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Changing MP40 buffer and drive springs?


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Are there instructions on how to disassemble the buffer to swap these two springs out in it? I bought NOS springs and would like to change mine out, but can't find any instructions online on how to do it. I am 5000 miles away from my MP40 right now, so I can't look at it now, but want to do this when I'm back by it again. Thanks!

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I tried to do mine and couldnt

 

Remove the firing pin

 

Then it should unthread I believe. But its staked

 

I had my smith do it for me for $25

 

I thought it might change the rof or spring tension. I could feel no change. Odds are these springs have all been changed 4x already over their life. These guns were used heavily for 20-30 years

Edited by huggytree
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Hi All,

 

Personally I would not bother. With the primary/secondary spring set-up, I find it very unlikely the springs would ever need replacing. If you think it will up your rate of fire, I'd guess no. The mp-40 is not a high rate of fire gun. They are slow. If it is smooth and not binding, I'd leave it and hack a FPB bolt assembly.

 

BTW, I was running a range orientation back in '01, Sept. 13. There was a nice older gentleman demonstrating the beat of the William Tell Overture with an MP-40. His comment was the MP-40 ran too slow. He indicated (with a smile) the Uzi had a better cyclic rate for the demonstration. That was the afternoon I spent shooting with Uzi Gal.

 

YMMV,

 

Grasshopper

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Like is mentioned above, there's a good chance that some of these guns have had the springs replaced more than once, while never really needing it at all. How could the springs wear out to start with? How did someone decide they needed replacement, using what standards to judge? Or, did the gun not work well and the springs could be replaced as easily as anything else?

 

I'm down to my last MP-40, an original all-matching piece. Those stakes have never been touched, the springs are original, and the gun runs fine.

 

IMHO, MP-40s have two Achilles heels, the Volmer telescoping bolt spring housing, and the double-stack, single-feed mags. Neither work particularly well. They were used in the design of the gun because they were patented and royalties for their use could be collected on every gun produced and sold to the German government.

 

In contrast, look at the double stack, double feed mag of the Thompson. It's a simple design that works every time, doesn't require heavy spring tension to be reliable, and needs no loader.

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Hi All,

 

Personally I would not bother. With the primary/secondary spring set-up, I find it very unlikely the springs would ever need replacing. If you think it will up your rate of fire, I'd guess no. The mp-40 is not a high rate of fire gun. They are slow. If it is smooth and not binding, I'd leave it and hack a FPB bolt assembly.

 

BTW, I was running a range orientation back in '01, Sept. 13. There was a nice older gentleman demonstrating the beat of the William Tell Overture with an MP-40. His comment was the MP-40 ran too slow. He indicated (with a smile) the Uzi had a better cyclic rate for the demonstration. That was the afternoon I spent shooting with Uzi Gal.

 

YMMV,

 

Grasshopper

 

Grasshopper,

 

That makes me want an Uzi, which I always wanted.

 

Robert

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Hi All,

 

Personally I would not bother. With the primary/secondary spring set-up, I find it very unlikely the springs would ever need replacing. If you think it will up your rate of fire, I'd guess no. The mp-40 is not a high rate of fire gun. They are slow. If it is smooth and not binding, I'd leave it and hack a FPB bolt assembly.

 

BTW, I was running a range orientation back in '01, Sept. 13. There was a nice older gentleman demonstrating the beat of the William Tell Overture with an MP-40. His comment was the MP-40 ran too slow. He indicated (with a smile) the Uzi had a better cyclic rate for the demonstration. That was the afternoon I spent shooting with Uzi Gal.

 

YMMV,

 

Grasshopper

 

Grasshopper,

 

That makes me want an Uzi, which I always wanted.

 

Robert

Robert, you really want the Vector Uzi. Here's an article about them. Vector made .45 and .22 conversion kits for them, too. The .22 kit runs like a dream.

 

http://www.smallarmsreview.com/display.article.cfm?idarticles=2867

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Unless it is obvious that the recoil and buffr springs are compromised there is no reason to replace them. Having had dozens of MP40s through the shop for all sorts of reasons, none one of them has hown evidence of needing new springs.

It is always interesting to me that often a new owner will fuss over the new MG and undertake parts replacements that the previous owner already did, and the owner previous to him did, etc, etc. how do I know this? Because I get calls from new owners who have bought MGs from owners that I know who bought them from previous owners that I know having advised all of them about what they might want to know and need for their guns as new owners. This has happened with MG42s as well and other types of guns over the years. Many of these guns have come here and I keep records of work on guns and serials that I have had through the shop.

It is amazing how many MGs have shown up here after the owner has replaced all sorts of parts and no improvement, but the real issue was ammo, mags or NO LUBRICATION, believe it or not. Unfortunately, the internet is full of the usual advice to replace all sorts of parts before the onwer even has an idea of what is the problem. So it goes......

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Mike...do you have a specific reason for changing out the recoil springs??

 

I don't want the ROF to get any faster. I just like to put new springs in my 70 year old guns. It was a rental MP40 in the 1970s lol, so I know it was well used. I have new springs, and would just like to put them in. That's all.

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i replace the main spring in every new gun i get...just because i dont know its condition and springs are often just $20

 

in the case of my mp40 it was at the gunsmiths already and cost me $25 labor to do it....now i never have to think about it...i have yet to ever notice a difference when i put a new spring in...but when i compare new to old the old one is always 1-2" shorter

 

cheap insurance is how i look at it.....just grabbed another new subgun last week---1st thing i bought were mags and (2) new main springs

 

i tried to change the one in my fbp assembly....i couldnt get the darn thing off.it was staked so well that it just stripped rather than unthreading....thats why i paid someone to do my mp40 spring....if you dont know what you are doing i would not do the mp40 spring myself...especially if its a # matching part

 

j

Edited by huggytree
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Hi All,

 

Personally I would not bother. With the primary/secondary spring set-up, I find it very unlikely the springs would ever need replacing. If you think it will up your rate of fire, I'd guess no. The mp-40 is not a high rate of fire gun. They are slow. If it is smooth and not binding, I'd leave it and hack a FPB bolt assembly.

 

BTW, I was running a range orientation back in '01, Sept. 13. There was a nice older gentleman demonstrating the beat of the William Tell Overture with an MP-40. His comment was the MP-40 ran too slow. He indicated (with a smile) the Uzi had a better cyclic rate for the demonstration. That was the afternoon I spent shooting with Uzi Gal.

 

YMMV,

 

Grasshopper

 

Grasshopper,

 

That makes me want an Uzi, which I always wanted.

 

Robert

Robert, you really want the Vector Uzi. Here's an article about them. Vector made .45 and .22 conversion kits for them, too. The .22 kit runs like a dream.

 

http://www.smallarmsreview.com/display.article.cfm?idarticles=2867

 

I read the article on the Uzi. Great background information. I used to see NIB ones not too long ago. I'll have to keep my eyes open. The .22 kit sounds great. Thanks

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Mike...do you have a specific reason for changing out the recoil springs??

I don't want the ROF to get any faster. I just like to put new springs in my 70 year old guns. It was a rental MP40 in the 1970s lol, so I know it was well used. I have new springs, and would just like to put them in. That's all.

I agree Mike i would replace it too.

Vin

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Hi All,

 

Personally I would not bother. With the primary/secondary spring set-up, I find it very unlikely the springs would ever need replacing. If you think it will up your rate of fire, I'd guess no. The mp-40 is not a high rate of fire gun. They are slow. If it is smooth and not binding, I'd leave it and hack a FPB bolt assembly.

 

BTW, I was running a range orientation back in '01, Sept. 13. There was a nice older gentleman demonstrating the beat of the William Tell Overture with an MP-40. His comment was the MP-40 ran too slow. He indicated (with a smile) the Uzi had a better cyclic rate for the demonstration. That was the afternoon I spent shooting with Uzi Gal.

 

YMMV,

 

Grasshopper

 

Grasshopper,

 

That makes me want an Uzi, which I always wanted.

 

Robert

Robert, you really want the Vector Uzi. Here's an article about them. Vector made .45 and .22 conversion kits for them, too. The .22 kit runs like a dream.

 

http://www.smallarmsreview.com/display.article.cfm?idarticles=2867

 

I read the article on the Uzi. Great background information. I used to see NIB ones not too long ago. I'll have to keep my eyes open. The .22 kit sounds great. Thanks

Warning on the Uzi....I bought a NIB Group industries and have owned it for 3 years....1.7 months of that time its been at various gunsmiths...the welds broke on the back the trunion is crooked...nothing is right....im thousands under water on that gun...i see Vectors shoot....they jam all the time...i see posts endless about vectors not working right....my gunsmith showed me a GI receiver and put a straight edge along it...its all over the place...#1 i would never buy a GI uzi, #2 if you buy a vector see if its been fixed and make sure you get a function guarantee...i have seem ONE vector uzi personally run correct....maybe 6 that have had similar jams to mine.....the uzi was my 1st FA purchase.....its been gone for 1.5 months now for rewelding....ive got a 22 kit for it too...they are decent if you use stingers...

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All goes back to - "If it ain't broke, keep fixing it until it is".

See this all the time!

 

Huggytree, your statement is rather misleading. You bought a vector uzi,not a group industries Uzi. They are not remotely the same other than engraving that was on the flats at the auction, vector did all the rest including making or having parts made from entirely different sources (substandard) than Group Industries when they were in business. At the time I noted Vector was at the bottom of the pile while the group guns (completely made by group) was at the top, followed by IMI. You bought the vector anyhow. You should probably research all this stuff a little more and if you're in for more than 1K to get it fixed, you probably sent it to the wrong people? Really a few hundred and a parts kit and even the vectors should be OK if sent to a decent gunsmith. Open bolt 9mm is about as simple as a ball peen hammer and a cartridge in a pipe to make work.

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Hi All,

 

Personally I would not bother. With the primary/secondary spring set-up, I find it very unlikely the springs would ever need replacing. If you think it will up your rate of fire, I'd guess no. The mp-40 is not a high rate of fire gun. They are slow. If it is smooth and not binding, I'd leave it and hack a FPB bolt assembly.

 

BTW, I was running a range orientation back in '01, Sept. 13. There was a nice older gentleman demonstrating the beat of the William Tell Overture with an MP-40. His comment was the MP-40 ran too slow. He indicated (with a smile) the Uzi had a better cyclic rate for the demonstration. That was the afternoon I spent shooting with Uzi Gal.

 

YMMV,

 

Grasshopper

 

Grasshopper,

 

That makes me want an Uzi, which I always wanted.

 

Robert

Robert, you really want the Vector Uzi. Here's an article about them. Vector made .45 and .22 conversion kits for them, too. The .22 kit runs like a dream.

 

http://www.smallarmsreview.com/display.article.cfm?idarticles=2867

 

I read the article on the Uzi. Great background information. I used to see NIB ones not too long ago. I'll have to keep my eyes open. The .22 kit sounds great. Thanks

Warning on the Uzi....I bought a NIB Group industries and have owned it for 3 years....1.7 months of that time its been at various gunsmiths...the welds broke on the back the trunion is crooked...nothing is right....im thousands under water on that gun...i see Vectors shoot....they jam all the time...i see posts endless about vectors not working right....my gunsmith showed me a GI receiver and put a straight edge along it...its all over the place...#1 i would never buy a GI uzi, #2 if you buy a vector see if its been fixed and make sure you get a function guarantee...i have seem ONE vector uzi personally run correct....maybe 6 that have had similar jams to mine.....the uzi was my 1st FA purchase.....its been gone for 1.5 months now for rewelding....ive got a 22 kit for it too...they are decent if you use stingers...

Sorry to hear your problems.

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I bought a group industries gun...my post clearly says i did.....

 

try to find a positive post about a GI Uzi...pretty hard to find....a few people claim to have a good GI gun...but we dont know what the previous owners did with it...might have been tweaked already

 

just shipping my gun $150 each way x 3 guns smiths= $900 in shipping

 

1st gun smith (famous guy--you would all know him)..said he fixed it..tweaked the trunion....didnt work....gun jammed on 1st round when it came back...he agreed to try again, but i decided to send it to gunsmith #2 who is famous for Uzi's...figured i pay for the best.....10 months go by...he says it will take 3-4...every 2 months i contact him and he gives me more excuses..at 10 months i say get it done in a month or give it back....so he tells me off and i get get my gun back...now off to gunsmith #3...he promises 2-3 months, but starts at 3.5 months and now were at 4.5 months...gun is fixed, it runs....just waiting for a refinish...no idea what ill have into it, but ill assume $500-1000 for a complete reweld and refinish...also getting a .22 kit tuned to the gun...a GI .22 kit..

 

gun smith #1 missed the fact that the whole back of the gun was blown off...1 weld cracked all the way down, the other side 1/2 way down....even though many consider him to be possibly the #1 gunsmith in the country for FA i do not.......i threw away $700 on him (including $300 for shipping)

 

ill be in $2k in repairs im sure...i paid $13,000 for the gun NIB 3 years ago...came with 15 mags(i think) and a spare wood stock....

 

You are correct that i should not have bought a GI or Vector uzi w/o research...but this was my first FA purchase...thats my excuse and many of you may not have made the best purchase on your first gun....you jump in...so ill have $15,000 into this gun.....plus spare barrels, top cover, IMI bolt....so maybe $15,500

 

anyone who is purchasing an Uzi whether it GI or Vector needs to be aware of their issues...you have a 50% shot your gun is a POS...unless it has spent some time with a gun smith to be fixed....some people swear their GI/Vector guns run 100% and have never had an issue...but read old posts and even some current ones on UT and you will see people endlessly have issues with these guns....

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I've not heard of any problems with Group industries guns including the one I own. Many issues with the vector guns but a lot of them were sent back for refurbishment while vector was still in business and repaired. Likely an NIB Vector would suffer many of the issues you state (fairly common discussion in the early 2000's) and not have been sent back for repairs. From what I recall most issues were resolved on the first trip back, but some did make two trips. Vector got pretty good at fixing them out of necessity.

 

Hopefully your gun gets fixed this time! The good news is if you can wait it out 3 years maybe you'll be even or ahead as prices escalate.

 

Gunsmiths are a lot like contractors, they have steady clients that take precedence over a new guy and try to "fit" other work in when possible. That's just the nature of business, but admittedly like contractors there are also a lot of lazy gunsmiths.

 

Guys in general have "issues" getting MG's to work so a lot of commentary is not worth much if you are trying to solve a problem. I find 75% to be operator error for a multitude of reasons when guns don't work. They broke them, lost parts, didn't clean them, etc. If MG's were as available and cheap as golf clubs imagine how many you would see hurled out on the range!

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i have heard worse issues with GI guns than Vector!!.....its why i would tell anyone to stay away from them specifically....but each of us has his own experience with different weapons...ive had many tell me their GI runs 100%...but unless you know its full history it may have had gunsmith work already to get it to that point...

 

all i am trying to say is not to blindly buy a UZI.....have 0 trust its correct...buy from Ruben or Frank which will fix/return it...or get a guarantee of function with a 3 day trial...then shoot the heck out of it...make sure it works....

 

main issue(which mine also had) is a crooked trunion...it seems to show itself by light/off center primer strikes on the left side of the mag....after gun smith #1 adjusted this the primer strike got closer to the center of the primer, but still jammed...once my gun heated up(2-3 mags) it ran 100%....others ive seen have had the exact same light primer strike jam....

 

its not like buying a ww2 thompson where the physical appearance is the main concern...they all seem to function......this is the opposite, the physical appearance can be fixed for $400 and made to look brand new...internally is where the uzi problems all exist

 

it is a great gun to shoot....(i can barely remember at this point, but did shoot one 2 months or so ago)

Edited by huggytree
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  • 2 weeks later...

emailed my gunsmith the other day....he says the metal is so junky and the previous factory welds have messed things up so much that he is having trouble welding the back end back on....he is burning through it...he had tried 2-3x last email..so he is on time #4....im now past 17 months with this gun at 3 different gunsmiths

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