Life of a Cartridge

Post by powdersmoke

See Also:- https://mp40modelguns.forumotion.net/modelgun-caps-cartridges-and-magazines-f6/restoring-old-cartridges-t366.htm


Hi guys
I posted a message which seems to have got lost in the ether. The jist of it is should a cartidge in a metal MP40 have a very short life? some of mine broke on the fist shot a couple of others on maybe the second or third. Are these PFC cartridges very fragile or do I need to make some adjustment? They broke at the threads with a loud report.
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Post by Claymore

I take it that these are marushin rounds. If so they are noted as not being the best and the screw base is the weak point, however they are not so bad that they break on the first shot. You need to make sure that the base is screwed on tight and the round inside lubed, how many caps are you using in it.
Not really sure why yours have broke that fast were they new rounds or old ones, the marushin round does get weak in the screw base area but over time not straight away, what about the detonator is it positioned right if it is too far forward it could be hitting the base of the round with too much force causing the threads to give.

Post by Mark

Usually, i get anywhere from 30-100 cap loadings during the cartridges life span.

However, they must be maintained properly by cleaning them after shooting them, using only ONE CAP and properly lubricating the inside of the cartridge case.

Also, each manufacturers cartridge design is different: The materials used, the cases thread location and other factors are the cartridge case life limitations.

Also, all metal modelguns give the cartriges a real work out due to the the heavy components used in their construction.
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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

Post by powdersmoke

Thank you for the info, the cartridges are MGC, so is the MP40. They were all brand new and contained only one cap per cartridge. Idid not however introduce any lubricant into the cartriges. Does grease damage the O-ring, whats best to use?
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Post by Mark

Quote :

Does grease damage the O-ring, whats best to use?

The O-rings are fairly immune to greases but, I suppose that they can be damaged by some types of greases. I personally use the RIG products stainless steel +P lube but, there are many greases that will work equally as good for the cartridge lube. However, I try to use firearms grade greases instead of the more common automotive/household/general purpose greases.

Post by Madmike


Well, it is hard to say how long carts last in general. I had two new MGC 5,56 mm M-16 carts breaking into pieces on their first shot! Others have been fired approx. 30 times and still look and work well. The Marushin 5,56 mm M-16 carts show dents on the bottom and some are even out of shape after having 50 - 70 shots through, but they still work.

Post by Mark

Hi MadMike I haven't seen you on the fourum for quite some time!

Anyway, the life of a cartridge is extremely hard and especially when the cartridge sometimes has threaded a seam in it's middle. The fact that the MGC M16 cartridge is so long and the threads that hold it together are so fine is a concern as they have a tendancy to loosen after they are loaded into the magazine. If the cartridge body isn't ridgid enough when it hits the ramp or the barrel entrance it can bend at this seam and break at the thin thread form. If the cartridges are tight and the cartidge is loaded correctly with one cap and the proper amount of grease it will live a fairly long time. However, the base will get those ejector dents and the cartridge rim might have some sections missing over time.

It's too bad that the cartridges don't last longer as they are expensive and hard to get...
_________________
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