Hakkaa päälle! (Suomi M31 review) Updated- Range Report

[blackeagle603]

Presumably that's his welding table. Thus so many vise grips.

[Netpackrat]

Goodness, NPR - you do have a lot of Vise-Grips!

Those are mostly welding clamps, and that's nowhere near enough. Trust me. For years, when people would ask what to get me for Christmas, I would tell them when in doubt, just buy clamps. Once, my wife's aunt frowned at this and made some sarcastic comment about how that was a great way to show they cared, and my father in law (professional shipwright) replied, "for that, you give bar clamps."

As a follow up, I contacted TNW today, and they are sending me a locking screw and a handful of barrel shroud shims. The guy I spoke with requested I email the picture of the kinked shells and a description of what it is doing, so they can suggest a course of action on that.

[Denis]

Those are mostly welding clamps, and that's nowhere near enough. Trust me.

I forget that you do grown-up welding. My 'welding table' is a rather scorched bit of chipboard that I throw on the ground as needed. When it goes on fire, I stamp it out. I don't have any clamps, other than a pile of small firebricks.

[Netpackrat]

Okay, so the smooshed case issue has just taken a turn for the weird, but I am pretty certain I have diagnosed the cause of the problem.

The first thing I tried to do, was just observe rounds feeding into the chamber from a mag at different rates of speed. This didn't really tell me anything other than that the design of the Suomi doesn't really lend itself to making such observations. Next, I started marking cases with a sharpie marker to see if I could find where they might be catching, and what orientation the smooshing was occurring in. I didn't really find any marks from anything catching or dragging, but I did determine that the smooshing was on the bottom of the cases as they fed into the chamber.

Not really knowing what else to do, I next polished the chamber throat slightly with some emery cloth wrapped around a dowel. No power tools involved, so it was just a very light smoothing. I did not expect this to make much difference, and it did not.

The next thing I did was take the bolt out of the rifle, and tested how easily a round slipped under the extractor, thinking maybe the extractor was too stiff, and jamming the round into the chamber too much before snapping over. There was nothing wrong with the extractor, but it turned out I was getting warmer.

Reassembled, and while holding the bolt back, I dropped a round in the chamber. Let fly with the bolt, and then cycled it again to eject the case. This resulted in the worst mooshed case of the bunch so far, and instead of being just on one side, it was a concentric band, clear around the case just behind the heel of the bullet. Hunh.... The only thing I could think of that would cause that is insufficient headspace.

The first thing I checked was to see if, and how much the bolt was contacting the breech face of the barrel, thinking that maybe something was mis-machined, and allowing the bolt to travel ahead too far. I marked the breech face with the sharpie, reassembled, and cycled the bolt a bunch. It's not making contact in any significant way Finally, I removed the shroud and barrel again, placed a round in the chamber, and slid the barrel into the receiver, such that the extractor snapped over the rim of the case. Then pushing the barrel so that it bottomed against the receiver, the bolt would visibly move backwards. I tried this with two different brands of 9mm ball ammunition (Blazer Brass and PMC), and got the same result, so it isn't out of spec ammo or anything like that.

So, at least now I have some information to give TNW when I contact them about it. I'm guessing that since I don't think that any machining was done to the breech end of the barrel, and the part of the receiver where it locks in is part of an original receiver (that's welded to new metal to make the new semi receiver), that this is due either to the chamber not being reamed properly by the Finns originally (see the comments above about them not being concerned about recovering brass), or just from putting together a rifle from a mix of parts, and then not doing a basic check of the headspace before shipping, which doesn't say much for the manufacturer, but we already knew they have some QC issues.

[EDIT: I ended up not contacting TNW again, figured there was no point since we are going to fix it locally. I may send them the link to this thread at some point.]

[toad]

From what I've read the Finns would engage at ranges much farther than your standard sub-machine gun were capable of. It threw tigh enough patterns that they could kill out to 200 meters IIRC. You would think with the longer barrel it would be nasty in just semi-auto?

[Netpackrat]

From what I've read the Finns would engage at ranges much farther than your standard sub-machine gun were capable of. It threw tigh enough patterns that they could kill out to 200 meters IIRC. You would think with the longer barrel it would be nasty in just semi-auto?

The barrel extension on this is just a piece of tubing welded onto the original length barrel, so it doesn't really add anything other than legality. The original barrel IS longer than those of many other subguns; is that what you were referring to? I do know that I would have a hard time hitting with this at 200 yards, between the crummy trigger, sights, and a stock that feels like it was made for a 5 foot, 6 inch Finn.

[Netpackrat]

Heard back from the gunsmith/FFL who received this for me and he does indeed have a 9mm chamber reamer, so I should be able to clear this up without having to send it off. He also mentioned the open bolt nature of the original weapon, with a fixed firing pin that fired the round before the bolt fully closed anyway. That doesn't in any way excuse TNW for not performing a basic headspace check before shipping their rifles, however.

At this point, I'd have to say that although the price is right, you should only buy one of these if you are either prepared to do some work on it, or instead ship it back and forth to the manufacturer until it is right. I'm still pretty sure that it will be worth the hassle in the end, but there's no excuse for the poor QC. The basic workmanship of the things they actually did is quite good, but the lack of attention to detail is aggravating. Even though the issues are pretty minor for me, I wouldn't blame anybody for sending it back.

[Windy Wilson]

Gee, if that were available in semi-auto only, with 10 round mags, it doesn' t seem to have but one evil feature, so it could conceivably be legal in California (sigh).

It is semi-auto only. And at the above link, they say they can supply magazines modified to only hold 10 rounds.

Ooooooh! Beauty. That's going on the short list, after the Ruger 10/22, the Krag, the M1917, the M1A and the neutered Cali AR.

[Rusty Ray]

Hmm, spider senses tingling here. Do the company make this rifle in any other caliber, say 9x18 or .380 ACP, perchance? Maybe for export, or film use with blanks etc etc. Could they have sent you a weapon chambered for the wrong 9mm, and if so, will reeming it out make it unsafe due to the pressure differences between the 9mms?

Cheers- Rusty

[Netpackrat]

Hmm, spider senses tingling here. Do the company make this rifle in any other caliber, say 9x18 or .380 ACP, perchance? Maybe for export, or film use with blanks etc etc. Could they have sent you a weapon chambered for the wrong 9mm, and if so, will reeming it out make it unsafe due to the pressure differences between the 9mms?

As far as I know all Suomis have always been 9mm Luger. The one I bought has an original military barrel that has had an extension welded to the muzzle end to avoid NFA entanglements, so it is certainly a 9mm barrel. It may even have been reamed properly for the subgun it was originally installed on, but these semi versions are mix-masters. It definitely isn't reamed properly for this combination of receiver, bolt, and barrel.