M1888 Mannlicher question

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Eaglelord17

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Hi all,

I was wondering if someone who has a 1888 Mannlicher or 1888/90 Mannlicher would be able to do a quick measurement for me? I am looking for a measurement of the locking block, both the thickness in the middle, and in the sides. I am currently designing a rifle I someday hope to make which is roughly based off the 1886/1888 Mannlicher style action (it is wedge locking but on the sides instead of the bottom). I just want to verify if I am heading in the right direction for my measurements (the rough design part is easy, adding dimensions is the hard part).

Thanks all.
 
If you need a complete rifle, we have few in stock, just need to add them to the website. They are ok shape for the age
 
Eaglelord: I have a spare '86 bolt lying around somewhere. If I can find it today I'll post the measurements. Sounds like what you're trying to build might resemble a G/K43 bolt?

milsurpo
 
Found the bolt and am surprised to see the locking wedge or block isn't quite as massive as I thought it would be. I've shown most of the dimensions on the photos. The upright sides of the block are approx. 0.111" thick. From wear patterns it looks to me like all the support at the rear is on the two outer radius'- the central portion has thick rust.

milsurpo
 
Thank you so much that is exactly what I am looking for. My goal is to design a 7.62x39 straight pull bolt action which instead of having the locking lug on the bottom having them on the sides. What interests me most with this bolt design is the ability to switch it from left hand to right hand with a simple reassembly of the bolt. Here is a photo of my bolt design so far, it is already outdated and I have tons of revisions and updates to make on it, but I think it gives a good idea of what I am aiming for (provided you can read schematics). So far this has been pretty eye opening to the amount of effort it takes to design one as I have already spent at least 4 hours to get as far as I have.

 
Woah. Awesome project!

But I believe one fundamental design issue with flapper and wedge lock designs is a lack of primary extraction. This can lead to binding and case head separations.
I think the 1886 somewhat overcomes this from the use of a rimmed cartridge as there is a greater surface area for the extractor to grab (?). 7.62x39 is rimless but has a very pronounced case taper so this maybe less of an issue.

Worst case scenario, you can flute the chamber. :p

You may want to look at the RPD for some design cues (locking surface area, extractor design, etc.). It's flapper locked, chambered in 7.62x39, and works. Although it does have the force advantage of gas operation.

Just my 2 cents. Might be gibberish.
 
Case head separations is caused by stretching of the brass as opposed to the style of locking system. For example the Lee Enfield is a rifle that is famous for them thanks to the oversized chambers and the distance between the rim of the case and the bolt. On some semi-autos those type of problems are caused by the system usually due to them extracting before the pressure has completely left the chamber, thereby ripping the case head off the brass and leaving the rest in the chamber.

Most tilting bolt firearms work on a very similar principle to the 1886/88 style actions, just they lock the whole bolt instead of just a wedge at the bottom (so rifles like the SKS, AG-42b etc.). If I have to I will just make the extractor wider.

Overall I suspect I have at least 40 hours of work left in the design, hopefully less but I wouldn't be surprised as it has already taken about 8 hours to get to this point. I have started saving up for some metal working machines, and hopefully sometime next year I will end up getting one so I can get started.
 
Well that is the bolt in the locked position, it would be locking into reinforced recesses in the rear of the receiver. It would be unlocked when the bolt handle is pulled back. The locking wedges are forced to follow some carefully planned cuts in the forcing block which when the forcing block (the bolt handle portion) is pulled back pulls the wedges out of battery.
 
Eaglelord17 said:
Case head separations is caused by stretching of the brass as opposed to the style of locking system. For example the Lee Enfield is a rifle that is famous for them thanks to the oversized chambers and the distance between the rim of the case and the bolt. On some semi-autos those type of problems are caused by the system usually due to them extracting before the pressure has completely left the chamber, thereby ripping the case head off the brass and leaving the rest in the chamber.

Most tilting bolt firearms work on a very similar principle to the 1886/88 style actions, just they lock the whole bolt instead of just a wedge at the bottom (so rifles like the SKS, AG-42b etc.). If I have to I will just make the extractor wider.

Overall I suspect I have at least 40 hours of work left in the design, hopefully less but I wouldn't be surprised as it has already taken about 8 hours to get to this point. I have started saving up for some metal working machines, and hopefully sometime next year I will end up getting one so I can get started.
Click to expand...

That makes sense. Those tilting bolt designs also lack primary extraction and don't really have any extraction or case issues. I guess it's more of a blowback thing.

But do those guns benefit from the fact they're self loaders? Do you think that case/chamber binding might make the bolt difficult to operate ('sticky') in your design? Most manually operated rifles have some sort of primary extraction (Even the straight pull K31 has angled locking lugs).

Interestingly, the Blaser R93 and Heym SR-30 are also straight pulls that lack primary extraction (as far as I can tell) yet they reportedly work fine. Is primary extraction less of a boon than people make it out to be?
 
Primary extraction is when you can move the bolt slightly and break the 'seal' between the brass and the chamber. Easiest example is a M98 Mauser where when you pull up on the bolt handle the bolt moves slightly to the rear. Pretty much all standard bolt guns benefit from this. Another advantage is it can allow you to sometimes force slightly larger brass into the chamber as well.

The Swiss rifles don't benefit from primary extraction. Those lugs are angled so they go into battery in the first place (as are the Austrians M90/95 action).

My main concern in regards to primary extraction isn't the rifle itself (many rifles without primary extraction have preformed there service for years) but the ammo used. 7.62x39 ranges from cheap lacquered crap to standard quality brass cased rounds. Some of the cheaper stuff will likely get stuck in the action, though that is a problem for even firearms like the SKS or nicer firearms like those Czech 7.62x39 bolt action rifles.

From what I have read and seen online the M1888 action is actually very smooth, the main issue with the design was the weakness of it (i.e. that single locking block). Personally I think that primary extraction is overrated. I have owned and used most major types of straight pull bolt actions (except the 1886/88 style action oddly enough) without issue, and the only issue I have encountered is ammo not wanting to chamber on my K31 (ammo was slightly out of spec for it, once I tightened up my standards the problem went away). M95s, Rosses, every major Swiss straight pull variant, and I still rely on them. I think primary extraction is more a excuse for poor ammo, and a argument against straight pulls as otherwise there isn't really much there which can't be countered.

And even though there isn't primary extraction you can get more force on that bolt than you can with a standard bolt for the simple reason you can just stomp on it (not recommended unless absolutely required).
 
With tilting block semi-autos, the extraction is facilitated by the free movement of the bolt carrier rearward and prior to the bolt being unlocked. The kinetic energy/ momentum of the assembly jars the case from the chamber and still has enough energy left to cycle the action. Needless to say, you can't cycle it as fast by hand so a design like SVT or SKS can't ever be fully functional as a hand operated design without lots of design changes. Interestingly, during early development of the SVT, case separations were a big issue indicating that sticking of the cases in the chamber was significant. The solution was the fluted chamber which allowed the gas system to effectively extract without separation.

milsurpo
 
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