wise lite semi auto to MG

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mt4x4
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wise lite semi auto to MG

Post by mt4x4 »

Don’t worry jbaum. Not long and I will have several manuals ordered from you. I’m thinking about converting my wise lite semi auto to full auto. After looking at it, It does not look like there will be too many problems. I have checked with the best of my abilities and it looks like my gun is 0.6875 longer than it needs to be. I could make a spacer for the main spring to stick behind it but not sure if I would need to. Half of everyone is probably going to tell me to buy or build the proper length receiver but that’s easy to say when you’re not paying for it. I’m not asking anyone here how to do it as I already have that down. I just want to see what you guys think about the longer receiver used in an auto. Would I be the first to do this? When going from semi auto to full is there things to look out for? I also have the FFL and pay the SOT for those that are going to ask.
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Re: wise lite semi auto to MG

Post by JBaum »

A few thoughts: I think that the longer receiver will slow the rate of fire, and the recoil spring will not be correct for the longer length. How the recoil spring/receiver mismatch will affect operation is a good question.

Considering the value of the Wiselite gun to start with compared with the cost of welding a correct receiver, I'm at a loss to see how using the Wiselite receiver is going to be cheaper than selling the Wiselite and welding together a correct MG42 receiver. Certainly having the correct receiver length would be less trouble than the unknown variables caused by recoil spring length and trigger system placement.

Enjoy your project, and let us know how it runs when you're done. It should be interesting.
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mt4x4
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Re: wise lite semi auto to MG

Post by mt4x4 »

I am interested to see how the longer receiver plays out also. So as I’m sure you know the buffer has already been extended to make the semi auto work. So that spacer I was talking about I could place behind the recoil spring, to me it seems like the rest of the gun would not know the difference. When you say the longer receiver will slow down the cycle rate would that be assuming im not using the spacer? If not then I’m missing something. As far as selling it I might end up doing that. At this point all I have is a little flux wire feed welder and I don’t really have an interest in using that to put the receiver together. At some point in time weather I convert this or not I will get a nice tig welder and maybe do another.
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Re: wise lite semi auto to MG

Post by mt4x4 »

So far things are going good. I have about 300 rounds threw it and I have only had one time where the last round in the belt did not feed. I did make a Spacer to put behind the recoil spring. What throws me off a little is it’s shooting about 1050 rounds per min. I’m using the steel case 150grn Romanian ammo. I understand my receiver is longer but I have added the spacer and the buffer spring was already extended to make it run in semi auto. I took a look at my booster and it has an 11.5 stamped on it. The 11.5 is much smaller than the stampings I see on booster for sale on gunbroker. I thought I would measure it to see if it really was 11.5mm and its more like 10 or 10.1. I thought maybe my caliper was broke so I pulled out my drill bit set to see what fit. It really is just over 10mm with an 11.5 stamped on it. It also has a 4 digit number on it but I can’t remember what it is right now. Maybe tonight I will post a pic. So I would like to ask.

1 is it normal for boosters to be marked bigger then they really are?
2 is it normal for the gun to run that slow using 150grn ammo and if not what could be making my gun run slow?
3 will the HDv 181/7 manual show detailed divisions of the receiver so I can figure out where I’m coming up short, or in this case long.
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Re: wise lite semi auto to MG

Post by gordie k »

german ammo has differnt pressur curves see volkey book test by us in ww11 on mg 42
if the force that the bolt strikes the buffer is to light forward speed will be low the harder it hits the faster will the faster it will return{see Chins books}
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Re: wise lite semi auto to MG

Post by mt4x4 »

Well I think I had an out of battery fire. No damage to the gun but it did bend the door witch I bent back and it blew the extractor out. I have it on video.
http://www.youtube.com/watch?v=F1Z9kaSu7zA

http://www.youtube.com/watch?v=F1Z9kaSu7zA[/video]
Anyways the gun headspaced just fine and I am using the spring in the bolt carrier??????? The front 85% of the case was left in the chamber. What seems strange is the back of the case looks to have blown out further back then the back of the inside of the case. I know that sounds confusing maybe I can get a pic up tonight. This was using the 50's yugo ammo.
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Re: wise lite semi auto to MG

Post by JBaum »

So, you're using 60 year old ammo, and it blew in the gun. That happens with 60 year old ammo. No surprise there.

If your gun was firing at 1,050 rpm, that's over 17 shots per second. So, about every 6/100ths of a second, a shot fires. It therefore takes less than 3/100ths of a second for the bolt to go each way, and maybe for less than 1/100th of a second, the bolt is locked and the firing pin strikes the primer.

If the primer delays by 1/100th of a second, the bolt is 1/3 of the way to the buffer by the time the cartridge fires. Could have been a bad primer, could have been bad powder with a slow ignition before the full charge ignited, could have been a casing that was internally corroded that couldn't take the strain of 50,000 pounds of pressure.

We all know that technically the MG42 can't fire when the bolt is open, but with 60 year old ammo, all bets are off.

Glad you weren't left bleeding in the video.... this could have been embarrassing. With a closed-bolt semi-auto, a 1/100th of a second hang fire would never have been noticed.

I'm not your mom, and I'm not slapping your fingers, but may I suggest that you shoot modern ammo in the future before you hurt yourself? The gun is capable of blowing with good ammo... don't decrease the odds of safety by using 60 year old ammo, which may not have been made properly, stored properly, or was just plain crap ammo to start with.

And is your anti-bounce spring in the bolt carrier facing the right direction? Some of them are directional.
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Re: wise lite semi auto to MG

Post by crash520 »

Hi JB,

Can you give a lesson on the anti bounce sping and their direction to be fitted please.

V/r
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Re: wise lite semi auto to MG

Post by mt4x4 »

That’s the kind of response I was expecting from you. Thanks for putting the hole timing thing in to perspective. Other than “If the primer delays by 1/100th of a second, the bolt is 1/3 of the way to the buffer by the time the cartridge fires.” I would think that if the round has not fired yet there would be nothing to push the bolt back yet. Unless the bolt can bounce back with the anti-bounce spring. Just not understanding I guess. I’m sure the anti-bounce spring is in the right direction as It won’t fit backwards. It has the ejector bar that clips on to it. Looks like this.
http://www.robertrtg.com/images/mgboltstabilizer.jpg
and
http://www.robertrtg.com/images/mg42ejectorbar.jpg
I would give just about anything to get some modern ammo. Other than $1 per round. I will be converting to 308 soon but would you have a link for some good 8mm. I’m almost out of my Romanian and will look on gunbroker and or forums. But I can’t always find it.
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Re: wise lite semi auto to MG

Post by amafrank »

The spring thing is called a Bolt Catch. Its purpose is to upset a harmonic whereby the bolt head hits the barrel extension, the rollers move outward to lock than bounce back toward the unlocked position and then return toward locked. The rollers basically cycle back and forth. The bolt catch bounces off the locking wedge to disturb the bouncing. The thing that makes the guns blow up is when the primer timing is such that the gun fires when the rollers have moved into the unlocked position. That allows the bolt to move rearward before the pressure drops and the unsupported case head now stretches beyond the capability of the brass or steel to support the pressure and it splits, letting large amounts of flaming hot gas escape and create havoc. The germans did some high speed photo studies of the phenomenon and started working on the bolt catch idea. They initially thought that the locking wedge should have spring pressure against it to prevent the dreaded unlocked firing but found that it merely changed the frequency of the rollers bouncing. The idea for the current setup came out at some point in the 60's as far as I know. It uses the inertia of the metal rod and spring to hit the locking piece with the spring being there to extend the amount of time that pressure is exerted.

I remember from my youth that we blew the door open on my buddies 42 a number of times because we didn't have a bolt catch. The parts were hard to find back in the 70's but now we know. Don't fire the gun without a proper bolt catch and make sure its installed the right direction. If its putting pressure on the locking piece when the bolt head is pushed back its in wrong. If you can take the bolt head, push it back, pull the rollers out to the locked position and the bolt catch will rattle when you shake the bolt than you have it right.

Hope some of that helps. and since the server won't allow a post with more than 2K characters see the next one below.

Frank
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Re: wise lite semi auto to MG

Post by amafrank »

Part II of above....



Other advice here is don't use crap ammo in these guns. Lots of guys used turkish 8mm ammo in these guns and I got a lot of work out of their mistake. The primers in the turk ammo are widely varied in their timing and when you add the huge variation in pressure from round to round you are looking a lottery of disaster. The same is true of the Indian .308 that was sold loose packed. I saw a 42 that had the imprint of the headstamp embossed into the bolt face, the extractor blown through the bottom of the receiver and the barrel door blown open. The bolt was still locked when my friend managed to open things up. Pretty scary.....

Some years back there was a huge amount of German WWII ammo on the market which came in boxes marked Fur MG. Most thought that it was low grade ammo for the WWII machinegunners. I mean, if you're blasting 1250 rounds per minute you don't want to spend a lot on it. Leave the expensive ammo for the snipers. In reality the markings were put on that ammo because the primers were known to be within spec for the MG42 and it was important to use the proper ammo in the guns. The bolt actions and G/K43's didn't care if there were some hangfires, the 42 did and would blow up to let you know. A bit sobering to think that in the late years of the war the germans were taking the time and spending what it took to make sure the ammo was correct for the 42's use. Take heed of that and use good ammo. We had very good luck with the Romanian light ball made in the 70's. We also had very good luck with the Yugo 50's and 80's ball which was made for the M53, the Yugo version of the 42. The ecuadorian ammo has had mixed reviews and I don't have any personal experience with it so I can't tell you anything useful.



Frank
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Re: wise lite semi auto to MG

Post by Gulfstream4 »

An excellent explantion Frank
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Re: wise lite semi auto to MG

Post by 42rocker »

Wow, that video should be required for anyone wanted to run cheap ammo. Glad everyone seemed ok.
John, nice write up on that. amafrank. you also pointed out some great ideas.

Later 42rocker
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