MP18,I - Best ammo 124gr. Or 115gr.

[hatrick]

Is either 124 gr. Or 115 gr. 9mm ammo better for shooting in an MP18,I? Just want to make sure to minimize any damage risks. If I’m not mistaken, 124 gr. was the original load back in WWI.

Thanks

[StrangeRanger]

I think you're right about 124 being the original.

To reduce wear and tear on an irreplaceable relic, stick to US SAAMI spec ammo. The European stuff is way hotter, essentially equal to SAAMI 9+P.

Have you found a source for NEW recoil springs? I'm kind of in the same situation with a Lanchester (MP28/II clone) that I'm in the process of acquiring. My handloads are way below Euro spec ammo and a skosh lighter than SAAMI but I'd really like to find a source for newly manufactured springs.

[hatrick]

Do you need the early small diameter springs or the later larger diameter springs like that used on the MP28?

[StrangeRanger]

For the MP18/I or the Lanchester?

Didn't know there were 2 diameters for Lanchesters. Mine are 1.15" OD x about 8-5/8" lg

[hatrick]

The MP18 had both sizes. The Lanchester uses the larger one. Sadly I don’t know if any source for the larger diameter springs. Maybe Sarco.

[StrangeRanger]

Used ones are all over the net but used 50+ year old springs may or may not be up to spec

[1gewehr]

NATO-spec ammo is nearly identical to the original German P08-spec 9mm. A 124gr bullet at about 36,500psi. The British and Swedish ammo is 116gr at the same pressure.

'Normal' US-spec ammo is 115gr at 35,000psi

 

FYI, '+P' is 38,500psi.

 

IIRC, Lanchester recoil springs are identical to STEn recoil springs. Can someone else verify that?

[johnsonlmg41]

After the MP18, they are all big spring including the MP28.

I've not seen any MP18's with big springs, but it probably wouldn't be a problem to modifiy it.

[hatrick]

A friend had a case of Fiocchi 115gr. Training Dynamics 9mm which I hope will be safe to use. It’s CIP certified versus SAAMI but it seems to be around normal spec and not crazy hot like +P 9mm.

Thanks for all the help and advise. Definitely don’t want to damage the gun.

 

Edited May 19, 2021 by hatrick

[Rekraps]

Hello, just found this forum. I own a beautiful MP 18.1, all matching (except recoil spring guide cap) and have experience with this gun. Mine is a 1920 police model, with factory modified magazine well for the 20 round magazine.

 

Replacement OEM recoil springs and firing pins (can you believe it!) are on Gunbroker. The seller found a number of each in his fathers stuff and it's for sale at a very reasonable price. I bought two of each and they function well. I also found original MP 18.1 extractors on SARCO and bought as many as I could.

 

Now, if you don't want to ruin or take a chance with your OEM bolt, I sent mine to Jason at Indianapolis Ordnance and he manufactured a replacement for me. Since the stick magazines are all but impossible to find, I also sent him the OEM magazine well specs and he modified four STEN mags to fit the well, and (THIS IS IMPORTANT), modified the replacement bolt magazine interface to work with the STEN mags. They use a slightly wider bolt well.

 

I am happy to report that the OEM gun shoots perfect with the original parts, and the replacement bolt with modified STEN mags also shoots perfect.

 

Both work best with 124 grain 9 MM.

 

One other hint. I installed a thin rubber buffer in the recoil spring cap to keep the impact of the firing pin against the rear to a minimum. Works great, but doing so mean you can use the manual safety position of the charging handle, so be careful.

 

If anyone has questions about this gun, let me know! Or text me at 404.290.2911

 

Scott Parker

Atlanta, GA

[hatrick]

Scott,

 

Good to hear you're having good luck with your MP18,I. It sounds like you've done a lot to ensure no issues and like myself don't want to damage a nice original piece. I also bought a few of those springs and spare firing pins from the GB seller but I haven't tried them yet. Great to know that the springs especially are good to go since it is always good knowing you have fresh springs... especially in a 100 year old gun.

 

Are the extractors you got from Sarco the Lanchester extractors? I've head they are the same and fully compatible with the MP18,I.

 

If you don't mind me asking, how much did Indianapolis Ordnance charge you to make a spare bolt? I may have one done as well. Maybe they can do a spare barrel as well.

 

I was thinking the same thing about a buffer so it's great to hear you've already done that. What material did you use?

 

After I shoot the case of 115 gr. Fiocchi I'm going to try to find some 124 gr. Haven't tried the 115 pg. yet but I'm sure it will be fine... especially if I can add a buffer for insurance.

 

Thanks for the help!!

 

Best regards,

Eric

[Rekraps]

Scott,

 

Good to hear you're having good luck with your MP18,I. It sounds like you've done a lot to ensure no issues and like myself don't want to damage a nice original piece. I also bought a few of those springs and spare firing pins from the GB seller but I haven't tried them yet. Great to know that the springs especially are good to go since it is always good knowing you have fresh springs... especially in a 100 year old gun.

 

Are the extractors you got from Sarco the Lanchester extractors? I've head they are the same and fully compatible with the MP18,I.

 

If you don't mind me asking, how much did Indianapolis Ordnance charge you to make a spare bolt? I may have one done as well. Maybe they can do a spare barrel as well.

 

I was thinking the same thing about a buffer so it's great to hear you've already done that. What material did you use?

 

After I shoot the case of 115 gr. Fiocchi I'm going to try to find some 124 gr. Haven't tried the 115 pg. yet but I'm sure it will be fine... especially if I can add a buffer for insurance.

 

Thanks for the help!!

 

Best regards,

Eric

 

Eric, thanks for the note. The Lanchester extractors are just a smidgen off from the MP 18 ones (so yes, this is what I bought. I have a Lanchester also), but they do have the unique Neanderthal Jaw type end that closely matches the MP 18. The insertion end is round to match the MP 18 bolt, but you may have to use a very light sand to facilitate an easier fit. the most important thing is that the extractor face (the part that rests against the bolt face) is flush. If not, then when the bolt goes into battery it will press against the extractor and push the long neck part up just enough to impart friction against the receiver and possibly cause the gun not to cycle. This is easily remedied by a quick sanding. Even my original extractor has a matching SN, so no way I want to damage it.

 

Jason and IO made me a few custom extractors (he is quite good). The bolt was a total custom job, and he has them on his website. Under "other smg" he has it listed for $350! What a deal, I did pay more since it was a first run production/test. He can also modify the STEN mags if you have a side feed version.

 

As for the buffer, you are going to laugh. I went to HD an bought round rubber spacers with a diameter about the same as the recoil guide, then cut out a tiny notch for the receiver release pin and it fit perfect. Maybe $2.

 

Final piece of learned knowledge. The springs may in fact need to be trimmed enough to fit well. You do not want any kinking of the spring when the bolt is to the rear, or the guide rod may not sit parallel to the firing pin and again, result in friction against the receiver.

 

Scott

[Rekraps]

Hey, any of your guys have extra/spare 20 round stick magazines for the MP 18.1? I cant find them anywhere.

[junglewalk]

....Is it not true that the MP-38/40 magazine will fit the 20 rd magazine well, because the MP-28 magazine became the later MP mags, except 32 rounders ?....... The MP-18 SMGs the Weimar Military possessed when the MP-28 came out, had their Mag wells replaced to accept the 20 rd MP-28 mags, which became the magazines for the MP-38/40, except expanded to 32 rounds.

[Rekraps]

Correct. Only Original MP18.1 stick mags will fit. Any others such as STEN, MP28 etc require some degree of machining. The upper magazine sleeve is too wide by about 2mm.

I had a machinist do the work. Even then, you may have feeding issues. I took care of that by having a replacement bolt made from scratch specific to the modified STEN mags.

[Rekraps]

So the MP 18.1 mags may work in other guns, but not the other way around.

[junglewalk]

So, a MP-38/40 magazine will fit the MP-18, with slight modification?....

 

I have a MP-18-1 SMG waiting transfer from Penn, to my Class III dealer here in Ky..........Gosh it has been almost 4 months, he did it by postal method, the old way.....I always thought dealer to dealer want fast?

[Rekraps]

Yes. STEN fit the best as they most closely approximate the MP 18 units. I would strongly suggest that you BOGO to Indianapolis ordnance where Jason manufactured a MP 18 bolt that has the magazine feed raid matched to STEN mags. He can then modify your STEN mags to git perfect in the Mp 18 mag well.

 

He did this for me and has the specs.

[Rekraps]

* not BOGO. Go to...

[junglewalk]

MP-34 magazines?..>> Right now, BRP has MP-34 mags, which they list as also fitting the MP-28.......Has anyone tried to see if the MP-34/28 mags work in a MP-18, which has the mag-well for the straight stick mag.

 

MP28 & MP34 Magazines (brpguns.com)

[johnsonlmg41]

MP34 mags do not fit either the MP18 nor the 28 even remotely close. MP18 mags generally may fit MP28's, but not the other way around. HTH

[Rekraps]

Since I own a Mp 18.1 and spent quite a bit of time on the magazine issue, I can say with certainty that the only magazines that will function (fit and feed) in the stick version of the gun are OEM mags. All others to include MP28, 35, Sten and Lanchester will have to have the magazine e collar modified. In addition, the MP 18.1 bolt, on the feed side, is machined so it does not match the MP 28/35, Sten and Lanchester mag ears. So, without modifying g that also, reliable function is doubtful.

[Rekraps]

My solution to the problem, since OEM MP 18.1 mags are impossible to find, is that I had a replacement bolt made from scratch that replicates the OEM bolt exactly, but is machined to accept the MP 28/35, Sten and Lanchester mags. Then I had the magazine collars modified to fit the MP 18.1,magazine well.

Works perfect

[johnsonlmg41]

Actually the MP28 and MP18 bolts are the same where feed entry is concerned. Are you sure you actually have a German MP18 bolt in your gun? There is no need at all for a modified bolt. I have sten mags with the sides trimmed down that work perfectly in an MP18 with no other mods necessary. Feed angle is the same and while the feed lips are slightly shorter they perform fine. The staggered follower is likely much better than original MP18 magazine flat followers. Sten mags (good ones) fit MP28's with no mods at all and the loaders work on the MP18 and MP28. All in all I opt to use sten mags/ loaders, armorer's magazine gauge, etc. on these guns because the German mags, loaders, tools, are rather scarce.

 

Just picked up another MP18 mag a couple weeks ago with a 3 cell pouch. The stuff is out there. There are currently MP28 magazines for sale, but they are not cheap and fit is not quite as good as a trimmed down Sten mag would be.

[hatrick]

Just want make sure everything looks good before test firing.

Thanks