H&K P9S 9mm: What's the recoil spring compression rating?

[passengerseven]

Hey Guys.
I have an HK P9S Combat in 9mm, manufactured in 1973. Looking to replace the recoil spring but spares are hard to find. Have located a recoil spring for the 45acp version. Are they interchangeable? I know that uncompressed spring length cannot be less than 130mm but have not been able to determine compression rating.
Wolff Springs has 45acp version recoil springs ranging from 11-16 lbs but Wolff did not know if they would fit the 9mm version.
Any experienced opinions would be appreciated. Thanks,

P7

 

[MTF]

I don't know why you want to do this, and I have to say I don't know the answer. However, if you really want to go ahead with the project, why not email Heckler & Koch to ask their technical support people. Unless you can find a gunsmith who knows information like that, I think only a specialty company like Wolff (and apparently they don't know) and the orginal manufacturer, H&K, can give you the information you want. The guns have been out of production for so long, H&K may not have the information any longer, and you might just have to try different springs to see if you can get the effect you're looking for. The spring for the .45 has to handle a much heavier mass than a spring for a 9mm, but I suppose you could try it and see if it does what you want. It may not work as you wish, but using it won't hurt the gun. Generally, though, unless you're using 9mm bullets that are radically different in weight, the normal recoil spring should work.

 

[redshooter]

What's the prob with the factory spring? Is it broken, cycling problems, or are you just wanting to shoot lighter/heavier loads?

If it's not too much coin buy the one for the 45 and compare them before you stuff it in the pistol.

 

[robin2y]

The wolff springs don't come in a factory weight. I've got the 45 version and opted for the (slightly over stock) 16 lb spring. I believe that both the 9 and 45 used the exact same spring from HK. My original one was a little mangled as came from previous owner - it is approximately 5 inches long and 18 mm in daimeter, if you wish to compare to yours - 13.5 coils and spring wire is around the 50 thou mark. I'd probably opt for the next lightest spring from wolff in mine were a 9 mm.

You will want to make sure that your buffer (under the barrel) is intact and functional!

R

 

[Miltiades]

If you write to Wolff springs with the length, inside coil diameter and the diameter of the wire itself, they can tell you what rating it had and they will be pretty close. They also can make custom spring, if they don't have an equivalent one for another pistol. By the way, I also seem to remember that the 9 mm and the .45 ACP versions had the same spring rating.

Hey Guys.
I have an HK P9S Combat in 9mm, manufactured in 1973. Looking to replace the recoil spring but spares are hard to find. Have located a recoil spring for the 45acp version. Are they interchangeable? I know that uncompressed spring length cannot be less than 130mm but have not been able to determine compression rating.
Wolff Springs has 45acp version recoil springs ranging from 11-16 lbs but Wolff did not know if they would fit the 9mm version.
Any experienced opinions would be appreciated. Thanks,

P7

 

[passengerseven]

The wolff springs don't come in a factory weight. I've got the 45 version and opted for the (slightly over stock) 16 lb spring. I believe that both the 9 and 45 used the exact same spring from HK. My original one was a little mangled as came from previous owner - it is approximately 5 inches long and 18 mm in daimeter, if you wish to compare to yours - 13.5 coils and spring wire is around the 50 thou mark. I'd probably opt for the next lightest spring from wolff in mine were a 9 mm.

You will want to make sure that your buffer (under the barrel) is intact and functional!

R

The spring is a little mangled and likely the original so i would like to replace it. Still fully functional but I believe in preventive maintenance. I contacted HK and was told sorry, product no longer supported, unable to provide the answer. I understand, it is a 40 year old pistol, and HK sold all of their parts inventory to Numrich Gun Parts out of the US. Recoil springs are sold out at Numrich but I managed to locate the 45 version from HKParts.net. They did not know if it would fit the 9mm version and they won't ship out of the US but I could have it shipped to a buddy who lives in the US and he could bring it the next time he visits.
I asked about interchangeability here on CGN before going through the US Buddy hassle.

The current spring is 15.5 coils and is about 40 thou spring wire thickness. Spring is 18mm in diameter and just over 152mm long (6").
For what Robin2y indicated about his 45 spring, they are different animals so I think I have my answer about interchangeability.

Thanks for the input.

 

[robin2y]

My 16 lb wolff spring is 12 coils of 50 thou wire and 6 inches long... ...the slide and barrel trunion are interchangeable between calibre (the removable bolt head is the important bit) so I would try out the next lightest wolff spring. What shape is the buffer in? Previous owner(s) let it decay and then fired it on my example (at least twice), resulting in breaking one of the ears of the current retainer off. Less likely in a 9, but be sure to check! They don't make the replacement bits anymore, so tracking down surplus can be a bit of a challenge...
R