Yesterday's fun with a belt-fed M1919A6

[PigFish]

That's exactly how it works. The 1919 design essentially fires out of battery - the firing pin is actually released by the sear before the bolt is fully locked into place. It's designed to happen in a very controlled manner, of course. Headspacing is adjusted simply by adjusting the ring on the barrel assembly. This can be done while the weapon is fully assembled by opening the top latch cover and using the special tool to adjust the ring or it can be done with the barrel assembly removed from the body of the weapon. One of my friends made a handy little video showing how headspacing is done without the tool:

If you're really into the mechanics of it all, you can also check out the timing video he made here:

Cheers,

~ Greg ~

Thank you!

I found that very interesting and informative. If you don't mind me carrying on the conversation a bit, I found a couple of things concerning about the video.

1: Your friend assumes that the chamber is properly fit. This might be considered a given buying a weapon that is "working." In that it states that if you back off the barrel one click too many, you may experience blown cartridge heads, case separation.

2: No SAAMI test cartridge is used to reference the actual means by which the 30-06 cartridge head spaces, and that is the cartridge shoulder to breech dimension.

I find this therefore a great means for field adjustment, making the correct assumptions, but lacking the importance of proper chamber fit.

If one click means that you will separate cartridge heads, I would bet that the overall chamber depth of a given barrel is too deep, perhaps shot out, where erosion and other wear has allowed the chamber depth to grow beyond the SAAMI spec. I am only guessing of course. Gauging the barrel per original design with a test case, I would consider an important operation, and in the event of a deep chamber, the simple facing of the breach face could perhaps prevent calamity where separated cartridge pieces are left in the chamber.

I would not consider this operation complete without testing with a test case, or measuring the actual chamber once the bolt/barrel combination is properly locked. I can see where 'very loose' would be considered normal but a few .001 of an inch via one click adjustment should not blow cases out!

As usual, I am probably being too technical! Just my 2 cts.

Looks like fun mate! I wish I could afford one of those!!! -LOL

Cheers! -Ray

[canadianbeaver]

And the board continues to be educational!

[winelover]

I'm actually loving the thread Greg. Although guns are tightly restricted in the UK if you have money to burn there are still gun clubs we can join here and at least fire off some rifles, shot guns and even smooth bore pistols! All a question of being able to afford it. I looked into their open days at NRA Bisley and never realised ammo was so expensive.

Pleased to see an educational discussion where those that are interested can participate and learn.

[PigFish]

My childhood would have been devoid of many rewarding hours with my family if it were not for shooting sports. They are great outdoor activities that helped me develop the technical skills and knowledge I hold to this day.

I have taught 100's of kids to shoot through programs from the NRA and Dept. of Civilian Marksmanship. This too has been highly rewarding to me as an adult and to the kids. Firearms have been an important part of my life and they are a helluva lot of fun!

Cheers. -Piggy

[jrb5783]

nice gun ... i would love to have one of those one day

[ptrthgr8]

I may be talking out of my @$$ here, but I read somewhere that you can stick a soup can under the feed tray to give the belt a smoother surface and stop it catching. Then you can have the ammo box just beneath. Course, that was about an M60, but the principle is the same.

That's the general idea behind a trunnion protector. It's not really something that's needed when using cloth belts, but the continual running of metal linked belts can cause wear/tear on the metal trunnion. Several places make bolt-on aluminum plates that can easily be swapped out as they wear down. Definitely easier to swap out a $15 consumable part than letting your trunnion (which can't really be replaced on these transferable weapons) get worn out. I've heard of people using pop cans in a pinch, but the purpose-made trunnion protectors are fairly inexpensive and will stay on longer.

Cheers,

~ Greg ~

[ptrthgr8]

Thank you!

I found that very interesting and informative. If you don't mind me carrying on the conversation a bit, I found a couple of things concerning about the video.

1: Your friend assumes that the chamber is properly fit. This might be considered a given buying a weapon that is "working." In that it states that if you back off the barrel one click too many, you may experience blown cartridge heads, case separation.

2: No SAAMI test cartridge is used to reference the actual means by which the 30-06 cartridge head spaces, and that is the cartridge shoulder to breech dimension.

I find this therefore a great means for field adjustment, making the correct assumptions, but lacking the importance of proper chamber fit.

I've not yet seen a 1919 barrel that wasn't USGI or USGI surplus (and frequently NOS). The USGI operator and armorer manuals make no mention of using a proper headspace gauge because it's not needed - the barrel is adjustable, so you only need to make sure the adjustments are properly made so the bolt will close or go into battery with the barrel clicked out as little as possible. On weapons that don't have adjustable barrels (i.e. Mausers, Mosins, Enfields, Springfields, etc.) you'll need to use an actual headspace gauge to ensure everything is within proper/safe tolerances. On a 1919 you just need to make the easy adjustments to ensure the weapon is within specs.

If one click means that you will separate cartridge heads, I would bet that the overall chamber depth of a given barrel is too deep, perhaps shot out, where erosion and other wear has allowed the chamber depth to grow beyond the SAAMI spec. I am only guessing of course. Gauging the barrel per original design with a test case, I would consider an important operation, and in the event of a deep chamber, the simple facing of the breach face could perhaps prevent calamity where separated cartridge pieces are left in the chamber.

I would not consider this operation complete without testing with a test case, or measuring the actual chamber once the bolt/barrel combination is properly locked. I can see where 'very loose' would be considered normal but a few .001 of an inch via one click adjustment should not blow cases out!

The 1919 is designed to fire as the bolt is going into battery. That's is, the firing pin will drop and strike the primer as the bolt is going into battery. If the headspacing ring is adjusted one too many clicks out, that means it takes that much longer for the bolt to go into battery, which would mean the firing pin is hitting the primer that much sooner. That's when you run the risk of a ruptured case (because the case is not fully supported by the bolt/chamber.) If the headspace is too tight (i.e. the barrel is screwed in too far), the weapon won't go into battery at all, which won't allow the trigger to release the sear.

I'm still learning when it comes to these LMGs, too, but it seems to be that the headspacing on the 1919 design is much more akin to how it's done with rimmed catridges (i.e. Mosin-Nagant, Enfield). The headspacing on those is measured off the rim of the catridge, as opposed to the shoulders of the case.

Cheers,

~ Greg ~

[cgarner]

Nice. Bought my first nonhunting rifle last week. Picked up an AR-15. Semi-auto of course

[Bunner]

So cool. Up her e in the great white north anything auto or scary looking is prohibited.... Love to have the chance to shoot that sucker. I have an svt 40 and shoot hungarian surplus through lots o fun thats as close as ill ever get. *sigh* lol

[adic88]

You know what would have been cooler?

Fire the gun until the barrel got hot, then use the hot barrel to light a cigar. Then smoke the cigar while firing some more. Oh man oh man. Just thinking about how that looks just puts a smile on my face.

[bbc]

You know what would have been cooler?

Fire the gun until the barrel got hot, then use the hot barrel to light a cigar. Then smoke the cigar while firing some more. Oh man oh man. Just thinking about how that looks just puts a smile on my face.

I don't have any thing as cool as a 1919 to do that off of, but I think I'll give it a shot with my AR. Thanks for the good idea.

-BSC