Ima Bolt For Mp40

[Mike Venturino]

Maybe you guys can help me. In order to have some spare parts for my MP40 without buying a complete parts kit, I bought one of the International Military Antique bolts for the MP40. I guess they are actually for some subgun made in Portugal but billed as "drop-in" for MP40s.

 

It does drop in alright but it doesn't function properly. It slides forward, chambers a cartridge and fires it. But it appears the problem is with ejecting the empty. It pulls it out of the chamber but doesn't throw it clear; leaving it rattling around inside to stop the bolt from closing on the next round.

 

This MP40 functions perfectly with its own bolt.

 

Anybody got any suggestions?

Thanks

Mike Venturino

[Uncle Dudley]

See if you can return it for another. I bought 2 from them (FBP bolts) and the first one had a chip out of the guide groove on the bottom. I didn't even try the chipped one. They replaced it and the second one works fine. I did buy an original MP40 bolt and firing pin assembly from them also and it works fine too.

 

My FBP recoil spring assembly has a sticky spot that slows it down every once in a while. I haven't dissasembled it yet to see what is the problem. That's next on the list before the next range trip.

 

Can you see if the extractor looks OK or the same as the MP40 bolt extractor? My FBP bolt was used and dirty. I scrubbed it and checked it for rough spots before I tried it. I was advised to not use a lot of oil on the assembly.

 

Most of my stoppages are ammo or magazines. I need to talk to a Nazi solder who used one of these for some first hand tips.

 

Uncle Dudley

 

 

 

 

 

 

Edited August 9, 2008 by Uncle Dudley

[Mike Venturino]

Uncle Dudley: Thanks for the reply. I think I answered my own question this morning. Yesterday I fired the IMA bolt with 115 factory loads. Today I fired it with 124 grain factory loads and it functioned perfectly. When I tried the 115 grain loads again, it went back to being a single shot.

 

Guess I need to get some heavier bullet factory loads for when I want to use the IMA bolt. It does seem a bit heavier than the original MP40 bolt.

 

Thanks for the response.

Mike V.

[RichUrich]

115gr. vs. 124gr.?

Some MP40's like one much better than the other for feeding and ejecting.

At the last shoot, the MP40 we had ate all the 115gr Wolf ammo, but wouldn't reliably function with 124gr. Wolf.

I have had MP40's that would not relaibly function with British SMG 9mm ammo that worked wonderfully in a Sterling or STEN.

Just make sure the 9mm ammo is HOT HOT HOT.

 

Rich Urich

[Mike Venturino]

Rich: With its original bolt my MP40 does function nigh on perfectly with both 115 and 124 grain bullets. The problem arose only with the IMA bolt I bought as a spare. It seems to require just a tad more "oomph."

 

MLV

[21 smoker]

I think you`ll find most blow back subguns will function more reliably with a heavier bullet.I don`t know exactly why this is so,but STens,Sterlings,MP5s,MP34s,MP40s,UZIs,..etc.,seem to operate more smoothly and for a longer duration without stoppages. Funny thing about the MP40,I found a complete internal set of parts for a reasonable price at a local gunshow.When I asked the seller why he was parting with this setup he said he had an MP40 and used this for a spare,but nothing ever breaks on an MP40,so he sold it to me several years ago and nothing ever broke on my MP40.The cycle rate is slow,which helps. I am fortunate to know a `Green Devil` WWII German paratrooper/engineer.Lite lubrication was recommended on the subguns but liberal lube on the beltfeds was the norm.I find this is true today in the civilian range recreation shooting that most of do,HTH.

[RoscoeTurner]

Same here. I have had a C&R MP40 since 1986 and have yet to have to replace anything on it. Since I have had it I have mainly shot reloads loaded to factory specs and it rarely if ever has malfunctioned.

[RichUrich]

Breaking MP40's

Guys, I have been a Class 2 and collected MP40's since 1974. I have seen and built and repaired MANY MP40's. MP40's are my specialty. I have fired thousands and thousands of rounds through MP40's. I like MP40's.

What I have seen as regards to repairs:

1. Do not assume that parts are inter-changeable. I have had MP40 bolts that worked perfectly in one weapon, that simply would not operate in another. RARE, yes, but I have seen it.

2. I have had plenty of extractors and firing pins break, or have had to replace them for customers whose did break.

3. Magazines are usually the problem if the MP40 doesn't feed / eject. Those magazine feed lips WILL wear out!

Also, clean the inside of the magazines from dirt and apply a light coat of oil inside the mag.

4. When the barrel wears out, and they WILL wear out eventually, there will not be enough back pressure to operate the bolt recoil, and the MP40 will fire sluggishly. I doubt the original "life expectancy" of the MP40 barrel was 10,000 rounds. (Compare with similar documented expectancy of other WWII German MG's)

5. When the sear and/or sear contact area on the bolt base wear, and they WILL wear, the bolt will "run-away."

6. Not all MP40 WWII German magazines are interchangeable!! Occasionally you will find mags that will just be impossible to fit in smaller dimensioned mag wells. Who knows why?

 

 

Spare parts needed:

Spare bolt

Spare extractors

Spare magazines

Spare barrel

 

If you have a chance, try to watch some original WWII videos of MP40's in use. Note the rate of fire and how high the empty shell casing eject from the ejection port. Seldom do I see MP40's are the ranges with the same forceful ejection.

 

Finally, consider VERY VERY carefully replacing the recoil springs with WOLF Springs. When removing the firing pin from the recoil assembly, remember it is under a lot of pressure!

 

[RoscoeTurner]

The majority of the MP40s I have seen that had problems had been "reenactored". In other words not well cared for or operated by an individual who knew little about firearms.