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Discussion Starter · #1 ·
So way back when in the spring time, as part of the Knob Creek discussion, I had mentioned some of the various trial and tribulations we had faced with our A4 at the Creek: http://1919a4.com/showthread.php?52207-KCR-Spring-15-Report-Please (buried in the last few pages)

Well today we finally went out to troubleshoot the gun. The gun had been cleaned since the Creek, but still had all of the same parts. We had new load ammo since the local MG shoot won't let us play with tracer. Temp was around 93-95 F, as opposed to in the 50s and 60s. It was daytime, it was in Florida, but there was a minigun making noise, as well as a Gatling gun and a 20MM.

Bottom line, the gun ran like a top - as long as it was single loop first. Double loop presented exactly the same problem as we had at the Creek where it would not advance the belt. 1200 rounds went single loop first in 2.5 hours so it looks like the solution is pretty clear.

Again a thank you to everyone who helped in April :)

Also, we often joke that the perfect load has the bullet make it to the end of the barrel and just fall out onto the ground so that we can recycle them.......Had it happen today. Scared me when I got just the little puff, but the barrel was clear and we later found the bullet directly under the gun.....Nice idea, but that light a load won't cycle the thing....Go figure :rofl:

Chris
 

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That's really funny how that works with the links in one direction and not the other.

You can't say these guns don't have a personality!:D
Nice to hear you got it ironed out.
 

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Using a trunnion protector? This is always interesting as linked ammo was packed and used double loop first because of the starter tab.
 

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Using a trunnion protector? This is always interesting as linked ammo was packed and used double loop first because of the starter tab.
I understand the use of a trunnion protector with a brass trunnion, but what's the point with a steel trunnioned weapon? It's not likely you're going to fire millions of sand covered linked rounds throughout the life of the weapon.
 

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Discussion Starter · #5 ·
The trunnion protector seems to make no difference. We normally run the gun with it, but it isn't a factor in this case. Odd thing was that it always ran double loop first until April, then it stopped. So right now I have a solution that works for an unknown problem. Something changed but we don't really understand what.

Chris
 

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Linked belt not advancing when double loop forward? Hmm. When you feed a linked belt backwards with the single loop forward it positions the ends of the link spring steel material upward. In this position the ends can be grabbed by the feed pawl. That's interesting. Assuming you are using factory FMJ ball ammo, I would check:

1) Belt hold pawl and spring. The pawl may have a burr and/or the spring may be too weak and allow the belt to slip backwards
2) Top cover extractor spring. It may be weak and not push the loaded extractor down t-slot.
3) Top cover slide, feed pawl, and spring. Check for burrs and/or a weak spring.
4) Top cover feed lever. It may be bent and sit too high to push belt forward.
5) Bolt assembly. Assure that the t-slot is crisp and clean with no burrs or dirt. Assure the ejector spring on the extractor assembly is strong and holds the ejector firmly onto the ammo case.

If you are short cycling, check for free barrel movement and the use of the correct muzzle bearing/booster assembly.
 

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I understand the use of a trunnion protector with a brass trunnion, but what's the point with a steel trunnioned weapon? It's not likely you're going to fire millions of sand covered linked rounds throughout the life of the weapon.
As you likely already know the floor of the feed way over the rear barrel bearing is very thin. The TM's are replete with drawings of chipped feed way floors and inspection/rejection of same because of the links causing chips or gouging. I don't think sand has anything to do with it. The original weapon was designed to use cloth belts JMB thought cloth was the only way to go. As linked ammo became more prevalent problems with chipping which apparently leads to feeding problems increased. SOOOO Ordnance started hard chroming the trunnion both to repair chipped trunnions and on new made to prevent the problem.
 

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The ammo in question is reloaded, not factory. At KCR, the feeding problem with belt lift was mainly solved by reversing the belt. But the cold weather was a factor in the loads not functioning well, creating a different problem with the short cycling. In warm weather, that problem doesn't occur. JDC uses a very light load, just enough to function, but the Creek experience showed that the light loads are definitely temperature sensitive, so I assume that a stronger load will be used in similar circumstances, should we have a cold October. Now as I recall, there was some surplus ammo purchased at the Creek to see how that would impact things, but I believe we were still struggling with the belt lift issue then. Once we flipped the belt, all we were using were the light reloads. JDC can confirm or counter if my recollection is incorrect. I think a successful string was fired at the end, when I was no longer on the line. So, that might have been the surplus ammo?
 

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Discussion Starter · #10 ·
Very close Lucky, the purchased ammo was PMC factory and it did run right at the end (like two minutes left in the last session for the night shoot) - but only single loop first. Double loop didn't work even with factory ammo. The loads we had at the Creek were/are very temperature sensitive, so much so that I will normally leave the ammo cans for the day open in direct sunlight to keep them warm on the colder days. The loads were light, but not short cycling until it started getting dark. I spend a lot of time working right at the bottom of the pressure range and can tell by the sound when the ammo just isn't going to work anymore.

We had actually changed top covers, every part in the top cover, and all of the springs while on the line. One thing that we found is that the feed pawl seemed to be a couple of thousandths short of completely hooking over the double loops. It seemed like if we manually pushed it to the extreme of the possible travel that it would snap into place and feed the links. Different feed pawl levers (some NOS) all had the same effect and trying a new bolt still left it just ever so slightly short of catching the links.

Chris
 

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"I think a successful string was fired at the end, when I was no longer on the line. So, that might have been the surplus ammo? "

Or it was coz you were the jinx! :rofl:
;)

I get that a lot about myself.:tongue:
 

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As one reads more one usually understands more.

US weapons were designed to fire a particular cartridge. Much thought went into this relative to primers and propellant and cartridges were required to perform under adverse conditions , if you reload you should try to do it in the parameters established by the Ordnance Dept.

Much research and study has been done on this subject no well read and advised person should have any questions regarding performance issues if variables as to ammunition are introduced.

Ammunition is the constant in the equation, vary that and..... well the solution to the problem will be incorrect.
 

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What are or where can one find the Ordnance Dept specs for 30-06 that will run in a 1919 ? You have my interest up now....:D

Steamer
M2 Ball was the standard 2740 +/- 30 fps at 78 feet from muzzle,152-153 gn projectile various propellants were used IMR 4895 (50 gns) and WC852 (50 gns) using a lead styphnate primer. OAL measured on several samples LC 69 and DEN 44 averages 3.324. The supply of M2 projectiles has pretty much dried up but the M80 7.62X51 Ball projectile will work except that the cannelure will be above the case mouth to get the correct OAL which is necessary to properly function in the BMG's without using a short round stop which in my view improves feeding and link ejection.
 

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Discussion Starter · #15 ·
Ammunition is the constant in the equation, vary that and..... well the solution to the problem will be incorrect.
You would not believe how many times we have proven this statement to be true. Reloading for the 1919 seems like it should be really straightforward, but it's not even close. It is perhaps the most challenging to get right.

In this case, however, 308 that was loaded with IMR4895 and at an OAL of 2.815" had the same problem as stuff loaded with the 50 powder. Both loads had run fine previously (the 4895 load was actually from the same batch that had previously run double loop) and when commercial was introduced, which was hotter still, it had the same problem. So while I have learned that a gun problem is usually an "I screwed up the ammo" problem, this one is presenting differently because we have loads that were known to feed correctly and suddenly stopped. Turning the links around on all of them solved the problem.

As an aside, one day we were playing with low power loads to find the bottom and we determined that 1517 FPS was the minimum required to make the gun function. Below that, the pressure was erratic and would not reliably cycle the gun (it did cycle with one round at about 1400 FPS), but at 1517 and above, every round cycled the action. This was no links, every round hand fed, on a hot Florida afternoon, and on our gun, which seems to run faster than other 1919s with the same ammo. Sometimes for my dad and I this thing turns into as much of a science experiment as it does anything else. Must be something with us both working in an engineering based company.....:help:

Chris
 

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Discussion Starter · #17 ·
Had to watch the language since my dad was standing right there.....so i spoke with it sternly in a very tense tone to ensure it would understand (I figured if it is good enough for geopolitics, it is good enough for me. Plus, the range gave me an orange line on the clay. I figured it was close enough to a red line in the sand.). And apparently, according to Troy, I needed to go further than just threaten it with the hammer, I needed to go ahead and bop it on the top cover a time or two to teach it a lesson. This is all very difficult for me since they get mad every time I practice doing either of those at work :mad: :rofl:

Chris
 

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Glad you Guys have such control..........and menacing dispositions to scare that thing straight without improper language! :rofl:

Also interesting on the "cool" loads and belt feeding direction. It's amazing how these weapons have their own personalities some times.

Matt
 

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I have found that it is not enough to swear at an object. It is important to use the correct words for that particular device. For example Mother F--- should only be applied to small engine devices such as lawn mowers and chain saws. Likewise a Browning air cooled machine gun requires different words form a water-cooled gun.

Example:

M1919A4 - dadblame, consarned
M1917A1 - dingbusted

I have to confess I don't use those words much.

Other words that pertain to feces can be used and a knowledge of a foreign language also helps in these instances.
 
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