M.P.18,I Mainspring, bolt & firing pin & extractors

[Rekraps]

For those who own one of these, spare parts are virtually impossible to fine, 20 round stick mags (for those who own the stick mag conversions) even harder.

My recoil spring (fits inside the firing pin and over the recoil spring guide) was a bit out of shape. Over the years, the spring that came with the gun has become slightly kinked which tended to force the recoil spring guide out of true, and interfere with the normal back and forth function of the bolt. I had always wondered if any other SMG spring might work... and I found one that does! The recoil spring of the TSMG is almost a perfect fit. You may have to trim one or two coils but the interior and exterior diameter is excellent. One problem solved. I picked up 4 OEM TSMG springs today, in the original govt wrapper for $35.

Jason at IO reverse engineered an OEM bolt I had, and modified the magazine feed lips to accept STEN mags (you have to trim the mag sleeve width). He has them for sale.

There is a guy on GB who still has a few OEM firing pins, they are original OEM M.P.18,I pins and they fit and work excellent. $125 each, a bargain as once they are gone, there will be no more.

At one time either Apex or one of the other gun parts dealers had a supply of what they called Lanchester/MP28 extractors. They fit and work well in the replacement bolt from IO.

20 round OEM stick mags? Forget it. I have 10 (lucky find last year) and StrangerRanger has 10 also if my memory serves correct. 

[StrangeRanger]

Not guilty. I have no parts of any sort for an MP18,1

[Blanksguy]

Try Rick-Keller over at Great-War-Militaria in Chambersburg, PA. Rick use to do a lot of WWI Reenacting.....and sold original and reproduction items for some weapons.

If I recall....doesn't some of the British-Lancaster bolt/items fit and/or act as a replacement for some MP18.1 items (?).

[Rekraps]

18 hours ago, Blanksguy said:

Try Rick-Keller over at Great-War-Militaria in Chambersburg, PA. Rick use to do a lot of WWI Reenacting.....and sold original and reproduction items for some weapons.

If I recall....doesn't some of the British-Lancaster bolt/items fit and/or act as a replacement for some MP18.1 items (?).

Now that you ask, I was in the basement over the weekend and as an owner of both a M.P.18,I and a Lanchester I got to looking at the bolts and they are dimensionally identical. Hmmmmm so I then pulled out my spare Lanchester bolt, firing pin and mainspring and they fit perfectly into the M.P.18,I. I'm going to test fire it this weekend, but this may be a perfect solution for shooting the gun.

[StrangeRanger]

.....except for the minor fact that Lanchester bolts are not substantially more common then MP18,1 bolts.

[Rekraps]

2 hours ago, StrangeRanger said:

.....except for the minor fact that Lanchester bolts are not substantially more common then MP18,1 bolts.

I had no idea! Well, IO sells those also! I reinstalled it tonight and it dry fires perfect. The issue with the M.P.18,I is that the OEM mainspring is very small diameter and will kink easily leading to binding etc., whereas the MP28, Lanchester, STEN and most all other SMGs use a main spring about the same diameter as the receiver. 

We'll see how it works. 

[Rekraps]

Well, a successful day at the range. The Lanchester bolt/firing pin and main spring fit perfectly into the M.P.18,I and the gun shot wonderfully. I used both original Bergmann 20 round stick mags and my sleeve modified STEN mags, everything fed without a hiccup. 

So, I'm putting my OEM M.P.18,I bolt/firing pin and recoil springs into storage (they SN match the gun) and using the Lanchester parts when I go to the range. 

 

[StrangeRanger]

...and when they break?????

Lanchester extractors and firing pins are both problematic

[APEXgunparts]

APEX Gun Parts has some of your LANCHESTER parts needs covered:

LANCHESTER parts

I thought we had the extractors too, but I don't see them.

Richard

[StrangeRanger]

I bought (2) firing pins, (3) springs and and an ejector from Apex, I got a trigger bar and (2) sears from a board member here and (4) extractors from a member on Sturm.  Then I got lucky and scored a complete FCG off GB.  I'm OK on Lanchester spares for the time being but I'd pick up another couple of extractors if I found them

I'm not too compulsive about spares am I? 🤔

 

Edited January 4 by StrangeRanger

[Rekraps]

5 hours ago, StrangeRanger said:

...and when they break?????

Lanchester extractors and firing pins are both problematic

I have 8 extra Lanchester extractors and two extra firing pins. IO sells replacement pins for just a paltry $75 each. 

Seriously, after shooting the M.P.18,I today with the Lanchester bolt/firing pin/main spring I am hooked. SMG ran like a sewing machine. Using the OEM stuff, there was almost always w hiccup or two with the tiny diameter recoil spring. The Lanchester bolt work perfect with original Bergmann 20 round stick mags AND STEN mags (collars narrowed). 

[Rekraps]

On 1/4/2024 at 5:28 PM, StrangeRanger said:

I bought (2) firing pins, (3) springs and and an ejector from Apex, I got a trigger bar and (2) sears from a board member here and (4) extractors from a member on Sturm.  Then I got lucky and scored a complete FCG off GB.  I'm OK on Lanchester spares for the time being but I'd pick up another couple of extractors if I found them

I'm not too compulsive about spares am I? 🤔

 

I'm like you. When I acquire a gun, the next few months are finding spare parts, manuals etc. Expensive but we always have stuff to make our guns run!

[Rekraps]

So the OEM TSMG main springs arrived today. Exactly as described, four springs in original wrapper with cosmoline. I cleaned them and to my surprise, they are exact fits for the M.P.18,I. Same coil #, lenth, thickness. Amazing. Today, i'm going to see if they work on the M3 also.... kinda look like they might!

[Rekraps]

7 hours ago, Rekraps said:

So the OEM TSMG main springs arrived today. Exactly as described, four springs in original wrapper with cosmoline. I cleaned them and to my surprise, they are exact fits for the M.P.18,I. Same coil #, lenth, thickness. Amazing. Today, i'm going to see if they work on the M3 also.... kinda look like they might!

And they do work on the M3! 

Now, after fitting them in the M.P.18,I I will have to trim some coils off to prevent kinking of the spring, but otherwise they fit nicely. 

[Zenithnadir]

Did you have to modify these TSMG main springs to work in a grease gun and is there a change to the cyclic rate?

On 1/6/2024 at 5:48 PM, Rekraps said:

And they do work on the M3! 

Now, after fitting them in the M.P.18,I I will have to trim some coils off to prevent kinking of the spring, but otherwise they fit nicely. 

 

[Rekraps]

7 hours ago, Zenithnadir said:

Did you have to modify these TSMG main springs to work in a grease gun and is there a change to the cyclic rate?

 

So they are slightly shorter than the OEM M3 springs and I have not shot with them yet. Maybe this weekend. I would expect the rate of fire to be a tad slower with the shorter springs. I assembled the bolt/guide/spring assembly and it works fine, and the spring tension feels good.