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

[Kommander]

Current Leet D00d thinking is that there is no such thing to much lubrication for an AR.

[Netpackrat]

Took the Suomi to the range Saturday morning. I still got some malfs, but I kept drenching the bolt in lube which seemed to help, and I did get through a few full 36 round mags without any malfunctions. I think I am on the right track and will be looking at where else I can smooth it up to reduce drag. I also think it might be one of those guns that just needs to be lubed with grease in order to work right. I am thinking I may go ahead and SBR it anyway since no matter what, it's never going to be a "serious" gun for me; it will always be just a fun gun.

Next thing I am going to do is see if there is any smoothing I can do where the bolt rides over the hammer, that seems to be causing a lot of drag. And also see if any polishing can reasonably be done inside the receiver.

[HTRN]

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.

When I finally move, I want a acorn table..

[Netpackrat]

A couple weeks ago I disassembled the M31 again... I found that with the trigger group removed, the bolt runs silky smooth in the receiver, so there isn't really anything more to be gained there. As I mentioned earlier in the thread, a lot of the drag is the bolt over the top of the hammer, which is a specific issue with the semi-auto conversion... The originals wouldn't have that source of drag. I reprofiled the end of the hammer slightly to give the bolt an easier time riding over it, and polished the top as I did with the bolt. Greased up the bolt and assembled; it works much more smoothly now.

Finally took it to the range tonight, and while I feel I made a step in the right direction, I still averaged about one FTF per magazine, always on a nearly full magazine (when drag from spring pressure is highest. I am really beginning to believe that the solution to the problem is just going to be hotter ammo. Subgun 9mm ammo (and Euro-spec) is known for being hotter than US SAAMI spec ammo anyway, so what I really need to do is get some of that for testing. Seems to be impossible here in AK.

There's lots of +P ammo around, but not sure how well this will do with hollowpoints. I don't really want to add that as an additional variable, so it looks like where I am, is where I will be on this until such time as I can set up my reloading gear again, and work up some +P equivalent ball ammo.

[Netpackrat]

I am ready to declare victory here. From browsing some of the testing Tam wrote up on her blog, I learned that PRVI 124gr FMJ chronos significantly hotter than the US made 9mm ball I have been using. I finally found some at Cabelas, and I now have 150 rounds of it through the Suomi so far, with ZERO malfunctions. Maybe the polishing I did made a difference, and maybe it didn't, but as I suspected the one thing that this gun needed to run better was hotter ammo.

Shot it at 100 yards today because the $%#*^& gun golfers had half the range closed off in order to set up for their matches tomorrow. Not sure why the assholes can't show up early in the morning before the matches and set up then. It's bad enough that they're allowed to monopolize portions of the range on the weekend, but they also have to screw with everyone trying to shoot the night before, too. Anyway, I managed to hit the steel quite a few times, which was made more interesting by the fact that the front sight was wider than my plate target when viewed at that distance. Plus it shoots to the right, which isn't as apparent at pistol range.

Oh yeah... Last month I filed a Form 1 on this to make it into an SBR. Once approved, I will obtain the original length barrel and shroud, and then I am going to cut the faux brake off the existing one, and shorten it by sectioning, and have the barrel chopped and threaded so I can run my pistol can on it.

[Combat Controller]

Sweet!

Yeah, sub guns love hot ammo....

[Cobar]

I can imagine subguns that work off recoil need enough recoil. Glad you got things going your way.

[Netpackrat]

[Darrell]

Alrighty then!

Surely a range report will follow.

Alec/Alex, late of the Firearm Blog, included the Suomi as one of the five guns he most regretted buying. I've read other reports of them being problematic. It'd be great if you get it running well.

[Netpackrat]

Alrighty then!

Surely a range report will follow.

Alec/Alex, late of the Firearm Blog, included the Suomi as one of the five guns he most regretted buying. I've read other reports of them being problematic. It'd be great if you get it running well.

Well, those assholes run the blog that I most regret ever commenting on, since they took it as license to send me spam on a daily basis.

The Suomi seems to run fine in its present state so long as I feed it PRVI 124 grain FMJ. I may have to go through portions of the re-working process again with the short barrel once I get it here.