 10M air pistol target. Ten shots, from seven yards, standing, offhand, using a two hand hold, and managed a score of 79/100. Not bad at all. It's actually quite a nice little plinker pistol, and would be great fun for plinking tin cans at 10 yards or so. So now, it a a nice, boxed, and working specimen of a very cool little spring pistol.

Image
Last edited by Leonardj on Fri Nov 15, 2013 7:25 pm, edited 1 time in total.

User avatar
pmh
Site Admin
Posts:1826
Joined:Sat Nov 10, 2012 5:07 pm

Re: Rebuilding the Herbert Schmidt Model 71 (HS-71) pistol.

Post by pmh » Tue Oct 29, 2013 9:06 pm

Another excellent post, and a gun I haven't heard of.

The grip reminds me of the plastic grip on the Original Model 5.

Kind regards,



Phil
M0KPH
I now have so many airguns I've had to make a list, which is >>HERE<<
>>North Manchester Target Club<<

Certus
Sharpshooter
Sharpshooter
Posts:430
Joined:Sun May 12, 2013 9:34 am

Re: Rebuilding the Herbert Schmidt Model 71 (HS-71) pistol.

Post by Certus » Wed Oct 30, 2013 11:39 am

Hello Leonard,

Thanks for sharing this very interesting re-build project with us.

Regards

Brian

User avatar
zunmik
Pistoleer
Pistoleer
Posts:741
Joined:Sat Nov 10, 2012 6:22 pm

Re: Rebuilding the Herbert Schmidt Model 71 (HS-71) pistol.

Post by zunmik » Thu Oct 31, 2013 5:11 pm

Once again an impressive pistol thread I to had never heard of this one, which only served to increase the interest, thanks, M. :handgestures-thumbupright: :D
WALTHER LP3],Etc[/b], G0JVB ex G6MUI.

gingernut
Plinker
Plinker
Posts:61
Joined:Tue Jan 29, 2013 8:52 pm

Re: Rebuilding the Herbert Schmidt Model 71 (HS-71) pistol.

Post by gingernut » Mon Nov 11, 2013 1:18 pm

I have got a boxed one and Lens post lead me to get it out and find that H&N balls work much better than Gamo.
Obvious really.
Len also sent me a copy of the Manual.
Nice Chap.

Post Reply