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Tanaka Works M870 shotgun


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The Intro

A while back, Tanaka released a new, more modern shotgun to compliment their m1897 trench gun. The first in the M870 range is a fixed stock , 14” police model. Here are some specs that I err… borrowed from somewhere: weight = 2 550g, length = 875.0 mm, capacity = 4+1, power = 350fps. I’m betting that the power Redwolf reports is based on a single bullet using green gas/propane., performance is significantly reduced when using 3 bbs. Tanaka shotguns, for those that do not know, utilize a gas in the shell system which differ from other gas shotguns and are more like tiny grenade shells.

 

The presentation

The gun came in a rather plain box, simple brown cardboard box with black graphics as shown in the picture. The cardboard is thick, like the boxes that house large LCD TVs but instead of a gun encased in polystyrene there were smaller pieces all around the inside of the box to keep the gun from shaking. I suppose it works, as the gun seems to have come to me undamaged. Within the box there also contained a short manual, two shotgun shells and a gas filling tool bundle together in a smaller box, and a poorly packaged bag of 0.2g bbs.

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The details

The gun is based on a 14” full stock version of the M870. It can house 4+1 shells but since I only have the two that are included, I can’t comment on the fitting of the shells (such as how tight the last round goes in the mag tube). There is only a front bead sight so this gun is intended for quick point and shoot, which I have not fully mastered yet but rest assured it is easy to aim. I’m just a bit thick. Trades are beautifully engraved with “ 12GA. FOR 2 ¾ OR SHORTER SHELLS” on the left side of the barrel and on the right, “TANAKA WORKS ASGK MADE IN JAPAN”. Similarly engraved on the left side of the receiver is “Model 870 POLICE MAGNUM” and a final “Tanaka Works” is molded into the end of the rubber butt stock. There is a wavy serration on top of the receiver for which I do not know why it exist (on the real steel one) but it is a nice accent in the gun.

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The M870 is a weighty beast and holding it, the user is immediately aware of the quality of this product. Pumping it produces a solid ker-clunk, and pulling the trigger brings the hammer down onto the firing pin with a loud clack. The trigger pull seems to be close to a KSC M11, so it is a bit heavy but short and the safety button securely clicks in place. The plastics on the gun are of a very high quality; they feel very solid and although there are faint seem lines they have been crucially sanded down to provide a smooth, comfortable area to hold. To best illustrate the quality, I point to the fore-grip. Instead of the fore-grip wrapping around the magazine tube, there is a channel in the middle (see picture) so it is more of a “U” shape. I squeezed as hard as I could and yet there was no flex, that’s amazing and the piece is also quite heavy. I was expecting something like an abs Glock barrel in proportion; light plastic pieces contrasted by heavy frame + internals, but the Tanaka M870 is not like that, every bit on the gun seems nice and robust. The checkering on the stock is nice and the whole thing is comfortable to hold, shoulder and operate.

Edited by user7
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The operation

Gassing up the shell requires the included special tool that prevents the valve from opening while filling. As seen in the pictures, the gas fill valve is located in the centre of the back of the shell and around it is the bit that the firing pin strikes to release the gas. I've said before that the shells are like little grenade shells, well they're not exactly like that. The gun does not hold the valve button open, rather like any GBB or NBB it strikes it briefly. I have found that the shells hold enough gas for at least six shots and frankly after the sixth time I got tired of reloading and waiting for it to warm up a bit. Like all gas mags, the shell has to be filled vertically and the BBs are loaded into the front simply by pushing them into the shell (3 BBs max). As you can imagine, loading the gun and firing is as you know in the movies and on TV; shells are loaded underneath and pump to chamber a round/extract spent round. The shells

fly out vigorously and it is very fun just to cycle the action and watch the shot shells fly out. One thing to note is that after pumping once, the gun locks the action and is unable to pump again without either squeezing the trigger or depressing the action bar lock. So to eject a live cartridge without firing it, one can press that lever and pump the action to get that shell out.

 

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(action bar lock disengaged)

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(action bar lock engaged)

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Edited by user7
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The guts

I’m sure everyone has heard that the Tanaka shotgun is close enough to the real steal version in terms of dimensions that one could fit aftermarket furniture and other real M870 accessories. However, comparing the internals of the Tanaka with the manual of the Remington M870, and many of the parts look the same as well. I am not saying that real steal internals can fit or that you could convert it to fire real ammunition, but it is nice to see this attention to detail. Because of a mysterious problem that prevented me from fully cycling my gun, I decided to take my gun apart in order to investigate this issue. ArniesAirsoft board member Crenna pointed out [link to post] that it seems the little bit that secures the barrel to the gun can loosen and jam the fore-end tube assembly, preventing it from going fully back (see picture for clarification).

Taking it apart does not have to be in the order I did it but there are some stuff that has to be removed before getting to another part; the mag tube and barrel guide ring for example.

 

 

First, I took off the trigger assembly by knocking out two retaining pins from the receiver with a hammer and small screwdriver. The trigger assembly pivots down and out with a little effort, it may be a bit tight so try some light jiggling to coerce it out of the receiver. What surprises me is how compact the part is considering it does the majority of the mechanical operations in the gun, including trigger/hammer release, safety mechanism, action locking, and part of the loading action.

Next I unscrewed the magazine cap and removed mag spring + follower. I probably should have mention this before, but make sure your gun is unloaded before attempting disassembly else the mag spring may fly out.

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Edited by user7
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Once that is done, unscrew the mag tube, twisting counter clock-wise and pulling it out from the front. This gives access to the barrel guide ring which is fixed to the barrel via a Philips screw. Incidentally the screw also holds the inner barrel assembly in place, so once that is out the inner barrel slides out the front. As shown in the pictures, there is a fixed hop up, most likely tuned for 0.2g BBs as that is what is recommended in the manual. I unfortuantely forgot to measure the inner barrel but I would estimate it to be around about 24cm in length.

 

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(flashlight shining at one end to highlight fixed hop-up)

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The fore-grip is removed by twisting the fore-end tube nut; I used a used a flat head screwdriver and sort of “stirred” it out, after which the fore-grip slides out. I didn’t remove the fore-end tube assembly because it was not necessary and it seemed difficult to remove; needing to pivot it up slightly and jimmying both of the action bars to disconnect it from the breech bolt.

 

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As said before, the outer barrel is held by a small metal pin underneath, near the receiver. The problem is after using the gun several times, the vibrations shake the pin loose, drops down slightly and jams the fore-end tube assembly (see picture). Removing it allows the barrel to be removed and exposes one of the few plastic pieces of the gun, the chamber. I should say that the outer barrel, chamber and breach bolt (which to remove, would require taking the chamber out) are not meant to be disassembled as the exploded diagram in the manual does not go into that detail.

 

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(shot from underneath gun, where the trigger assembly would be)

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(half pump (?), notice the ejector rod and spring. rod hits end of receiver and pushes shell out as bolt continues to retract.)

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(back of breach bolt detailing firing pin)

 

 

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(face of bolt detailing firing pin, note the extractor rod that pushes the shell out)

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(the pin that jams the pump action)

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(the damage)

 

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(barrel removed, plastic chamber that shell goes into)

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(the solution I used, gluing the pin to the barrel)

 

The stock can be removed quite straightforwardly by unscrewing two Phillips screws in the rubber shoulder pad and then unscrewing a long screw inside the stock. The reason that there are no pictures of this is because I had forgotten to take them the first time I took it apart and I did not feel like struggling to do it again. It may sound simple to remove the stock but the reality is that the holes in the shoulder pad are pretty tight for the screw heads and as the holes are quite small in diameter, I had to use a small screwdriver which did not afford myself much grip. The long screw is not hard to remove but screwing it back on was tricky as the nut was at one end of the stock and the screw sliding into the other. Did I mention that normal human hands will not be able to fit inside and precisely guide the screw back in? So I had to drop it while holding the position of the holes as vertical as possible then prod the end with a screwdriver until the Luck Gods gave in and it found the nut on the receiver. It was a bit like trying to thread a stick through a marginally bigger hole with a single fingertip pushing the rear to guide it in. Of course this may mean that I am not familiar at taking the stock off and I just need practice, but I’m not eager to take it off again.

 

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Edited by user7
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The performance

On duster the power is fairly weak, but that is to be expected with the gas pushing 3 BBs through one barrel. Although I do not have access to a crono, I think under 200fps on duster is believable. The range I’m using is 25ft / 7.6M long with an ambient temperature of about 15 C/ 59 F. The first couple of shots on duster seem to show a rather tight grouping; the first shot produced two holes 2cm apart and the second shot produced a single hole. However, it was only after all the shots were fired that I noticed some flyers that did not catch my eye. These where located near the top and bottom of the targets and were most likely from shot 1, 2, and 3 as the number of shots equalled the amount of BBs fired. I am unable to discern which of the holes were made at which shot but the general conclusion thus far is that the spread is up 13cm (measured from the 1st shot hole to the closes unidentified hole. The results using green gas (or propane as I am using) are better and I assume that is what most people will want to use with this gun. The power is similar to what you should expect on typical 134a GBB guns: low-mid 200fps. I’m basing my judgment on my experience with other GBB guns and how different propellants react with my targets and backstop. BB spread remains about the same with green gas: 5.8cm and 10cm on my 3rd and 4th shot respectively. My second target paper showed similar results: 1st shot - duster - 9.5cm, 2nd shot – green – 11cm, 3rd shot – green – 4.2cm. Note that some shots did not register on the target as they may have hit off to the side of the paper. I do not know why the second round of using duster provided such a large spread; maybe that is how variable the shot pattern can be. I can’t say what the max effective range is or how skirmish worthy it is, I’ll let the reader decide on that. I should also say that you could load the shells with 2 or even a single BB to increase fps but the spread is of course, smaller. Accuracy of under loaded shells is about the same as 3 BBs.

 

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(distance from target)

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(first paper target, how convenient for this to appear in the paper on that day)

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(second paper target)

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The conclusion

Is this the best shotgun of modern-day airsoft? I would say yes but this being my only shotgun experience, I’m probably not qualified to say that. Many would argue that the ejecting shells, gas-powered, expensive Tanaka is not suited for skirmishes but I would disagree. It feels robust enough to be dragged through the mud and despite being based on a very common firearm, it’s definitely a special piece in airsoft.

Edited by user7
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  • 2 weeks later...

Nice review, but we do need to see a manufacturer come out with a shotgun of Tanaka's realism, but without the shells being ejected from the gun. Another solution I'm fairly sure we won't see is the shells being somehow disposable and very cheap to replace.

 

Sure, the shells are reusable, but you might soon grow tired of hunting through the grass to pick up the ones you just shot in a skirmish and still losing half of them in the process. A indoor CQB environment may only be slightly better suited to this gun, as the shells are more easierly recovered, but the risk of someone stepping on them and causing damage is almost as great as losing them outside.

 

Velocity is yet another problem on most shotguns firing more than one BB at a time. AEG's are commonly shooting at least 130-150 FPS faster without an upgrade, and also on full automatic, so the firepower advantage that you have is zeroed right out in a skirmish situation. Again, even room clearing in a short distance CQB environment leaves you at a disadvantage.

 

A great collector's and plinking gun? Yes. Cool as hell from that angle. A skirmishable weapon? As you said before, it's up to the owner. More trouble and money to most than it's worth to skirmish with, it's a reason why people bring them to a game, but never play with them in my experience.

 

Until a company comes out with a shotgun that has all three key issues: higher velocity, fires multiple shots without having to lose and then repurchase shells, they'll never get a bigger market share from the airsoft community.

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http://redwolfairsoft.com/redwolf/airsoft/...il?prodID=22550

Tanaka's new 18inch model.

Really good review! Its just, Im sorta skeptical, Tanaka's shotguns are known for having more power-were you able to see the BBs flying easily on green gas? Anything higher than 270-280 or so is usually harder to see. The Tanaka shotguns are usually slightly stronger than a stock AEGs. The MAruzen shotguns lack power because the gas comes out of the gun into the shell rather than from the shell into the BBs. Oh and Ranger Stubbs, have you ever heard of a brass catcher?

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Until a company comes out with a shotgun that has all three key issues: higher velocity, fires multiple shots without having to lose and then repurchase shells, they'll never get a bigger market share from the airsoft community.

 

These things do see a good deal of skirmish use over here - along with the old Maruzen shell jobs. I acquired an M1100 Shell ejector a while back and have been having a world of fun in CQB. a 15 dollar shell pouch sorted out the problems of scootage (and anyone using a SE shotty should have one of these) and a badolier+a gun mounted rack sorted out reloading.

 

I'm not sure that manufacturers a looking for a larger market place for shotties. People who want to skirmish shotties 'effectively' will go to the springers for power, reliability and upgrades round here (remember how the M1100 defender, though an excellent idea was shelved by Maruzen as not appealing to the shotty fraternity in J-land). People who want a certain style will go for the thwacky guns like this one.

 

However, each to his own as always.

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Bottom line of my post was, that while some people skirmish with shotguns of ANY type, most player interest is still firmly on the side of AEG's due to the mentioned issues in my post. It still remains the same: The companies marketing shotguns would have a bigger following if they could figure this out.

 

Brass catchers? Sure, fine for a range envirionment where you're shooting a benched rifle and saving the casings for reloading, or for slow stealth entries where silence is key above all. But for hard-core play on a skirmish field in a densely wooded area, I could definitely see a catcher being ripped off the side of the gun. In my substantial experience, branches and vines have a funny way of taking ammo pouches away from you, along with PEQ-4's, bayonets or knives, grenade pins (other guys found this out the hard way) and various other things that hang off your body or a gun. Sooner or later you go missing some of your gear, and a brass catcher is most exposed to movement issues. Not an entirely viable solution to the problem. Also messes with the realism of the gun's looks as well, not something most people want to do.

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Bottom line of my post was, that while some people skirmish with shotguns of ANY type, most player interest is still firmly on the side of AEG's due to the mentioned issues in my post. It still remains the same: The companies marketing shotguns would have a bigger following if they could figure this out.

 

And yet my point still stands. Tanaka and Maruzen (the only outfits for which I can speak in this regard) are happy with the sales figures they have for their shell shotties. You are right about them not seeing more uptake in the state they are, but these guys are not huge producers and feed the market goods which it (and I do mean the Japanese market here, for - right or wrong - this is the market the companies see as most important) seems to want in a way which suits it.

 

They may not be to everyone's taste, but they are to the taste of enough people to keep these companies ticking over (on both shell and mag shotties, or "pump action rifles" as the Maruzen/P&G varients are called) nicely.

 

And as for the shell pouches, your experience is different from my own. Looks be damed in some ways, for when our shotty people take out the shell loaders for a game, we will none of us be seen without them. You get some pretty thick underbrush in the woods and bamboo groves in the wilds of Japan and I've not lost a shell (or my holder) to any flora yet. Its not an ideal solution, but when I want a change from my M870 mag loader, or my defender or my AEGs, then its either the pouch or leave my shell spitter on the shelf.

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Oh, yeah, before I quit arguing with you here and screw up the post by going off topic, don't forget that both Tanaka and Maruzen also market gas/spring sniper rifles and pistols. Maruzen also has added income from a series of gas rifles and submachine guns. Both make much more money off the sniper rifle area in particular, with high prices being paid for any of both companies different models of guns.

 

Shotguns only share a small niche in their sales out of all the other things they sell, so you dont have TOO much of a point, other than you like shotguns for whatever reason you like them and that's up to you. I've only seen two shotguns being used at various skirmish fields I've been on in five years, one was a shell ejecting Maruzen 870 BV, the other a TM Benelli M3. The Maruzen was shot only on the target range and not on the field. The TM was used only for a short time before the owner switched to his AEG. This is at two skirmishes out of about 200 I've been to in five years. Not enough to convince me of the widespread merits of using a shotgun regularly on the field and the backround of Tanaka and Maruzen is fairly well known on what products they sell.

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  • 4 weeks later...

it's sooo long, its fantastic. two questions, how many shells does it hold now? and did you replace the old spring with a longer one? (though that would most likely be a yes).

 

 

fyi, i recently measured the inner barrel to be 241mm. still do not know if aftermarket aeg barrels would fit as i didn't take apart the hop up to see how it worked.

 

if anyone cares about my opinion, it seems the new CL slugshots don't use an inner barrel system so in theory one could remove the inner barrel unit, find a way to affix the ring thingy that connects the barrel & mag tube at the front end, it might work. barring that the slugshot rounds don't need to use the cl upgraded firing pin or that there is no hidden lip or anything inside that prevents the shell from working. I might buy a pack to try out when they become available.

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it's sooo long, its fantastic. two questions, how many shells does it hold now? and did you replace the old spring with a longer one? (though that would most likely be a yes).

fyi, i recently measured the inner barrel to be 241mm. still do not know if aftermarket aeg barrels would fit as i didn't take apart the hop up to see how it worked.

 

if anyone cares about my opinion, it seems the new CL slugshots don't use an inner barrel system so in theory one could remove the inner barrel unit, find a way to affix the ring thingy that connects the barrel & mag tube at the front end, it might work. barring that the slugshot rounds don't need to use the cl upgraded firing pin or that there is no hidden lip or anything inside that prevents the shell from working. I might buy a pack to try out when they  become available.

 

Well. I have a confession to make. The extended mag tube is a part of the mag tube that came on the G&P set. The mag tube is still stock, the endcap is still screwed on.

 

The piece of mag tube just sits on top of the endcap, it's held in place by a sling mount and the ring that holds the barrel and tube together.

 

Originally it was my plan to put a pin in the original mag tube, and fit a custom piece of tube on it. Just for fun, I put a piece of the G&P set on, and it was the right length. So it's on now :) I might mod it lateron, but I like it how it is now.

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