Hudson PPSh41... Cartridge Problems

NEW HUDSON PPSh41 Cartridges

I've a problem with my new PPSh41 that MAY be down to using .38Super MGC rounds.

General opinion and recommendations favours the .38s over Hudsons own cartridges without doubt but I can't get them to work in my new gun.

Rough measuring shows a definate difference in case diameters between the Hudsons and .38s, the .38s being the larger diameter.
Little wonder I think that they won't feed through and out of the drum mag properly.

Could it be then that either MGC have started machining the .38s bigger, or that Hudson have modified the rounds / drums as well as major reworking of the bolt?

Is anyone aware of any significant differences please?
Could anyone owning these cartridges measure a few for comparison and let me know the average case diameters please?


Cerwyn
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Hobby collector of mainly WW2 era uniforms, headgear, field equipment and replica weapons.

Post by Claymore

cerwyn, i have 38 super rounds that i bought only a couple of months ago and i have no problem firing them in the ppsh with no modification at all. I think you have the really new model maybe they changed more than just the bolt on it.

Hiya Claymore,

You may well be right. The gun is a brand new one and the cartridges supplied with it slip in and out of the drum easily, but the 38s are slightly larger in diameter and there's a clear difference trying to load them into the drum and they are horrendously tight to get out of the feedlips.

I bought 2 x spare drums privately, I don't know how old they are but they are unused and as good as new. The 38s are a problem in these also.

Not that it would make any difference but the "bullet" portion of the rounds are a different shape comparing the ones I have. I know the 38s have thicker rims but that's an advantage isn't it!

I'll have to wait till tonight till I can borrow a readable caliper to measure these up properly.

I'll get this PPSh firing if it bloody kills me

Cerwyn
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Hobby collector of mainly WW2 era uniforms, headgear, field equipment and replica weapons.

Post by Mark

Cerwyn,

That is a strange problem that you are having with your Hudson. I am reasonably sure that Hudson has changed some dimensions on the PPSH over the last few years. They must have as I really doubt that MGC changed the exterior dimensions of the .38 super cartridges. Hudson very probably changed the bolt face, extractor, magazine as well as the chamber in an effort to improve the firing performance.
_________________
Wanted to buy: MGC Sten MK3....trades?(still)

MGC MP40 Marushin MP40 Nakata MP40 TRC MP40

Modelgun manufacturers, past and present:CMC,CAW,Hudson,HWS,LS,MGC(R.I.P. 1960's~2007) Marushin,Marui,Kokusai,Shoei,Tanaka and Western Arms

Hi Mark,

I too would doubt that MGC would modify an established cartidge.

It does seem more plausible that Hudson have done some major reworking of the gun and its' components to improve it's poor firing performance.

The new bolt is significantly different,






I've taken these shots of the new one, the extractor is not the original, this is a Kickback special (thanks Mate!)

I don't have photos as yet of the old type bolt but I'm sure some of you will be very familiar with it.

If Hudson went this far, they may indeed have modified the drum and cartridges too?

I'll be back with some dimensions of the 2 cartridge types later.

Cerwyn
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Hobby collector of mainly WW2 era uniforms, headgear, field equipment and replica weapons.

I think I've found my problem...

Measuring a sample of 3 of the .38Super carts

Cartridge Diameter 0.391" - Rim Diameter 0.409"
Cartridge Dia. 0.393" - Rim Dia. 0.402"
Cartridge Dia. 0.399" - Rim Dia. 0.410"

Mearuring 3 of Hudsons new cartridges...

Cartridge Dia. 0.393" - Rim Dia. 0.393"
Cartridge Dia. 0.395" - Rim Dia. 0.395"
Cartridge Dia. 0.395" - Rim Dia. 0.395"

Whilst the cartridge case diameters are within 0.004" max I'd say that's pretty safely within limits but the Rims of my .38s are knocking on 0.015" wider than the Hudsons and would therefore seem to be fouling and jamming in the drum itself as well as in the feed lips.

I'd be really interested to learn what sort of measurements you lads find on your cartridges please?
With any luck these .38s should turn in a lathe and clean up down to a nice true 0.395" ?

Who do I know with a lathe? ... erm, 8ace? Are you doing anything mate?

Cerwyn
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Hobby collector of mainly WW2 era uniforms, headgear, field equipment and replica weapons.

Post by 8ace

It should be no problem to turn the rim to fit.

It would be interesting to see if other peoples rounds are the same dimensions


8ace

My thoughts exactly 8ace

I am keen to learn how the "old" style PPSh rounds compare to the "new" ones.

I'm setting up to shoot the PPSh now... Wish me luck!

Cerwyn
_________________
Hobby collector of mainly WW2 era uniforms, headgear, field equipment and replica weapons.

Hiya,

Test firing using the Hudson cartridges has been a complete success
I've only got 6 of them but it works.
I re-loaded the 6 4 times in succession and pulled the trigger, successful firing, extraction and ejecting almost every time.
And that was with the Hudson pistons.

I tried them again using MGC pistons but it didn't seem to like that set up! Goes against every bit of advice that does, but it seems to trip itself up. Last time I saw that kind of thing was putting 7mm + 5mm caps in my Marushin MP40. Too much pressure by far for the recoil spring to cope with so it lost control of the bolt?

Next step was to try loading 6 .38s in behind the Hudson rounds. I found ones that dropped into the drum the easiest, as most tended to stick.
No-way would the drum feed then. The .38s get fouled up along the track so spring tension isn't effective.

The only thing the PPSh won't do very well is fire in single shot, it prefers Full Auto regardless of setting, but what the Hell, I ain't complaining! It fires in Auto...

It seems then that either Hudson have tightened up the width of the track in the drum or that I've a faulty batch of .38s?
I still cannot see nor understand how the rims could be machined differently to the cases as I'd have thought a blank would be turned to final o/d then the groove cut in leaving it parallel overall.
But here's this variation...

Looking at the rounds travelling in the drum, the ones that drop in easily, it's easy to see now that the rim catches and snags in the feedlips.

I'm really curious to see how everybody else's Hudson and .38s cartridges measure up though before I ask to have these all skimmed in the lathe!

Cerwyn
_________________
Hobby collector of mainly WW2 era uniforms, headgear, field equipment and replica weapons.

Post by Mark

Hi Cerwyn!

It's nice to see that you had some success on firing your Hudson! Even though Hudson does have problems and their modelguns don't always work as they should they sometimes will surprise you. I have had some luck with my Hudson's that i have had over the years. But, most of the Hudson's problems seem to be rooted in their piston/detonator design. Sometimes their cartridges work out of the box with no modifications at all and other times they are nothing but a frustrating time. However, if you swap over the pistons from like say an MGC CP cartridge the Hudson cartridges can and do work. I am not sure just why Hudson can't come up with a good piston design but, for the most part, their cartridges aren't that bad. I use the Hudson Sten cartridges in my Madsen M50 as well as my CMC Sten and they work great.

It seems to me that another reason that the Hudson cartridges don't always work very well is their internal diameter seems to be larger than 7mm and their O-rings seem to be "loose" as the pistons, caps and O-rings seem to fit rather easily....

I am not sure why your MGC .38 super cartridges have some dimensional changes as the MGC cartridges that i have seen over the years have been highly consistent in dimensions.
_________________
Wanted to buy: MGC Sten MK3....trades?(still)

MGC MP40 Marushin MP40 Nakata MP40 TRC MP40

Modelgun manufacturers, past and present:CMC,CAW,Hudson,HWS,LS,MGC(R.I.P. 1960's~2007) Marushin,Marui,Kokusai,Shoei,Tanaka and Western Arms

Hi Mark,

Thanks for the encouragement! To be honest I had dismissed Hudson's own cartridges that came in the box simply because their reputation is very poor and that the general consensus favours the 38s for this gun.

It was desperation that drove me to use them in the end as the MGC carts were simply not working.
As you know I rely on other folks to handle my guns etc so I hadn't been able to "feel" how the 38s stacked in the drum.
They were obviously stubbornly tight and needed some effort to get them out of the feedlips and I was thinking more incorrect spring tension than anything else.

It wasn't until one of my helpers pointed out that "these bullets are a bit tight" that the penny dropped.

Trying the Hudson rounds and then measuring both types pointed out the problem!

I am still mystified why the rims differ in diameter. Makes no sense does it? Unless of course the drum's feedlips are marginally tight, the 38s on Top Limits for machining and these are a poor match in this specific case?
Maybe several attempts to cycle them through the gun has struck the rims enough to flare them out?

At least the root of the problem is solved now, now I know what to modify or replace.

The PPSh is back in favour again now. I always liked these guns, I very nearly trashed it through frustration but now it has managed to behave in a proper machine gun manner it is back in my favourites box!

I will take this opportunity to thank, sincerely, Kickback, Claymore and 8ace for their tremendous help so far. Thanks guys!
Thanks to Brad also for selling me the old heavyweight bolt, now repaired by Kickback.

Could anyone owning either Hudson PPSh or .38 Super carts please let me know outside diameters of case and rims please, for comparison?

Cerwyn
_________________
Hobby collector of mainly WW2 era uniforms, headgear, field equipment and replica weapons.

Kickback kindly measured a sample of his Hudson PPSh41 and MGC .38 Super cartridges for me and confirmed my own findings:-

The 6 new hudson shells that he checked where all identical with the main body and rims both comming in at 9.78mm/0.385 inch, and the .38 carts came in at different sizes:-

1/ body 9.81mm rim 10.21mm
2/ body 9.81mm rim 10.23mm
3/ body 9.82mm rim 10.22 mm

Despite the wider rims his.38s work perfectly well in his PPSh drums though which doesn't answer my problem but ...

It suddenly dawned on me, are these .38 Super carts intended for REVOLVERS by any chance?
If that's the case, little wonder the rims are wider, they wouldn't sit in the revolvers chamber otherwise would they?

Have I missed the obvious here

Cerwyn
_________________
Hobby collector of mainly WW2 era uniforms, headgear, field equipment and replica weapons.

Post by 8ace

The plot thickens

In the real gun world the .38 super uses the .38 ACP case which has a case dia of 9.75mm and a rim dia of 10.31 (not sure if it is the same in the modelgun world but it appears so) but they are for auto pistols.

The real PPSH round is the 7.62 x 25mm which has a base dia of 9.65mm and a rim dia of 9.91.

I have a cunning plan…… it’s a long shot………. But it might just work ....... you could GIVE my the PPSH and you wouldn't have a problem anymore


8ace

That is a Cunning Plan indeed matey, but, alas, it ain't gonna work!
I like your style though, cheeky sod!

Sounds like the modelgun world has replicated the .38 Super rounds perfectly then, wider rims and all.

Hudson's version of the Ppsh's 7.62 rounds are not exact replicas but they do work in the model regardless!

I was in the middle of sending you a PM 'ace (and nope, it wasn't to beg you to take my PPSh41 off my hands!)...

Stand by,

Cerwyn
_________________
Hobby collector of mainly WW2 era uniforms, headgear, field equipment and replica weapons.

Post by 8ace

It would have gone to a good home

It looks like the the MGC rounds are the problem in your PPSH and should be easy to tweak them to fit the drum.

8ace

8ace wrote:

should be easy to tweak them to fit the drum.
8ace

I certainly hope so 'ace I'll be in touch
Cerwyn