www.MG42.us

I have been thinking about what I consider excessive recoil on the MG42 and was curious if any one else had considered the issue. The cause and source of the excess recoil is the bolt slamming into the buffer, since the bolt HAS to slam into the buffer to eject a fired case. I have been considering replacing the stock buffer spring with a lighter spring that would soak up some of the impact before it bottomed out.
Any thoughts on this guys?

ratatatman wrote:..... a lighter spring that would soak up some of the impact before it bottomed out.

Whatever you do to absorb the shock , if it so much as touches the bolt, it's
likely to eject the round a little too soon. I do like your thinking though.
I've seen a buttstock somewhere online that was modified on the rear for a recoil
sleeve.....shotgun like. It would break the traditional look though. I guess you could
srcrew a pad onto the very end, and form fit so it looks like a continuation of the wood.

Karb-it was here-in the mg42 build it yourself section,second stickie down in that section.It looks good.Some extra work,but uses full length spring. ---bil

Bil wrote:Karb-it was here-in the mg42 build it yourself section,second stickie down in that section.It looks good.Some extra work,but uses full length spring. ---bil

I remember that one, but not sure that's what he means since no matter how you
do it, the bolt is going to smack the buffer.
I think he wants a buffer spring that's collapsing when the bolt hits it( AR15 ? ). , and not as
steady as the original. My thought was that if he unintentionally made something that actuated the
ejector too soon, he would have a prob.

The only thing I can think of might be to bore out the stock and put a shaft through it with a heavy weight riding on it and a pair of springs on both sides; a heavy one to the front and a lighter one to the rear, to try and add a loaded resistance to the rearward impulse to be overcome when fired. Now, if the stock could hold a weight big enough to have any noticable effect in absorbing any of the recoil or not would be the question. but it would have to be kept seperate from the mainspring, I would think, to avoid messing with the function of the weapon.

Or he could just hit the easy button, and go buy an MG-3 tripod with the spring-mounted carriage.

On a FAL rifle, there is a dual set of recoil springs and no buffer. Yes, they sell aftermarket buffers, but I don't care for them as it seems the bolt & carrier needs the full travel range within the receiver to operate properly.

The FAL also has the added option of a gas adjustment regulator that controls how much pressure is given to the gas piston to unlock the bolt & carrier from battery.

The gas regulation does not control the rearward speed of the b&c assembly when unlocked, but residual pressure in the barrel does.

This brings me to the 42 and things to ponder.

Will opening the muzzle booster hole reduce recoil pressure?
You only need enough pressure to push the barrel and bolt assbly rearward to unlock, then enough residual pressure to push the bolt rearward to strike the buffer, advance another rnd, etc. This may be do-able, but the ammo has to be very uniform.

Does the added weight of a semi bolt help recoil?
Heavier is slower to move, but will hit harder once moving.

Definitly need all the recoil spring you can get to strip rnds from the belt.

Since the buffer is only a buffer and ejector kicker maybe do something here.
While doing some testing w/ 7.62, I noticed the ejector hits the brass really hard. It would seem the buffer does not have to be that stiff to eject empty brass down. How much does the coil spring buffer really compress? Could the first initial coils be ground on their edges some making them a little lighter in strength? Basically a progressive rate spring starting out light and getting stronger as compressed.

Then we go to the buffer in the buttstock option which has been mentioned.

Just some thoughts.
Larry

A few thoughts? It seems that the balance between the buffer spring, the recoil spring, and the recuperator spring must be pretty critical. The recuperator spring has to give enough to let the bolt unlock with enough residual speed to make it's full travel, then the buffer spring/recoil spring has to send the bolt forward fast enough to strip the next round from the belt.

This allows for very fast bolt travel speed compared to a gas operated weapon, correct? The one advantage we have in our semiauto builds is that we can change the bolt speed quite a bit as long as we keep within the correct range for function. I have noticed quite a tension variance in the belts that I have purchased as well, this may add another variable to this equation.

Some of the later MG42/MG3 modifications seem to use a heavier carrier to slow the rate of fire, this should also slow down the bolt travel and still, by way of the increased mass, allow enough force to strip the next round from the belt. So maybe adding weight to the carrier would help? Perhaps a set of clamp-on or screw-on weights?

I was also thinking about the booster nozzle and recuperator/recoil springs for my build. I'd like to try heavier springs in the recuperator and a stronger/shorter recoil spring to try and slow the bolt down more at the rear of it's travel, and perhaps opening up the booster nozzle to reduce the rearward thrust. Trouble will be, I think, finding the right combination that allows everything to work together.

My two cents, FWIW.

artech

By the way, has anyone tried to do a spring loaded ejector on one of these? It might help make things easier with the buffer spring/ejector spoon thing.

On second thought, wouldn't that make the bolt lock-up harder? Dammit, I have to get this reciever together so I can get going on this thing!

Wow, there is quite a bit of response to my thoughts on reducing MG 42 recoil.

The very first thing though is I don't like the shooting from the tripod - It is just more junk to haul around and with the 42 it make me feel unconnected with the gun. I am not against tripods, I have a full auto Vickers on one, but for semi? Not for me.

Here is where I am going with my build:

First I am building a buffer extension of my own design but simular to the one posted here earlier that will allow me to use a full length recoil spring. You really do need the full length spring for reliability. Then I am going to play with lighter spring cross sections, replacing the buffer spring with lighter ones to soak up the energy and allow the bolt to still have lots of return force. All of this time I will maintain the ejector piece (that contacts the bolt for ejection) distance or space in side the gun the same as an unmodified piece.

Secondly, my bolt will be heavier than most since my bolt extension
will be larger in OD and smaller in ID with the OD profile milled down to match the rear of the bolt profile and the ID just enough to clear the ejector operator spool.
The primary reason for this is that I have two modified bolts that have cracked out the rear OD of the extension after firing a couple of hundred rounds. Secondary reason is to add mass to the bolt.

i don't own a MG42 but after looking at the buffer i have an idea u might like to try. Instead of the hard metal part that extrudes out towards the front, replace it with a hard rubber bumper that would be bolted through the rear.
here is my idea in pic form. http://i132.photobucket.com/albums/q1/T ... a/idea.jpg
that is how i reduced recoil on my paintball gun, i know its 2 different things but it might work. The mg42 needs a hard surface to contact with but the rubber would absorb some of it.

hope this helps

you guys are way over thinking this .................................



the solution is simple

artech wrote:A few thoughts?
perhaps opening up the booster nozzle to reduce the rearward thrust.
Trouble will be, I think, finding the right combination that allows everything to work together.

artech

Problem is, opening the nozzle size while it will reduce the rearward thrust to some degree thereby somewhat reducing recoil it does not solve the problem of the bolt slamming the buffer and the sharp kick it produces when contacting the buffer. Might work in combination with a softer buffer spring. Looks like it is time to go to the range with a bag of tools and extra parts to experiment.

well there is at least 3 generations of Germans who have been able to tolerate the recoil at 1200 RPM+ with the correct nozzle.

free advice is worth what you paid for it.

I agree with DI. You guys are trying to fix something that doesn't need fixing. I don't mind the recoil. But then again, I think shooting my .416 Rigby is great fun. If the recoil bothers you too much, try using a shoulder pad.
I agree that the recoil booster has a large effect on the recoil. It is designed to operate that way. Even with the weight of the gun, my .308 has a healthy recoil. But I have a 9mm booster in it. Which I am going to change out. But not because of the felt recoil on my shoulder, but because of the increased wear and tear on the components. I'm going to an 11mm. booster in order to reduce that.
All of the various components have to work together as originally designed. Otherwise you will have problems getting the gun to run correctly.
My 8mm conversion won't eject the fired cartridge. An unfired cartridge will however. A 14.5mm recoil booster is the cause of the problem I believe. Too much gas is being bled off causing the bolt not to hit the buffer with enough force to eject the cartridge. I checked the ejector in the bolt head and it is the same length as the one in my .308. I did clip off about 1/4 of a coil on the recoil spring also. Now that the weather has moderated and it's not 0 degrees outside, a range test is in order to see if my tweaking has worked. The .308 runs great so I'm thinking that the larger opening in the 14.5 mm booster is the culprit.
Anybody need a 14.5 mm. recoil booster? Anybody know why the Yugoslavs used a 14.5 mm recoil booster on the M53's? It's a real shame because the booster appears to be unused.
Of course, just to be persnickety, I'm going to try the gun with the 14.5 mm recoil booster in place just to see what happens now that the temp is warmer. Last time I shot it, the temp was below freezing. Who knows, maybe I'll be surprised this time.
Final thought. If you guys want to play around with softening the recoil, have at it. After all, that's what keeps things interesting. And you never know where it might lead.

My '42 isn't running yet, but the first thing I would try is something that is easy to play with and easily reversible - screwing the flash supressor in and out. This would affect the amount of gas utilized to open the bolt, and affect the speed of that reaction.
If we back the nozzle off the threads until it doesn't open the bolt, all recoil is from the bullet leaving and the gas pushing the gun. Screwing it in a little will (if my thinking is clear) give the minimal amount of gas necessary for functioning. Gas is then creating the recoil, not the bolt slamming into the rear, buttstock spring.
I would think this would be the minimum felt recoil for the bolt slamming rearward.

Logical or am I missing something?

One more thought - different direction - Bellville washers - replace the stout spring in the buttstock with a stack of bellville washers. MSC has them. They look like dinner plates in a stack. Individually they look like washers. Squeeze them in a vise and they flatten out. Open the vise and they go back to the dish shape. Stack them higher and the stack gets stronger. Stack them top-top-bottom-bottom-top-top and they are weaker but have more travel. You can also mix the stack. A web search of bellville washers may explain it better. Look here: http://www.rctek.com/fixings/bellville_washers.html The note on that page though it says that they always must be placed a certain way. This is not true. They will work when stacked like dishes- and they make a very strong spring.

Either 88coms or DroolingIdiots methods could work.


I persnally plan to tinker with the nozzle size a I have a few to play with.

I'm wondering why someone hasn't come up with an adjustable recoil nozzle. Or one that is threaded to use different size inserts which would allow you to experiment with which one will give the proper response.
Any of you machinists out there care to give it a try? Well?

The easiest and best way to adjust recoil (imho) is to install a large boster cone (mine is 14mm) then slowly back off muzzle nut till the thing stops ejecting shells - then tighten her back up a tad.

I do this everytime I start shooting - I've learned this lesson with after broken sear pins, craked bolt carriers, broken firing pins etc

Unfortunately my 8mm doesn't want to eject cartridges when using the 14.5 or 14mm nozzle. That's why I'm going to try an 11mm nozzle. That is when the weather isn't as cold as the hinges of hell. Can't wait for this global warming to start. Snow in April sucks.

Propos,
Does your gun eject 8mm by hand when pulling the charging handle back? (coil binding the main spring?)
Also I heard something this weekend that I had not thought about. And that is if you have too much firing pin extrution it can try to act like the ejector. Even eject the case up instead of down.
Just some thoughts!
Good luck,
Steve