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PBE Shield Stickers and Deagle Boltface Patches On Sale Now!



File 151537899348.jpg - (1.81MB , 3591x852 , P1066153.jpg )
106706 No. 106706 ID: 19518e
There's a machine gun thread a while ago but I felt like I should start a specific thread for firearms fed by belts.

Mostly because of this MG34 that followed me home.

Since this really is the first rifle of this type that I've had to play with, I'm a little out of my element. This is a TNW semi-auto only 7.92x57 and I wouldn't mind learning everything I can about this particular piece.
61 posts omitted. Last 50 shown. Expand all images
>> No. 107021 ID: 0adccc
>>107017
>light firing pin spring

Da fuk? What kind of spring constant do you have on that? Is it factory? When I got mine, the spring was RIDICULOUSLY strong. I've had to cut off a few coils just to make the trigger stop sucking. I'll try to compress the spring as I have it to maximum compression to see where we're at. I'd like to replace this spring with something designed for commercial primers instead of hard-as-fuck south american surplus (which was cheap when the TNW rifles first went into production), which would help clean up the trigger a lot more (and hopefully reduce the force on the aforementioned sear collar and lever).

And I'm sure you learned to wear gloves when operating it in bolt action mode. The knurling on the bolt handle is fairly aggressive.

I'd also recommend picking up a new production mainspring online or something if yours looks used, after I replaced mine, it felt like it ran a bit smoother, and it wasn't expensive. Further, if yours is old stock, you might want to get a replacement buttstock as well (I didn't though). NFA guys with them down in Portland told me to be careful since the stock is thin in places, and theyve had cracks/breaks...then again, who knows how well old fudds treated these things and could have dropped them on the stock or something. There's some polish kid on ebay who makes beech repros.

I also had some issues with the pawl slipping the belt, but that cleared up after 2-3 belts.

The gurttrommel required filing to fit mine, btw, and more spring cutting was involved (maximum compression was not open enough to get the clip over the guide) but mines a post-war yugo which had obviously not seen use.
>> No. 107022 ID: d44f9d
>>107020
>>107021
Yeah the stock spring was replaced with a lighter one as the stock ones are stupid. The gun worked on the bench with empty primed cases in regular room temperature, but once it was taken to the cold, no rounds could fire even when I tried cycling them back and hitting them again.

I have some slightly heavier 1911 springs on order. The trick is finding a spring light enough to make the trigger not terrible but heavy enough to fire reliably.

This was a 14lbs 1911 spring and just warming the rounds up a but was enough to let them fire so there's not a whole lot of spring force missing to make it reliable. A lighter firing pin also increases reliability in cycling normal ammo as it reduces the force required by the main spring to close the bolt.
>> No. 107023 ID: 7fecba
File 15191799095.jpg - (73.86KB , 742x554 , German WW2 trooper with a smile & some goggles.jpg )
107023
I heard gunsmiths commenting that German weapons had notoriously stiff springs. I had a WW2 German Mauser K98 and a Walther P.38 and those had stiff springs. Firing pins really put deep dents in the primers.
>> No. 107796 ID: bbee29
File CIMG0946.webm - (154.03KB )
107796
Welp it's been quite the learning experience, and I feel like I'm closer to understanding the fine details in operating and maintaining the semi-auto MG34.

When I was doing my first shots and trying to diagnose the issues with mine, I completely overlooked the booster. The MG34 is recoil operated, but it's assisted by a muzzle device that turns the barrel into a bit of a gas piston to give the system a bit more oomph, and also allow for adjustment between 85 grain aluminum core bullets and regular heavier grain bullet ammo like 198 grain FMJ. As it turns out, the booster in my gun was a "9mm" booster, made for the aforementioned aluminum core ammo. This drove the action much too hard as I was shooting PPU/Prvi Partizan 198 grain FMJ. The action speed was so high that the ejector wore out in ~20 rounds.

Here is a single shot I fired as a test to isolate problems because the belt and related mechanisms could induce malfunctions that would complicate diagnosis. We can clearly see the problems caused by over-boosting, parts wear aside. The brass in this shot slipped off the extractor as it was being struck by the ejector pin, thus failing to eject and getting fed back into the chamber.
>> No. 107797 ID: bbee29
File 153887551860.jpg - (743.81KB , 2120x1576 , bewst.jpg )
107797
So I made new boosters. The way to "dial" down a booster is simply to bore a larger exit hole, allowing more gas to escape and less gas to push on the crown of the barrel.

They're simple enough, I made 4 in total, not all shown here, in various sizes from 10mm to 11mm. I don't exactly need that many, but I don't mind having a "spare" that I can bore out later if I need another size for whatever reason. The original is the one sporting patina in the middle.
>> No. 107798 ID: bbee29
File 153887578424.jpg - (58.62KB , 1600x1200 , IMG_3105.jpg )
107798
I also made new ejector pins, they're dirt simple so not much use going into them. I made a couple out of mild steel bullshit so I could easily file them at the range if they needed some minor tweaking. Whereas the original hard steel ejector lasted but a handful of rounds, with the new larger exit hole booster installed, even the mild steel ejector lasted almost a hundred rounds.

I'll order some better steel (4mm hardened dowel pin) and make some good ejectors.
>> No. 107799 ID: bbee29
File underside_bolt.webm - (820.87KB , underside bolt.webm )
107799
With the new booster in place, things started to go a little better. As we can see in this video, the bolt speed is much more reasonable, opening at about the same rate as it closes under spring tension.

I do believe the main recoil spring driving the gun is a little old. I'll have to order one of those as well, or make one, not sure yet.
>> No. 107800 ID: bbee29
File giv'er_pt1cropped.webm - (1.59MB , giv'er_pt1cropped.webm )
107800
Needless to say that after this string of rounds, I now feel that this purchase was worth every penny. I agree with Ian McCollum with semi-auto belt-feds not being worth the trouble in the United States of America but here in no-fun land this is by far the best purchase I've made in ages.

DAKKA/10.
>> No. 107802 ID: bbee29
File giv'er_pt2cropped.webm - (1.00MB , giv'er_pt2cropped.webm )
107802
I've thought about getting a 1919 or an M2, but it would be quite a lot more difficult to do this (webm related) with other belt-feds that can be acquired up here. I might end up tracking down an MG42, just because it's that pretty.

At this point all I need are some more belts, a spare barrel or two, and tons of ammo.
>> No. 107902 ID: 1ee05f
>>107797
nice finish. considered crawling your feed to make it even better?
>> No. 107903 ID: 4eaeff
File 154057259876.jpg - (150.60KB , 1200x265 , 34_308_CONV1__53231_1455823550.jpg )
107903
Waiting on getting my 34 from TNW on a brand new build. Hopefully it works out of the box, but I've seen enough issues with other people's that probably won't be the case.

In my case I intend on immediately converting it to shoot .308 because 8mm ain't cheap anymore. Involved in the process is modifying the feed tray to accept a spacer for .308, a new barrel (slimmer profile for the recoil operation as .308 has less oomph than 8mm), a narrower booster cone, and a top cover feed pawl modification that is longer which puts pressure on the shorter .308 round (which can be used with 8mm too).

Will report back as to how the .308 conversion goes once I get it all set up.
>> No. 107905 ID: bbee29
File 154060032853.jpg - (735.55KB , 1557x1545 , mousel.jpg )
107905
>>107902
Wasn't concerned about surface finish, just dimensions. It's not really visible from anywhere once inside the muzzle assembly so making it pretty was not a priority. Picture related, if you're worried about the surface finish while looking at this I'm afraid the autism is in terminal phase. Luckily if you are looking at it like this, you won't have to wait long for the euthanasia.

>double stamped 4
I'm terrible at stamping shit ffffffffff

>>107903
>8mm isn't cheap
I'm kinda torn. The 8mm is glorious and original, also from what I've heard, it'll be more reliable once my TNW is running well. But then there's the cheap .308 Win stuff. If it's reliable, shooting more would be fun, but I doubt it would run properly without a lot of work. I think that for now I'll stick to 8mm until all my current minor issues are sorted out despite the seductive cheapness of 308.

I know a guy with a legitimate full giggle MG34 (he's allowed to have it, horsecops please go and stay go), and he said we could compare MGs and I could measure/take notes on the original parts.
>> No. 107907 ID: faf462
>>107802
It's fucking cool that you got an MG34. I dig the slomo.

Buuuutt... just can't do semi-auto conversions of machine guns. Like a semi auto KRISS Vector, PS90, 1919, or Suomi. All would be amazing in full auto, but pretty pointless in semi.

I did shoot a semi auto MG42 some guy built out of a parts kit. I was amazed at how much it recoiled.
>> No. 107908 ID: bbee29
>>107907
I agree with you. If it wasn't for my unfortunate location, I don't think I'd have a belt-fed either, unless I was able to scrape up enough pennies for a full auto one.

That said, I disagree with your thoughts on the Kriss Vector. That gun is retarded in any configuration, and is by design a failed abortion that only has a completely flawed concept to begin with and space-pew-pew aesthetics to ride on. I can forever hear the tortured screaming of it's machine spirit, begging "kill me, it hurts to live".
>> No. 108420 ID: e6ec85
File 15553543211.jpg - (1.35MB , 4032x3024 , signal-attachment-2019-04-14-223529.jpg )
108420
>>107903
Well, I managed to finally take my 34 out to the range the other day and shot it in .308. It fed and chambered properly after installing the necessary parts for the conversion (feed tray block, barrel, and extended outer pawl to push the shorter round down).

Had an issue with the first fifty rounds where the extractor somehow blew off the bolt and the extractor spring got mangled. Extractor looks a little chipped on the underside of the lug, too (as pictured). Gun was down after that, though fortunately I had a friend who also went to the range with me who's an MG-34 hoarder so I was able to borrow one of his spare bolt heads and continue shooting.

After that it was just experimenting with different booster cones and flash hider inserts. I have a flash hider that was "converted" to be a brake with a welded insert (because I live in Commiefornia), which the guy who did it for me said it would increase backpressure a little.

Apparently the reason why the extractor blew off my original bolt head was because I was overgassing the system using the BRP 308 diameter booster cone (I believe that's like an 8mm orifice), in conjunction with my "brake" cone. I also have a normal cone I got for testing and it seemed to cycle well with my friend's spare bolt (which I should mention also has a normal firing pin spring; my original bolt still had the TNW thicc machined spring which is ridiculously heavy to recock).

So I contacted TNW and they said send the bolt in so Lance can fix the extractor free of charge. Nice. I also decided to get a second spare semi auto bolt so I can have something as a backup in case my primary bolt goes down.

Was able to shoot about 300 rounds of .308 down the pipe. Some stoppages, sometimes it ran pretty well. I think it will require a bit more fiddling with the gas system but nothing blew up and no major issues or parts breakages aside from the extractor spring, I figure most of the issues will work itself out as soon as I get the extractor fixed and plop in a coiled full auto firing pin spring to reduce the cocking force necessary to cycle the gun. These guns are very sensitive to the backpressure generated by the booster cones, I’ve been told.
>> No. 108421 ID: bbee29
File 155539309119.jpg - (121.22KB , 632x685 , IMG_20190407_144343.jpg )
108421
>extractor chipped
>increased backpressure
Yep that makes sense looking at where it broke. I'd always start with a more open booster because running the gun hard will put a lot of wear on the ejector pin and other components. It's pretty easy to put in a tighter booster for more gas if it doesn't cycle fast enough and fails to eject rounds but the gun will beat its parts out cycling too hard but still cycle until it spits out guts. As stated earlier in the thread, mine was very overgassed at first and ate an ejector pin in ~20 rounds so I think I stopped and lucked out before anything else broke.

I've also made progress on the TNW MG34 on my end.

So I've been learning that the cyclic rate is affected by more than just booster port. Mainly, the firing pin spring. Mine seems to need a stiff spring as anything less doesn't seem to hit primers hard enough. In turn that'll slow the action down and it should make ejector pins last longer. I also think my main recoil spring (the big one) is a little weak. The barrel return spring might also need to get beefed up but it does feel quite stiff so I'm not going to mess with it now. Needless to say, making a handful of boosters at various diameters is saving my butt in this process. I found that pencil-testing my firing pin spring tension worked well. Assemble the bolt, cock it outside the gun, balance a pencil on the bolt face, and push the sear in to release the firing pin. At least three feet straight up for a regular pencil worked for me, less than that and I had failures to fire from weak pin strikes in good PPU 8mm (not really hard primer surplus). During my testing, the sear ended up wearing so I ordered some high impact resistant S7 tool steel. I'll be making new semi-auto sears and sear rings (not sure what that part is called, it's what the TNW sear catches to cock the firing pin) from S7, it should hold up quite a lot better than the buttery soft TNW ones.

I've also found some original ejector pins with the wedge-shape cuts that did help ejection quite a lot. I've replicated the original and my replica ejectors function perfectly. I made them from drill rod and gave them a quick heat treat only in the rear, and not too hard. Just a little bit to prevent the pin from deforming when hitting the ejector plate. Picture related, the original is on the left. Despite the shittiness of my garbage chinese """metal""" lathe, it makes quick work of this kinda part and I just hand filed the rest of the features.

Other than that, stoppages were mostly belt related. The TNW 34 advances the belt as the bolt is moving forward, so there's energy lost from the main recoil spring simply from advancing the belt to ready a fresh round. As the bolt is then moving a bit slower, it can be slowed down too much during feeding if the link holds the round too tightly. I'm not sure why they did it that way, I would have thought that a system that advances the belt as the bolt is opening, taking advantage of the recoil power, and only advancing the pawls (very little force required) would leave the bolt with as much energy as possible to strip a round from the belt and push it in the chamber. As a result, mine seems sensitive to how tight the belt is on the actual rounds, this could be exacerbated by the old main recoil spring. When I find belts or specific belt links that feed well, I push a round through it with my fingers (no gun, just holding everything in my hands), and then check tension by comparing other belt links. They're often much too tight, and require very carefully prying them open just a tiny bit. I carefully pry them open with needle-nosed pliers, matching the case taper as carefully as I can, and testing with a round to get the right tension. I might make a tool for this that can pry the belt link to the right tension automatically as I've bought like 25 belts and most of them have links that are too tight. Like many guns, once the minor issues with gassing/springs are resolved, the rest of the troubles end up being shitty magazines or in our cases, belts that just aren't quite right. I suggest you have a go at feeling your belt link tension as I think it's one of the final things to square away before the gun gets really quite reliable.

it's nice having belts and starter tabs now but the issue is buying enough ammo to fill 25 belts f f f f f u u u u c k
>> No. 108422 ID: 6fe1bd
File 155543256466.jpg - (1.04MB , 1020x1920 , IMG_20190416_101740.jpg )
108422
Here we go.
>> No. 108423 ID: 6fe1bd
File 155543285151.jpg - (1.17MB , 1381x1920 , IMG_20190416_101821.jpg )
108423
Damn I suck at this freehand shit but this should be close enough. The optical comparator has seen better days so dimensions could be a tiny bit off, minor fitting by hand will likely be required.
>> No. 108425 ID: 4eaeff
File 155544186210.jpg - (51.49KB , 900x600 , MG34-GNPT-XX08-BKXX-4B37-2.jpg )
108425
>>108421
>So I've been learning that the cyclic rate is affected by more than just booster port. Mainly, the firing pin spring. Mine seems to need a stiff spring as anything less doesn't seem to hit primers hard enough. In turn that'll slow the action down and it should make ejector pins last longer. I also think my main recoil spring (the big one) is a little weak. The barrel return spring might also need to get beefed up but it does feel quite stiff so I'm not going to mess with it now. Needless to say, making a handful of boosters at various diameters is saving my butt in this process. I found that pencil-testing my firing pin spring tension worked well. Assemble the bolt, cock it outside the gun, balance a pencil on the bolt face, and push the sear in to release the firing pin. At least three feet straight up for a regular pencil worked for me, less than that and I had failures to fire from weak pin strikes in good PPU 8mm (not really hard primer surplus).


Are you using the thicc machined TNW spring or a coiled spring that was found in the original full auto MG-34? I was using the TNW spring in my gun for the first fifty rounds until the extractor on my original bolt blew off. It was lighting the ammo off fine (MKE 2014 kebab 7.62x51 NATO ammo ZQI brand), and when I swapped out the bolt body with my friend's spare, he used a coiled full auto MG-34 spring, probably one acquired from BRP Guns. I continued to fire with my reloaded 7.62 ammo using CCI #34 primers and the coiled spring had no problems lighting that ammo up. I didn't have any light strike issues.

I think I will probably go with the coiled spring going forward. It should be enough to light up the primers I use in my general purpose 7.62x51 reloads. The added benefit of having a less stiff spring is that the cocking force necessary to unlock the bolt under recoil is a lot reduced so I don't have to restrict the cone so much in order to get it to fully cycle.
>> No. 108426 ID: 6fe1bd
>>108425
My TNW spring was shortened a little bit, but it's still not perfect. I would like to try a coiled MG34 spring, because so far the other springs I've tried short of the TNW were too weak.

I have ordered music wire and some compression springs from Mcmaster Carr. Perhaps an industrial spring will work, the dimensions are really quite close. I'll also be attempting to make a main recoil spring from theusic wire as I can't seem to find much up here for that. I'll be fiddling with all this soon but first I need to finish the sears.
>> No. 108432 ID: bbee29
File 155565223877.jpg - (227.45KB , 1274x967 , IMG_20190418_233258.jpg )
108432
Aight so the S7 tool steel machined ok, but I don't really know what's the proper way to heat treat them.

What do?
>> No. 108434 ID: e6ec85
>>108432
Maybe call TNW and ask for Lance, maybe he could tell you what Brinell hardness they do for their own sears?
>> No. 108437 ID: bbee29
>>108434
As far as I can tell by scratching at the original with various metals, the original sear seems to be medium carbon steel in a mildly hard state. I've heard of the softness of sears from many owners so I'm not sure TNW even knows how hard their sears are supposed to be, and if they do, their quality control could use some improvements as I see no evidence of harness testing on the sear.

Even >>106836 had the same issue.
>> No. 108438 ID: e6ec85
>>108437
If you decide to sell any of those sears LMK, I would be interested after you figure out how hard these things should be.

My friend who is knowledgeable about these TNW 34s said that the sear in my particular gun (built in 2018) has a third style of sear that he's observed so far, so it seems like TNW is still tweaking the sear design. I haven't had any slamfiring in my particular gun, either with the original machined firing pin spring or a coiled firing pin spring, FWIW.
>> No. 108440 ID: bbee29
>>108438
I'll be testing them soon, I'm not considering selling anything unless I'm satisfied that it'll work well. I don't want to cause any unfortunate/expensive "malfunctions" by jumping the gun and selling stuff that might not be good enough.

Just trying to figure out how S7 likes its heat treatments. From what I can see, I don't think I have the equipment to heat treat it reliably, so I might have to send them out and have it done right.
>> No. 108443 ID: 51b0a9
>>108440
You don't/ However you do have access to steels the Natzis only dreamed of, Even marginal shit like A2 was unheard of in the 40's.
>> No. 108445 ID: bbee29
>>108443
I'd have to actually compare internals with a real MG34, but I know TNW has made changes to make their gun semi-only. Do correct me if I'm wrong, but in the original gun, the sear doesn't take the kind of beating that it suffers from the semi gun.

I might try the magnet dangle over a metal bowl full of oil. What could go wrong?
>> No. 108447 ID: e6ec85
File 15560416151.jpg - (22.87KB , 260x346 , 51Dem2MXu-L__SY344_BO1,204,203,200_.jpg )
108447
>>108445
There's actually a snippet from the Folke Myrvang "MG34 and MG42 German Universal Machine Guns" book that has a report from a U.S. Army-commissioned metallurgy report on a captured MG-34 and it reported that most parts of the MG-34 just utilized carbon steel and other steels that were absent nickel except for some few critical parts, such as the bolt, bolt rollers, and sear would be hardened and made from alloyed steel.

Interestingly the metallurgical report stated that the barrel was also made from basic steel, probably to keep costs of producing barrels low as they were considered readily-replaced consumables. I'll take a screenshot of the relevant pages of the book for your reference.
>> No. 108451 ID: 4eaeff
File 155626678728.jpg - (3.17MB , 4032x3024 , 20190426_011647.jpg )
108451
>>108447
As promised, here's the U.S. Army metallurgical of a captured MG-34, found in the Folke Myrvang book "MG-34 and MG-42 German Universal Machineguns".
>> No. 108452 ID: 4eaeff
File 155626684413.jpg - (2.47MB , 4032x3024 , 20190426_011703.jpg )
108452
>>108451
Not sure why the hell page 1 rotated but should be easy enough to rotate the page on your own.

Page 2
>> No. 108453 ID: 4eaeff
File 155626687336.jpg - (2.54MB , 4032x3024 , 20190426_011724.jpg )
108453
>>108452
Page 3
>> No. 108454 ID: bbee29
File 155628667598.gif - (507.47KB , 318x212 , my_human_of_african_american_descent.gif )
108454
>>108453
>>108452
>>108451
Thanks my dude.
>> No. 108457 ID: e153ed
>>106982
This right here. Stuff nearly made my FN 49 beat itself to death
>> No. 108458 ID: e153ed
>>106982
This right here. Stuff nearly made my FN 49 beat itself to death
>> No. 108459 ID: e56201
>>108451
>>108452
>>108453
I personally don't give a shit about this particular info, but this is the kind of stuff that made this place great back in the day. People posting actual solid information.
>> No. 108462 ID: b224b5
File 20190426_195002.webm - (3.81MB )
108462
My 34 seems to run well with my brake cone + 9.15mm booster. 11mm booster occasionally leads to stovepipe, which would indicate to me the bolt isn't traveling fully rearwards under recoil.

These things are gonna be bad for my wallet. Way too easy to shoot shit tons of ammo quickly.

Also, how do I tighten the rear AA sight? Seeing it bounce around under recoil kinda sucks. Maybe I'm missing a leaf spring or something underneath it because it just flops around.
>> No. 108463 ID: bbee29
>>108462
I've heard 11mm is basically past the tolerance for open booster, I would suggest something around 10mm perhaps. It could be a bit more gentle to the parts. They're pretty simple to make if you have access to a lathe, but I don't think they're that expensive in freedomland, it could be worth it in the long run. You could buy a spare booster and drill it out incrementally larger to get the perfect boost.

I don't have the AA sights so I'm afraid I can't be much help there, sorry.
>> No. 108467 ID: bbee29
File 15568589157.jpg - (742.77KB , 1981x1385 , bowlettes.jpg )
108467
Anyone have experience with this stuff?

Seems to be an FMJBT with a crimp groove, an exposed lead bottom, brass case, crimped-in berdan primer. There seems to be a faint (probably) laser etch on the case of the letter K followed by 8x57 IS. No headstamps.

Bullets measure a tiny bit oval at .3231 to .3234 off my Mitutoyo mic, and don't worry I didn't bother measuring the bullet I pulled out with the pliers.

Weighed 44.1 grains of some flake powder, advertized muzzle velocity from their test barrel is "2500ft/s", after checking some reloading manuals (Lyman, Barnes, Speer, Lee, Hornady, Nosler) that's not too crazy, a few manuals list some IMR powders (3031, 8208, 4064) doing about that fast from 24" barrels with that much powder. I know IMR is sticks and this powder is flakes, but I'm just trying to see if shit makes some kinda sense.
>> No. 108470 ID: e6ec85
>>108467
Only way to know if it's safe to shoot is to chrono it and see if it lies within the expected velocity range for 8x57 JS ball ammo that was commonly used during the war.
>> No. 108590 ID: 51b0a9
>>108467
Shoot it out pf a disposeable rifle. test three from each lot.
Note any (if all) deviance. More than 10% from publushed, fire 15 from same rifle and note deviance. Send same to seller.

If they try to shuffle it off let me know, I will make sure none of their product sees the major shows/ MG shoots.

Dangerous 7,92 kills people, and horribly damages MG42's.
>> No. 108613 ID: e6ec85
>>108590
Bolt bounce also kills MG-42s
>> No. 108686 ID: 51b0a9
>>108613
Yes I mentioned that. I've dealt with a few '42's with "fat" sections.
>> No. 108781 ID: 975b3d
File 20190511_095824.webm - (4.18MB )
108781
Another rapid fire shooting video. Yes, I am aware of the flopping AA flip-up rear sight. I am working with TNW on getting the tensioner spring for that, which they neglected to install on my particular gun.

If you noticed, I actually did not finish the belt. Had a failure to advance to next round on the belt, which caused the bolt to not pick up the next round. My gun in particular seems to be very sensitive to belt weight and the "pull strength" of the MG34 is known to be pretty weak, necessitating support of the belt of cartridges to feed smoothly into the gun. Not sure what can be done to improve this, since it's all depedent on the cam track of the top cover.
>> No. 108783 ID: e41002
>>108781
Check how tight the links are. The bolt is moving forward trying to pull the belt around, so the bolt is already being slowed by that. Then the bolt hits the round, if the links are holding the rounds too tightly, it takes too much energy to push the round through.

That's what I've found anyway. I've had to pry open links on a few belts, dramatically improving feeding and general reliability.
>> No. 108786 ID: e6ec85
>>108783
I don't think it's an issue about failure to feed by pushing the next round through the link. The kind of stoppages I encounter based on the failure to advance next link in the belt is fixed by simply pulling on the belt from the right side of the gun (the empty links), and it will click indicating the next round in position ready to feed as it slips underneath the main feed pawl on the feed block. If it were a failure to feed link failure, then this wouldn't be possible.
>> No. 108788 ID: 6fe1bd
File 155862795276.jpg - (26.12KB , 450x285 , 37-german-mg34-in-action.jpg )
108788
>>108786
Ahhh I see, that does make more sense, I'm still learning the intricacies of the MG34,thank you for clearing that up.

Would there be ways of adjusting the feed pawl travel to help it position the belt better? Of course it would have to be done carefully to prevent issues once the belt is almost empty and isn't resisting the pawl movement as much...
Maybe it's just a matter of pulling the starter tab for a bit or supporting the loaded belt at the beginning as seen here with the lad next to the gunner.
>> No. 108790 ID: 6fe1bd
File 15586339222.jpg - (421.37KB , 1056x700 , blue34.jpg )
108790
Outing planned later today. I've hardened the S7 sear and "sear ring" to the best of my very limited abilities, dry tests are promising. I'm also trying out this Microlon Ultrablue on the bolt carrier and sliding surfaces of the top cover components. There's also a thin layer on the bolt/bolt carrier camming surfaces. Having dry tested before and after, there was a noticeable improvement regardless of my dislike for unicorn dust snake oil. This blue stuff might actually be worth it. It's a very very light grease and so far it seems to be good stuff.

I'll bring my Doppler radar and my buddy is bringing his historically unimportant K98, we'll test that Russian ammo. I have ~400 rounds so I'll grab three from every other box and try it until I'm satisfied that it won't hurt mein fräulein.
>> No. 108793 ID: bbee29
File 155881692773.jpg - (1.04MB , 2360x1968 , huuurrrr.jpg )
108793
Welp I fucked up but it wasn't a complete loss.

>drive 3 hours to nice spot
>get there
>remember that radar battery is on charger
>at home

I did remember to bring plenty of the usual PPU and I discovered a very weird thing. I had a .413" booster in, and the gun wasn't running too well. Stovepiping every ~3 rounds. I thought that it might be cycling a little slow, so I put in a tighter booster. The gun ran a bit better, 1 stoppage every ~7 rounds or so, so again I thought maybe it needs a bit tighter booster. Then I noticed I'd mixed up and put in a LESS restrictive booster, the .430" one. So it ran better on a booster with a bigger port. So I went up a step, to my most open booster, a .450" one. Again, the gun ran more reliably, but still not perfectly. So I removed the booster entirely and was getting it to 1 malfunction per belt on average.

No booster at all was the most reliable, the malfunctions were also always stovepipes, and those were happening MORE as the gun ran harder. This seems to indicate that the action is still running a bit too fast with NO booster.

I don't think it's the ammo, PPU is 3-ply soft load ammo. My firing pin spring is pretty stiff, and really detonates the primers properly, so I don't want to mess with that. The harder the firing pin spring, the slower the action should drive as it cocks on opening. Maybe the Ultrablue is TOO good and I should use a thicker grease to slow the gun down? Could my barrel return spring be way too light? Even then that particular spring probably doesn't do that much to slow the action down. I am confus pls halp.
>> No. 108794 ID: bbee29
In all I ran 200 rounds of PPU and the kitchen heat-treat S7 of the sear and sear ring show no signs of wear at all. All I did was heat them to bright orange, almost yellow, keeping them at that temp for 30 to 45 seconds. I then plunged them into cold water, shaking them in a figure 8. I found that you must have the water very close to the parts so the parts spend virtually no time out of the heat, the parts hardened successfully when the flame was 2" above the water and the movement to shove them in the water was as quick as possible.

I know this type of thing is not proper heat treat, but so far it has worked. I think the awesome chemistry of S7 steel is making up for my horrible shortcomings in heat treat method and equipment.
>> No. 108795 ID: 9dcda2
>>108793
Sucks about the battery, but at least you got some interesting data about the recoil boosters.

> All I did was heat them to bright orange, almost yellow, keeping them at that temp for 30 to 45 seconds. I then plunged them into cold water, shaking them in a figure 8.

M1903 approved.
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